CN117204112A

CN117204112A - Method for efficient paging of user equipment to network relay

Info

Publication number: CN117204112A
Application number: CN202280031054.7A
Authority: CN
Inventors: 马蒂诺·弗雷达; 李文一; 保罗·马里内尔; 黄祥; 贾耶·拉奥; O·泰耶
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2021-03-29
Filing date: 2022-03-29
Publication date: 2023-12-08
Also published as: CN118250837A

Abstract

A method performed by a relay wireless transmit/receive unit (WTRU) includes receiving an indication of a change in state of a remote WTRU having a paging link with the relay WTRU, receiving a paging message from a network. The paging message includes a System Information (SI) change indication, wherein the SI change indication indicates an availability of updated SI information from the network to the remote WTRU. The relay WTRU transmits the updated SI information to the remote WTRU based on the received indication of the change in state of the remote WTRU.

Description

Method for efficient paging of user equipment to network relay

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional patent application No. 63/167,307 filed on 3 months 29 of 2021, U.S. provisional patent application No. 63/185,634 filed on 5 months 7 of 2021, and U.S. provisional patent application No. 63/249,832 filed on 9 months 29 of 2021, which are incorporated herein by reference in their entirety for all purposes.

Background

Third generation partnership project (3 GPP) release 16 (release 16) for the first version of the new air interface (NR) Side Link (SL) has been developed and focused only on supporting vehicle-to-everything (V2X) related road safety services. Release 16 designs are intended to provide support for broadcast, multicast and unicast communications in both out-of-coverage scenarios and in-network coverage scenarios.

Regarding coverage extension for SL-based communications, release 13 solutions for user equipment to network (UE to network) relay are limited to Evolved Universal Terrestrial Radio Access (EUTRA) based technologies and therefore cannot be applied to NR-based systems for both next generation radio access networks (NG-RAN) and NR-based side link communications. Regarding UE-to-UE coverage extension, current proximity reachability is limited to single hop side links via EUTRA-based or NR-based side link technologies. However, this approach is not sufficient without Uu reference point interface coverage considering limited single hop side link coverage. Accordingly, the side link connection should be further extended in the NR framework in order to support the enhanced QoS requirements. The disclosure herein addresses these and other issues.

Drawings

A more detailed understanding can be obtained from the following detailed description, which is given by way of example in connection with the accompanying drawings. As with the detailed description, the drawings in such figures are examples. Accordingly, the drawings (figures) and detailed description are not to be taken in a limiting sense, and other equally effective examples are possible and contemplated. In addition, like reference numerals ("ref") in the drawings denote like elements, and wherein:

FIG. 1A is a system diagram illustrating an exemplary communication system;

fig. 1B is a system diagram illustrating an exemplary wireless transmit/receive unit (WTRU) that may be used within the communication system shown in fig. 1A;

fig. 1C is a system diagram illustrating an exemplary Radio Access Network (RAN) and an exemplary Core Network (CN) that may be used within the communication system shown in fig. 1A;

fig. 1D is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system shown in fig. 1A;

fig. 2 depicts a diagram of a user plane protocol stack for UE-to-network relay;

fig. 3 depicts a diagram of a control plane protocol stack for UE-to-network relay;

FIG. 4 depicts an exemplary timing diagram of paging occasions;

fig. 5 depicts an exemplary flow chart of a relay WTRU calculating an allowable side link slot for relaying paging messages;

fig. 6 depicts an exemplary flowchart of a relay WTRU determining which of the network configured paging occasions to use for waking up and monitoring in a particular DRX cycle;

fig. 7 depicts an exemplary flowchart of a relay WTRU handling one or both of system information change and paging opportunities for a remote WTRU;

fig. 8 depicts an exemplary flowchart of a relay WTRU transmitting updated system information to a remote WTRU based on a change in state of the remote WTRU;

Fig. 9 depicts an exemplary flowchart of a relay WTRU forwarding updated system information based on a received information type; and is also provided with

Figure 10 depicts an exemplary flow diagram of a relay WTRU processing a paging short message containing a common warning system indication.

Detailed Description

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments and/or examples disclosed herein. However, it should be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the description below. Furthermore, embodiments and examples not specifically described herein may be practiced in place of or in combination with embodiments and other examples that are explicitly, implicitly, and/or inherently described, disclosed, or otherwise provided (collectively, "provided"). Although various embodiments are described and/or claimed herein, wherein an apparatus, system, device, etc., and/or any element thereof, performs an operation, procedure, algorithm, function, etc., and/or any portion thereof, it is to be understood that any embodiment described and/or claimed herein assumes that any apparatus, system, device, etc., and/or any element thereof, is configured to perform any operation, procedure, algorithm, function, etc., and/or any portion thereof.

Exemplary communication System

The methods, apparatus and systems provided herein are well suited for communications involving both wired and wireless networks. An overview of various types of wireless devices and infrastructure is provided with respect to fig. 1A-1D, wherein various elements of a network may utilize, perform, adapt and/or configure the methods, apparatuses and systems provided herein, according to and/or with respect to the methods, apparatuses and systems provided herein.

A detailed description of exemplary embodiments will now be described with reference to various drawings. While this specification provides a detailed example of a possible implementation, it should be noted that the details are intended to be exemplary and in no way limit the scope of the application. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments and/or examples disclosed herein. However, it should be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the description below. Furthermore, embodiments and examples not specifically described herein may be practiced in place of or in combination with embodiments and other examples that are explicitly, implicitly, and/or inherently described, disclosed, or otherwise provided (collectively, "provided").

Fig. 1A is a schematic diagram illustrating an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messages, broadcasts, etc., to a plurality of wireless users. Communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), time Division Multiple Access (TDMA), frequency Division Multiple Access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter Bank Multicarrier (FBMC), and the like.

As shown in fig. 1A, the communication system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104/113, CNs 106/115, public Switched Telephone Networks (PSTN) 108, the internet 110, and other networks 112, although it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. As an example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a "station" and/or a "STA") may be configured to transmit and/or receive wireless signals and may include User Equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular telephones, personal Digital Assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hot spot or Mi-Fi devices, internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automated processing chain environment), consumer electronic devices, devices operating on a commercial and/or industrial wireless network, and the like. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

Communication system 100 may also include base station 114a and/or base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106/115, the internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114B may be Base Transceiver Stations (BTSs), node bs, evolved node bs, home evolved node bs, gnbs, NR node bs, site controllers, access Points (APs), wireless routers, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

Base station 114a may be part of RAN 104/113 that may also include other base stations and/or network elements (not shown), such as Base Station Controllers (BSCs), radio Network Controllers (RNCs), relay nodes, and the like. Base station 114a and/or base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a particular geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in an embodiment, the base station 114a may include three transceivers, i.e., one for each sector of a cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of a cell. For example, beamforming may be used to transmit and/or receive signals in a desired spatial direction.

The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio Frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable Radio Access Technology (RAT).

More specifically, as noted above, communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, or the like. For example, a base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interfaces 115/116/117.WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or evolved HSPA (hspa+). HSPA may include high speed Downlink (DL) packet access (HSDPA) and/or High Speed UL Packet Access (HSUPA).

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as evolved UMTS terrestrial radio access (E-UTRA), which may use Long Term Evolution (LTE) and/or LTE-advanced (LTE-a) and/or LTE-advanced Pro (LTE-a Pro) to establish the air interface 116.

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access that may use a new air interface (NR) to establish the air interface 116.

In embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using a Dual Connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., enbs and gnbs).

In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., wireless fidelity (WiFi)), IEEE 802.16 (i.e., worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000 1X, CDMA EV-DO, tentative standard 2000 (IS-2000), tentative standard 95 (IS-95), tentative standard 856 (IS-856), global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114B in fig. 1A may be, for example, a wireless router, home node B, home evolved node B, or access point, and may utilize any suitable RAT to facilitate wireless connections in local areas such as business, home, vehicle, campus, industrial facility, air corridor (e.g., for use by drones), road, etc. In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a Wireless Local Area Network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a Wireless Personal Area Network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-a Pro, NR, etc.) to establish a pico cell or femto cell. As shown in fig. 1A, the base station 114b may have a direct connection with the internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106/115.

The RANs 104/113 may communicate with the CNs 106/115, which may be any type of network configured to provide voice, data, application, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102 d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location based services, prepaid calls, internet connections, video distribution, etc., and/or perform advanced security functions such as user authentication. Although not shown in fig. 1A, it should be appreciated that the RANs 104/113 and/or CNs 106/115 may communicate directly or indirectly with other RANs that employ the same RAT as the RANs 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113 that may utilize NR radio technology, the CN 106/115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA, wiMAX, E-UTRA, or WiFi radio technology.

The CN 106/115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or other networks 112.PSTN 108 may include circuit-switched telephone networks that provide Plain Old Telephone Services (POTS). The internet 110 may include a global system for interconnecting computer networks and devices using common communication protocols, such as Transmission Control Protocol (TCP), user Datagram Protocol (UDP), and/or Internet Protocol (IP) in the TCP/IP internet protocol suite. Network 112 may include wired and/or wireless communication networks owned and/or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RANs 104/113 or a different RAT.

Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in fig. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based radio technology, and with a base station 114b, which may employ an IEEE 802 radio technology.

Fig. 1B is a system diagram illustrating an exemplary WTRU 102. As shown in fig. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a Global Positioning System (GPS) chipset 136, and/or other peripheral devices 138, etc. It should be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs) circuits, any other type of Integrated Circuit (IC), a state machine, or the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120, which may be coupled to a transmit/receive element 122. Although fig. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

The transmit/receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114 a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to emit and/or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive RF and optical signals. It should be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted as a single element in fig. 1B, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate signals to be transmitted by the transmit/receive element 122 and demodulate signals received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs (such as NR and IEEE 802.11).

The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker/microphone 124, a keypad 126, and/or a display/touchpad 128, such as a Liquid Crystal Display (LCD) display unit or an Organic Light Emitting Diode (OLED) display unit. The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. Further, the processor 118 may access information from and store data in any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include Random Access Memory (RAM), read Only Memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a Subscriber Identity Module (SIM) card, a memory stick, a Secure Digital (SD) memory card, and the like. In other embodiments, the processor 118 may never physically locate memory access information on the WTRU 102, such as on a server or home computer (not shown), and store the data in that memory.

The processor 118 may receive power from the power source 134 and may be configured to distribute and/or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry battery packs (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114 b) over the air interface 116 and/or determine its location based on the timing of signals received from two or more nearby base stations. It should be appreciated that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with an embodiment.

The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software modules and/or hardware modules that provide additional features, functionality, and/or wired or wireless connections. For example, the number of the cells to be processed, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photographs and/or video), universal Serial Bus (USB) ports, vibrating devices, television transceivers, hands-free headsets, wireless communications devices, and the like,Modules, frequency Modulation (FM) radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and/or augmented reality (VR/AR) devices, activity trackers, and the like. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; a geographic position sensor; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and/or humidity sensors.

WTRU 102 may include a full duplex radio for which transmission and reception of some or all signals (e.g., associated with a particular subframe for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and/or simultaneous. The full duplex radio station may include an interference management unit 139 for reducing and/or substantially eliminating self-interference via hardware (e.g., choke) or via signal processing by a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with a particular subframe for UL (e.g., for transmission) or downlink (e.g., for reception)).

Fig. 1C is a system diagram illustrating a RAN 104 and a CN 106 according to one embodiment. As noted above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using an E-UTRA radio technology. RAN 104 may also communicate with CN 106.

RAN 104 may include enode bs 160a, 160B, 160c, but it should be understood that RAN 104 may include any number of enode bs while remaining consistent with an embodiment. The enode bs 160a, 160B, 160c may each include one or more transceivers to communicate with the WTRUs 102a, 102B, 102c over the air interface 116. In an embodiment, the evolved node bs 160a, 160B, 160c may implement MIMO technology. Thus, the enode B160 a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or to receive wireless signals from the WTRU 102a, for example.

Each of the evolved node bs 160a, 160B, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and/or DL, and the like. As shown in fig. 1C, the enode bs 160a, 160B, 160C may communicate with each other over an X2 interface.

The CN 106 shown in fig. 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and/or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the evolved node bs 162a, 162B, 162c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating the user of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, and the like. MME 162 may provide control plane functionality for switching between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and/or WCDMA.

SGW 164 may be connected to each of the evolved node bs 160a, 160B, 160c in RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102 c. The SGW 164 may perform other functions such as anchoring user planes during inter-enode B handover, triggering paging when DL data is available to the WTRUs 102a, 102B, 102c, managing and storing the contexts of the WTRUs 102a, 102B, 102c, etc.

The SGW 164 may be connected to a PGW 166 that may provide the WTRUs 102a, 102b, 102c with access to a packet switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network (such as the PSTN 108) to facilitate communications between the WTRUs 102a, 102b, 102c and legacy landline communication devices. For example, the CN 106 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and/or wireless networks owned and/or operated by other service providers.

Although the WTRU is depicted in fig. 1A-1D as a wireless terminal, it is contemplated that in some representative embodiments such a terminal may use a wired communication interface with a communication network (e.g., temporarily or permanently).

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in an infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic to and/or from the BSS. Traffic originating outside the BSS and directed to the STA may arrive through the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may pass the traffic to the destination STA. Traffic between STAs within a BSS may be considered and/or referred to as point-to-point traffic. Point-to-point traffic may be sent between (e.g., directly between) the source and destination STAs using Direct Link Setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunnel DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

When using the 802.11ac infrastructure mode of operation or similar modes of operation, the AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20MHz wide bandwidth) or a width dynamically set by signaling. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access/collision avoidance (CSMA/CA) may be implemented, for example, in an 802.11 system. For CSMA/CA, STAs (e.g., each STA), including the AP, may listen to the primary channel. If the primary channel is listened to/detected by a particular STA and/or determined to be busy, the particular STA may backoff. One STA (e.g., only one station) may transmit at any given time in a given BSS.

High Throughput (HT) STAs may communicate using 40MHz wide channels, for example, via a combination of a primary 20MHz channel with an adjacent or non-adjacent 20MHz channel to form a 40MHz wide channel.

Very High Throughput (VHT) STAs may support channels that are 20MHz, 40MHz, 80MHz, and/or 160MHz wide. 40MHz and/or 80MHz channels may be formed by combining consecutive 20MHz channels. The 160MHz channel may be formed by combining 8 consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels (this may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data may pass through a segment parser that may split the data into two streams. An Inverse Fast Fourier Transform (IFFT) process and a time domain process may be performed on each stream separately. These streams may be mapped to two 80MHz channels and data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be sent to a Medium Access Control (MAC).

The 802.11af and 802.11ah support modes of operation below 1 GHz. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11 ac. The 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the television white space (TVWS) spectrum, and the 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter type control/machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., supporting only) certain bandwidths and/or limited bandwidths. MTC devices may include batteries with battery lives above a threshold (e.g., to maintain very long battery lives).

WLAN systems that can support multiple channels, and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by STAs from all STAs operating in the BSS (which support a minimum bandwidth mode of operation). In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only) 1MHz mode, the primary channel may be 1MHz wide, even though the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and/or other channel bandwidth modes of operation. The carrier sense and/or Network Allocation Vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because the STA (supporting only 1MHz mode of operation) is transmitting to the AP, the entire available frequency band may be considered busy even though most of the frequency band remains idle and possibly available.

The available frequency band for 802.11ah in the united states is 902MHz to 928MHz. In korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

Fig. 1D is a system diagram illustrating RAN 113 and CN 115 according to one embodiment. As noted above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, 102c over an air interface 116. RAN 113 may also communicate with CN 115.

RAN 113 may include gnbs 180a, 180b, 180c, but it should be understood that RAN 113 may include any number of gnbs while remaining consistent with an embodiment. Each of the gnbs 180a, 180b, 180c may include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gnbs 180a, 180b, 180c may implement MIMO technology. For example, gnbs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from gnbs 180a, 180b, 180 c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or receive wireless signals from the WTRU 102a, for example. In an embodiment, the gnbs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on the unlicensed spectrum while the remaining component carriers may be on the licensed spectrum. In embodiments, the gnbs 180a, 180b, 180c may implement coordinated multipoint (CoMP) techniques. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180 c).

The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using transmissions associated with the scalable parameter sets. For example, the OFDM symbol interval and/or OFDM subcarrier interval may vary from one transmission to another, from one cell to another, and/or from one portion of the wireless transmission spectrum to another. The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using various or scalable length subframes or Transmission Time Intervals (TTIs) (e.g., including different numbers of OFDM symbols and/or continuously varying absolute time lengths).

The gnbs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in an independent configuration and/or in a non-independent configuration. In a standalone configuration, the WTRUs 102a, 102B, 102c may communicate with the gnbs 180a, 180B, 180c while also not accessing other RANs (e.g., such as the enode bs 160a, 160B, 160 c). In an independent configuration, the WTRUs 102a, 102b, 102c may use one or more of the gnbs 180a, 180b, 180c as mobility anchor points. In an independent configuration, the WTRUs 102a, 102b, 102c may use signals in unlicensed frequency bands to communicate with the gnbs 180a, 180b, 180 c. In a non-standalone configuration, the WTRUs 102a, 102B, 102c may communicate or connect with the gnbs 180a, 180B, 180c, while also communicating or connecting with other RANs (such as the enode bs 160a, 160B, 160 c). For example, the WTRUs 102a, 102B, 102c may implement DC principles to communicate with one or more gnbs 180a, 180B, 180c and one or more enodebs 160a, 160B, 160c substantially simultaneously. In a non-standalone configuration, the enode bs 160a, 160B, 160c may serve as mobility anchors for the WTRUs 102a, 102B, 102c, and the gnbs 180a, 180B, 180c may provide additional coverage and/or throughput for serving the WTRUs 102a, 102B, 102 c.

Each of the gnbs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and/or DL, support of network slices, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and so on. As shown in fig. 1D, gnbs 180a, 180b, 180c may communicate with each other through an Xn interface.

The CN 115 shown in fig. 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements are depicted as part of the CN 115, it should be understood that any of these elements may be owned and/or operated by entities other than the CN operator.

AMFs 182a, 182b may be connected to one or more of gNB 180a, 180b, 180c in RAN 113 via an N2 interface and may function as a control node. For example, the AMFs 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slices (e.g., handling of different Protocol Data Unit (PDU) sessions with different requirements), selection of a particular SMF 183a, 183b, management of registration areas, (non-access stratum) (NAS) signaling termination, mobility management, etc. The AMFs 182a, 182b may use network slices to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102 c. For example, different network slices may be established for different use cases, such as services relying on ultra high reliability low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for Machine Type Communication (MTC) access, and so on. AMF 162 may provide control plane functionality for switching between RAN 113 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-a Pro, and/or non-3 GPP access technologies, such as WiFi.

The SMFs 183a, 183b may be connected to AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to UPFs 184a, 184b in the CN 115 via an N4 interface. SMFs 183a, 183b may select and control UPFs 184a, 184b and configure traffic routing through UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning WTRU/UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, ethernet-based, etc.

UPFs 184a, 184b may be connected to one or more of the gnbs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to a packet-switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-host PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and/or wireless networks owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may connect to the local Data Networks (DNs) 185a, 185b through the UPFs 184a, 184b through an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

In view of fig. 1A-1D and the corresponding descriptions of fig. 1A-1D, one or more or all of the functions described herein for one or more of the following may be performed by one or more emulation devices (not shown): the WTRUs 102a-d, base stations 114a-B, evolved node bs 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMFs 182a-ab, UPFs 184a-B, SMFs 183a-B, DNs 185a-B, and/or any one or more other devices described herein. The emulated device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation device may be used to test other devices and/or analog network and/or WTRU functions.

The simulation device may be designed to enable one or more tests of other devices in a laboratory environment and/or an operator network environment. For example, the one or more emulation devices can perform one or more or all of the functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices can perform one or more functions or all functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for testing purposes and/or may perform testing using over-the-air wireless communications.

The one or more emulation devices can perform one or more (including all) functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the simulation device may be used in a test laboratory and/or a test scenario in a non-deployed (e.g., test) wired and/or wireless communication network in order to enable testing of one or more components. The one or more simulation devices may be test equipment. Direct RF coupling and/or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation device to transmit and/or receive data.

The examples provided herein do not limit the applicability of the subject matter to other wireless technologies, e.g., using the same or different principles as may be applicable.

As explained herein, a Wireless Transmit Receive Unit (WTRU) may be an example of a User Equipment (UE). Thus, the terms UE and WTRU are used interchangeably herein.

Introduction to the invention

UE/WTRU to Network (NW) relay in 3GPP release 13

As described in 3GPP TS 36.300-TSGRAN E-UTRA and E-UTRAN general description phase 2 (V15.4.0), relay via proximity services (ProSe) UE to network relay is introduced in 3GPP release 13 to extend network coverage to out-of-coverage UEs by using PC5 device-to-device (D2D) communication between out-of-coverage UEs and UE-to-network relay, as follows in the relevant part:

ProSe UE-to-network relay provides a generic L3 forwarding function that can relay any type of IP traffic between a remote UE and the network. One-to-one and one-to-many side link communications may be used between the remote UE and ProSe UE to network relay. For both remote and relay UEs, only one single carrier (i.e., public safety ProSe carrier) operation is supported (i.e., uu and PC5 link interfaces should use the same carrier for relay/remote UEs). The remote UE is authorized by the upper layer and may be within the coverage of the public safety ProSe carrier or outside the coverage of any supported carrier, including the public safety ProSe carrier for UE-to-network relay discovery, (re) selection and communication. ProSe UE-to-network relay is always within coverage of the evolved UMTS RAN (E-UTRAN). ProSe UE-to-network relay and remote UEs perform side link communication and side link discovery as described in sections 23.10 and 23.11, respectively.

Relay selection for UE/WTRU to NW relay

The relay selection/reselection of ProSe UE to NW relay is performed based on a combination of Access Stratum (AS) layer quality measurements, such AS Reference Signal Received Power (RSRP), and upper layer criteria. As described in 3gpp TS 36.300-TSGRAN E-UTRA and E-UTRAN general description phase 2 (V15.4.0), which is described in more detail in the phase 2 specification, in the relevant part as follows:

The eNB controls whether the UE can act as ProSe UE-to-network relay:

a. supporting ProSe UE-to-network relay operation in the cell if the eNB broadcasts any information associated with ProSe UE-to-network relay operation;

the enb may provide:

i. a ProSe UE to network relay discovered transmission resources using broadcast signaling of Radio Resource Control (RRC) rrc_idle state and dedicated signaling of rrc_connected state;

a reception resource for ProSe UE-to-network relay discovery using broadcast signaling;

the enb may broadcast minimum and/or maximum Uu link quality (RSRP) thresholds that ProSe UE-to-network relay needs to adhere to before it can initiate a UE-to-network relay discovery procedure. In rrc_idle, the UE uses a threshold to autonomously start or stop the UE-to-network relay discovery procedure when the eNB broadcasts a pool of transmission resources. In rrc_connected, the UE uses a threshold to determine if it can indicate to the eNB that it is a relay UE and wishes to start ProSe UE to network relay discovery;

if the eNB does not broadcast a pool of transmission resources for the ProSe-UE to network relay discovery, the UE may initiate a request for the ProSe-UE to network relay discovery resources by dedicated signaling, taking into account these broadcast thresholds.

c. ProSe-UE to network relay discovery may be performed while in rrc_idle if ProSe-UE to network relay is initiated by broadcast signaling. If ProSe UE-to-network relay is initiated by dedicated signaling, relay discovery may be performed as long as it is in rrc_connected.

ProSe UE-to-network relay performing Side Link (SL) communication for ProSe UE-to-network relay operation must be in rrc_connected. After receiving a layer 2 link setup request or a Temporary Mobile Group Identity (TMGI) monitoring request (upper layer message) from the remote UE, the ProSe UE-to-network relay indicates to the eNB that it is a ProSe UE-to-network relay and is intended to perform ProSe UE-to-network relay side link communication. The eNB may provide resources for ProSe UE-to-network relay communications.

The remote UE may decide when to start monitoring ProSe UE to network relay discovery. Depending on the configuration of resources for ProSe UE-to-network relay discovery, the remote UE may transmit a ProSe UE-to-network relay discovery request message while in rrc_idle or in rrc_connected. The eNB may broadcast a threshold that the remote UE uses to determine whether it can transmit ProSe UE-to-network relay discovery request messages to connect or communicate with ProSe UE-to-network relay UEs. The rrc_connected remote UE uses the broadcasted threshold to determine whether it can indicate to the eNB that it is a remote UE and wishes to participate in ProSe UE-to-network relay discovery and/or communication. The eNB may use broadcast or dedicated signaling to provide transmission resources and broadcast signaling to provide reception resources for ProSe UE-to-network relay operation. When RSRP exceeds the broadcast threshold, the remote UE ceases to use ProSe UE-to-network relay discovery and communication resources.

Note that: the exact time of the traffic switch from Uu to PC5 or from PC5 to Uu may be up to higher layers.

The remote UE performs radio measurements at the PC5 interface and uses them with higher layer standards for ProSe UE-to-network relay selection and reselection. ProSe UE-to-network relay is considered appropriate in terms of radio standards if PC5 link quality exceeds a configured threshold (pre-configured or provided by the eNB). The remote UE selects a ProSe UE-to-network relay that meets the higher layer criteria and has the best PC5 link quality among all suitable ProSe UE-to-network relays.

The remote UE triggers ProSe UE to network relay reselection when:

a. the PC5 signal strength of the current ProSe UE to network relay is lower than a configured signal strength threshold;

b. it receives layer 2 link release messages (upper layer messages) from ProSe UE to network relay.

UE/WTRU-to-network relay for wearable devices

In 3GPP release 14, a study of UE-to-NW relay for business use cases tailored to wearable devices and IoT devices was performed in the RAN. Although such studies did not produce any specifications, technical Report (TR) provided some preferred solutions for such relays. According to 3gpp TR 36.746-research on further enhancements to LTE D2D, UE to network relay for IoT and wearable devices (V15.1.1), as opposed to ProSe UE to NW relay using L3 (IP layer) relay methods, UE to NW relay of wearable devices is expected to be L2 relay based on the protocol stacks shown in fig. 2 and 3.

Connection establishment for unicast links in NR V2X

The relay solution in the previous release of the LTE specification is based on a one-to-one communication link established at an upper layer (ProSe layer) between two UEs (remote UE and UE-to-NW relay). Such connections are transparent to the access layer (AS) layer and connection management signaling and procedures performed at the upper layer are carried by the AS layer data channels. The AS layer is unaware of such a one-to-one connection.

In NR V2X (16 th edition), the AS layer supports the concept of a unicast link between two UEs. Such unicast links are initiated by the upper layer (as in ProSe one-to-one connections). However, the AS is informed of the existence of such unicast links, AS well AS any data transmitted between peer UEs in unicast. With such knowledge, the AS layer may support hybrid automatic repeat request (HARQ) feedback, channel Quality Indicator (CQI) feedback, and unicast-specific power control schemes.

Unicast links at the AS layer are supported via a PC 5-Radio Resource Control (RRC) connection. In 3GPP TS 38.300-NR and NG-Radio Access Network (RAN) general description phase 2 (V16.1.1), the PC5-RRC connection is defined in the relevant sections as follows:

the PC5-RRC connection is a logical connection between the source layer 2ID and the destination layer 2ID pair in the AS. One PC5-RRC connection corresponds to one PC5 unicast link. PC5-RRC signaling as specified in sub clause 5.X.9 may be initiated after its corresponding PC5 unicast link is established. When the PC5 unicast link is released as indicated by the upper layer, the PC5-RRC connection and corresponding side link Signaling Radio Bearers (SRBs) and side link Data Radio Bearers (DRBs) are released.

For each PC5-RRC connection unicast, one side link SRB is used to transmit a PC5-S (signaling) message before PC5-S security has been established. One side chain SRB is used to transmit PC5-S messages to establish PC5-S security. One side link SRB is used to transmit a PC5-S message after the PC5-S security has been established, protecting the message. One side link SRB is used to transmit PC5-RRC signaling, protect this signaling, and send it only after PC5-S security has been established.

The PC5-RRC signaling includes a side link configuration message (rrcrecon configuration sidelink) in which one UE configures Reception (RX) related parameters for each Side Link Radio Bearer (SLRB) in the peer UE. Such reconfiguration messages may configure parameters of each protocol (service data adaptation protocol (SDAP), packet Data Convergence Protocol (PDCP), etc.) in the L2 stack. The receiving UE may confirm or reject such a configuration depending on whether it can support the configuration suggested by the peer UE.

Paging in NR

In NR Uu, the UE/WTRU may use Discontinuous Reception (DRX) in rrc_idle and rrc_inactive states to reduce power consumption. The UE monitors one Paging Occasion (PO) per DRX cycle. The PO is a set of Physical Downlink Control Channel (PDCCH) monitoring occasions and may include a plurality of slots (e.g., subframes or OFDM symbols) in which paging Downlink Control Information (DCI) may be transmitted. According to 3GPP TS 38.300-NR and NG-RAN general description stage 2 (V16.1.1), a Paging Frame (PF) is a radio frame and may contain one or more POs or a starting point for a PO.

In multi-beam operation, the UE assumes that the same paging message and the same short message are repeated in all transmit beams, and thus the selection of the beam for receiving the paging message and the short message depends on the UE implementation. The paging message is the same for Radio Access Network (RAN) initiated paging and Core Network (CN) initiated paging and includes a set of paging records. The paging message may include one or more paging records (i.e., one or more UE IDs) corresponding to UEs mapped to the same paging occasion and in which pages are received from the network. According to 3GPP TS 38.300-NR and NG-RAN general description stage 2 (V16.1.1), the UE ID in the paging record may be a 5G serving temporary mobile subscriber identifier (5G-S-TMSI) in case of paging with CN (48 bits) or an inactive radio network temporary identifier (I-RNTI) in case of paging with RAN (40 bits).

A UE at IDLE/INACTIVE determines its Paging Frame (PF) and Paging Occasion (PO) based on any one of:

a. paging frame configuration in a System Information Block (SIB).

Ue specific or default DRX cycle.

i. Specifically, a UE in rrc_idle determines its DRX cycle according to the minimum of:

1) Default DRX cycle broadcasted in SIB, and

2) UE-specific DRX cycles provided in dedicated non-access stratum (NAS) signaling.

The UE in rrc_inactive determines its DRX cycle according to the minimum of:

1) The default DRX cycle broadcast in the SIB,

2) UE-specific DRX cycles provided in dedicated non-access stratum (NAS) signaling, and

3) UE-specific DRX cycles provided in dedicated Radio Resource Control (RRC) signaling.

Ue ID (i.e. 5G-S-TMSI).

PF and PO are defined according to the following formulas of 3GPP TS 38.304-NR and NG-RAN IDLE mode Specification (V16.3.0).

A Single Frequency Network (SFN) for a PF is determined by:

(SFN+PF_offset)mod T＝(T div N)*(UE_ID mod N)

index (i_s) indicating the Index of the PO is determined by:

i_s＝floor(UE_ID/N)mod Ns

the following parameters were used for the calculation of PF and i_s above:

t: in the RRC_IDLE state, the default value is applied if the UE-specific DRX is not configured by the upper layers.

N: total number of paging frames in T.

Ns: the paging occasion number of the PF.

Pf_offset: offset for PF determination.

UE_ID:5G-S-TMSI mod 1024。

The PDCCH monitoring occasion for paging is determined according to the tagsetspace as specified in 3gpp TS 38.213 and, if configured as specified in 3gpp TS 38.331, according to the first PDCCH-monitoringoccidiofpo and nrofPDCCH-monitoringoccidioperssb-InPO. When searchspace=0 is configured for the pagesearchspace, the PDCCH monitoring occasion for paging is the same as for the Remaining Minimum System Information (RMSI) as defined in clause 13 of 3gpp TS 38.213.

When searchspace=0 is configured for the pagesearchspace, ns is 1 or 2. For ns=1, only one PO in the PF starts from the first PDCCH monitoring occasion of paging. For ns=2, po is located in the first half frame (i_s=0) or the second half frame (i_s=1) of the PF.

When SearchSpaceid is configured for the pageSearchSpace to be non-0, the UE monitors the (i_s+1) th PO. PO is a set of "S X" consecutive PDCCH monitoring occasions, where "S" is the number of actually transmitted Synchronization Signal Blocks (SSBs) determined from SSB-PositionInBurst in SIB1, and X is nrofPDCCH-MonitoringOccasionPerSSB-InPO (if configured), otherwise equal to 1. The [ X s+k ] th PDCCH monitoring occasion in PO for paging corresponds to SSB of the kth transmission, where x=0, 1, …, X-1, k=1, 2, …, S. The PDCCH monitoring occasions of paging that do not overlap with UL symbols (determined according to tdd-UL-DL-configuration command) are numbered in the PF sequentially from zero starting from the first PDCCH monitoring occasion of paging. When the first PDCCH-MonitoringOccasionofPO exists, the starting PDCCH monitoring occasion number of the (i_s+1) th PO is the (i_s+1) th value of the first PDCCH-MonitoringOccasionofPO parameter; if not, it is equal to i_s S X. If X >1, then when the UE detects a PDCCH transmission addressed to a paging radio network temporary identifier (P-RNTI) within its PO, the UE is not required to monitor subsequent PDCCH monitoring occasions for 3GPP TS 38.304-NR and NG-RAN IDLE mode Specification (V16.3.0) for that PO.

The following parameters were used for the calculation of PF and i_s above:

N: total number of paging frames in T.

Ns: the paging occasion number of the PF.

Pf_offset: offset for PF determination.

UE_ID:5G-S-TMSI mod 1024。

Parameters Ns, nAndPagingFrameOffset, nrofPDCCH-MonitoringOccasionPerSSB-InPO and the length of the default DRX cycle are signaled in SIB 1. The values of N and pf_offset are derived from the parameter nandpnagingframeoffset as defined in TS 38.331. The parameter first-PDCCH-monitoringoccidioofpo is signaled in SIB1 for paging in the initial DL BWP. For paging in DL BWP other than the initial DL BWP, a signaling parameter first-PDCCH-monitoringoccidioofpo is transmitted in a corresponding BWP configuration of the 3gpp TS 38.304-NR and NG-RAN IDLE mode specification (V16.3.0).

Paging of UE/WTRU to NW relay

In System Information (SI) for LTE wearable devices, three options for paging reception for remote UEs were investigated in accordance with 3gpp TR 36.746-study on further enhancements to LTE D2D, UE to network relay for IoT and wearable devices (V15.1.1).

a. Option 1-remote UE monitors its own PO for receiving NW pages.

b. Option 2-relay UE monitors the POs associated with each of its connected remote UEs and forwards the paging message (if received) to the remote UE.

c. Option 3-the relay UE receives any paging messages associated with the connected remote UE in the PO of the relay UE.

In the study, option 2 was recommended. For NR UE to NW relay in release 17, option 2 is also assumed.

SI notification in paging messages

The UE may receive a notification in the page that the SI and/or PWS indication has been modified (thereby referred to as SI notification). Such SI notification may be sent in a so-called short message on a paging channel. The short message may individually indicate the presence of a PWS SIB being broadcast by the network (for emergency situations). Further, the short message may individually indicate that one or more of the SIBs of the cell have changed. The UE notified of the modified SI or PWS indication may follow a normal SI acquisition procedure to acquire applicable SI.

Statement of problem

In side-link (SL) UE/WTRU to NW relay for NR, it is assumed that the remote UE/WTRU receives pages from NW using option 2 defined in 3gpp TR 36.746-study on further enhancements to LTE D2D, UE to network relay for IoT and wearable devices (V15.1.1). Specifically, the relay UE monitors the POs of the connected remote UE and relays any received paging messages to the remote UE. Essentially, this creates a number of problems as described below.

Power consumption at relay UE/WTRU

Remote UE POs is defined based on the UE' S5G-S-TMSI. Thus, in addition to the relay UE's own PO of a remote UE having multiple PC5-RRC connections, the relay UE may need to monitor multiple different POs configured by the network. This is illustrated in fig. 4, where relay UE 401 needs to monitor its own paging occasions (shown as 402). Relay UE 401 may also monitor its remote UEs 403 and 405 for paging occasions that happen to occur in different time slots, shown as 404 and 406, respectively. As the number of remote UEs increases, the power saving of relay UEs in IDLE DRX (i.e., in rrc_idle or rrc_inactive) decreases. This reduction becomes more severe as the number of remote UEs served by the relay increases, and as we begin to consider more complex architectures (e.g., multi-hop relay).

While other options would be to change the definition of the remote UE's PO so that the remote UE under a single relay UE would have the same/similar PO, or simply transmit the remote UE page in the relayed PO, this would eliminate the basic advantage of option 2, as the remote UE has the flexibility to receive paging messages via Uu or via relay without informing the network of the change.

Another aspect of the power consumption of a relay UE is associated with the need to forward a single paging message (which may contain multiple paging records, whereby the paging records may be associated with remote UEs connected to the same relay) using multiple unicast transmissions to each unicast link. The problem may become more serious if we support multiple unicast links between a single remote UE and a relay UE for Uu relay connections.

Thus, one problem with the following may be addressed: how to implement option 2 at the relay UE/WTRU in a power efficient manner (i.e., minimizing additional power consumption at the relay UE/WTRU associated with monitoring the POs associated with all remote UEs/WTRUs).

Power consumption at remote UE/WTRU

The UE served by Uu in rrc_idle/rrc_inactive will be configured with DRX defined based on its paging DRX cycle and PO timing. This allows the UE to save power while in these states. If a UE in rrc_idle/rrc_inactive receives a page via the relay UE, it needs to monitor the side link instead of Uu. To achieve similar power savings, some limited monitoring of the side link should be defined for the remote UE to receive relay pages. Although this limited monitoring time should have a certain time relation to the Uu PO of the UE (assuming option 2 is used), an accurate one-to-one relation cannot be derived due to the uncertainty associated with relaying on the side link (in terms of side link characteristics (e.g. the need to use pattern 2 to perform resource selection on the shared resource pool) and factors associated with the relay itself (e.g. relay delay, beam configuration).

Thus, another problem may be posed as follows: how to avoid remote UE/WTRUs in rrc_idle/rrc_inactive requires continuous monitoring of the side link to receive Uu pages when connected to the UE/WTRU to NW relay and defining a limited monitoring period that accounts for uncertainty associated with Uu. There is currently no concept of paging occasions on the side link.

Lack of knowledge of remote UE/WTRU relationship to paging record due to security of remote UE/WTRU identity

L2 relay inherently implements the security of data transmission in its protocol stack. In particular, since Packet Data Convergence Protocol (PDCP) is end-to-end, encrypted data transmissions by a remote UE/NW cannot be relay decoded when transmitted to the NW/remote UE.

On the other hand, the 5G-S-TMSI of the remote UE is used to calculate the paging occasion of the remote UE. To avoid this information being known by the relay UE (which may be an attacker), it would be preferable for the relay UE to know only the paging occasion itself, and not the remote UE ID. However, since multiple UEs may be mapped to the same PO, the relay UE cannot know whether/with which remote UE a particular paging message received at the PO is associated. This may result in inefficiencies associated with transmitting the relayed paging message at the relay UE, such as repeating the paging message multiple times, or transmitting the paging message to a remote UE that is not being paged.

Thus, since the UE/WTRU ID of the remote UE/WTRU is hidden from the relay UE/WTRU, another problem may be raised with respect to: how to avoid redundant transmission of relayed paging messages by a relay UE/WTRU.

A method for efficient paging of SL UE/WTRU to NW relay.

Methods for paging reception by relay UE/WTRUs.

Relay UE/WTThe RU determines a remote UE/WTRU PO to monitor based on information in the active PO indication.

In one solution, a relay UE, which may be in rrc_idle/rrc_inactive, may receive an active PO indication from the network. Such an indication may inform the remote UE that one or more paging messages will be sent in one or more upcoming paging occasions associated with another UE, and may also indicate which PO, PO group, remote UE group, paging frame group will be paged in the near future.

The relay UE may determine whether to monitor for an upcoming paging occasion or a paging occasion in a future time period based on information in such an indication along with possible knowledge of whether one or more particular UEs associated/referenced by the paging occasion are currently connected to the relay UE. In particular, the relay UE may receive an active PO indication from the network, which is applicable for a predefined (pre-) configured or indicated future period of time. If the active PO indication indicates that a paging message is to be sent for a particular UE/PO/PF/etc., and the relay UE is currently serving the particular UE associated with the UE (e.g., has a PC5-RRC unicast link with the UE), the relay UE may monitor/wake up at a time associated with the particular UE/PO/PF/etc. to monitor the paging channel. Otherwise, the relay UE may not need to wake up/monitor the paging channel at this point.

Timing of active paging indication

The relay UE may be configured to monitor the PDCCH for one or more defined/configured times in which the relay UE may expect an active paging indication, possibly while in rrc_idle/rrc_inactive. Possibly in addition to the relay UE's PDCCH monitoring occasions associated with paging, the relay UE may also monitor PDCCH at such times. The relay UE may receive the active paging indication at any one or a combination of the following times:

a. during IDLE/INACTIVE paging occasions or paging monitoring occasions of the relay UE.

i. In particular, the relay UE may receive the active paging indication at the same PDCCH monitoring occasion associated with its own paging occasion.

b. At a time related to a paging occasion or a paging monitoring occasion of the relay UE.

i. For example, the UE may be configured with a time offset in terms of time slots, symbols, radio frames, etc. from the first/last monitoring occasion associated with its paging occasion.

For example, the UE may be configured to receive an active paging indication at a predefined time slot or set of time slots within its own paging frame.

For example, the UE may be configured to receive an active paging indication at a predefined time slot or set of time slots within a frame containing a first/last PDCCH monitoring occasion associated with the paging occasion of the UE.

c. At another PO configured by the network and defined for receiving an active paging indication.

i. For example, the UE may be configured to receive an active paging indication at another PO configured by the network using the current paging configuration. The UE may also be configured with specific rules on how to determine the POs associated with the reception of the active paging indication. Such rules may be defined with respect to the current PO of the relay UE or may be independent of the current PO of the relay UE. Such rules may involve determining the PO used to receive the active paging indication, but using different parameters (e.g., UE ID, T, etc.) in the calculation of the PF/PO for the UE.

1. For example, the UE may be configured to receive an active paging indication in a PO that follows/precedes its own PO.

2. For example, the UE may be configured to receive an active paging indication in a PO calculated using a predefined or configured UE ID (instead of a 5G-S-TMSI).

3. For example, the UE may be configured to receive the active paging indication at a PO defined by using a value of T (i.e., a DRX cycle) that is different from the determined DRX cycle of the UE (e.g., using the minimum defined DRX cycle in the specification).

d. At a predefined or configured frame/slot/symbol.

The timing of the expected POs may also depend on the DRX configuration itself. In particular (and in order to handle the case of large configured DRX), the UE may be configured with a first expected time for receiving messages when the DRX cycle has a first set of values or ranges of values, and the UE may be configured with a second/different expected time for receiving messages when the DRX cycle has a second set of values or ranges of values.

The relay UE may determine the frequency (how often) or density of Uu resources/timing for receiving the message based on any one or a combination of:

a. the DRX cycle of the relay UE.

i. For example, messages may be received/expected more frequently for longer DRX cycles.

Depending on whether the relay UE is configured with a minimum DRX cycle, the message may be expected on different resource sets.

b. Number of connected UEs.

i. For example, for relay UEs with a larger number of connected remote UEs, messages may be received/expected more frequently.

c. The UE ID and/or mode/timing of the PO associated with the connected remote UE.

i. For example, the frequency or timing associated with the receipt of the message may depend on the number/pattern of paging occasions associated with the connected remote UE. For example, the relay UE may receive messages more frequently in time slots located (in time) closer to the paging occasions of the connected remote UE. For example, the relay UE may receive the message once for every N paging occasions associated with the connected remote UE. For example, the message may be located at most/at least a number of slots before/after any POs to which the remote UE has been connected.

d. QoS/bearer/service established at the remote UE.

i. For example, the relay UE may receive/expect messages more frequently for one or any of the remote UEs that have bearers/QoS flows/priorities associated with higher QoS transitions. e. RRC state associated with one or more of the remote UEs.

i. For example, if at least one of the remote UEs is in rrc_inactive state, the relay UE may receive/expect messages more frequently.

Time validity of active paging indication

The active paging indication may be associated with a time validity. In particular, the relay UE may determine the period of time for which the information in the active paging indication is valid, possibly in terms of the number of frames and/or slots and/or symbols, or in terms of NW-configured POs, or NW-configured PF/POs, or defined/indicated in the active paging indication message itself. In particular, the relay UE may determine whether to monitor the PDCCH for pages at a particular time based on information in the received active paging indication message, as long as the particular time in question falls within the time validity of the active paging indication. The UE may determine the time validity of the active paging indication message using any one or a combination of the following:

a. based on information in the message itself.

i. For example, the active page indication message may indicate the number of frames, subframes, DRX cycles, POs, etc. that it is indicating active paging

b. A predefined period is used.

i. For example, the active paging indication may always provide information for a fixed set of DRX cycles, POs, etc. after the time the active paging indication was received, or for a defined period of time starting at some defined time after the active paging indication was received.

For example, the active paging indication may provide activity (whether paging is provided or not) for a set of network configured POs in a DRX cycle after receiving the indication, where the DRX cycle may be a specific DRX cycle (e.g., a minimum/maximum configurable DRX cycle, a default DRX cycle) or a DRX cycle indicated in the message itself.

c. Until the next received page indication message.

i. For example, the UE may determine its paging reception activity for each PO after receiving the paging indication message and maintain the determined activity until another paging indication message is received.

In particular to time effectiveness, in one exemplary solution, the UE may expect an active paging indication per DRX cycle. In one example embodiment, the UE may use information in the active paging indication message to derive the monitoring behavior for NW configured POs in the DRX cycle after receiving the active paging indication. In such embodiments, when the UE does not receive an active paging indication in an expected time associated with the DRX cycle, the UE may be configured with default behavior to be applied in the DRX cycle. For example, the relay UE may assume that all POs in the DRX cycle following a missed or not received active page indication message are considered active. For example, the relay UE may consider every other PO/no PO in the DRX cycle following a missed or not received active page indication message as active. For example, the relay UE may consider the active PO in the DRX cycle to be the same as the active PO in the previous DRX cycle.

In another exemplary embodiment, the UE may expect/receive an active paging indication message only when one or more of the upcoming POs are indicated as active. In such embodiments, the UE may consider the next indicated PO to be active only. Alternatively, the UE may consider the next N instances of the indicated PO to be active, where N may be predefined or further configured by the network.

In each of the above implementations, the UE may also determine whether to monitor the PO based on the activity determined as part of the active paging indication message and whether the UE associated with the PO is currently connected to the relay UE, as defined herein. Specifically, the UE monitors a PO only when the message indicates the activity of the PO, and the UE has a PC5-RRC connection with a relay UE associated with the PO.Content of active paging indication and association with remote UE/WTRUThe relay UE may receive any of the following information in the active paging indication message:

a. the validity time of the message, as described herein.

b. CONNECTED mode gap mode, as described further herein, if the relay UE is in rrc_connected.

c. The format of the message.

i. For example, if the message contains a bitmap, the message may also define the granularity of the bitmap (e.g., whether each bit is associated with a single PO or a group of POs, and the information needed for the relay UE to determine the grouping and/or mapping to each group).

For example, if the message contains a bitmap, the message may also define a grouping of UE IDs associated with each bit (e.g., the number of UEs in each group associated with each bit).

d. One or more UE IDs, which may be 5G-S-TMSI, I-RNTI, L2 source and/or destination IDs. Such an ID may be associated with a UE that will receive pages in the following PO or in a future PO.

i. For example, the relay UE may receive the UE ID of the connected remote UE that the NW expects to page in the next DRX cycle after the transmission of the active paging indication message (by the network). In particular, if the UE ID is included in the message, the relay UE may determine that a particular remote UE (with the UE ID provided in the message) is to be paged within a predefined/configured period of time.

Such IDs may also be truncated versions of any of the above IDs. In particular, if the relay UE receives a message with a particular truncated ID, the relay UE may determine that the network may page one or any of the remote UEs whose subset of bits of the complete UE ID matches the received truncated UE ID.

e. An index of the remote UE is identified.

i. For example, the message may contain an index, whereby the index may identify remote UEs in the list of UEs. Such a list of UEs may be a list of remote UEs currently served by the relay UE at the current time or served at some previous time. Such a list of UEs may be derived from a list of remote UEs provided and/or updated by the relay UE to the network, as further described herein. In particular, if the message contains an index of a particular remote UE, the relay UE may determine that the index UE may be network paged for some future period of time.

f. An index identifying one or more NW-configured paging occasions or paging frames or groups thereof.

i. For example, it may contain an index referencing a particular PO in a set of POs for NW configuration based on a predefined or configured number.

For example, it may contain an index referencing the PO groups in the set of POs of NW configuration, wherein the grouping and index of groups may be further predefined or configured.

Specifically, the relay UE may maintain an association between the UE (e.g., one of its remote UEs) and Uu POs configured for that UE. When the message contains an index of the PO or group of POs to which one of the remote UEs of the relay UE is associated based on the association described above, the relay UE may determine that it should monitor the PO (i.e., the remote UE may be paged in an upcoming paging occasion).

g. A bitmap, wherein each bit in the bitmap is associated with a remote UE, a remote UE group, a PO or PF, or a PO or PF group, etc.

i. For example, the message may include a bitmap, wherein each bit in the bitmap is associated with a UE, a group of UEs, a PO, or a group of POs. In particular, if the corresponding bit in the bitmap is set, the relay UE may determine that the network may page one or more remote UEs in the connected remote UE group.

For example, each bit in the bitmap may be associated with each possible value (mod N) of the remote UE ID. If the bit is set, the relay UE may consider that at least one remote UE whose PO maps to any PO defined by the value of the UE ID (mod N) may be paged.

Mechanism for receiving active paging indication messages

The relay UE may receive the active paging indication message using any of the following:

dedicated DCI on pdcch.

i. For example, the information associated in the active paging indication message may be encoded on the PDCCH using DCI. In particular, the relay UE may receive information of an active paging indication message encoded as part of DCI.

b. A MAC control element (MAC CE) is used.

i. For example, the relay UE may identify the page indication message based on a Logical Channel (LCH) ID or MAC header information, wherein this may indicate a MAC CE, and the information may be embedded in the content of the MAC CE.

c. Paging messages are used.

i. For example, the relay UE may receive an active paging indication message in the paging message. In particular, the relay UE may receive an active paging indication message in an RRC message transmitted to the relay UE on a Paging Channel (PCH) (i.e., the UE receives the message after decoding the PDCCH using the P-RNTI). The relay UE may receive the message in a separate RRC message received on the PCH. In this case, the message may contain an identifier indicating that the RRC message contains an active paging indication message. Alternatively, the message (or information associated with the message) may be included in a normal paging message that contains other records. In this case, the message may be included at the beginning/end of the paging message, or may be included as a string (instead of NAS information) associated with a special UE ID IE (e.g., all zeros or a UE ID of a different length)

d. In the paging message indicated by the short paging DCI.

i. For example, the relay UE may receive an indication in the short paging DCI, where such an indication may indicate to the relay UE that the associated paging message is replaced or includes an active paging indication message.

e. A dedicated (special) RNTI is used-e.g. a relay (R) -RNTI.

i. The relay UE may be configured with a new RNTI (e.g., R-RNTI). The relay UE may receive the active paging indication message in DCI or MAC CE obtained by decoding PDCCH with R-RNTI.

Relay UE/WTRU receives individual active paging indication messages based on its RRC state

In one solution, the relay UE may receive a separate active paging indication message depending on its RRC state. In particular, the relay UE may receive the first message when it is in rrc_idle, and/or may receive the second message when it is in rrc_inactive, and/or may receive the third message when it is in rrc_connected. The content/format of such messages may be different. For example, a relay UE in rrc_idle may receive an activity indication for any POs configured by the network. On the other hand, a relay UE in rrc_connected may receive an activity indication associated with only a subset of the POs. Such subsets may be indicated as part of a message. Such subsets may be derived/based on information provided by relay UEs as described herein for further reducing the POs or UEs that the network needs to report in an active paging indication message.

Mechanism for determining/receiving UE/WTRU-PO association

The relay UE may determine whether to monitor a PO associated with another UE (e.g., a remote UE) depending on whether the UE in question is connected or served by the relay UE. For example, the relay UE may serve the remote UE when the remote UE and the relay UE have a PC5-RRC connection. For example, the relay UE may serve the remote UE when the remote UE has indicated that it requests page forwarding from the relay UE to which the remote UE PC5-RRC is connected.

The relay UE may maintain an association of one or more PFs, POs, etc. with the remote UE, possibly for all served remote UEs. For example, the relay UE may maintain a PO associated with each of its served remote UEs. For example, the relay UE may maintain a table/list of all attached/served remote UEs and their corresponding PO and/or DRX cycles. The relay UE may determine the association of the remote UE with the PO based on information obtained by any one of:

a. directly from the remote UE itself.

i. For example, the relay UE may receive the PO (e.g., in the form of an index to a table or an indirect mapping to the PO) from the remote UE in PC5-RRC signaling. For example, when the remote UE establishes a PC5-RRC connection with the relay UE, the remote UE may send a PO to the relay UE. For example, when the PO changes (e.g., due to RRC reconfiguration), the remote UE may send the PO to the relay UE.

For example, the relay UE may receive information from the remote UE in PC5-RRC signaling that allows it to calculate the PO. For example, such information may be a UE/WTRU ID, a value of UE mod K (e.g., UE mod 1024), or a subset of bits of a UE ID of a remote UE.

b. Received directly from the network.

i. For example, the relay UE may receive the PO of the remote UE from the network, e.g., in an rrcrecon configuration message. For example, the relay UE may receive a PO indicating a new/released PC5-RRC connection after transmitting the sidlinkiueinformation to the network.

c. Calculated by the relay UE.

i. For example, the relay UE may receive the UE ID of the remote UE (from the remote UE or NW) and may use the UE ID of the remote UE to calculate the PO based on the paging configuration.

In each of the above mechanisms (received from the network or from a remote UE), the relay UE may also receive:

a. information about which specific POs should/should not be monitored.

b. Information as to whether monitoring of the PO of a particular remote UE is necessary.

i. The relay UE may derive such information indirectly from the PC5-RRC link monitoring state. In particular, the relay UE may receive an indication (from the network, the remote UE, or from an upper layer) that the PC5-RRC link has been released. The relay UE may then cease monitoring all POs associated with the remote UE.

As referred to herein, a PO associated with a remote UE may include any of the associations described above. Similar to the above, the relay UE may also receive the DRX cycle of the remote UE from the remote UE itself or from the network and possibly other DRX parameters that allow the relay UE to calculate the associated PO of the remote UE.

Remote UE/WTRU determines which DRX cycle/information to send to relay UE/WTRU

In one solution, the remote UE may send one or more DRX cycles to the relay UE. In one example, the remote UE may send both its NAS layer configured DRX cycle and its RRC layer configured DRX cycle to the relay UE. If one is not configured, the UE may send only the other of these. If not configured with any of these, the remote UE may indicate this (by sending a null field/message or explicit indication). Alternatively, if not configured with any of them, the remote UE may send a default DRX cycle. In another example, the remote UE may send the minimum value in the DRX cycle to the relay UE. Specifically, the relay UE may transmit only the minimum value of the NAS layer configured DRX cycle and the RRC layer configured DRX cycle. In this case, the relay UE may determine the DRX cycle of the remote UE as the minimum of the DRX cycle received from the remote UE and the default DRX cycle. If a DRX cycle is not received from the remote UE, the relay UE may use a default DRX cycle. In another solution, the relay UE may send the minimum of the NAS layer configured DRX cycle, the RRC layer configured DRX cycle, and the default DRX cycle. The relay UE may use the DRX cycle received from the remote UE to determine the DRX cycle to be used to determine paging occasions for the remote UE.

The remote UE may also determine which DRX cycle information to send to the relay UE based on its RRC state. For example, if the remote UE is in rrc_idle, it may send a NAS configured DRX cycle (if one is configured), or a minimum between NAS value and default value. If the remote UE is in rrc_inactive, it may send the NAS configured DRX cycle (if configured) and the RRC configured DRX cycle (if configured), or the minimum of the NAS and RRC configured DRX cycles, or the minimum of the NAS configured, RRC configured DRX cycles, and a default value.

The remote UE may send the DRX cycle at connection establishment, at relay UE request to change the DRX cycle (e.g., calculated minimum value), or at change of RRC state of the remote UE.

The remote UE/WTRU may determine whether to send a complete or partial UE/WTRU ID

The remote UE may send a full UE ID (I-RNTI and/or 5G-S-TMSI) or a partial UE ID (I-RNTI and/or 5G-S-TMSI-mod N). The remote UE may send only one of these to a given relay. The remote UE may determine whether to send a full ID or a partial ID based on any one or a combination of:

a. network configuration:

i. for example, the remote UE may be (pre) configured with a list of "trusted" relay IDs (e.g., L2 IDs) in SIB or dedicated signaling. If the remote UE is connected to a relay from the "trusted" list, the remote UE may send the full UE ID.

For example, if the remote UE is not configured with a list of trusted UEs, the remote UE may send the partial ID. After connection establishment with the relay, the remote UE may determine that the relay UE is a trusted relay (using other methods described herein), after which the remote UE may send the complete UE (either immediately upon a change in UE ID or upon a relay request).

b. From above (e.g., after network access/authentication or remote or relay)

i. For example, the remote UE may be notified of the trusted UE ID from an upper layer (e.g., NAS layer). This may occur after an initial access to the relay UE or an authentication to the core network. Similar to other embodiments, the remote UE may first send the partial ID and once the relay has been determined to be authentic, send the full ID. c. Based on previous connection with relay UE

i. For example, the remote UE may maintain a list of trusted L2 IDs (after connection and authentication). If the remote UE initiates a connection to the same L2 ID as in the past, the remote UE may assume a trusted relay UE.

The relay UE may connect to a remote UE that has provided a full UE ID and/or a remote UE that has provided a partial UE ID. The relay UE may read and forward the page differently depending on the particular situation/UE (whether it has a full or partial ID).

For a remote UE that provides a partial ID, the relay UE may forward any message received in the PO associated with the remote UE to the remote UE, regardless of its content. The relay UE may also include a list of UE IDs included in the paging message along with the forwarded paging message from the network.

For a remote UE that provides a complete UE ID, the relay UE may decode the paging message and send a PC5-RRC paging message with what is described herein (i.e., possibly without a UE ID). Further, in this case, the relay UE may determine other fields (e.g., paging type) to be included in the paging message (but not in other cases).

Relay UE/WTRU sends updated linking information to NW

In one solution, which may be used in combination with the previous solution, the relay UE may send remote UE link information to the network. For example, such information may be used to reduce/optimize the size of the active paging indication message. In particular, the relay UE may send a list of connected remote UEs to the network. For example, the relay UE may send an indication of the UE or more than one UE connected/disconnected with the relay UE (from the perspective of the PC5-RRC message).

Rules for sending messages

The relay UE may send the updated link information based on one or more of the following rules or a combination of these rules:

a. Periodically.

i. For example, the relay UE may be configured with periodicity for reporting the link information.

For example, the periodicity of the reporting may also depend on:

1. number of connected remote UEs.

2. The RRC state of the relay UE.

3. RRC state of one or more of the remote UEs.

Qos/services are relayed (e.g., radio bearers established at any of the remote UE and/or relay UE).

b. When a new remote UE is connected.

c. Upon disconnecting (releasing) one or a configured number of PC5-RRC connections with the remote UE.

d. Depending on the size of the active paging indication message (e.g., the number of bits in the bitmap) and/or whether the joining/leaving of the remote UE results in a change in the size of such message by a specific amount.

e. Depending on the power preference/capability at the remote UE.

Content of a message

The relay UE may include any of the following in the updated link message:

a. a list of UE IDs associated with connected remote UEs (where this may be L2 source/destination IDs, I-RNTI, 5G-S-TMSI, etc.).

b. Recently (e.g., since the last message transmission), the UE ID of the joining/leaving relay UE, along with an indication of joining or leaving for each UE.

c. A list of all POs associated with each of the linked remote UEs.

d. The PO of the UE that has recently joined/left the relay UE (e.g., since the last message transmission), along with an indication of the joining/leaving for the particular PO.

How to send a message

The relay UE may send the message using any of the following:

ul RRC message transmission (e.g., when relay UE is rrc_connected).

i. For example, the relay UE may send a sidlinkiueinformation message.

b. A recovery procedure or a similar RAN-based procedure for notification area update (RNAU).

i. For example, a relay UE in rrc_inactive may trigger a recovery procedure and include information in an RRC recovery request message or another message transmitted with the recovery request message.

Data transmission in INACTIVE.

For example, the relay UE (e.g., in rrc_inactive) may transmit small data containing an RRC message containing the message.

d. Similar to the SI requested procedure.

i. For example, the relay UE (e.g., in rrc_idle/rrc_inactive) may send a SI request-like procedure, where the requested System Information (SI) is replaced with linking information.

Relay/remote UE/WTRU sends paging change request

In one solution, the relay UE may receive a page change request from the remote UE. Upon receiving such a request, the relay UE may change from one paging reception method/option to another paging reception method/option for the particular remote UE. In particular, the relay UE may change from expecting to page the remote UE from its own PO to expecting to page the remote UE in its own PO (or vice versa). For example, the relay UE may start/stop monitoring paging occasions associated with the remote UE in question upon such receipt of a paging change request. The relay UE may notify the network upon receiving an expected paging change from the remote UE. For example, the relay UE may transmit an RRC message to the NW upon receiving the paging change request from the remote UE. For example, the relay UE may initiate/resume the RRC connection upon receiving a page change request from the remote UE. For example, the relay UE may initiate a SI request-like procedure upon receiving the page-change request message, or a data transmission in an INACTIVE procedure. The relay UE may include in the message a UE ID (e.g., L2 source/destination ID) of the requesting remote UE.

After receiving the message and/or informing the network, the relay UE may change its paging monitoring behavior.

The relay UE may perform any of the following:

a. monitoring of the PO associated with the remote UE requesting the change may be started/stopped without other remote UEs associated with the PO or without previous remote UEs associated with the PO.

b. The active page indication message from the network is decoded in different ways, such as:

i. the expected location of the expected page indication message is changed.

Changing the coding (e.g., number of bits, size, etc.) of the message.

Changing the mapping/interpretation of the codes for each remote UE.

The remote UE may send a page change request when the remote UE needs to receive pages from the relay UE (or no longer needs to receive pages). Such a request may be triggered because the remote UE no longer needs to receive pages. Such a request may be triggered by the remote UE directly starting/stopping paging reception from Uu while also connected via a relay, in which case reception via a relay is not required. Such a request may be triggered due to a condition, thereby requiring redundancy of paging reception (directly via Uu and via relay). The remote UE may determine whether to obtain pages directly via Uu and/or to obtain pages via relay and/or whether to send page change requests based on one or more or a combination of the following conditions or a change in such conditions:

Conditions of uu link.

i. For example Uu RSRP is above/below a threshold. For example, the remote UE may monitor for pages on Uu when Uu RSRP is above a threshold and may monitor for pages from relays when Uu RSRP is below a threshold. When the remote UE monitors the Uu relative side link for a paging change, it may notify the relay UE by sending a paging change request.

For example, the UE triggers a Radio Link Failure (RLF) or SL-RLF. For example, when the SL RLF is triggered at the remote UE, the remote UE may move from monitoring pages on SL to monitoring pages on Uu. The remote UE may also indicate these to the relay UE.

b. Conditions at the UE related to power consumption or temperature.

i. For example, the UE indicates overheating.

For example, UE power consumption preference changes. For example, the remote UE may move to monitor for pages on the SL when it receives such an indication and may notify the relay.

c. Conditions concerning Uu between relay and network.

i. Such conditions/measurements may be provided by the relay UE to the remote UE for paging as a result of further decisions about which link to monitor.

d. Conditions associated with RRC state of remote UE.

i. For example, the remote UE may send an indication when it moves from rrc_connected to rrc_idle/rrc_inactive, or vice versa. The indication may be a message/signaling sent from the remote UE to the relay UE as an indication of a change in the operating state of the remote UE. An exemplary indication of a state change may be a PC5-RRC message/signaling with direct or implicit state indication information. For example, the relay UE may monitor the PO of the remote UE when it is instructed to notify the relay UE that the remote UE is in rrc_idle/rrc_inactive. The relay UE may not monitor the PO of the remote UE when the remote UE is in rrc_connected.

e. Conditions on the side chain.

i. For example, the measured Channel Busy Rate (CBR) moves above/below a threshold.

For example, SL RSRP is above/below a threshold. For example, when CBR exceeds a threshold, the remote UE may move to monitor for pages on Uu. For example, the remote UE may move to monitor for pages on Uu when the SL RSRP is below a threshold and may monitor for pages from relays when the SL RSRP is above the threshold.

f. Conditions associated with active bearers.

i. For example, the remote UE is configured with bearers that require/prioritize paging reception on Uu and/or on side links.

if such bearers are established/released/activated/deactivated, the remote UE may send an indication to the relay UE.

g. Conditions related to remote/relay UE mobility/coverage.

i. For example, a remote UE moves from the coverage of the same/different gcb to the coverage of a different/same gcb, RAN area, or tracking area relative to a gcb to which the relay UE is connected/within its coverage.

For example, the remote UE is notified of a change in coverage/connectivity of the relay UE (e.g., via receipt of system information) such that the relay/remote UE is under coverage of the same/different gNB, RAN area, or tracking area.

h. Conditions associated with tracking area/RAN announcement area (TA/RNA) of the remote UE.

i. For example, if the cell on the direct interface is in the UE's configured TA/RNA, the remote UE may monitor for pages directly on Uu or on both Uu and relay. Otherwise, the remote UE may monitor for pages from only relays.

The remote UE may send an indication to the relay UE upon movement, wherein the remote UE moves in/out of its TA/RNA relative to the direct link.

The above conditions or combinations of conditions may also be used to determine a situation in which a remote UE may monitor pages from both Uu and from relay simultaneously. For example, if the SL RSRP is below a threshold and/or the Uu RSRP is below a threshold, the remote UE may monitor for pages from both Uu and SL. This may be motivated to receive coverage extension of the paging message.

In combination with other solutions, the remote UE may send a paging change request to the NW via Uu or to the relay channel via relay. The remote UE may receive/expect a page via Uu and/or relay based on any of the above conditions. For example, if Uu RSRP is below a first threshold and above a second threshold, while SL RSRP is above another threshold, the remote UE may receive pages via Uu and relay. The remote UE may send a page change request prior to the expected change in page source.

Remote UE/WTRU may be inIndicating a subset of POs (or beams) in a paging change request

In one solution, the remote UE may indicate that it wants the relay UE to represent the subset of POs it monitors. Such a subset of POs may be associated with a limited period of time (e.g., the next x DRX cycles). Such a subset of POs may be a regularly occurring subset of POs for remote UEs that the relay UE should/should not monitor. The remote UE may also indicate a subset of beams or slots within the PO for the relay to monitor on its behalf.

The remote UE may determine, based on the conditions given above, a subset of POs, slots, or beams that the relay UE should monitor based on a percentage of such opportunities. In particular, for a given condition (e.g., a measured value of RSRP), the remote UE may be configured with a percentage of PO to monitor and may provide the PO and/or the percentage to the relay UE. The relay UE may then monitor the required PO or use the obtained percentages to derive the PO of the remote UE to be monitored.

In another solution, the remote UE may determine that it will not be able to monitor its PO in Uu or SL for a certain period of time or sequence of time slots. The remote UE may indicate such a time period or sequence of time slots to the relay UE. Such unavailability may be caused, for example, by:

a. The remote UE determines a collision between SL transmission/reception and the remote UE's PO.

i. For example, the remote UE may need to receive the SL during one or more POs (e.g., for another unicast link associated with the SL service) and may not be able to receive pages on Uu in those POs.

For example, the remote UE may perform/schedule transmissions on SL slots associated with the reception of the page and may receive the page for the PO directly from Uu.

b. The remote UE needs to receive SL over Uu for a certain period of time (possibly associated with a collision between SL and Uu).

c. The remote UE needs to turn off Uu monitoring for a certain period of time (e.g., due to power saving preferences, indications within the UE, etc.).

In another solution, the remote UE may indicate to the relay UE whether it is able to monitor for pages directly on Uu. Such a determination may be made based on the above conditions. In such solutions, whether the remote UE performs paging monitoring directly on Uu may depend on subsequent instructions/commands from the relay UE and/or the network. Alternatively, when the remote UE is able to monitor for pages directly on Uu, the remote UE may be configured with default behavior (always/never monitor for pages on Uu, or determined using the rules described herein).

The relay UE/WTRU indicates that paging can/cannot be monitored on behalf of the remote UE/WTRU.

In a similar solution, the relay UE may inform the remote UE that the relay UE is unable to monitor for pages (possibly for a subset of POs/slots). The relay UE may provide such indication only if the remote UE indicates that it is able to monitor for pages directly on Uu. In particular, such an indication to the remote UE may cause the remote UE to monitor for pages (possibly on a subset of time slots) directly via Uu. Conditions similar to those described for the paging change request or the subset of indication slots may be used by the relay UE to indicate to the remote UE that the relay UE is not able to monitor paging for the remote UE. For example, the relay UE may prioritize SL transmission/reception over Uu for a period of time in which paging of the remote UE may be missed. The relay UE may then send such an indication to the remote UE, possibly indicating a missed PO.

Upon receiving such an indication, the remote UE may perform any of the following:

a. if the remote UE is able to receive its page via Uu, the remote UE may directly monitor for pages on Uu, possibly only for POs sent by the relay UE in the indication.

b. If the remote UE is unable to receive its page via Uu, the remote UE may perform any one or a combination of the following:

i. RRC connection is established/restored via relay (in particular in order to avoid potentially missed paging messages transmitted by the network).

Triggering relay reselection (in particular to find an alternative relay that can monitor paging for a remote UE). For example, the remote UE may trigger relay and/or cell reselection. If the remote UE is unable to find a suitable relay, it may initiate RRC connection establishment/restoration to the currently connected relay.

The relay UE/WTRU initiates the connect/resume procedure upon receiving the page.

In one solution, a relay UE at rrc_idle/rrc_connected may initiate a connection/recovery procedure upon receiving a paging message for a remote UE or received in one of the POs associated with the CONNECTED remote UE.

The relay UE may also decide whether to perform such connection establishment based on one or more or a combination of the following conditions:

a. indication in the paging message.

i. For example, the relay UE may receive an indication in the paging message indicating whether the relay UE initiates the connection/restoration.

b. The RRC state of the relay UE.

i. For example, the relay UE may initiate connection establishment if it is in rrc_idle, but not initiate such connection if it is in rrc_inactive.

c. UE ID associated with the received paging message.

i. For example, if a UE ID (e.g., L2 source/destination ID, 5G-S-TMSI, I-RNTI) associated with one of the remote UEs associated therewith is received, the relay UE may initiate the connection establishment.

d. Establishing or mapping bearers/LCHs onto Uu LCHs at remote UEs

i. For example, the relay UE may initiate connection establishment for a connected remote UE (possibly identified in a paging message) having an LCH mapped to Uu LCH that is configured (or required) for the relay UE to perform connection establishment/restoration at paging.

For example, if the remote UE has at least one configured LCH (e.g., PC5 LCH) with a priority above a threshold or is configured with attributes that require establishment/restoration of a connection by the relay, the relay UE may initiate connection establishment/restoration.

e. UE ID type in paging message.

i. For example, if at least one of the UE IDs or an associated UE ID in the paging message is associated with an I-RNTI, the relay UE may initiate RRC connection/recovery.

Relay UE/WTRU monitors paging associated with remote UE/WTRU for a limited period of time

In one solution, the relay UE may monitor pages associated with the remote UE for a limited period of time since the last occurrence of a particular event. Such behavior may be further limited to a subset of scenarios such as:

a. The relay UE is configured to determine whether to perform limited time monitoring based on the NW configuration.

b. The relay UE is configured to perform limited time monitoring depending on RRC states of the relay UE and/or the remote UE.

i. For example, when the remote UE and/or relay UE is in rrc_idle, the relay UE performs limited time monitoring of paging of the remote UE, otherwise it performs monitoring of paging of the remote UE independent of such events/timers.

For example, the relay UE may be configured with a timer for remote UE paging monitoring. The relay UE may monitor pages associated with the remote UE as long as the timer is running. The relay UE may reset the timer upon occurrence of one or more events. Such events may consist of any of the following: transmissions, data, control, HARQ feedback, channel State Information (CSI) requests/reports, SCI, etc. are received from the remote UE. These may be associated with only a particular type of transmission. For example, the timer may be reset when a HARQ ACK only, or HARQ ACK or HARQ NACK is received.

c. A paging message is received from the network, which may be associated with the remote UE or the remote UE's PO.

d. An indication or message is received from the network, which may be associated with a remote UE.

e. A SL WUS (wake-up signal) is received for the purpose of SL DRX control or an acknowledgement of such a SL WUS is received.

f. A receiving MAC CE (such as a SL DRX command MAC CE).

Relay UE/WTRU monitoring for paging and/or System Information (SI) modification may depend onRelay/remote UE- WTRU RRC state and/or paging change request.

The relay UE/WTRU determines a remote UE/WTRU RRC state.

The relay UE may be informed of the status of the remote UE:

a. slave network (e.g., via dedicated RRC signaling)

b. From remote UE (e.g., via PC5-RRC signaling)

c. The RRC state of the remote UE is implicitly determined by based on:

i. state transition signaling relayed by the relay UE. For example, as a result of the receiving, the relay UE may determine that the remote UE has moved from rrc_idle/rrc_inactive.

There is an established adaptation layer and/or relay configuration for the remote UE at the relay UE. For example, the relay UE may determine that the remote UE is in rrc_connected based on whether the remote UE has been configured (by the network) with a relay configuration (such as an adaptation layer configuration, a mapping in ingress to egress LCH, etc.).

PC5 signaling or transmission/behavior by a remote UE associated with rrc_connected.

1. For example, the relay UE may determine Uu RRC state of the remote UE based on the SL DRX configuration with the remote UE. In particular, if the remote UE requests/configures SL DRX on a unicast link with the relay UE, the relay UE may assume that the remote UE is in rrc_connected.

2. For example, the relay UE may determine that the remote UE is in rrc_connected based on the presence and/or configuration of regular SL transmissions (e.g., configuration of SL RSRP reports, regular presence of SL CSI requests/reports, timers associated with SL data transmissions between the remote UE and the relay UE, etc.).

Relay UE/WTRU determines which paging occasions to monitor

Paging monitoring and/or SI monitoring behavior of the relay UE may depend on RRC states of the relay and/or remote UE. The relay UE may monitor the paging occasions or a subset of paging occasions for all remote UEs known to be in rrc_idle/rrc_inactive in accordance with the methods described herein (indicated by the network in an active paging indication or by the remote UE in a paging change request).

Alternatively, the relay UE may monitor the paging occasions or a subset of paging occasions based on an indication from the network and/or receipt of a paging change indication message for all PC5-RRC connected remote UEs for which paging occasions are requested to be monitored.

When the relay UE itself is in rrc_connected, the relay UE may stop monitoring paging occasions for all PC5-RRC CONNECTED remote UEs. Specifically, in this case, the relay UE may rely on dedicated RRC signaling to receive paging messages of the remote UE. The relay UE may receive the paging message addressed to the remote UE in a dedicated RRC message. Upon receiving such paging messages, the relay UE may forward the paging messages to the addressed remote UE in PC5-RRC signaling. For example, the dedicated RRC message containing the paging message may include the UE ID of the remote UE for which the paging message is intended.

Relay UE/WTRU determines how to handle SI modification indication in paging

In one solution, the management/handling of the reception of paging and/or SI modification indications from the network by the relay UE may depend on the RRC state of the relay/remote UE. As expressed above, when the remote UE changes state, the remote UE may send an indication via messaging/signaling. One example may be a state change indication message/signaling that occurs when a remote UE moves from an rrc_connected state to an rrc_idle/rrc_inactive state (and vice versa). Specifically:

a. if the relay UE is in rrc_connected, the relay UE may forward SI indication and/or information of the changed SI and/or actual SI depending on the RRC state of the remote UE. The SI indication information may indicate availability of changed (updated) SI information (i.e., actual, new SI information) from the network. Specifically:

i. if the remote UE is in rrc_connected, the relay UE may forward the SI indication to the rrc_connected remote UE. The relay UE may send the indication immediately or may send the indication when the relay UE acquires the updated SI. Further, the relay UE may send a list of modified SIs to the remote UE based on the value tag in SIB 1. In particular, the relay UE may determine the SI whose value tag has changed and send the changed SI (or a subset, e.g., based on those of interest to the remote UE) and/or the value tag of the changed SI to the remote UE.

if the remote UE is in rrc_idle/rrc_inactive, the relay UE may not forward the SI indication to the remote UE. The relay UE may instead send the changed SI itself (based on the changed value tag) to the remote UE. Thus, an RRC idle state or RRC inactive state change indication (move from RRC connection to RRC idle or inactive) may be associated with the relay UE sending changed (updated, actual) SI information to the remote UE. Alternatively, if the relay UE is in rrc_connected, the relay UE may first receive/determine the actual SI that has changed after receiving the SI indication. Specifically, the relay UE may determine that the SI has been changed based on the value tag received in SIB 1. Based on the changed SI, the relay UE may send the changed SI (or a subset, e.g., based on those of interest to the remote UE).

b. If the relay UE is in rrc_idle/rrc_inactive, the relay UE may forward the changed SI to all remote UEs regardless of their RRC states. In particular, the relay UE may determine a list of modified SIs (based on the value tag in SIB1 and/or the SI of interest at the remote UE) and may forward all (SI of interest) to each PC5-RRC connected remote UE.

In another solution, the management/processing of the reception of paging and/or SI modification indications from the network by the relay UE may depend on whether the modified SI is of interest to the relay UE or needs to be received by the relay UE. Specifically:

a. If the relay UE receives the SI change indication and determines that the (possibly all) changed SI is of interest to the relay UE, the relay UE may forward the changed SI to the remote UE without forwarding the SI modification indication. On the other hand, if the relay UE determines that the modified SI is not of interest to the relay UE (and may be of interest to the remote UE and may be in rrc_connected), the remote UE may only forward the SI change indication. Possibly, if the relay UE determines that the SI change indication is not of interest to the relay UE and the remote UE (or at least one remote UE, or at least N remote UEs) is in rrc_idle/rrc_inactive, the relay may acquire and forward the changed SI.

In another solution, the management/processing of the receipt of the SI modification indication from the network by the relay UE may depend on whether the remote UE is interested in the changed SI. Specifically:

a. the relay UE may maintain a list of SI of interest for each remote UE and may forward the modified SI and/or SI change indication only if the changed SI is of interest to the remote UE (possibly at least one of them). Otherwise, the relay UE may choose not to forward the SI indication and/or the SI has changed.

In another solution, the management/processing of the reception of SI modification indications from the network by the relay UE may depend on the number or type of SIBs/SIs that are changed and/or are SI/SIBs of interest from the remote UE. For example, if the number of SIBs/SIs of interest that have changed is below a configuration threshold, the relay may forward the changed SIs. Otherwise, the relay UE may forward only the SI modification notification. For example, the relay UE may receive and forward changed SIBs for certain particular SIBs or SIB types, while for SIBs or SIB types, the relay UE may forward SIB modification indications. For example, the relay UE may always forward a common warning system (PWS) SIB or a positioning SIB, but may forward the SI modification indication (instead of the SIB) for only some SIBs.

Combinations of the above solutions are also possible in terms of conditions for forwarding SIBs or paging messages.

In another solution, the management/handling of paging and/or modified SI by the relay UE may depend on whether the relay UE is configured with a common search space in the current DL bandwidth portion. Such a solution may be specific to relay UEs that are in rrc_connected. Specifically:

a. the relay UE may use one of the solutions defined above if the relay UE is configured with a common search space in the current DL bandwidth portion.

b. If the relay UE is not configured with the common search space in the current DL bandwidth portion.

i. The relay UE may use dedicated RRC signaling to receive any modified SI directly from the network. In this case, the relay UE is not expected to monitor the paging occasion of the remote UE (for the case of paging reception). Upon receiving the modified SI, the relay UE may send the modified SI to the remote UE in PC5-RRC signaling if the modified SI is also considered to be of interest to the remote UE.

Alternatively, the relay UE may use dedicated RRC signaling to receive any modified SI directly from the network and upon receiving the modified SI, may send the SI to the remote UE depending on the RRC state of the remote UE. Specifically:

1. If the remote UE is in RRC_IDLE/RRC_INACTIVE, the relay UE may send the modified SI to the remote UE in PC5-RRC signaling.

2. If the remote UE is in RRC_CONNECTED, the relay UE may send an indication of the modified SI and/or a list of modified SIs to the remote UE in PC5-RRC signaling.

In the case of success/error, a relay UE/WTRU receiving a page in dedicated signaling may respond to the network

The network may send pages to relay UEs that are rrc_connected using dedicated RRC signaling, but the remote UE may no longer rrc_connected to the given relay UE. In this case the network should be aware of this.

In one solution, the relay UE may send an acknowledgement message (in the case of successful arrival/capable of successful arrival at the remote UE) or a failure message (otherwise). The relay UE may send an acknowledgement/failure message:

a. upon receiving a dedicated paging message from a relay UE

i. For example, if a remote UE paged by the network in a dedicated paging message received by the relay UE is not PC5-RRC connected to the relay UE, the remote UE may send a failure message to the network. If the remote UE is connected, the relay UE may send an acknowledgement message to the network.

b. When an attempt is made to forward the paging message through the PC 5-RRC.

i. For example, the remote UE may expect an acknowledgement (e.g., in RLC or in PC 5-RRC) when forwarding the paging message to the remote UE. If no acknowledgement is received, the relay UE may send a failure message to the network. Otherwise, if an acknowledgement is received from the remote UE, the relay UE may send an acknowledgement message.

The dedicated RRC messages and responses from the relay UE may take the form of request/response RRC signaling (e.g., rrcrecon configuration and acknowledgement/failure messages, or new RRC message combinations for delivering pages and corresponding responses). Alternatively, the remote UE may send a UL RRC message (e.g., ulinfomation transfer or the like) when delivery of the page to the remote UE fails, and not send any message if successful.

Content of dedicated Uu RRC messages sent from network to relay UE/WTRU

The dedicated RRC message may include any of the following information:

a. UE ID of remote UE being paged by network

The UE ID may be the I-RNTI, 5G-S-TMSI or local UE ID of the remote UE.

The relay UE may send a unicast PC5-RRC message to the remote UE whose UE ID is included in the paging message.

The relay UE may determine the paging type to include in the forwarded paging message based on whether the received ID for the UE is an I-RNTI or a 5G-S-TMSI (as described herein). This behavior may be the same for the case where the relay UE receives a page (i.e., not in dedicated signaling) while monitoring the remote UE's PO. Alternatively, the dedicated Uu RRC message may contain the remote UE ID (possibly a local ID instead of one of the paging IDs) and the paging type (RAN paging or CN paging), and the relay may reflect this paging type in the forwarded paging message.

b. The link/path on which the remote UE should initiate connection establishment (e.g., directly, via relay, etc.)

i. The relay UE may forward the link/path to the remote UE.

Upon receiving the indicated link/path from the relay, the remote UE may initiate connection setup/restoration via the link.

c. Relay UE ID via which remote UE should initiate connection establishment in response to receipt of page

i. The relay UE may forward a relay UE ID to the remote UE, which may be different from its own ID (i.e., another relay is selected by the network). Furthermore, in the event that a different relay is selected, the relay UE may release the PC5-RRC connection after forwarding the page to the remote UE

if the indicated relay UE ID does not match its current relay, the remote UE may release the PC5-RRC connection. The remote UE may then initiate a connection setup via the connected relay or indicated relay based on whether/which UE ID is indicated in the forwarded paging message on the PC 5-RRC.

d. CBR threshold for deciding which path/link to select

i. The relay UE may forward such thresholds to the remote UE

The remote UE may determine whether to initiate connection establishment via direct or indirect based on a comparison of the measured CBR to a threshold (e.g., via a direct path if CBR > threshold)

Relay UE/WTRU determines the content of PC5-RRC message containing the forwarded page

The PC5-RRC message indicating paging to the remote UE (sent by the relay UE) may contain any of the information received by the relay UE and forwarded to the remote UE. Furthermore, the relay UE may include the following information in the PC5-RRC message:

a. paging type (e.g., CN paging, RAN paging). Such fields may be sent as an enumeration type.

i. For example, the relay UE may determine whether the page is a CN page or a RAN page based on the following and indicate this to the remote UE:

1. the type of ID received from the network in the dedicated Uu RRC message. For example, the relay UE may determine the type of paging based on whether it receives the I-RNTI or the 5G-S-TMSI.

2. Explicit/implicit indication in dedicated Uu RRC messages. For example, the relay UE may receive the local UE ID in a dedicated Uu RRC message along with an indication of whether it is CN paging or RAN paging that should be sent. The relay may then forward such an indication.

For example, upon receiving a paging message of the paging type with a CN page or a RAN page, the remote UE may consider it as if it were receiving a CN page or a RAN page, respectively. The remote UE in rrc_idle receiving the RAN page may ignore the message. Alternatively, it may send a PC5-RRC message to the relay UE indicating the error condition. Alternatively, it may initiate a connection establishment procedure to the network, possibly indicating an error condition to the network (in the cause value or RRC message/field).

For example, a remote UE in rrc_inactive that receives a paging message for a type RAN page may initiate a recovery procedure. A remote UE in rrc_inactive that receives a paging message for a type CN page may transition to rrc_idle, release its context, and initiate a connection establishment procedure.

Si change/PWS notification indication.

i. For example, the relay UE may receive the SI change indication along with (or at a similar time as) the paging message. If the relay UE receives two separate paging messages (e.g., a paging message and an SI modification message for the remote UE) within a configured time window, the relay UE may combine the two indications into a single PC5-RRC message. For example, after receiving a first message (e.g., a page for a remote UE), if a second message (PWS notification) is received before the relay UE generates a PC5-RRC message, the relay UE may send both in a single PC5-RRC message.

SI or part of SI, possibly associated with SI modified by the network and for which SI modifications were sent, possibly associated with SI of interest to a particular remote UE.

i. For example, the relay UE may indicate in the page forwarding message that the included SI corresponds to the modified SI.

For example, when a paging message containing SI (e.g., a forwarded PC5-RRC message dedicated to paging) is received, the remote UE will assume that the SI corresponds to the changed SI and will update its own SI based on the content of the paging message.

d. Modified specific SIB or SI

i. For example, when receiving a paging message indicating SI modification, the relay UE may read SIB1 to determine the modified SI/SIB, and may then indicate the modified SIB/SI to the remote UE in a PC5-RRC message.

SIB1 or parts of SIB1 (e.g., validity tags, region IDs, etc.).

i. For example, the relay UE may forward the complete SIB1 all the time whenever an SI modification is received, or may forward part of SIB1 (such as a validity tag) or all SIBs that may be associated with only the modified SIB.

f. The UE ID of the remote UE being paged. For example, the relay may include only the UE ID of the remote UE being paged into the PC5-RRC message to the relay UE, and not include other UE IDs in the paging record. The relay UE may repeatedly transmit a PC5-RRC message to each remote UE included in the paging message, and include only a remote UE ID corresponding to the remote UE in the corresponding message.

The timing of the transmission of the forwarded paging message may depend on its content

The relay UE transmitting the page in mode 2 may be configured with a time window for forwarding the paging message on the PC5 RRC. Such a time window may also depend on whether the paging message is carrying a UE page, SI change indication, or PWS notification. Such paging messages may determine the minimum/maximum amount of time the UE has before generating a PC5-RRC message to forward the page and/or a resource selection window for transmitting the paging message. As described herein, if a paging message (e.g., including a paging message with an SI change indication or PWS notification) is received within an overlapping window, the relay UE may combine the messages.

In one example, the relay may forward some paging messages immediately and forward other paging messages after a predefined or configured period of time. For example, paging messages containing PWS notifications and/or UE pages may be forwarded immediately, while paging messages containing SI modifications may be forwarded only before/after the next modification period (or at a preconfigured time).

The timing of the transmission of the forwarded paging message may depend on the SL DRX activity time of the remote UE/WTRU

In another example, the relay UE may forward the paging message only during an active time (e.g., defined by SL DRX) of the corresponding remote UE to which the paging message is being forwarded. In particular, if the relay UE receives a paging message to be forwarded to the remote UE during the remote UE's inactive time, or when the remaining time in the remote UE's active time is less than a configured/predefined threshold, the relay UE may delay transmission of the paging message until a subsequent active time of the remote UE.

In another example, the relay UE may forward the SI modification to all remote UEs in the multicast (e.g., with the multicast L2 ID). The relay UE may wait for a multicast specific active time, or a time when all remote UEs are active, in order to forward the SI modification.

The relay UE/WTRU itself receiving paging while inactive may send an indication to the remote UE/WTRU

In one solution, the relay UE may send an indication to one or more remote UEs upon receiving a page for the relay UE itself. Such an indication may be in the form of a PC5-RRC message, such as a release message or a SL reconfiguration message. Such messages may be in the form of SL MAC CEs or SCI transmissions dedicated to this purpose.

In some cases, the relay UE may send such messages on the sidelink, which may depend on any of the RRC states of the relay UE and/or the remote UE, information received by the remote UE in the paging message, and so on. For example:

a. (transition to IDLE due to CN paging) when a relay UE in rrc_inactive receives the core network paging message, the relay UE may send an indication to the remote UE. The relay UE may also send such a message only to remote UEs that are in rrc_inactive.

b. (receiving SI notification) when the relay UE receives the SI change notification in the paging message, the relay UE may send an indication to the remote UE. The relay UE may also include modified SIs (or subsets, e.g., based on those of interest to the remote UE). Alternatively, if the relay UE knows that the remote UE is monitoring SI directly on Uu, the relay UE may not include the modified SI. The relay UE may use similar messaging (e.g., to monitor paging from Uu) to determine that the remote UE is monitoring SI directly on Uu, as described herein.

Upon receiving such an indication, the remote UE may perform one or more of:

a. a Uu RRC state transition is initiated (e.g., moving from one Uu RRC state to another Uu RRC state).

i. For example, if the remote UE is currently in rrc_connected, the indication may instruct the remote UE to transition to rrc_idle.

b. Initiation of a relay reselection procedure and/or initiation of a PC5 connection release and/or a PC5 connection establishment and/or recovery procedure with another relay.

i. For example, the remote UE may be configured to attempt to remain in rrc_inactive and may initiate a relay reselection procedure to find an alternative relay.

1. The remote UE may trigger relay reselection depending on the QoS of the established bearer and/or the bearer configuration.

2. The remote UE may trigger connection establishment with another relay depending on whether the remote UE has determined that an alternative relay/has been provided with an alternative relay.

c. The cell reselection procedure and/or the recovery procedure is initiated directly via Uu.

i. Similar restrictions/conditions/actions of relay reselection as above may also be applied to cell reselection.

d. All relay bearers are temporarily suspended, possibly until a subsequent RRC message from the relay UE is received.

i. For example, the relay UE may send a first indication to any remote UE that is in rrc_inactive upon receiving the CN page. Upon receiving the first indication, the remote UE may suspend all bearers (including SRB 1) to avoid initiating a resume procedure triggered by the remote UE. Upon completion of connection establishment triggered by receipt of the CN page, the relay UE may transmit a second indication to the remote UE. Upon receiving the second indication, the remote UE may resume all bearers (including SRB 1) to re-enable triggering of the resume procedure by the remote UE.

Method for relaying paging on SL

The relay UE/WTRU determines a SL time window for the paging transmission based on the PO and the relay configuration.

In one solution, the relay UE may determine a limited time window for transmitting/relaying paging messages to one or more remote UEs. Such windows may be defined with respect to Uu POs associated with one or more connected remote UEs. In particular, such a window may begin at an offset of a paging frame or paging occasion associated with one or more remote UEs. Such windows may also depend on the configuration at the relay UE.

In one option, the relay UE may determine a window (e.g., a starting time slot and duration) and send such window to the remote UE. The relay UE may transmit window information (e.g., in a side link configuration message) to the remote UE via a PC5-RRC message. The remote UE may use this information to determine its side link monitoring time. In particular, the remote UE may be required to monitor the side link at least for SL slots defined by the window. Alternatively, the remote UE may calculate the same window as calculated by the relay UE based on receipt of configuration information (described herein) that may be sent by the relay and/or the network to the remote UE. Relay UE calculation of the paging transmission window is described below. Without loss of generality, the remote UE may perform the same behavior to determine its monitoring window.

The relay UE may determine a new transmission window for relaying the paging message and/or send the calculated window or an indication of a change in the calculated window to the remote UE:

a. upon establishment of a PC5-RRC connection with the remote UE.

b. When the calculated window changes from the previous calculation, the amount of a certain (pre) configuration may change.

i. For example, if the remote UE changes by at least X slots, the relay UE may send the calculated window to the remote UE, where X may be (pre) configured or predefined.

For example, the calculated change in the window may be caused by a change in any of the parameters described above for calculating the beginning and/or end and/or duration of the window.

c. During one or each of the paging message transmission windows.

i. For example, the relay UE may send the calculated window or offset at each SL paging window or each set of slots associated with Uu paging occasions.

For example, if the calculated window has changed by a certain amount, the relay UE may send the calculated window or offset only at the SL paging window.

After receiving the paging window and/or calculating the paging window from the relay at the remote UE, the remote UE may apply the newly calculated SL paging window at the next window time or the next remote UE PO.

The relay UE may determine a start and/or end time slot and/or duration of a paging transmission window relative to the PO/PFs of one or more connected remote UEs based on one or more of the following factors:

a. beam pattern/configuration at relay UE.

i. For example, the relay UE may determine the starting SL slot as the (pre) configured number of slots after the first/last possible beam on which the relay may receive pages for the remote UE in the PO of the remote UE. For example, the UE may employ such a starting slot when configured to be in rrc_idle/rrc_inactive.

For example, the relay UE may determine the starting SL slot as a (pre) configured number of slots before/after the current (best) beam that the relay UE uses when communicating with the network. For example, the UE may employ such a starting slot when configured to be in rrc_idle/rrc_inactive.

For example, the relay UE may determine the starting slot as a (pre) configured number of slots before/after the first/last PDCCH monitoring occasion of the PO.

For example, the relay UE may determine the starting slot according to any of the paging SearchSpaceID or nrofPDCCH-MonitoringOccommonPerSSB-InPO RRC parameters or any RRC parameters defining the paging occasion configuration at the relay UE.

b. Relay UE scheduling mode.

i. For example, the starting slot may be calculated differently depending on the scheduling mode of the relay UE. For example, the relay UE may add a first offset (e.g., NW configured offset) when configured in mode 1 and may add a second offset (e.g., UE-determined offset) when configured in mode 2.

c. The RRC state of the relay UE.

i. For example, the starting slot calculated by the relay UE at rrc_connected may be relative to the current/best beam of the relay UE. For example, a starting slot calculated by a relay UE that is in rrc_idle/rrc_inactive may be relative to a first/last beam in which the relay UE may receive a page associated with a particular PO. Alternatively, the relay UE may define it based on a (pre) configured number of beams between the first beam and the last beam.

in one solution, the relay UE calculates/informs the remote UE of the starting point for both the rrc_connected case and the rrc_idle/active case, and may later indicate the current RRC state to the remote UE. The remote UE may determine the starting slot based on the current RRC state of the relay UE.

in one solution, the relay UE may calculate an offset to the previously calculated starting slot. The relay UE may determine such an offset based on the change in the best/current beam measured by the relay UE. The relay UE may send an offset to the remote UE during the SL monitoring period. The remote UE may apply such an offset to determine the starting slot of the SL paging cycle for the next PO.

d. The number of attached remote UEs that may be associated with the same PO.

i. For example, the relay UE may configure multiple (additional) slots in the SL paging window for each attached remote UE associated with the same PF/PO. In particular, the relay UE may scale the size of the SL paging window based on the number of attached remote UEs associated with the PO.

e. The number of POs in the paging frame that may be associated with the remote UE.

i. For example, the relay UE may configure the starting time slot and/or duration of the SL paging window based on the number of POs in the paging frame and/or the number of monitoring occasions in the PO/paging frame associated with the remote UE attached to the relay UE. For example, if only one PO in the PF is associated with an attached remote UE, the relay UE may configure the starting slot to occur after the POs of one or more remote UEs. Alternatively, if there is more than one PO in the PF associated with at least one remote UE attached to the relay, the relay UE may configure the starting slot to occur after the paging frame.

For example, the relay UE may configure the starting slot at different offsets relative to the POs/PF depending on the configuration value of Ns (the number of POs configured per paging frame).

f. The configuration/sensing result is sensed at the relay UE.

i. In one solution, the relay UE may calculate the starting time slot based on the sensing configuration and/or the sensing result. In another solution, the relay UE may calculate the length of the SL paging window based on the sensing configuration and/or the sensing result.

1. In one example, the relay UE may determine the starting slot based on whether the relay UE is configured with full or partial sensing. In particular, the relay UE may use a first offset from the PO for the starting slot when configured with full sensing and may use a second offset from the PO for the starting slot when configured with partial sensing. The second offset may be determined by the partial sensing configuration. In particular, the second offset may be determined based on a time instant at which the UE has sufficient sensing results for transmission.

2. In one example, a relay UE configured to fully sense may determine a starting time slot based on UE capabilities. The relay UE configured to be partially sensed may determine its starting slot according to the value of K (the number of periods of partial sensing result to be used) and/or t_sep (period or interval between sensing opportunities) and/or t_async (minimum amount of sensing time required immediately before transmission). For example, the UE may be (pre) configured with the minimum required values of these parameters and the starting time slot may be derived as the first time slot for the allowable transmission to achieve the minimum sensing result.

3. In one example, the relay UE may calculate the length of the SL paging window based on the most recent resource selection results, perhaps where those resource selection results are specific to the resource selection of the transmission application for paging, perhaps in the SL paging transmission window associated with the UE's currently correctly-sized PO, such as:

(a) The amount/percentage of resources determined to be available based on the resource selection.

(b) A SL RSRP threshold for determining the required amount of target available resources to continue resource selection.

(c) The average number of available/occupied resources determined during the selection of resources.

g. CBR measured at relay UE.

i. For example, the relay UE may determine the length of the SL paging window based on the measured CBR. For example, the relay UE may be (pre) configured with CBR or a mapping of CBR ranges to SL paging window lengths.

h. Priority of LCH configured at relay UE (e.g., for rrc_inactive scenario).

i. For example, if the relay UE is configured with one or more relay LCHs with higher priority, the relay UE may configure an earlier starting slot and/or a shorter SL paging window.

h. Buffer status at relay UE, or measurement of relay load at relay UE.

i. For example, the relay UE may configure the starting slot based on the current buffer status of the relay logical channel that may be associated with other UEs (e.g., not in IDLE/INACTIVE).

For example, the relay UE may configure different starting slots and/or window durations depending on the number of remote UEs that may be rrc_connected.

I. Relay scheduling mode (i.e., mode 1 or mode 2).

i. For example, the relay UE in mode 1 may use NW-defined values of the starting time slot and/or duration. On the other hand, the relay UE in mode 2 may define the value of the starting slot and/or duration based on other solutions mentioned herein (e.g., sensing configuration, etc.).

The relay UE/WTRU extends the SL time window for paging transmissions.

In one solution, the relay UE may extend one or more instances of a SL time window for paging transmissions to one or more remote UEs, possibly associated with one PO or PF. In particular, the relay UE may perform SL transmissions to one or more remote UEs in order to extend the duration of the SL time window for the transmission, perhaps in the event that the relay UE is unable to transmit the received paging message in the original time window.

The relay UE may trigger such transmissions if the time window has expired or is about to expire and the relay UE has a pending paging message to transmit. The relay UE may trigger such transmissions based on expiration of a timer (e.g., related to the duration of a window), whereby a paging message has not been transmitted when the timer expires. Due to congestion control, the relay UE may trigger transmission of paging messages during a window if such transmission is not possible. The relay UE may transmit such a message if the relay UE performs relay selection at the first window size and the relay selection fails. The relay UE may then perform relay selection with a second window size. The relay UE may perform transmission of the extension message, although limited due to CBR. The relay UE may trigger a paging transmission at the time of the initial scheduled page due to a missed such transmission, as UL is prioritized over SL. The relay UE may extend the time window by a (pre) configured amount after successful transmission of the extension message. Due to the transmission of the extension message, the relay UE may extend an inactivity timer associated with the transmission to the one or more remote UEs.

The extended message may be any of the following transmissions:

a.SL MAC CE。

b. dedicated/independent SCI messages.

Sl RRC message.

Sl Channel State Information (CSI) reporting, which may be proactively provided by a remote UE.

e. A SL wake-up signal or similar SL signal indicating that SL needs to be monitored for a specific DRX cycle (on duration) at the remote UE.

The extended message may indicate the number of time slots that have the window either ended from the initial schedule of the window or extended from the receipt of the message. Alternatively, such a number of time slots may be (pre) configured or exchanged between UEs (e.g. in unicast link setup/configuration).

The reception of the extension message by the remote UE may extend the expected SL paging window duration. For example, receipt of the extended message by the remote UE may result in a reset of the inactivity timer by the remote UE.

The relay UE/WTRU determines whether to discard/delay the paging transmission on SL.

In an alternative solution, the relay UE may discard or delay the transmission of the paging transmission on the SL if the paging transmission on the SL is not performed within the SL paging window. In particular, the relay UE may not be able to perform transmission on the SL during the SL paging window and/or may not be able to transmit the extension message. In this case, the relay UE may discard the paging message. Alternatively, the relay UE may maintain the paging message pending and transmit it during the next SL paging window that may be associated with the same Uu PO/PF. The UE may also determine whether to drop or delay paging depending on:

a.CBR。

b. QoS and/or SLRB configuration at a remote UE.

c. RRC state of relay and/or remote UE.

d. Until the time of the next SL paging window.

Specifically, the UE relay UE may start a timer when initiating the SL paging transmission window. If no paging message is transmitted at the expiration of the timer, the relay UE may discard the message or delay it until the next SL paging transmission window for the message. The relay may discard the paging message if the remote UE does not have any SLRBs configured for high QoS or requiring the paging message to be delayed to the next window.

The relay UE/WTRU transmits paging messages using mode 1/mode 2.

The relay UE in mode 2 may trigger resource selection for transmitting paging messages on the side link when any of the following events occur:

a. the relay UE receives Uu paging messages in a PO associated with one or more of the PC5-RRC connected remote UEs.

b. The relay UE receives Uu paging messages in the POs, with one of the identified UEs in the paging message for one of the connected PC5-RRC connected remote UEs.

c. The relay UE receives Uu paging messages in the PO and an additional indication of the paging messages for one of the connected PC5-RRC connected remote UEs from the network.

i. For example, the relay UE may receive such indication as a set of L2 IDs in an embedded paging message.

For example, the relay UE may receive such indication as a separate RRC message or MAC CE, which may be received in the same time slot, in the same PO, or within a certain time of the reception of the actual paging message.

For example, the relay UE may receive such an indication in the DCI. For example:

1. the relay UE may receive in DCI paging messages scheduled in PDSCH in relation to the relay or should be considered for an indication of relay by the UE configured for relay.

A UE receiving a remote UE ID from the network along with a page and/or indication may trigger a resource reselection.

a. Upon receiving an active paging indication from the network, wherein the PO associated with the attached remote UE is indicated as having an expected paging message.

i. The relay UE may trigger the resource selection immediately.

Alternatively, the relay UE may trigger the resource selection at some later time before the occurrence of the PO/PF or SL paging window.

Upon triggering the resource selection, the relay UE may use the defined SL transmission window as a parameter (e.g., T1/T2) for the resource selection.

In another alternative, the relay UE may trigger transmission of SL UE assistance information upon receiving a page from Uu (in a PO associated with the remote UE) or upon receiving an active paging indication from the network. The relay UE may provide information (e.g., periodicity, location/offset) related to the SL paging window in the UE assistance information. The relay UE may also indicate in the UE assistance information that a grant (CG) of SL configuration is being requested for forwarding the paging message. The relay UE may also indicate in the UE assistance information a specific PF/PO for pages that are expected to be received by the relay UE that needs to relay. The grant of such SL configuration may be provided in a temporary manner (e.g., it may be provided for a pre-configured/predefined number of DRX cycles).

In another alternative, the relay UE may trigger a Scheduling Request (SR) upon receiving a page from Uu (in a PO associated with the remote UE) or upon receiving an active paging indication from the network. Such SRs may be dedicated to indicating a need to relay paging messages. The separate SR may be configured for transmission of paging and for transmission of SI indication and/or PWS. Alternatively, the relay UE may be configured with multiple SR resources/configurations and may select an SR configuration associated with the PF/PO of the associated remote UE, or paging message to be relayed. The relay UE may trigger such SRs if the relay UE potentially does not have SL resources in the SL paging transmission window for transmitting the paging message. Whether the relay UE triggers the SR may depend on whether the relay UE has a side link grant that falls within the configured paging forwarding window. If there is no side chain grant, the relay UE may trigger the SR. Whether the relay UE triggers an SR may depend on the type of page received. For example, if the page is marked as high priority, or if the page message is a PWS indication, the relay UE may trigger the SR, otherwise the relay UE may trigger the SR only if the UE does not have SL grant within the page forwarding window.

In another alternative, the relay UE may receive CG or CG activation along with a Uu paging message. This may be used by relay UEs in rrc_connected. Such CG may be predefined/preconfigured to have its resources appear within the SL paging transmission window.

Relay UE/WTRU uses WUS-like signals to notify remote UE/WTRUs of an upcoming page (seeking in SL In the call window).

In one solution, when a relay UE receives or expects to receive a page for a remote UE, a set of remote UEs, or associated with a paging occasion, the relay UE may transmit a wake-up signal (WUS) like signal on a side link.

In one solution, the relay UE may transmit WUS after receiving an active paging indication message from the network. In particular, the relay UE may determine whether to transmit WUS to one or more remote UEs based on whether an active paging indication from the network indicates that a paging message is to be sent for a particular UE/PO, and the relay UE determines whether the UE is PC5 connected to a relay or that the PO is associated with a relay where PC5 is connected to a relay.

In another solution, the relay UE may transmit WUS after receiving an active paging message from the network. For example, if a paging message is received sometime before the intended remote UE's PO (e.g., for an rrc_connected relay UE), the relay UE may transmit WUS.

The remote UE may be configured with a time window for receiving WUS. In particular, the remote UE may determine the time window from the relay UE. In particular, the remote UE may determine the time window based on its own PO or the PO of the relay UE using a similar mechanism defined herein for determining the start of the SL transmission window. The relay UE may determine a time resource for WUS to receive with respect to its own paging occasion, with respect to the scheduled reception time of an active paging indication from the network, or for transmission at some (pre) configuration or predefined time resource associated with the DRX cycle of the remote UE.

In another solution, the relay UE may potentially transmit a single WUS-like signal on SL to all PC5-CONNECTED remote UEs. Such signals may indicate a particular PO and/or PF that is expected to have an active page. Such signals may indicate particular remote UEs that should monitor the side link during a defined SL paging window in order to potentially receive pages. The relay UE may determine the content of the SL signal based on the received active paging indication received from the network. Upon receiving the WUS-like signal on the SL, the remote UE may determine whether to monitor the SL over a defined SL paging window associated with the PO/PF depending on whether the WUS-like signal indicates that the PO/PF will contain a paging message.

A method for determining whether/when to forward a received paging message.

Relay UE/WTRU provides remoteLinking UE/WTRU ID to NW.

In view of potential security issues (described herein), there is a need for a method for a relay/remote UE to provide a link of a remote UE ID (i.e., 5G-S-TMSI, I-RNTI) for paging with an L2 ID used by the relay UE to address the remote UE, and a need for a method of hiding the remote UE ID from the relay UE.

In one approach, the remote UE may include the source/destination L2 ID to the network along with its connection setup/restoration (which provides the paging UE ID). In this case, the network may establish a link between IDs. When the upper layer changes the L2 ID (e.g., due to a UE ID refresh procedure for the upper layer defined L2 ID), the remote UE may further trigger such a procedure or may trigger transmission of a Uu RRC message.

In another approach, the relay UE may include the source/destination L2 ID to the network along with the receipt of any messages associated with the SL RLC channel associated with the signaling radio bearer (such as SRB 0) transmission of the remote UE. In particular, the relay UE may relay any message on the SL Radio Link Control (RLC) channel dedicated to SRB0 to the network and may include an L2 source/destination ID associated with the unicast link (between the relay and remote UE) in the relayed message.

The relay UE/WTRU receives an individual UE/WTRU ID with a paging message.

In one solution, in addition to the paging message on Uu, the relay UE may also receive a list of L2 source/destination IDs corresponding to any remote UEs paged in the paging message. If the paging message received via Uu contains at least one source/destination ID associated with the remote UE to which the relay is currently connected, the relay UE may forward the paging message over the unicast link on the PC 5. Otherwise, the relay UE may not forward the paging message or may forward the paging message to all remote UEs that may be associated with the PO using broadcast/multicast.

For example, a relay UE in rrc_connected may receive a list of source/destination IDs in a dedicated RRC message containing a paging record.

For example, a relay UE in rrc_idle/rrc_inactive may receive a list of source/destination IDs.

a. In a separate transmission within the remote UE's PO/PF (e.g., using a different RNTI, or using the same P-RNTI used to receive the paging message).

b. Embedded in the paging record itself.

i. For example, the paging record may include an additional field associated with the L2 source/destination ID of each UE in the paging record.

The relay UE/WTRU defines a multicast/multicast UE/WTRU ID for SL paging transmissions.

In one solution, the relay UE may use the multicast/multicast UE ID for transmitting the SL paging message. The upper layer may in particular provide (reserve) an L2 ID for such a purpose. In particular, the relay UE may be configured with a single broadcast/multicast L2 ID for transmitting paging. Alternatively, the relay UE may have a set of broadcast/multicast L2 IDs for transmitting pages, each associated with the transmission of a paging message that is bound to:

PF or PF group.

PO or PO group.

Sl paging transmission window.

The value of ue ID mod K (e.g., k=1024) or similar value that can be used to derive the position of the PO.

In one solution, the relay UE may be assigned a group/pool of L2 IDs and may assign the L2 IDs to specific POs when making a PC5-RRC connection with the remote UE. In particular, the remote UE may provide its PO (or a value that may be used to derive the PO, such as UE ID mod k) to the relay UE during a sidelink configuration after unicast link establishment with the relay. Thus, the relay UE may provide the remote UE with the available L2 IDs from the L2 ID pool in similar PC5-RRC configuration signaling. Upon receiving the L2 ID, the remote UE may monitor/receive Uu pages for the side link from multicast transmissions using the L2 ID as the destination L2 ID in the message. The remote UE may also determine whether a page is for it by checking the paging message for a paging record (i.e., with its I-RNTI or S-TMSI), as it does in Uu.

In another solution, the relay/remote UE may be (pre) configured with a mapping of L2 IDs to POs or PO-related information (e.g., PO index or UE ID mod k). For example, such a mapping may be predefined by a table in the standard. For example, the L2 ID may contain a portion of a PO index or a UE mod K value that allows one or more POs or UE IDs mod K to be mapped to a single L2 ID. For example, such tables may be provided by the network (e.g., in a SIB). While connected to the relay, the remote UE may begin monitoring the SL for a mapped L2 ID of the multicast transmission containing the page. Upon connection to at least one remote UE, the relay UE may perform a transmission multicast transmission (based on the PO, PO index, UE ID mod K, etc.) through a relay paging message having an L2 ID associated with the paging record. The relay UE may also perform such multicast transmissions only within the SL paging window associated with the PO in which the page was received.

The UE may use multicast transmission in paging in some cases and unicast in other cases to forward the page. The condition for forwarding the paging message using unicast or multicast may be related to any one of the following:

a. the RRC state of the relay UE.

i. For example, if the relay is in rrc_connected, the relay UE may send the page using unicast, otherwise multicast may be used.

b. Knowledge of the L2 ID associated with paging.

i. For example, if the relay UE receives the L2 source/destination ID of the UE being paged in a paging message, the relay may transmit using unicast, otherwise it may transmit via multicast.

c. Reliability requirements for paging messages.

i. For example, a high reliability paging message may be transmitted through unicast, and a low reliability paging message may be transmitted through multicast. The relay UE may determine the reliability of the paging message from:

1. paging messages or indications in paging DCI.

2. Configured with SLRBs of any remote UE associated with the paging message.

3. RRC state of any remote UE associated with the paging message.

d. Measured CBR.

i. For example, if CBR is above a threshold, the relay UE may use multicast. Otherwise, the relay UE may forward the paging message using unicast

e. Availability of SL grants in the SL paging window.

i. For example, the relay UE may use unicast if it has sufficient SL grant in the paging window, otherwise it may use multicast

f. The size of the paging message, or the number of paging records in the paging message.

g. Number of remote UEs attached to relay UE.

The relay UE may forward the paging message by unicast or multicast depending on whether the received paging message is associated with an SI modification/PWS notification or with the paging message. In particular, the relay UE may transmit a multicast/broadcast message (using the configured L2 ID) for transmitting SI modifications and/or PWS notifications, while UE paging and/or PWS notifications and/or SI modifications may be transmitted to the particular UE being paged using unicast. The relay UE may include SI modification and/or PWS indications to the UE in unicast and also transmit the SI modification and/or PWS indications to all its remote UEs in multicast/broadcast. For example, if the relay UE has pending SI modifications to transmit, the relay UE may include SI modifications to the remote UE in any unicast transmissions that it may have pending (e.g., UE page forwarding), and also transmit SI modifications in multicast/broadcast at some later time. The relay UE may transmit SI modifications and/or modified SI in multicast/broadcast as long as at least N (where N may be 1 or a configuration value) remote UEs do not receive SI modifications and/or modified SI.

After SI modification or modified SI has been received in unicast, the remote UE may ignore any SI modification indication or modified SI received in multicast/broadcast within the same modification period.

Fig. 5 depicts an exemplary flowchart 500 of a relay UE/WTRU determining allowable SL slots for relaying a paging message to one or more remote UEs associated with the same PO. In one example, the relay UE may be in an rrc_idle/rrc_inactive state to determine allowable SL slots for relaying paging messages to one or more remote UEs associated with the same PO, and may broadcast the relayed paging messages to all remote UEs associated with the PO during those allowable SL slots.

In the example of fig. 5, at 505, a relay UE receives a Paging Occasion (PO) of a connected UE. In one example, the relay UE receives a PO associated with a remote UE of a PC5-RRC connection (e.g., a remote UE in PC5-RRC communication). The reception of the PO information may be transmitted from a remote UE or NW connection.

At 510, the relay UE may assign or configure an L2 destination ID to connected remote UEs sharing the same paging occasion. Here, the UE may be allocated or configured for remote UEs sharing one or more PC5-RRC connections of the same PO. At 515, the relay UE determines the starting slot/offset of the sidelink paging relay cycle. Here, the relay UE may determine a starting slot/offset of the SL paging relay period relative to the paging occasion of the remote UE. The determination may be based on any one or more of a paging search space configuration of the relay UE, an SSB/beam configuration configured at the relay UE for paging, and/or a sensing/partial sensing configuration of the relay UE.

At 520, the relay UE determines the duration of the SL paging relay period. Here, the relay UE may make the duration determination based on the measured CBR. At 525, the relay UE may send/transmit the determined starting slot/offset and duration to the remote UE. In one example, the remote UE is in association with a PC5-RRC message of the relay UE.

In one example, upon receiving a paging message to be relayed on a given Uu PO associated with one or more remote UEs, the relay UE may perform mode 2 resource selection to select SL resources determined by a starting slot/offset and duration. The relay UE may then send/transmit the received paging message on the selected resource using the L2 destination ID associated with the PO.

Fig. 6 depicts an exemplary flowchart 600 of a relay UE/WTRU determining which of NW-configured Paging Occasions (POs) to wake up or monitor in a particular DRX cycle based on an indication of an active PO in an upcoming DRX cycle received during the connected remote UE/WTRU and the PO of the relay UE/WTRU itself. In one example, the relay UE/WTRU operates in an rrc_idle/rrc_inactive state, but has communication with the remote UE/WTRU or may use a PC5-RRC connection to establish or reestablish communication with the remote UE/WTRU.

In the example of fig. 6, at 605, it is assumed that the relay UE/WTRU is configured with/associated with a DRX configuration and paging radio network temporary identifier (P-RNTI). The relay UE/WTRU may use a relay RNTI (R-RNTI) to receive the active PO indication. Optionally, at 610, the relay UE/WTRU may maintain a list of POs associated with each remote UE/WTRU connected to the relay UE/WTRU as needed. The maintaining includes adding or deleting the capability of the PO associated with each remote UE/WTRU having a PC5-RRC connection to the relay UE/WTRU.

At 615, the relay UE/WTRU may monitor a downlink control channel (such as PDCCH) using the R-RNTI to receive the active PO indication. At 620, the relay UE/WTRU detects whether an active PO indication exists. If an active PO indication is not received at 620, the relay UE/WTRU does not wake up at PO for the current DRX cycle of the relay UE/WTRU at 625. If a PO indication is detected at 620, the relay UE/WTRU performs a wake-up at the PO for the current DRX cycle to monitor a downlink control channel (such as PDCCH) at 630. The control channel monitoring uses relay UE/WTRU R-RNTI.

The procedure of the above described illustrative examples and the methods described with respect to the figures may be combined without exception unless explicitly stated otherwise. Thus, for example, the establishment or configuration of paging capability or DRX information may be cooperatively coupled with the reception of SI or paging information by the relay WTRU and the subsequent delivery of SI or paging information to one or more remote WTRUs. In another example of a combination of the described features, the features of message structure, delivery, reception, and timing described above may be combined, unless specifically omitted otherwise in this description.

Fig. 7 depicts an exemplary flowchart 700 of a relay WTRU handling one or both of a system information change and a paging opportunity for a remote WTRU. At 705, a relay WTRU may be configured with Discontinuous Reception (DRX) configurations of one or more remote WTRUs. At 710, the relay WTRU may receive an indication of a Paging Opportunity (PO) for monitoring at least one of the remote WTRUs. At 715, the relay WTRU monitors PO and/or System Information (SI) received by the relay WTRU for at least one of the remote WTRUs. If SI information is received, the relay WTRU may forward the information to the associated remote WTRU at 720. If the relay WTRU receives PO information for the remote WTRU at 715, the relay WTRU may optionally provide an acknowledgement of success or failure of the reception of the PO information at 725. Assuming that the PO information is successfully received for at least one remote WTRU, the relay WTRU may then forward the paging message to the corresponding remote WTRU at 730.

In a paging environment as presented above, a combination of solution features is possible. For example, fig. 8 depicts a method 800 in which a relay UE/WTRU may forward System Information (SI) change information to a remote UE/ETRU based on an indication of a status of the remote UE/WTRU. At 805, the relay UE may receive an indication of a change in state of a remote WTRU having a link with the relay UE (such as a PC5-RRC link supporting paging). For example, the relay UE may receive an indication of a change in state of the remote UE by receiving a PC5 RRC message from the remote UE. The received PC5 RRC message/signaling indicates directly or implicitly to the relay UE the RRC state or state change of the remote UE.

At 810, the relay UE may receive a paging message from a network. The paging message may include a System Information (SI) change indication, wherein the SI change indication indicates availability of updated SI information from the network to the remote UE. The updated SI information is actual SI information. The network may notify the relay UE of the SI information change via an indication in the paging message. The paging message from the network may be a paging short message. The updated SI information available from the network is the actual SI information and the SI change indication is simply an indication that the updated SI information in the paging message is available from the network.

At 815, the relay UE may transmit updated SI information to the remote UE based on the received indication of the change in state of the remote UE. For example, if the received indication of the change of state of the remote UE is associated with sending updated SI information to the remote UE, the relay UE transmits the updated SI information to the remote UE. In another example, if the received indication of the change of state of the remote UE indicates that the remote UE has changed to or is currently in an RRC idle or RRC inactive state, the relay UE transmits updated SI information to the remote UE. In the RRC idle or RRC inactive state, the remote UE relies on the relay UE to provide updated SI data.

Alternatively, if the relay UE determines that the remote UE is in RRC connected state and receives the SI change indication in the paging message, the relay UE may forward the SI change indication to the remote UE instead of forwarding the updated SI data itself. Thus, if the received indication of the change of state of the remote UE indicates that the remote WTRU has changed to a connected state, the relay UE may transmit an SI change indication to the remote UE. In such an instance (of RRC CONNECTED state), the remote UE may obtain the updated SI data/information itself directly from the network.

Another example of a combination of features discussed above is presented in fig. 9. In the example method 900 of fig. 9, a system information type, such as a System Information Block (SIB) type, may be used to forward SI change information from a relay UE/WTRU to a remote UE/WTRU when the remote UE is in an idle or inactive state. At 905, the relay UE has a link with the remote UE (such as a PC5-RRC link supporting paging). The relay UE may determine that the state of the remote UE is one of an idle state or an inactive state. The status of the remote UE may be determined by monitoring signaling of the remote UE. For example, the relay UE may determine the status of the remote UE through RRC messages/signaling. As expressed above, the status of the remote UE may be determined directly from RRC signaling or implicitly using, for example, PC5 RRC signaling. At 910 in fig. 9, a relay UE may receive a paging message from a network. The paging message may include a System Information (SI) change indication. The SI change indication indicates availability of updated SI information from the network to the remote UE. At 915, the relay UE may forward the updated SI information to the remote UE based on one or more of a previous update of the SI information received by the remote UE or a type of SI information change. Thus, forwarding updated SI information to the remote WTRU is performed when one or more of the previous requests for SI information are received from the remote WTRU or when a particular SIB is changed. In one example, when the relay UE receives an indication that an update to SIB information previously received by the remote UE is available, the relay UE may forward actual SI update information (acquired from the network). The forwarding is based on the selected SI information type. For example, SIB updates for the selected type of remote UE that have been previously received by the remote UE may be SI updates of a type that the remote UE is interested in receiving and thus may be forwarded from the relay UE to the remote UE. In another example, a relay UE may be indicated a SIB of a particular type (or a particular SIB) update for a remote UE. One type or specific SIB update that may be forwarded from the relay UE to the remote UE is SIB1. The actual SIB information may be forwarded by the relay UE to the remote UE, either partially or entirely. The forwarding in the above example depends on the remote UE being in an idle or inactive state.

Another example of a combination of the features discussed above is presented in fig. 10. In the exemplary method 1000 of fig. 10, a paging message containing PWS and SI information update indication is processed by a relay UE/WTRU. At 1005 in fig. 10, the relay UE/WTRU receives status information from the remote UE/WTRU. As indicated herein above, the relay UE may directly use RRC signaling to determine the status of the remote UE, or may implicitly determine the status of the remote UE via monitoring the RRC signaling of the remote UE. At 1010, the relay UE may receive the paging short message. The paging short message may include a PWS indication and an SI change indication. At 1015, the relay UE determines whether the received short message contains a PWS indication. If the received paging message has a PWS indication, the relay UE forwards the actual SI update information (acquired from the network) to the remote UE at 1025. If there is no PWS indication in the paging short message at 1015, the relay UE determines whether the remote UE is in a connected state at 1020. If the remote UE is not in a connected state, such as the remote UE is determined to be in an idle or inactive state, the relay UE forwards the actual SI update information (acquired from the network) to the remote UE at 1025. If it is determined at 1020 that the remote UE is in a connected state, the relay UE may forward the received short message to the remote UE. After an affirmative decision at 1020, the remote UE in a connected state may acquire updated SI information (data) from the network.

Conclusion(s)

Although features and elements are provided above in particular combinations, one of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with other features and elements. The present disclosure is not limited to the specific embodiments described in this patent application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from the spirit and scope of the application, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the application unless explicitly described as such. Functionally equivalent methods and apparatus, other than those enumerated herein, which are within the scope of the present disclosure, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It should be understood that the present disclosure is not limited to a particular method or system.

For simplicity, the foregoing embodiments are discussed with respect to the terminology and structure of infrared-capable devices (i.e., infrared emitters and receivers). However, the embodiments discussed are not limited to these systems, but may be applied to other systems using other forms of electromagnetic waves or non-electromagnetic waves (such as acoustic waves).

It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the term "video" or the term "image" may mean any of a snapshot, a single image, and/or multiple images that are displayed on a temporal basis. As another example, as referred to herein, the term "user equipment" and its abbreviation "UE", the term "remote" and/or the term "head mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and/or receive unit (WTRU); (ii) Any of a number of embodiments of the WTRU; (iii) Devices with wireless capabilities and/or with wired capabilities (e.g., tethered) are configured with some or all of the structure and functionality of a WTRU, in particular; (iii) Wireless capability and/or wireline capability devices configured with less than the full structure and functionality of the WTRU; or (iv) etc. Details of an exemplary WTRU that may represent any of the WTRUs described herein are provided herein with respect to fig. 1A-1D. As another example, various disclosed embodiments herein are described above and below as utilizing a head mounted display. Those skilled in the art will recognize that devices other than head mounted displays may be utilized and that some or all of the present disclosure and various disclosed embodiments may be modified accordingly without undue experimentation. Examples of such other devices may include drones or other devices configured to stream information to provide an adapted real-world experience.

Additionally, the methods provided herein may be implemented in a computer program, software, or firmware incorporated in a computer readable medium for execution by a computer or processor. Examples of computer readable media include electronic signals (transmitted over a wired or wireless connection) and computer readable storage media. Examples of computer readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and Digital Versatile Disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Variations of the methods, apparatus, and systems provided above are possible without departing from the scope of the invention. In view of the various embodiments that may be employed, it should be understood that the illustrated embodiments are examples only and should not be taken as limiting the scope of the following claims. For example, embodiments provided herein include a handheld device that may include or be used with any suitable voltage source (such as a battery or the like) that provides any suitable voltage.

Furthermore, in the embodiments provided above, processing platforms, computing systems, controllers, and other devices including processors are indicated. These devices may include at least one central processing unit ("CPU") and memory. References to actions and symbolic representations of operations or instructions may be performed by various CPUs and memories in accordance with practices of persons skilled in the art of computer programming. Such acts and operations, or instructions, may be considered to be "executing," computer-executed, "or" CPU-executed.

Those of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. The electrical system represents data bits that may result in a final transformation of the electrical signal or a reduction of the electrical signal and a retention of the data bits at memory locations in the memory system, thereby reconfiguring or otherwise altering the operation of the CPU and performing other processing of the signal. The memory location holding the data bit is a physical location having a particular electrical, magnetic, optical, or organic attribute corresponding to or representing the data bit. It should be understood that embodiments are not limited to the above-described platforms or CPUs, and that other platforms and CPUs may also support the provided methods.

The data bits may also be maintained on computer readable media including magnetic disks, optical disks, and any other volatile (e.g., random access memory ("RAM")) or non-volatile (e.g., read only memory ("ROM")) mass storage system readable by the CPU. The computer readable media may comprise cooperating or interconnected computer readable media that reside exclusively on the processing system or are distributed among a plurality of interconnected processing systems, which may be local or remote relative to the processing system. It should be understood that embodiments are not limited to the above-described memories, and that other platforms and memories may support the provided methods.

In an exemplary embodiment, any of the operations, processes, etc. described herein may be implemented as computer readable instructions stored on a computer readable medium. The computer readable instructions may be executed by a processor of the mobile unit, the network element, and/or any other computing device.

There is little distinction between hardware implementations and software implementations of aspects of the system. The use of hardware or software is often (but not always, as in some contexts the choice between hardware and software may become important) a design choice representing a tradeoff between cost and efficiency. There may be various media (e.g., hardware, software, and/or firmware) that may implement the processes and/or systems and/or other techniques described herein, and the preferred media may vary with the context in which the processes and/or systems and/or other techniques are deployed. For example, if the implementer determines that speed and accuracy are paramount, the implementer may opt for a medium of mainly hardware and/or firmware. If flexibility is paramount, the implementer may opt for a particular implementation of mainly software. Alternatively, the implementer may opt for some combination of hardware, software, and/or firmware.

The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Where such block diagrams, flowcharts, and/or examples include one or more functions and/or operations, it will be understood by those skilled in the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In an embodiment, portions of the subject matter described herein may be implemented via an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), and/or other integrated format. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and/or firmware would be well within the skill of one of skill in the art in light of this disclosure. Furthermore, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing media used to actually carry out the distribution. Examples of signal bearing media include, but are not limited to, the following: recordable type media (such as floppy disks, hard disk drives, CDs, DVDs, digital tapes, computer memory, etc.); and transmission type media such as digital and/or analog communications media (e.g., fiber optic cable, waveguide, wired communications link, wireless communications link, etc.).

Those skilled in the art will recognize that it is common in the art to describe devices and/or processes in the manner set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. Those skilled in the art will recognize that a typical data processing system may generally include one or more of the following: a system unit housing; a video display device; memories such as volatile memories and nonvolatile memories; a processor, such as a microprocessor and a digital signal processor; computing entities such as operating systems, drivers, graphical user interfaces, and applications; one or more interactive devices, such as a touch pad or screen; and/or a control system comprising a feedback loop and a control motor (e.g. feedback for sensing position and/or speed, a control motor for moving and/or adjusting components and/or amounts). Typical data processing systems may be implemented using any suitable commercially available components, such as those typically found in data computing/communication and/or network computing/communication systems.

The subject matter described herein sometimes illustrates different components included within or connected with different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Thus, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include, but are not limited to, physically mateable and/or physically interactable components and/or wirelessly interactable components and/or logically interactable components.

With respect to substantially any plural and/or singular terms used herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. For clarity, various singular/plural permutations may be explicitly listed herein.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "comprising" should be interpreted as "including but not limited to," etc.). It will be further understood by those with skill in the art that if a specific number of an introduced claim recitation is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, where only one item is contemplated, the term "single" or similar language may be used. To facilitate understanding, the following appended claims and/or descriptions herein may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation object by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation object to embodiments containing only one such recitation object. Even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"). The same holds true for the use of definite articles used to introduce claim recitations. Furthermore, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). In addition, in those instances where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction has the meaning that one having skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B and C together, etc.). In those instances where a convention analogous to "at least one of A, B or C, etc." is used, in general such a construction has the meaning that one having skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B and C together, etc.). It should also be understood by those within the art that virtually any separate word and/or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "a or B" will be understood to include the possibilities of "a" or "B" or "a and B". In addition, as used herein, the term "…" followed by listing a plurality of items and/or a plurality of item categories is intended to include items and/or item categories "any one of", "any combination of", "any multiple of" and/or any combination of multiples of "alone or in combination with other items and/or other item categories. Furthermore, as used herein, the term "group" is intended to include any number of items, including zero. Furthermore, as used herein, the term "number" is intended to include any number, including zero. Also, as used herein, the term "multiple" is intended to be synonymous with "multiple".

Further, where features or aspects of the present disclosure are described in terms of markush groups, those skilled in the art will recognize thereby that the present disclosure is also described in terms of any individual member or subgroup of members of the markush group.

As will be understood by those skilled in the art, for any and all purposes (such as in terms of providing a written description), all ranges disclosed herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof. Any listed range can be readily identified as sufficiently descriptive and so that the same range can be divided into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily divided into a lower third, a middle third, an upper third, and the like. As will also be understood by those skilled in the art, all language such as "up to", "at least", "greater than", "less than", etc., include the recited numbers and refer to ranges that may be subsequently divided into sub-ranges as described above. Finally, as will be understood by those skilled in the art, the scope includes each individual number. Thus, for example, a group having 1 to 3 units refers to a group having 1, 2, or 3 units. Similarly, a group having 1 to 5 units refers to a group having 1, 2, 3, 4, or 5 units, or the like.

Furthermore, the claims should not be read as limited to the order or elements provided, unless stated to that effect.

Claims

1. A method performed by a relay wireless transmit/receive unit, WTRU, the method comprising:

receiving an indication of a change in state of a remote WTRU having a link with the relay WTRU;

receiving a paging message from a network, the paging message including a system information, SI, change indication, wherein the SI change indication indicates availability of updated SI information from the network to the remote WTRU;

the updated SI information is transmitted to the remote WTRU based on the received indication of the change in state of the remote WTRU.

2. The method of claim 1 wherein receiving the indication of the change in status of the remote WTRU comprises receiving a PC5 radio resource control message.

3. The method of claim 1, wherein the indication to receive the state change is a change in a radio resource control state of the remote WTRU.

4. The method of claim 1, wherein receiving the paging message from the network comprises receiving a paging short message.

5. The method of claim 1, wherein transmitting the updated SI information to the remote WTRU is performed if the received indication of the remote WTRU state change is associated with transmitting the updated SI information to the remote WTRU.

6. The method of claim 1, wherein transmitting the updated SI information to the remote WTRU is performed if the received indication of the change of state of the remote WTRU includes the remote WTRU changing to an idle state or an inactive state.

7. The method of claim 1, the method further comprising:

the SI change indication is transmitted to the remote WTRU if the received indication of the change in status of the remote WTRU is associated with sending the change indication to the remote WTRU instead of sending the updated SI information.

8. The method of claim 7, wherein transmitting the SI change indication to the remote WTRU is performed if the received indication of the change in state of the remote WTRU includes the remote WTRU changing to a connected state.

9. A method performed by a relay wireless transmit/receive unit, WTRU, the method comprising:

determining that a state of a remote WTRU having a link with the relay WTRU is one of an idle state or an inactive state;

receiving a paging message from a network, the paging message having a system information, SI, change indication, wherein the SI change indication indicates availability of updated SI information from the network to the remote WTRU;

The updated SI information is forwarded to the remote WTRU when one or more of the previous requests for SI information are received from the remote WTRU or when a particular system information block SIB is changed.

10. The method of claim 9, wherein receiving the paging message with the SI change indication comprises receiving a system information block change indication.

11. The method of claim 9, wherein forwarding the updated SI information to the remote WTRU comprises forwarding a selected type of system information block.

12. The method of claim 9, wherein forwarding the updated SI information to the remote WTRU comprises forwarding a complete SIB1 or a portion of the SIB 1.

13. A relay wireless transmit/receive unit, WTRU, the relay WTRU comprising circuitry including a transmitter, a receiver, a processor, and a memory, the relay WTRU configured to:

performing the method according to any one of claims 1 to 8.

14. A relay wireless transmit/receive unit, WTRU, the relay WTRU comprising circuitry including a transmitter, a receiver, a processor, and a memory, the relay WTRU configured to:

Method according to any of claims 9 to 12.

15. A non-transitory computer readable medium having instructions which, when executed by a processor, perform the method of any one of claims 1 to 8.

16. A non-transitory computer readable medium having instructions therein, which when executed by a processor perform the method of any of claims 9 to 12.