WO2018204351A1 - Synchronization signal multiplexing and mappings in nr - Google Patents

Abstract

A wireless transmit/receive unit (WTRU) and a method implemented in the WTRU for receiving a plurality of messages from a base station. The messages include an indication of a synchronization signal (SS) and physical broadcast channel (PBCH) (SS/PBCH) block to be monitored. The SS/PBCH block may be used by the WTRU to acquire the primary synchronization signal (PSS) and secondary synchronization signal (SSS) at a fixed location within the indicated SS/PBCH block. Next the WTRU may acquire one or more PBCHs and then an entire SS/PBCH block based on the determined SS/PBCH block type. The SS/PBCH block includes 4 symbols and the PBCH may be located on 3 of the 4 symbols and the PSS and SSS are each located on a different one of the four symbols from each other. The PBCH symbols may each include its own frequency-multiplexed demodulation reference symbols (DMRS).

Description

SYNCHRONIZATION SIGNAL MULTIPLEXING AND MAPPINGS IN NR

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional application Nos. 62/492,711 filed May 1, 2017; 62/543,266 filed August 9, 2017; 62/586,016 filed November 14, 2017, the contents of which are hereby incorporated by reference herein.

BACKGROUND

[0002] There may be many uses for a 5th generation of a wireless communication protocol. Some of those uses may be Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC) and Ultra Reliable and Low latency Communications (URLLC). Different use cases may focus on different requirements such as higher data rate, higher spectrum efficiency, low power and higher energy efficiency, lower latency and higher reliability. A wide range of spectrum bands ranging from 700 MHz to 80 GHz are being considered for a variety of deployment scenarios. In any of these use cases, there may be a need for a protocol to handle the organization of the transmission of wireless signals.

SUMMARY

[0003] A wireless transmit/receive unit (WTRU) and a method implemented in the WTRU for receiving a plurality of messages from a base station is disclosed. The messages include an indication of a synchronization signal (SS) and physical broadcast channel (PBCH) (SS/PBCH) block to be monitored. The SS/PBCH block may be used by the WTRU to acquire the primary synchronization signal (PSS) and secondary synchronization signal (SSS) at a fixed location within the indicated SS/PBCH block. Next the WTRU may acquire one or more PBCHs and then an entire SS/PBCH block based on the determined SS/PBCH block type. The SS/PBCH block includes 4 symbols and the PBCH may be located on 3 of the 4 symbols and the PSS and SSS are each located on a different one of the four symbols from each other. The PBCH symbols may each include its own frequency-multiplexed demodulation reference symbols (DMRS). Also, the PBCH may include a DMRS located on resources that determined as a function of an OFDM symbol index. Also, the SSS may be located on a symbol between two symbols that each include the PBCH. Alos the the PSS and SSS may located on subcarriers between 56 and 182 in their respective symbols. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

[0005] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0006] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit

(WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0007] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0008] FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0009] FIG. 2 illustrates an example of SS burst and SS block;

[0010] FIGS. 3A-3L illustrate examples of an example SS block design;

[0011] FIGS. 4A-4B illustrate examples of an SS block design;

[0012] FIG. 5A illustrates an example of an example SS block design carrying PBCH,

PSS, and SSS;

[0013] FIG. 5B illustrates an example of a special SS block carrying DL control channel;

[0014] FIG. 5C illustrates an example of a special SS block carrying UL control channel;

[0015] FIG. 5D illustrates an example of a special SS block carrying mini-slot;

[0016] FIG. 5E illustrates an example of a blank SS block carrying empty OFDM symbols;

[0017] FIGS. 6A-6F illustrate examples of mapping SS block types to slots;

[0018] FIGS. 7A-7D illustrate examples of regular SS block mappings to a SS burst set with common periodicity of 2 radio frames and L=1, 2, 4, and 8, respectively;

[0019] FIGS. 8 and 9 are flow diagrams of two exemplary SI/OSI delivery approaches; and

[0020] FIG. 10 is a flow diagram of an example process for receiving a PDCH or SS/PBCH

Block.

DETAILED DESCRIPTION

[0021] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 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.

[0022] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a CN 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated 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. By way of 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 a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0023] The communications systems 100 may also include a base station 114a and/or a 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 a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0024] The base station 114a may be part of the RAN 104/113, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and/or the 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 a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the 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 the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0025] 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, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0026] More specifically, as noted above, the communications 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, and the like. For example, the 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 establish the air interface 115/116/117 using wideband CDMA (WCDMA). 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).

[0027] 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 establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using New Radio (NR).

[0029] In an embodiment, 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, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by 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., a eNB and a gNB).

[0030] 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, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0031] The base station 114b in FIG. 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one 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 picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106/115.

[0032] The RAN 104/113 may be in communication with the CN 106/115, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency 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, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0033] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c,

102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/113 or a different RAT.

[0034] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications 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 the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0035] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG.

1 B, 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 peripherals 138, among others. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0036] 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, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0037] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) 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 transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0038] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, 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.

[0039] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0040] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or 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. In addition, 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. The 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 access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0041] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the 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 cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0042] The processor 118 may also be coupled to the 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, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0043] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor.

[0044] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit 139 to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0045] FIG. 1 C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0046] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the 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 for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0047] Each of the eNode-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 the UL and/or DL, and the like. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0048] The CN 106 shown in FIG. 1 C 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 will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0049] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the

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

[0050] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the

RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0051] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs

102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0052] The CN 106 may facilitate communications with other networks. For example, the

CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications 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 the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

[0053] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0054] In representative embodiments, the other network 112 may be a WLAN.

[0055] A WLAN in 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 an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. 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 deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer- to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad-hoc" mode of communication. [0056] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0057] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0058] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or

160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0059] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11 η, and 802.11 ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life). [0060] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 η, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0061] In the United States, the available frequency bands, which may be used by

802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0062] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0063] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one 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 the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. 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 unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0064] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0065] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs

102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0066] 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 the UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0067] The CN 115 shown in FIG. 1 D 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. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0068] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b,

180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and/or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi.

[0069] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0070] The UPF 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 packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi- homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0071] 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 the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0072] In view of Figures 1A-1 D, and the corresponding description of Figures 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0073] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, 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 may perform the one or more, 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 purposes of testing and/or may performing testing using over-the-air wireless communications.

[0074] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0075] Based on the general requirements set out by ITU-R, NGMN and 3GPP, a broad classification of the use cases for emerging 5G systems may be depicted as follows: Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC) and Ultra Reliable and Low latency Communications (URLLC). Different use cases may focus on different requirements such as higher data rate, higher spectrum efficiency, low power and higher energy efficiency, lower latency and higher reliability. A wide range of spectrum bands ranging from 700 MHz to 80 GHz are being considered for a variety of deployment scenarios.

[0076] In some cases, as the carrier frequency increases, severe path loss may become a crucial limitation to guarantee sufficient coverage area. Transmission in millimeter wave systems could additionally suffer from non-line-of-sight losses, for example, diffraction loss, penetration loss, Oxygen absorption loss, and foliage loss.. During an initial access, a base station and a WTRU need to overcome these high path losses and discover each other. For example, utilizing multiple antenna elements to generate a beam-formed signal is an effective way to compensate the severe path losses by providing a significant beamforming gain. Beamforming techniques may include digital, analogue, or hybrid beamforming.

[0077] Cell search is the procedure by which a WTRU acquires time and frequency synchronization with a cell and detects the Cell ID. In LTE, synchronization signals may be transmitted in the 0th and 5th subframes of every radio frame and are used for time and frequency synchronization during initialization. As part of a system acquisition process, a WTRU may synchronize sequentially to the OFDM symbol, slot, subframe, half-frame, and radio frame, based on the synchronization signals, which are Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS). A PSS may be used to obtain slot, subframe and half-frame boundary. The PSS also provides physical layer cell identity (PCI) within a cell identity group. A SSS may be used to obtain the radio frame boundary. The SSS further enables a WTRU to determine a cell identity group, which may range from 0 to 167.

[0078] After a successful synchronization and a physical layer cell identity (PCI) acquisition, the WTRU decodes the Physical Broadcast Channel (PBCH) with the help of Cell specific Reference Signal (CRS) and acquire the Master Information Block (MIB) regarding system bandwidth, System Frame Number (SFN) and Physical Hybrid-ARQ Indicator Channel (PHICH) configuration.

[0079] In LTE, the synchronization signals (PSS and SSS) and PBCH may be transmitted continuously according to a standardized periodicity. In LTE, a single transmission beam is used for initial access. In 5G NR, multi-beams are employed and concepts of synchronization signal block (SS block) and synchronization signal burst (SS burst) are introduced to support the multi-beams. Efficient and flexible design of SS block is needed to enable fast acquisition, low complexity, and accurate detection. [0080] SS blocks are included in a SS burst for initial access by using the multi-beams.

The SS burst may be transmitted periodically (e.g., every 20ms) and the SS burst may include one or more SS blocks.

[0081] The SS blocks in a SS burst may each be associated with one or more beams. The number of the SS blocks in one SS burst may be determined by a gNB, based on the number of beams used at the gNB. For example, if N beams are used at a gNB, N SS blocks may be used or transmitted in a SS burst.

[0082] Each SS block may include at least one PSS, at least one SSS, and at least one physical broadcast channel (PBCH). FIG. 2 shows an example SS burst 200 in 5G NR with x ms cycle and multiple SS blocks in a SS burst. That is, one SS burst comprises multiple (N) SS blocks, which further comprises PSS, SSS, and PBCH.

[0083] Examples disclosed herein may apply to NR designs for initial access, and synchronization signals and channels. In particular examples are described for: SS blocks design including multiplexing of OFDM symbols for different signals; multiplexing and mappings of SS blocks to slots and subframes; designs for special SS blocks, regular SS blocks, and blank SS blocks; and multiplexing and mappings of SS bursts to radio frame and SS burst set. It should be noted that multiple blocks, channels, and OFDM symbols are described in the order from left to right.

[0084] FIGS. 3A-3L illustrate various examples of a example SS block design.

[0085] In FIG. 3A, an example SS block comprises two PBCHs 302 and 304, a PSS 306, and a SSS 308, which are arranged in the order of the PSS, the PBCH, the SSS, and the PBCH in a time domain.

[0086] In FIG. 3B, an example SS block comprises three PBCHs 302, 304, and 310, a

PSS, and a SSS, which are arranged in the order of the PSS, the PBCH, the SSS, the PBCH, and the PBCH.

[0087] In FIG. 3C, an example SS block comprises four PBCHs, a PSS, and a SSS, where the SSS is located between two consecutive PBCHs 312 and 314, which are arranged in the order of the PSS, the PBCH, the PBCH, the SSS, the PBCH, and the PBCH.

[0088] In FIG. 3D, an example SS block comprises four PBCHs, a PSS, and a SSS, where the SSS is located between one PBCH and three consecutive PBCHs, which are arranged in the order of the PSS, the PBCH, the SSS, the PBCH, the PBCH, and the PBCH.

[0089] In FIG 3E, an example SS block comprises two PBCHs and two SSSs, which are arranged in the order of the PBCH, the SSS, the PBCH, and the PSS. [0090] In FIGS 3F and 3G, an example SS block comprises two PBCHs and a SSS/a PSS located between the two PBCHs.

[0091] In FIG 3H, an example SS block comprises two consecutive PBCHs and a SSS/a

PSS located left to the two consecutive PBCHs, which are arranged in the order of the PBCH, the PSS, the SSS, and the PBCH.

[0092] In FIG 3I, an example SS block comprises two consecutive PBCHs and a SSS/a

PSS located right to the two consecutive PBCHs, which are arranged in the order of the PBCH, the PBCH, the SSS, and the PSS.

[0093] In FIG 3J, an example SS block comprises two PBCHs, a PSS, and a combination of a SSS and two paging channels located between the two PBCHs, which are arranged in the order of the PSS, the PBCH, the paging/the SSS/the paging, and the PBCH. It should be noted that in any of Figures 3A-3K, the paging may be replaced with another signal or channel such as PBCH or CSI- RS.

[0094] In FIG 3L, an example SS block comprises two PBCHs, a PSS, and a combination of a SSS and two other signals or channels (OSC) located between the two PBCHs, which are arranged in the order of the PSS, the PBCH, the OSC/the SSS/the OSC, and the PBCH. If OSC is Paging, it becomes Fig 3J. If OSC is CSI-RS, it becomes Fig 3K. If OSC is PBCH, it becomes Fig 4B. A gap between OSC and SSS may be used. For example, K null subcarriers (empty subcarriers) may be used between OSC and SSS. For another example, K1 null subcarriers (empty subcarriers) may be used between OSC1 (top OSC) and SSS and K2 null subcarriers (empty subcarriers) may be used between SSS and OSC2 (bottom OSC). K1 may be equal to K2. Null subcarriers may be applied when OSC is PBCH, Paging, CSI-RS or other signal/channel.

[0095] In FIG 3K, an example SS block comprises two PBCHs, a PSS, and a combination of a SSS and two channel state information reference signals (CSI-RSs), 320 and 322, located between the two PBCHs, which are arranged in the order of the PSS, the PBCH, the CSI-RS/the SSS/the CSI-RS, and the PBCH. This is the case where paging is replaced with CSI-RS, or OSC is a CSI-RS in Fig 3J.

[0096] An example SS block illustrated in FIGS 3A-3K may comprise N_reg OFDM symbols. N_reg may be equal to four. In FIG. 3A, an example SS block may comprise one OFDM symbol for a PSS, one OFDM symbol for a SSS, and two OFDM symbols for a PBCH. N_PBCH subcarriers may be used for the PBCH while N_ss subcarriers may be used for either PSS or SSS. For example, N_PBCH = 288 subcarriers may be used for a PBCH while N_ss = 144 subcarriers may be used for either PSS or SSS. The design principle is to have PBCH closer to SSS as much as possible.

[0097] The multiplexing may be extended to N PBCH OFDM symbols where N>2, as shown in FIGS 3B-3D. Example SS blocks have N=3 PBCH OFDM symbols (FIG. 3B), N=4 PBCH OFDM symbols (alt 1) (FIG. 3C), and N=4 PBCH OFDM symbols (alt 2) (FIG. 3D). FIG. 3E shows an example SS block where the PSS and SSS may be swapped. The design principle is to keep SSS closer to PBCH.

[0098] In 3F, PBCH may be placed on both sides while keeping PSS and SSS in between the PBCHs. Alternatively, PSS and SSS may be swapped as illustrated in FIG. 3G.

[0099] FIGS. 3H and 3I show that two consecutive PBCHs may be placed on one side while keeping PSS and SSS on the other side. The design principle in FIG. 3H is to keep PSS closer to SSS and at the same time keep SSS closer to PBCHs. Alternatively, as illustrated in FIG 3I, PSS and SSS may be swapped. The design principle is again to keep PSS closer to SSS and at the same time keep SSS closer to PBCHs. Therefore, when swapping PSS and SSS, the PBCHs are also moved to the other side.

[0100] FIG. 3J shows an example having a paging channel, which may occur in a certain frame. When a paging channel occurs, the paging channel may be multiplexed within an example SS block. The paging channel may be placed on one side or both sides of SSS in frequency domain in the same OFDM symbol.

[0101] FIG. 3K shows an example having a channel state information reference signal

(CSI-RS), which may be placed in a regular or special SS block. In such case, the CSI-RS may be multiplexed with a SSS in a frequency division multiplexing (FDM) fashion. The CSI-RS may be placed on one side or both sides of the SSS in a frequency domain in the same OFDM symbol. The CSI-RS may also be replaced with a mobility reference signal (MRS) if needed.

[0102] FIGS. 4A and 4B show example SS/PBCH blocks 400A, 400B in the time- frequency structure. In FIG. 4A, each SS/PBCH block (402, 404, 406, 408) may comprise 4 OFDM symbols in the time domain. The SS/PBCH blocks 404 and 408 comprise PBCH only, while the SS/PBCH block 402 comprises PBCH/PSS/PBCH and the SS/PBCH block 406 comprises PBCH/SSS/PBCH. FIG. 4B illustrates another combination of the SS/PBCH blocks 400B: PSS only; PBCH only; PBCH/SSS/PBCH; PBCH (from left to right). This is the case where paging is replaced with PBCH in Fig 3J, or OSC is a PBCH in Fig 3L. K subcarriers may be used between SSS and PBCH. For example, K subcarriers may be used between PBCH (top PBCH) and SSS in FIG 4B. Another K subcarriers may be used between PBCH (bottom PBCH) and SSS in FIG 4B. [0103] The PSS, the SSS, and the PBCH in FIG. 4A, which are associated with PBCH- specific demodulation reference signal (DMRS), may occupy different symbols shown in Table 1 below:

Table 1 : Resources within a SS/PBCH block (in FIG 4A) for PSS, SSS, PBCH, and DMRS for

PBCH

[0104] In the example shown in FIG. 4A, in the frequency domain, each block (402, 404,

406, 408) may comprise 240 contiguous subcarriers numbered in increasing order from 0 to 239 within each block (402, 404, 406, 408). A subcarrier ^k in the block may correspond to a subcarrier

SSB TI T-RB . 7 SSB 7 /n 1

^{PRB sc 0} in resource block ^PRB where ° ^e >"

and subcarriers are expressed in the SCS used for the block. [0105] FIG. 4B shows another example of an SS block design taking into account time- frequency structure. Just like the SS/PBCH blocks in FIG. 4A, the SS/PBCH blocks in FIG. 4B may also comprise 4 OFDM symbols numbered in increasing order from 0 to 3 and include a PSS, a SSS, or a PBCH as shown in FIG. 4B. Within the SS/PBCH block, the PSS, the SSS, or the PBCH, which are associated with PBCH-specific DMRS, may occupy different symbols shown in Table 2 below:

Table 2: Resources within an SS/PBCH block (in FIG. 4B) for PSS, SSS, PBCH, and DMRS or

PBCH

[0106] In the frequency domain, an SS/PBCH block in FIG. 4B may comprise 216 contiguous subcarriers with the subcarriers numbered in increasing order from 0 to 215 within the SS/PBCH block. Subcarrier k in an SS/PBCH block may correspond to subcarrier p^N^ +k₀ in resource block «pj¾ where k₀ e {0,1, 2,...,11} and subcarriers are expressed in the SCS used for the SS/PBCH block.

[0107] For an SS/PBCH block, the WTRU may assume a single antenna port (where p represents the port number), SCS configuration // e {0,1,3,4}, and the same cyclic prefix (CP) length and SCS for the PSS, SSS, and PBCH. The WTRU may assume that SS/PBCH blocks transmitted with the same SS block time index within a SS/PBCH burst set periodicity are quasi co-located (QCL-ed) with respect to Doppler spread, Doppler shift, average gain, average delay, and spatial RX parameters. The WTRU may not assume QCL for any other SS/PBCH block transmissions.

[0108] For mapping of a PSS within an SS/PBCH block, the WTRU may assume the sequence of symbols J_PSS(0),...,</_PSS(126) constituting the PSS to be scaled by a PSS power allocation factor /½ and mapped to resource elements (REs) {k,l)_{P M} in increasing order of k where k and / may be given by Table 1 and Table 2 and represent the frequency and time indices, respectively, within one SS/PBCH block.

[0109] For mapping of a SSS within an SS/PBCH block, the WTRU may assume the sequence of symbols _SSS(0),..., _SSS(126) constituting the SSS to be scaled by a SSS power allocation factor /¾ and mapped to resource elements {Κή_ρ,μ in increasing order of k where k and / may be given by Table 1 and Table 2 and represent the frequency and time indices, respectively, within one SS/PBCH block.

[01 10] For mapping a PBCH and a DMRS within an SS/PBCH block, a WTRU may assume the sequence of complex-valued symbols ^^PBCH^⁰^ - '^^PBCH(-^{Ms mb} ^ constituting the PBCH to be scaled by a PBCH power allocation factor ^ _ancj mapped in sequence starting with ^ ⁰) to resource elements ^^ρ·^μ which are not used for PBCH DMRS.

[01 1 1] The mapping to resource elements not reserved for other purposes may be in the increasing order of the first index ^k in frequency and then the index ¹ in time, where ^k and ¹ represent the frequency and time indices, respectively, within one SS/PBCH block and may be given by Table 1 and Table 2.

[01 12] The WTRU may assume the sequence of complex-valued symbols ^Γ/(°)'···'^Γ/ (¹⁴³) constituting the DMRS for the SS/PBCH block to be scaled by a PBCH DMRS power allocation factor of ^ _ancj mapped to resource elements ' '^ρ-^μ in the increasing order of first ^k and then ¹ where ^k and ¹ are given by Table 1 and Table 2 with ^{v _ /V}ID ^moa4 and represent the frequency and time indices, respectively, within one SS/PBCH block. The time-domain locations that a WTRU monitors for a possible SS/PBCH block may be predetermined.

[0113] In another example, different types of SS blocks and their mapping to slots and subframes may be addressed. Types of SS blocks may include special SS blocks, regular SS blocks, blank SS blocks, and measurement SS blocks.

[0114] Regular SS blocks may be used to carry a NR primary synchronization signal

(PSS), secondary synchronization signal (SSS), or a physical broadcast channel (PBCH).

[0115] Special SS blocks may be used to carry downlink (DL) control channels and uplink

(UL) control channels. Special SS blocks may be used to carry paging channels. In addition, special SS blocks may be used to carry one or more mini-slots.

[0116] Blank SS blocks may be used to reserve the resources for future proof and forward compatibility. Blank SS blocks may be empty or almost empty depending on their designs.

[0117] Measurement SS blocks may be used to carry MRS or channel state information reference signals (CSI-RS).

[0118] FIG. 5A shows an example regular SS block 500A comprising N_reg OFDM symbols, where N_reg is equal to four (4). The regular SS block may comprise one OFDM symbol for a PSS, one OFDM symbol for a SSS and two OFDM symbols for a PBCH, as described previously. As shown in FIG. 5A, the PSS, the SSS and the PBCH may be arranged in the order of the PSS, the PBCH, the SSS, and the PBCH.

[0119] FIG. 5B shows an example special SS block 500B carrying DL control channels.

FIG. 5C shows another special SS block 500C carrying UL control channels. A special SS block may comprise N_spec OFDM symbol to carry a DL control channel, a paging channel, or a UL control channel. N_spec is equal to two (2). As shown in FIGS. 5B and 5C, the special SS block may comprise two OFDM symbols for the DL control channel or the UL control channel, respectively.

[0120] FIG. 5D shows an example special SS block 500D carrying mini-slots comprising two (Nspec) OFDM symbols. FIG. 5E shows an example blank SS block 500E carrying empty two {Nmank) OFDM symbols.

[0121] FIGS. 6A-6F illustrate various examples 600A-600F of combining the blocks in

FIGS 5A-5E. FIG. 6A illustrates an example SS block 600A that combines one DL control channel 614 (a special SS block shown in FIG. 5B), two PSS/PBCH/SSS blocks 602, 604 (two regular SS blocks shown in FIG. 5A), one blank SS block 602 (shown in FIG. 5E), and one UL control channel 616 (a special SS block shown in FIG. 5C). Those blocks may comprise 2, 4+4, 2, and 2 OFDM symbols, respectively.

[0122] FIGS. 6B-6F illustrate different example combinations of the SS blocks included in

FIG. 6A. FIG. 6B shows a different example SS block 600B, where the blank SS block 606 is moved to a position between the two PSS/PBCH/SSS blocks 602, 604. FIG. 6C shows another different example SS block 600C, where the blank SS block 606 is split into two and each of the split portion 608, 610 (each corresponding to one OFDM symbol) is located at a position right of the regular PSS/PBCH/SSS blocks 602, 604. In FIG. 6D, the consecutive regular PSS/PBCH/SSS blocks 602, 604 are located between one split portion 608 and another split portion 610 of the blank SS block. In FIG. 6E, the blank SS block 606 is located at a position before the two consecutive PSS/PBCH/SSS blocks 602, 604. FIG. 6F illustrates a combination of the blocks similar to that in FIG. 6A, except that the DL control channel 614 is replaced with the mini-slot channel 612. SS blocks discussed above may be included in one or multiple SS bursts (a SS burst set). The SS burst set may be placed within a radio frame. Under different scenarios, 'consecutive or localized' or 'non-consecutive or distributed' methods may be used.

[0123] For consecutive or localized methods, SS blocks or SS bursts may be arranged from the beginning of every P radio frame until all the SS blocks or SS bursts have been consumed. P may be 0.5, 1 , 2, 4, 8 and 16. There may be some offset for SS blocks or SS bursts from the beginning of the radio frame. Such offset may have zero or non-zero value. There may be some gap between two consecutive SS blocks or SS bursts. For non-consecutive or distributed methods SS bursts may be arranged from the beginning of a SS burst set and distributed uniformly within the SS burst set. Based on the SS burst set periodicity, a number of SS bursts may be defined accordingly. For example, for a SS burst set periodicity of N_{radio frames}, a total N_{radio frames} SS bursts for each SS burst set may be defined.

[0124] For L SS blocks and N_ss__bursts SS bursts within a SS burst set, the number of SS blocks for each SS burst may be determined by

L

Nss_blocks — 77

l ^lSS_bursts

[0125] For L SS blocks and when N_ss__bursts = N_{radio frame} within a SS burst set, the number of SS blocks for each SS burst may be determined by

L [0126] SS burst set may comprise one or multiple SS blocks placed within a SS burst set periodicity. For example, a SS burst set may comprise L SS blocks and L may be equal to 1 , 2, 4, 8 or 64. The SS burst set periodicity may be N_{radi0 frame} , which is equal to two radio frames.

[0127] FIGS. 7A-7D illustrate examples of regular SS block mappings to a SS burst set. In

FIG. 7A, when L=1 , a single SS block may be placed within a SS burst set periodicity of 2 radio frames, e.g., in the beginning of the periodicity cycle. In FIG. 7B, when L=2, two SS blocks may be placed within the SS burst set periodicity of 2 radio frames, e.g., each SS block may be placed in the beginning of every radio frame of these two radio frames. In FIG. 7C, when L=4, four SS blocks may be placed within the SS burst set periodicity of 2 radio frames. The first and second SS blocks may be placed in the first radio frame while the third and fourth SS blocks may be placed in the second radio frame. In FIG. 7D, when L=8, eight SS blocks may be placed within the SS burst set periodicity of 2 radio frames. The SS blocks # 1, 2, 3 and 4 may be placed in the first radio frame while SS blocks # 5, 6, 7 and 8 may be placed in the second radio frame.

[0128] The SS block, burst and burst set may be a carrier frequency-dependent SS block/burst design. There may be one SS block/burst multiplexing and mapping for one carrier frequency or frequency band, while there is another SS block/burst multiplexing and mapping for another carrier frequency or frequency band. For example, a SS block/burst multiplexing and mapping scheme may be used for lower frequency e.g., below 6GHz, while another SS block/burst multiplexing and mapping scheme may be used for higher frequency e.g., above 6GHz. Also, there may be different SS block/burst multiplexing and mapping schemes for standalone and non- standalone SS block/burst design. Furthermore, there may also be licensed or unlicensed band dependent SS block/burst designs.

[0129] In one example, system information (SI) may be delivered in a periodic manner, an on-demand manner or both the periodic and the on-demand methods simultaneously. Periodic and on-demand SI delivery may co-exist in a system. When a WTRU requests Sl# X (or a set of Sl# X), an indicator to Sl# X may be set to "one" or turned on. The WTRU may check a SI delivery indicator (SIDI) first before requesting SI. This may allow SI to be shared between different WTRUs. A SIDI may be carried in a broadcast signal or a broadcast channel, such as minimum system information (MSI), remaining minimum system information (RMSI), PBCH, a secondary broadcast signal or channel, or a combination thereof.

[0130] An association among an SS block, RMSI, and other system information (OSI) may be established. RMSI and OSI may be associated with an SS block index. The SS block may be a time/frequency block consisting of PSS-PBCH-SSS-PBCH as discussed herein. Furthermore, OSI may also be associated with RMSI. A WTRU may explicitly receive information related to which signal or channel that the OSI may be associated. For example, the WTRU may receive a flag or other indication that OSI reception may be associated with SS/PBCH block or RMSI. The flag or other indicator may be carried in the SS/PBCH block, NR-PBCH, or RMSI. The WTRU may be associated with both the SS/PBCH block and RMSI. Alternatively, the WTRU may receive an implicit indication related to with which block the WTRU may associate. For example, if the SS/PBCH block is closer to OSI in time, the WTRU may associate with the SS/PBCH block. If the RMSI is closer to OSI in time, then the WTRU may associate with the RMSI. An explicit indication may override an implicit indication for a WTRU to determine the association. The association may be applied to other signals and/or channels e.g., synchronization signal, control channel, data channel, reference signal, or the like.

[0131] A WTRU may monitor or measure the best SS block. The WTRU may also find the

RMSI or OSI, based on the best SS block according to an association between an SS block and RMSI or OSI. A broadcast signal or broadcast channel (e.g., PBCH) may indicate quasi-collocated (QCL) for the SS block and RMSI or OSI. If the same beam has been used for the SS block and RMSI or OSI, a WTRU may not need to perform beam sweep to find RMSI or OSI. When RMSI or OSI uses a different configuration than an SS block, the beam direction, beamwidth, and beam repetition may be specifically configured.

[0132] In an example, if an SS block is QCL associated with RMSI or OSI, then a WTRU may assume the same beam or same beam direction for RMSI or OSI as the SS block. The WTRU may not need to perform beam sweep for RMSI or OSI. Otherwise, the WTRU may need to perform beam sweep. An indicator (e.g., bitmap indicator) may be used to indicate if beam direction is the same or not for an RMSI or OSI that is associated with the SS block.

[0133] In an example, if a beamwidth indicator indicates different beamwidths but QCL is indicated (same beam direction), then a WTRU may not need to perform beam sweep. Otherwise, the WTRU may need to perform local or global beam sweep. An indicator (e.g., bitmap indicator) may be used to indicate if beamwidth is the same or not for RMSI that is associated with an SS block.

[0134] In an example, if a beam is repeated, a WTRU may receive an indication about how the beam is repeated or how many SS block beams have been repeated. The WTRU may use the time location associated with the SS blocks where a beam is repeated for RMSI and/or OSI. An indicator (e.g., bitmap indicator) may be used to indicate if a beam direction is the same or not for RMSI associated with an SS block. Further, if an indicator specifies that a beam is repeated for RMSI or OSI associated with an SS block, a WTRU may assume that the beam is repeated R times for the RMSI and/or OSI. The repetition factor R may be indicated in a broadcast signal or broadcast channel (e.g., PBCH, RMSI, OSI, PSS or SSS). Different repetition factors may be used for RMSI and OSI. Also, different repetition factors may be used for different cells (e.g., one repetition factor may be used for a serving cell, and another repetition factor may be used for a non-serving cell).

[0135] In the examples discussed above for periodic OSI, a similar approach may be used for RMSI. For 'aperiodic SI or OSI', or On-demand SI or OSI', a WTRU may request a combination of beam and SI via SS block index feedback and an SI request signal. The WTRU may request a specific SI delivered on a specific beam for SI delivery. The WTRU may find the best SS block and feedback for the SS block index directed towards a gNB, which may send SI or OSI using the same beam or beam ID associated with the SS block index. The WTRU may wait until the next time location associated with the SS block index to receive SI or OSI. Alternatively, the WTRU may wait for a fixed time (e.g., a time offset) to receive SI or OSI. The time offset may be T OFDM symbols, T slots, T mini-slots, T ms, or the like.

[0136] FIG. 8 shows one example 800 of system information/other system information

(SI/OSI, SI or OSI) delivery. In order for SI/OSI to be shared by WTRUs in an on-demand operation, an indicator (e.g., bitmap indicator or bit indicator Qn for a number n of SI/OSI (Sl#n)) may indicate SI/OSI transmission status, e.g., whether Sl#n is transmitted or not. When Sl#n is being transmitted, Qn is set to "1" ("ON"), otherwise "0" ("OFF").

[0137] At the moment a WTRU requests a number x of SI/OSI (Sl#x), a bit indicator for the number x of SI/OSI, Qx, may be set to "1". The indicator, Qx, may be carried in a broadcast signal or a broadcast channel, such as RMSI. The WTRU may read the RMSI first before making the request for Sl#x. The WTRU attempts to request Sl#x 802, the WTRU may read a broadcast signal like RMSI containing Qx. 804. Next, the WTRU finds whether Qx is set to "1" or "0". 806. If Qx is set to "1", which indicates that the corresponding Sl#x is transmitting, the WTRU may attempt to read Sl#x transmitted in the following broadcast signal. 818.

[0138] If the WTRU successfully read Sl#x, it will end the SI/OSI delivery procedure. If the

WTRU cannot read Sl#x in the following transmission, the WTRU may continue attempting to read Sl#x transmitted in the subsequent transmissions, while a counter or a timer runs 820. If the counter or the timer expires, the WTRU may determine whether Qx is "1". 808.

[0139] If Qx is "0", the WTRU may need to send a request for Sl#x. 810. Before sending the request, the WTRU may wait for a backoff time and/or apply a backoff power. The WTRU may determine the back-off time based on a priority or a latency requirement. The back-off time (or back- off indicator, backoff power, etc) may be scaled up or down based on a priority for RACH. For example, if RACH priority is high, a back-off time may be scaled down or backoff power may be scaled properly. In contrast, if RACH priority is low, a back-off time may be scaled up or backoff power may be scaled properly. In another example, if a latency requirement is low (e.g., high latency), a back-off time may be scaled up or backoff power may be scaled properly. In contrast, if a latency requirement is high (e.g., low latency), a back-off time may be scaled down or backoff power may be scaled properly. Different backoff procedures or a combination of backoff procedures (backoff time, backoff power, etc) based on RACH priority may be used. The WTRU may determine the back-off time based and/or backoff power on other parameters or conditions (e.g., mobility) other than a priority or a latency requirement. Similarly, power ramping such as power ramping step size or initial transmit power may be based on RACH priority or latency requirement. For example, power ramping step size may be large for high priority RACH or low latency RACH. Power ramping step size may be small for low priority RACH or high latency RACH. For another example, initial transmit power may be large for high priority RACH or low latency RACH. Initial transmit power may be small for low priority RACH or high latency RACH.

[0140] Next, the WTRU may determine whether the request for SI#X has a high priority or a low latency requirement. 812. If so, the WTRU may wait for a zero or small backoff time and/or apply a proper backoff power for RACH and send the request for Sl#x. 814. Otherwise, the WTRU may wait for random backoff time and/or apply proper backoff power for RACH before sending the request. 816. The WTRU may apply proper power ramping step size and/or initial transmit power for RACH based on RACH and/or SI priority and/or latency requirement and send the request for Sl#x based on RACH and/or SI priority or latency or the like.

[0141] The WTRU may send a request via a physical random access channel (PRACH) preamble or a random access channel RACH resource like RACH messages 1 or 3 when an association among the PRACH preamble, the RACH resource, and SI is configured or indicated. Upon receiving a request for Sl#x from a WTRU, a gNB may set a corresponding indicator, Qx, to "1" and start sending Sl#x for L times or L transmissions. If the request is sent via a PRACH preamble or a RACH message 1 , L may be a predefined value. If the request is sent via a RACH message 3, L may be a predefined value or L may be indicated in the RACH message 3 along with the request for Sl#x. Parameters such as estimated power, pathloss, coverage, or others may be used to determine L.

[0142] Sl#x may be SIB#x, a set of system information blocks (SIBs) (e.g., SIB set#x), a subset of SIBs (e.g., SIB subset#x), a piece of SI (e.g., SI piece#x), or the like. A request for all SIBs delivery may be included in the request for Sl#x. For example, a specific PRACH preamble, RACH message 1 may be reserved for the purpose of requesting all SIBs delivery simultaneously.

[0143] FIG. 9 shows another example 900 of system information/other system information

(SI/OSI, SI or OSI) delivery. Some of the elements, 902-914 924-928, are similar to those in FIG. 8 (802-808, 818 and 820 and 810-816). The elements 916, 918, and 920 are newly added in FIG. 9.

[0144] At 916, the WTRU determines if an association of the SS block and PRACH is indicated to WTRU from gNB. Such indication may be conveyed to a WTRU via signaling e.g., broadcast signal or channel, system information such as remaining minimum system information (RMSI) or other system information (OSI), RRC signaling, paging or random access channel, etc. Once the WTRU receives such indication for association, the WTRU may determine the association between SS block and PRACH. At 918 , if the association is not indicated, a WTRU sends a request for Sl#x via RACH message 3, where the WTRU indicates a number of transmissions (L) for Sl#x. At 920, if the association is indicated, the WTRU send the request via PRACH preamble or RACH message 1 and a default number of transmission (L) for Sl#x is used.At 924, the WTRU determines whether the request has a high priority or a low latency requirement. At 926, if the request or RACH has high priority the WTRU waits for a zero or small backoff time for RACH and then sends the request. At 928, if the request does not have high priority, the WTRU waits for a random backoff time for RACH and then sends the request. Backoff indication may be scaled up and down based on priority of RACH. Backoff may be applied to (random) backoff time and/or power backoff which may be based on priority of RACH. RACH may have two or multiple priority categories or classes. Depending on priority, backoff may be scaled properly to meet the RACH priority and/or SI priority requirements.

[0145] A WTRU may be indicated for the transmitted SS blocks. If a WTRU is indicated, the WTRU may monitor these indicated transmitted SS blocks (e.g., a subset of SS blocks that are transmitted), otherwise the WTRU may monitor all SS blocks. Such indication may be carried in system information (such as RMSI or OSI), broadcast channel (e.g. NR-PBCH), paging or RACH. For the monitored SS blocks, the WTRU may find the SS block associated with the DL beam. The WTRU may send an UL signal that is associated with the SS block to indicate the DL beam or SS block. A gNB or transmission reception point (TRP) may use received UL signal(s) from the WTRU to send an associated DL signal to the WTRU. A PRACH may be used for such a purpose. PRACH preamble, resource, or beam may be used to indicate the gNB or TRP for the SS block (e.g., best SS block) or DL beam (e.g., best DL beam) for the WTRU. When the WTRU selects the PRACH preamble, resource, and/or beam and transmits using the selected PRACH preamble, resource, and/or beam to the gNB or TRP, the gNB or TRP may know the SS block and/or DL beam for the WTRU.

[0146] The WTRU may also request SI delivery from a gNB or TRP via an UL signal. The

UL signal may be associated with SI and an SS block simultaneously. The WTRU may request a simultaneous SI and SS block transmission via an associated UL signal with DL signal. There may be an association between the UL signal, PRACH, physical uplink control channel (PUCCH), and UL beam; additionally/alternatively, the DL signal, SI, SS block, PBCH, RMSI, OSI, and DL beam may be associated.

[0147] PRACH preamble, resource, or beam may be used to indicate a gNB or TRP for the requested SI or DL beam for the WTRU. When the WTRU selects the PRACH preamble, resource, and/or beam and transmits using the selected PRACH preamble, resource, and/or beam to a gNB or TRP, the gNB or TRP may know the requested SI, SS block, and/or DL beam for the WTRU.

[0148] The following may be used for association for the UL signal: PRACH preamble or sequence; PRACH orthogonal cover code (OCC); PRACH resource (e.g., time and/or frequency resource); Beam (e.g., Tx/Rx beam); channel state information (CSI) feedback; CQI; or any combination of thereof.

[0149] The following may be used for association for the DL signal: SS block index; SS block; PSS, SSS; PBCH; DMRS; SI; RMSI; OSI; CSI-RS; Paging; or any combination thereof.

[0150] In one example, a PRACH resource may be used to indicate an SS block index and a PRACH preamble may be used to indicate SI. The PRACH resource # x may be used to indicate SS block index # y. A simple association may be x=y; that is, PRACH resource # x may be used to indicate SS block index # x and PRACH resource # y may be used to indicate SS block index # y and so on. Additionally, the PRACH preamble # w may be used to indicate SI # z. A simple association may be w=z; that is, PRACH preamble sequence # w may be used to indicate SI # w and PRACH preamble sequence # z may be used to indicate SI # z and so on. The WTRU may select the PRACH resource # x and send PRACH preamble # w using the selected PRACH resource # x to indicate or feedback the SS block index # y and request SI # z jointly or simultaneously. In this example the PRACH resource may be a time resource, frequency resource, code resource, beam resource, time and frequency resources, or a combination thereof. Also in this example, the PRACH preamble may be a preamble sequence, preamble OCC, preamble format, or a combination thereof.

[0151] In an example where the PRACH resource and PRACH preamble is not used to indicate SI to the WTRU, the WTRU may use a RACH message 3 to indicate an SS block index and to request SI. In one scenario, the WTRU may include an SS block index in a RACH message 3 (e.g., payload and transmit message 3 with SS block index to gNB or TRP). In another scenario, the WTRU may include an SI request such as which Sl(s) the WTRU may request in the RACH message 3 (e.g., payload and transmit message 3 with requested SI info to gNB or TRP). In another scenario, the WTRU may include both an SS block index and an SI request in a RACH message 3 (e.g., payload and transmit message 3 with SS block index and requested SI info to gNB or TRP). If an association between SS block index and PRACH is configured and indicated to the WTRU, the WTRU may use PRACH preamble or message 1 to indicate and feedback the SS block index. Otherwise the WTRU may use RACH message 3 to indicate and feedback the SS block index.

[0152] In another example, the RACH resource and PRACH preamble may be used to indicate an SS block index and SI. Alternatively, the RACH resource and PRACH preamble group may be used to indicate an SS block index and the PRACH preamble within the PRACH preamble group may be used to indicate the SI. Other combinations of using the RACH resource and PRACH preamble to indicate an SS block (or SS block index) and request SI, or set of Sl(s), are possible.

[0153] The WTRU may assume that the demodulation reference signal (DMRS) of the

PDCCH and the DMRS of the PDSCH transmitting a RACH message 2 may be QCL-ed with the SS/PBCH block that the WTRU selects for RACH association and transmission. The WTRU may assume that the DMRS of the PDCCH transmitting the RACH message 3 and/or retransmission grant may be QCL-ed with the SS/PBCH block that the WTRU selects for RACH association and transmission. The WTRU may assume that the DMRS of the PDCCH and the DMRS of the PDSCH transmitting a RACH message 4 may be QCL-ed with the SS block that the WTRU selects for RACH association and transmission. However, the WTRU may perform SS/PBCH block reporting, SS blockSS block reporting, or beam reporting during the RACH procedure. The gNB may indicate to the WTRU to report gNB Tx beam, SS block, or SS/PBCH block index during RACH procedure. Such report may trigger an indication that a SS/PBCH block, SS block or beam reporting may be carried in SS block, SS/PBCH block, NR-PBCH, random access response (RAR), RACH message 2 or message 4. Such SS/PBCH block, SS block index, or beam report(s) may be carried in a RACH message 3, RACH message 1 , RACH preamble, or other feedback signal or channel. If the WTRU receives the indication for SS/PBCH block, SS block, or beam reporting, the WTRU may use the indicated SS/PBCH block, SS block, or beam for the remaining RACH procedure and override the default QCL association. The WTRU may use the reported SS/PBCH block, SS block, or beam for the RACH message 4, message 2, or other DL signal/channel reception. SS block confirmation message, SS/PBCH block confirmation message, or beam confirmation message may be used to inform the WTRU whether to use the reported SS block, SS/PBCH block or beam, (e.g., the latest reported SS block, SS/PBCH block or beam). SS/PBCH block confirmation message, SS block confirmation message, or beam confirmation message may be 1 bit or more than 1 bit which may be included in the downlink control information (DCI) carried in the PDCCH or included in the data carried in the PDSCH (e.g., RAR, RACH message 2 or message 4). For example, if SS block confirmation, SS/PBCH block confirmation, or beam confirmation is received and indicates "Yes" or "Confirm", then the WTRU may use the reported SS block(s), SS/PBCH block(s) or beam(s) for reception. Otherwise the WTRU may use the indicated SS block(s), SS/PBCH block(s) or beam(s), a subset of beams, SS blocks, SS/PBCH blocks, or try all the beams, SS blocks, SS/PBCH blocks for reception.

[0154] An association between an SS block and a PUCCH may be established to enable efficient system operation. An SS block index may be associated with a PUCCH resource and/or sequence. Such a PUCCH resource may be a time/frequency resource, PUCCH sequence, cyclic shift, or a combination thereof.

[0155] The PUCCH resource may be associated with an SS block or an SS block index for

SS block index reporting. The PUCCH time/frequency, cyclic shifts, sequence, and/or other parameters may be associated with an SS block or SS block index. For example, PUCCH #x may be associated with SS block #x or SS block index x. PUCCH #x may be PUCCH resource #x, a PUCCH index such as time index x, frequency index x, time/frequency index x, cyclic shift x, sequence x, or a combination thereof.

[0156] When a WTRU reports an SS block x or an SS block index x, the WTRU may use the associated PUCCH and its resource and/or parameters associated with the SS block or SS block index.

[0157] The association between an SS block and physical uplink shared channel (PUSCH) may be established to enable efficient system operation. An association for PUSCH may include PUSCH time and/or frequency resource.

[0158] An association between an SS block and a control resource set (CORESET) for

RMSI or OSI may be established to enable efficient system operation. An association for CORESET(s) between RMSI and OSI may also be established. An association between physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) for RMSI and PDCCH and PDSCH for OSI may also be established.

[0159] The configuration of CORESET for RMSI may include frequency location, size (e.g., number of physical resource blocks (PRB) or number of resource block groups (RBG)), time location, periodicity, and an offset in time and/or frequency. Alternatively, time location may be predefined and periodicity may be the same as RMSI. The number of OFDM symbols for CORESET and QCL between SS blocks and associated CORESET may be signaled or indicated.

[0160] Information about system bandwidth may be indicated, for example, in NR-PBCH and/or RMSI. If system bandwidth is indicated, absolute frequency location for NR-PBCH, CORESET, RMSI, and/or OSI may be indicated. Otherwise if system bandwidth is not indicated, relative frequency location (with respect to some reference point) for NR-PBCH, CORESET, RMSI, and/or OSI may be indicated. The reference point may be a location in frequency or time of a NR- PBCH location, SS block location, and/or PSS/SSS. For example, the reference point may be the lowest or highest frequency index of NR-PBCH, SS block, PSS, SSS, or the like. The reference point may be a middle frequency index of NR-PBCH, SS block PSS, SSS, or the like.

[0161] An SS block may be associated with RMSI and/or OSI as well as the corresponding

PDCCH of RMSI and/or OSI. OSI and/or the corresponding PDCCH of OSI may be associated with RMSI and/or the corresponding PDCCH of RMSI. The beam associated with the SS block may be used for transmission of RMSI and/or a corresponding PDCCH. The beam associated with the SS block may be used for transmission of OSI and a corresponding PDCCH. Alternatively, the beam associated with RMSI and/or a corresponding PDCCH may be used for transmission of OSI and/or a corresponding PDCCH.

[0162] For each beam associated with an SS block there may be a different CORESET to be used for beam level interference mitigation. A CORESET may be a function of an SS block index and/or beam index. The configuration or parameters of the CORESET for RMSI or OSI such as frequency location, size (e.g., number of physical resource blocks (PRB) or number of resource block groups (RBG)), time location, periodicity, offset in time and/or frequency, number of OFDM symbols for CORESET, QCL between SS blocks and associated CORESET, and/or the like, may be dependent on the SS block index, beam index, and/or cell identity. For example, different frequency shifts or offsets of the CORESET per cell may be used for cell level interference mitigation. In another example, different frequency shifts or offsets of the CORESET per cell may be associated with an SS block or SS block index, beam index, actually transmitted SS block or SS block index, actually transmitted beam or beam index, cell identity, or the like. The configuration or parameters of a CORESET for RMSI, OSI, or other channels may be dependent on a slot index, mini-slot index, OFDM symbol index, subframe index, frame index, or system frame number. The configuration or parameters of a CORESET for RMSI, OSI or other channels may be a function of at least one of the following: an SS block or SS block index (in time or frequency), beam index, actually transmitted SS block or SS block index (in time or frequency), actually transmitted beam or beam index, cell identity, slot index, mini-slot index, OFDM symbol index, subframe index, frame index, or system frame number.

[0163] A CORESET may be indicated using another CORESET based on either the actually transmitted or a maximum number of SS blocks (or beams). A WTRU-specific CORESET may be based on the detected SS block (or beam) by that WTRU.

[0164] The examples provided herein may apply to RMSI, OSI, control channels, data channels, or a combination thereof.

[0165] A CSI-RS may be multiplexed on the same OFDM symbols as an SS block. If time/frequency resource of a CSI-RS is conflicting with an SS block, the following options may be considered: CSI-RS may be punctured and ignored; and/or an SS block may be punctured and ignored.

[0166] An association between an SS block and a CSI-RS may be established. CSI-RS may be associated with an SS block index. QCL between SS blocks may be established and indicated. QCL between CSI-RSs may be established and indicated. QCL between an SS block and a CSI-RS may also be established and indicated. Repetition factor R for SS blocks and/or CSI-RSs may be indicated. Different repetition factors R (e.g., R1 and R2) may be used and indicated for an SS block and a CSI-RS separately.

[0167] An SS block may be identified in wideband operation. An SS block may be identified via at least one of the following: an SS block time index; an SS block frequency index; and/or a bandwidth part index.

[0168] An SS block may be identified by an SS block time index when the SS block is in non-wideband operation. An SS block may be identified by an SS block frequency index and an SS block time index when the SS block is in wideband operation. In either operation, multiple SS blocks may coexist in a frequency domain within the same time instance. An SS block may be identified by a bandwidth part index and an SS block time index. Global indexing for an SS block in both time and frequency may also be used. Such indexing may cover both frequency and time indexing. For example, a global SS block index may start with the lowest frequency index then the higher frequency index; after frequency indexing is done, the global SS block index may start with next time index, and for each time index, the SS block index may start with the lowest frequency index then the higher frequency index, and continue until all time indexing is done.

[0169] Fig. 10 illustrates a flow diagram showing how a WTRU acquires a set of SS/PBCH blocks (or SS blocks) 1000, namely "a synchronization signal(SS) set," that are configurable under various multiplexing or resource allocation schemes. First, a WTRU receives information or an indicator specifying the SS set from at least one access point that the WTRU is associated with 1002. Then, the WTRU monitors the identified SS set 1004. Next, the WTRU acquires a PSS or a SSS from the identified SS set 1006. Based on the acquired PSS or SSS, the WTRU may determine a block type (BT) of the SS/PBCH block included in the SS set 1008. Based on the block type (BT), the WTRU may detect or decode one or more PBCHs within the SS/PBCH blocks. 1010. The location of the PBCH is flexible within the SS/PBCH blocks and depends on the block type of the SS/PBCH blocks. The block type is determined by many factors like PBCH resource allocation, multiplexing, RE mapping, DMRS location for the PBCH, TDM or FDM. Finally, the WTRU acquires the PBCH or the entire SS set, based on the block type of the SS/PBCH blocksstep 1012.

[0170] The WTRU may find the location of a PBCH within a SS/PBCH block, based on the block type of the SS/PBCH block. Also, the resource element (RE) allocation of a PBCH is a function of the block type. The RE mapping and multiplexing of a PBCH is a function of an OFDM symbol index. DMRS location for a PBCH is a function of the block type. The RE mapping for DMRS within a PBCH is a function of OFDM symbol index and cell ID.

[0171] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element may be used alone or in any combination with the other features and elements. Although examples described herein discuss LTE, LTE-A, NR or 5G specific protocols, the solutions described herein are not restricted to these scenarios and are applicable to other wireless systems as well. In addition, the methods described 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 wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, 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 in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is claimed:

1. A method implemented in a wireless transmit/receive unit (WTRU) for receiving a plurality of messages from a base station, the method comprising:

receiving an indication of a synchronization signal (SS) and physical broadcast channel (PBCH) (SS/PBCH) block to be monitored;

acquiring the primary synchronization signal (PSS) and secondary synchronization signal (SSS) at a fixed location within the indicated SS/PBCH block; and

acquiring one or more PBCHs and then an entire SS/PBCH block based on the determined SS/PBCH block type; wherein the SS/PBCH block includes 4 symbols and the PBCH is located on 3 of the 4 symbols and the PSS and SSS are each located on a different one of the four symbols from each other.

2. The method of claim 1 , wherein the PBCH symbols each include its own frequency- multiplexed demodulation reference symbols (DMRS).

3. The method of claim 1 wherein the PBCH includes DMRS located on resources that determined as a function of an OFDM symbol index.

4. The method of claim 1 , wherein the SSS is located on a symbol between two symbols that include the PBCH.

5. The method of claim 1, wherein the PSS and SSS are located on subcarriers between 56 and 182 in their respective symbols.

6. The method of claim 1 , wherein the PBCH is located on subcarriers between 0 and 55 and 183 and 239 in two of the three symbols and 0-239 on the third symbol.

7. A wireless transmit/receive unit (WTRU) receiving a synchronization signal from a base station, the WTRU comprising:

a processor and receiver configured to:

receive an indication of a synchronization signal (SS) and physical broadcast channel (PBCH) (SS/PBCH) block to be monitored;

acquire the primary synchronization signal (PSS) and secondary synchronization signal (SSS) at a fixed location within the indicated SS/PBCH block; and

acquire one or more PBCHs and then an entire SS/PBCH block based on the determined SS/PBCH block type; wherein the SS/PBCH block includes 4 symbols and the PBCH is located on 3 of the 4 symbols and the PSS and SSS are each located on a different one of the four symbols from each other.

8. The WTRU of claim 7, wherein the PBCH symbols each include its own frequency- multiplexed demodulation reference symbols (DMRS).

9. The WTRU of claim 7, wherein the PBCH includes DMRS located on resources that determined as a function of an OFDM symbol index.

10. The WTRU of claim 7, wherein the SSS is located on a symbol between two symbols that include the PBCH.

11. The WTRU of claim 7, wherein the PSS and SSS are located on subcarriers between 56 and 182 in their respective symbols.

12. The WTRU of claim 7, wherein the PBCH is located on subcarriers between 0 and 55 and 183 and 239 in two of the three symbols and 0-239 on the third symbol.