WO2023230947A1

WO2023230947A1 - Techniques for selecting communication parameters based on sidelink synchronization signals

Info

Publication number: WO2023230947A1
Application number: PCT/CN2022/096527
Authority: WO
Inventors: Hui Guo; Tien Viet NGUYEN; Kapil Gulati; Shuanshuan Wu; Gabi Sarkis; Praveen Kumar Appani; Cheol Hee Park
Original assignee: Qualcomm Incorporated
Priority date: 2022-06-01
Filing date: 2022-06-01
Publication date: 2023-12-07

Abstract

Some aspects described herein relate to synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source, and transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

Description

TECHNIQUES FOR SELECTING COMMUNICATION PARAMETERS BASED ON SIDELINK SYNCHRONIZATION SIGNALS

BACKGROUND

Aspects of the present disclosure relate generally to sidelink wireless communication systems, and more particularly, to synchronizing sidelink communications.

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communications technology (which can be referred to as 5G new radio (5G NR) ) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology can include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable low-latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which can allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, further improvements in 5G communications technology and beyond may be desired.

In some wireless communication technologies, such as 5G, user equipment (UEs) communicate over one or more of multiple interfaces. The multiple interfaces may include a Uu interface between the UE and a base station, where the UE can receive communications from the base station over a downlink and transmit communications to the base station over an uplink. In addition, the multiple interfaces may include a sidelink interface to communicate with one or more other UEs directly over a sidelink channel (e.g., without traversing the base station) .

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

According to an aspect, an apparatus for wireless communication is provided that includes a memory configured to store instructions, and one or more processors coupled with the memory. The one or more processors are configured to synchronize, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, select, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source, and transmit, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

In another aspect, a method for wireless communication is provided that includes synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source, and transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

In another aspect, an apparatus for wireless communication is provided that includes means for synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, means for selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source, and means for transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

In another aspect, a computer-readable medium is provided that includes code executable by one or more processors for wireless communication. The code includes code for synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source, and transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

FIG. 1 illustrates an example of a wireless communication system, in accordance with various aspects of the present disclosure;

FIG. 2 is a block diagram illustrating an example of a user equipment (UE) , in accordance with various aspects of the present disclosure;

FIG. 3 is a flow chart illustrating an example of a method for selecting sidelink (SL) communication parameters based at least in part on a synchronization source, in accordance with various aspects of the present disclosure;

FIG. 4 illustrates an example of a synchronization chain, in accordance with various aspects of the present disclosure; and

FIG. 5 is a block diagram illustrating an example of a multiple-input multiple-output (MIMO) communication system including a base station and a UE, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect (s) may be practiced without these specific details.

The described features generally relate to synchronizing devices using sidelink (SL) communications, and selecting communication parameters based at least in part on a synchronization source. For example, SL communications can refer to device-to-device (D2D) communication among devices (e.g., user equipment (UEs) ) in a wireless network. In a specific example, SL communications can be defined for vehicle-based communications, such as vehicle-to-vehicle (V2V) communications between two vehicle-based communication device that are on a vehicle (e.g., onboard units (OBUs) , vehicle-to-infrastructure (V2I) communications (e.g., from a vehicle-based communication device, such as a OBU, to a road infrastructure node (e.g., roadside unit (RSU) ) , vehicle-to-network (V2N) communications (e.g., from a vehicle-based communication device to one or more network nodes, such as a base station) , a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications. In V2X communications, OBUs can communicate with one another and/or with RSUs over a SL channel.

V2X communications can occur over one or more slots. A slot can be defined in a wireless communication technology (e.g., third generation partnership project (3GPP) long term evolution (LTE) or fifth generation (5G) new radio (NR) , etc. ) as including a collection of multiple symbols, where the multiple symbols can be one of orthogonal frequency division multiplexing (OFDM) symbols, single carrier-frequency division multiplexing (SC-FDM) symbols, or other types of symbols. In an example, the number of symbols in a slot may vary based on a cyclic prefix (CP) length defined for the symbols.

In LTE V2X, for example, a UE can synchronize timing and/or frequency to one or more of a satellite source, such as a global navigation satellite system (GNSS) , or to another UE using a sidelink synchronization signal (SLSS) . In some LTE V2X deployments, evolved Node Bs (eNBs) may not be present, such as deployments in intelligent transport system (ITS) spectrum, and GNSS may be a main synchronization source for the UEs. In some regions or scenarios (e.g., in a tunnel, parking garage, or other scenarios where the UE may not have clear line-of-sight to GNSS) , however, a UE may not be able to receive GNSS signals for synchronization, and UEs can transmit SLSS to one another to propagate GNSS timing. In some examples, a RSU, which can be static in position or location as compared to a OBU, can provide SLSS to vehicle-based communication devices (OBUs) , where the RSU can directly synchronize to GNSS or indirectly synchronize to GNSS via other RSU SLSS.

In some examples, when UEs are synchronized using secondary synchronization sources (e.g., not directly from GNSS) , the UEs may experience more timing error and/or frequency error than UEs directly synchronized to GNSS. This degrades demodulation performance for receiving data using higher modulation and coding schemes (MCSs) . The amount of timing/frequency error can also depend on how far the UE is from the SLSS synchronization source (e.g., in distance or in number of secondary sources between the UE and GNSS) . For example, a UE near the SLSS synchronization source can be more likely to communicate with other UEs synchronized to the same synchronization source, and thus the relative timing/frequency error between these UEs can be less than UE’s far from the SLSS synchronization source. Similarly, for example, UEs far from the SLSS synchronization source can be more likely to communicate with other UEs synchronized to a different synchronization source, and thus relative timing/frequency error can be more than UE’s near the SLSS synchronization source. It can be desirable to maintain demodulation performance (compared to UEs directly synchronized with GNSS) . For example, this can come as a cost of reducing capacity offered to an application layer at the UE. In an example, where LTE V2X traffic includes basic safety messages (BSMs) , where the BSM is not expected to be sent if the UE cannot get its position fix with high reliability, the cost of reducing capacity may be justified.

Accordingly, aspects described herein relate to selecting communication parameters for SL communications of a UE based on the SLSS synchronization source of the UE. For example, the MCS, a number of hybrid automatic repeat/request (HARQ) transmissions/retransmissions, etc. can be selected for a UE based on the SLSS synchronization source of the UE. In an example, the parameters can be selected based on a type of a timing source (e.g., whether the SLSS synchronization source is GNSS or a secondary SLSS synchronization source) , a number of secondary SLSS synchronization sources between the UE and GNSS, a priority group associated with the SLSS synchronization source, etc. In another example, the communication parameters for SL communications can be further selected based on a signal strength or quality measurement of a signal received from the SLSS synchronization source. In addition, in an example, a number of subchannels for the UE to use for SL communications can be selected based on the parameters as well. The number of subchannels may cause the UE to exceed a channel ratio limit, in which case an application layer of the UE can be notified for reducing transport block (TB) size, packet segmentation, packet frequency, etc.

The aspects described herein can allow for adapting SL communication parameters based on SLSS synchronization source. Thus, UEs that are synchronized to the same, or similar, SLSS synchronization source can use similar SL communication parameters. This can facilitate improved modulation/demodulation performance in selecting an optimal MCS for the UEs to use in communicating with one another in SL communications. This can, in turn, improve quality of communications and communication throughput for the devices, which can allow for improved likelihood of receiving messages (e.g., BSMs in LTE V2X) , thus improving overall user experience, etc.

The described features will be presented in more detail below with reference to FIGS. 1-5.

As used in this application, the terms “component, ” “module, ” “system” and the like are intended to include a computer-related entity, such as but not limited to hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms “system” and “network” may often be used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM ^TM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) . 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description below, however, describes an LTE/LTE-Asystem for purposes of example, and LTE terminology is used in much of the description below, although the techniques are applicable beyond LTE/LTE-A applications (e.g., to fifth generation (5G) new radio (NR) networks or other next generation communication systems) .

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in other examples.

Various aspects or features will be presented in terms of systems that can include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems can include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches can also be used.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) can include base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and/or a 5G Core (5GC) 190. The base stations 102 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells can include base stations. The small cells can include femtocells, picocells, and microcells. In an example, the base stations 102 may also include gNBs 180, as described further herein. In one example, some nodes of the wireless communication system may have a modem 240 and communicating component 242 for selecting SL communication parameters based on SLSS synchronization source, as described further herein. Though UE 104-a is shown as having the modem 240 and communicating component 242, this is one illustrative example, and substantially any node or type of node may include a modem 240 and communicating component 242 for providing corresponding functionalities described herein.

The base stations 102 configured for 4G LTE (which can collectively be referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through backhaul links 132 (e.g., using an S1 interface) . The base stations 102 configured for 5G NR (which can collectively be referred to as Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over backhaul links 134 (e.g., using an X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with one or more UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102'may have a coverage area 110'that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group, which can be referred to as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (e.g., for x component carriers) used for transmission in the DL and/or the UL direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

In another example, certain UEs (e.g., UE 104-a and 104-b) may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102'may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102'may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. In addition, in this regard, UEs 104-a, 104-b can use a portion of frequency in the 5 GHz unlicensed frequency spectrum in communicating with the small cell 102’ , with other cells, with one another using sidelink communications, etc. The UEs 104-a, 104-b, small cell 102’ , other cells, etc. can use other unlicensed frequency spectrums as well, such as a portion of frequency in the 60 GHz unlicensed frequency spectrum.

A base station 102, whether a small cell 102'or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) , or other type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. A base station 102 referred to herein can include a gNB 180.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The 5GC 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 can be a control node that processes the signaling between the UEs 104 and the 5GC 190. Generally, the AMF 192 can provide QoS flow and session management. User Internet protocol (IP) packets (e.g., from one or more UEs 104) can be transferred through the UPF 195. The UPF 195 can provide UE IP address allocation for one or more UEs, as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a positioning system (e.g., satellite, terrestrial) , a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, robots, drones, an industrial/manufacturing device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet) ) , a vehicle/a vehicular device, a meter (e.g., parking meter, electric meter, gas meter, water meter, flow meter) , a gas pump, a large or small kitchen appliance, a medical/healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., meters, pumps, monitors, cameras, industrial/manufacturing devices, appliances, vehicles, robots, drones, etc. ) . IoT UEs may include machine type communications (MTC) /enhanced MTC (eMTC, also referred to as category (CAT) -M, Cat M1) UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC) , eFeMTC (enhanced further eMTC) , mMTC (massive MTC) , etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT) , FeNB-IoT (further enhanced NB-IoT) , etc. The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

In an example, in a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS) , or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB) , evolved NB (eNB) , NR BS, 5G NB, access point (AP) , a transmit receive point (TRP) , or a cell, etc. ) , including base station 102 described above and further herein, may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs) , one or more distributed units (DUs) , or one or more radio units (RUs) ) . In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU also can be implemented as virtual units, i.e., a virtual central unit (VCU) , a virtual distributed unit (VDU) , or a virtual radio unit (VRU) .

Base station-type operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance) ) , or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN) ) . Disaggregation may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality for at least one unit, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

In an example, UE 104-a can synchronize timing with a satellite system 198, which may include a GNSS. UE 104-a, for example, can include a RSU, OBU, etc. In an example, UE 104-a may not be able to synchronize with the satellite system 198 (e.g., based on a region in which the UE 104-a is located) , but the UE 104-a may be able to communicate with UE 104-b, where the UE 104-b may be able to synchronize with the satellite system 198 or another synchronization source (e.g., another UE) . In accordance with aspects described herein, communicating component 242 can select SL communication parameters to use for SL communications based on the SL synchronization source to which UE 104-a synchronizes timing and/or frequency. For example, communicating component 242 can select the parameters based on a type of the synchronization source (e.g., select higher MCS or a lesser number of HARQ retransmissions where UE 104-a directly synchronizes with the satellite system 198 than where the UE 104-a synchronizes with a secondary synchronization source, such as a reference device source –e.g., UE 104-b) .

Turning now to FIGS. 2-5, aspects are depicted with reference to one or more components and one or more methods that may perform the actions or operations described herein, where aspects in dashed line may be optional. Although the operations described below in FIG. 3 are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions, functions, and/or described components may be performed by a specially programmed processor, a processor executing specially programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions.

Referring to FIG. 2, one example of an implementation of UE 104 may include a variety of components, some of which have already been described above and are described further herein, including components such as one or more processors 212 and memory 216 and transceiver 202 in communication via one or more buses 244, which may operate in conjunction with modem 240 and/or communicating component 242 for selecting SL communication parameters based on SLSS synchronization source, as described herein.

In an aspect, the one or more processors 212 can include a modem 240 and/or can be part of the modem 240 that uses one or more modem processors. Thus, the various functions related to communicating component 242 may be included in modem 240 and/or processors 212 and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 212 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver 202. In other aspects, some of the features of the one or more processors 212 and/or modem 240 associated with communicating component 242 may be performed by transceiver 202.

Also, memory 216 may be configured to store data used herein and/or local versions of applications 275 or communicating component 242 and/or one or more of its subcomponents being executed by at least one processor 212. Memory 216 can include any type of computer-readable medium usable by a computer or at least one processor 212, such as random access memory (RAM) , read only memory (ROM) , tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory 216 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining communicating component 242 and/or one or more of its subcomponents, and/or data associated therewith, when UE 104 is operating at least one processor 212 to execute communicating component 242 and/or one or more of its subcomponents.

Transceiver 202 may include at least one receiver 206 and at least one transmitter 208. Receiver 206 may include hardware and/or software executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . Receiver 206 may be, for example, a radio frequency (RF) receiver. In an aspect, receiver 206 may receive signals transmitted by at least one base station 102 or a SL transmitting UE. Additionally, receiver 206 may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, signal-to-noise ratio (SNR) , reference signal received power (RSRP) , reference signal received quality (RSRQ) , received signal strength indicator (RSSI) , etc. Transmitter 208 may include hardware and/or software executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . A suitable example of transmitter 208 may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, UE 104 may include RF front end 288, which may operate in communication with one or more antennas 265 and transceiver 202 for receiving and transmitting radio transmissions, for example, receiving wireless communications transmitted by at least one base station 102 or a SL transmitting UE, transmitting wireless communications to at least one base station 102 or a SL receiving UE, etc. RF front end 288 may be connected to one or more antennas 265 and can include one or more low-noise amplifiers (LNAs) 290, one or more switches 292, one or more power amplifiers (PAs) 298, and one or more filters 296 for transmitting and receiving RF signals.

In an aspect, LNA 290 can amplify a received signal at a desired output level. In an aspect, each LNA 290 may have a specified minimum and maximum gain values. In an aspect, RF front end 288 may use one or more switches 292 to select a particular LNA 290 and its specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA (s) 298 may be used by RF front end 288 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 298 may have specified minimum and maximum gain values. In an aspect, RF front end 288 may use one or more switches 292 to select a particular PA 298 and its specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters 296 can be used by RF front end 288 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 296 can be used to filter an output from a respective PA 298 to produce an output signal for transmission. In an aspect, each filter 296 can be connected to a specific LNA 290 and/or PA 298. In an aspect, RF front end 288 can use one or more switches 292 to select a transmit or receive path using a specified filter 296, LNA 290, and/or PA 298, based on a configuration as specified by transceiver 202 and/or processor 212.

As such, transceiver 202 may be configured to transmit and receive wireless signals through one or more antennas 265 via RF front end 288. In an aspect, transceiver may be tuned to operate at specified frequencies such that UE 104 can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102, one or more other UEs in SL communications, etc. In an aspect, for example, modem 240 can configure transceiver 202 to operate at a specified frequency and power level based on the UE configuration of the UE 104 and the communication protocol used by modem 240.

In an aspect, modem 240 can be a multiband-multimode modem, which can process digital data and communicate with transceiver 202 such that the digital data is sent and received using transceiver 202. In an aspect, modem 240 can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem 240 can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem 240 can control one or more components of UE 104 (e.g., RF front end 288, transceiver 202) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration can be based on UE configuration information associated with UE 104 as provided by the network during cell selection and/or cell reselection.

In an aspect, communicating component 242 can optionally include a synchronizing component 252 for synchronizing timing and/or frequency with a satellite system or by receiving SLSSs from one or more other UEs, and/or a parameter selecting component 254 for selecting one or more SL communication parameters based on a synchronization source (or type of source) with which the UE 104 synchronizes timing and/or frequency, as described herein.

In an aspect, the processor (s) 212 may correspond to one or more of the processors described in connection with the UE in FIG. 5. Similarly, the memory 216 may correspond to the memory described in connection with the UE in FIG. 5.

FIG. 3 illustrates a flow chart of an example of a method 300 for selecting SL communication parameters based at least in part on a synchronization source. In an example, a UE (e.g., UE 104-a) , which can include a OBU in SL communications, can perform the functions described in method 300 using one or more of the components described in FIGS. 1 and 2.

In method 300, at Block 302, a timing or frequency for transmitting signals in a wireless communication network can be synchronized with a synchronization source. In an aspect, synchronizing component 252, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can synchronize, with the synchronization source, the timing or frequency for transmitting signals in the wireless communication network. For example, synchronizing component 252 can attempt to synchronize with a satellite system 198, such as GNSS, by attempting to receive GNSS signals. If synchronizing component 252 can receive the GNSS signals, it can synchronize timing and/or frequency for the UE 104 based on the received GNSS signals. If synchronizing component 252 cannot receive the GNSS signals, it can attempt to receive SLSSs from one or more other UEs in SL communications. For example, the other UEs (e.g., UE 104-b) can periodically transmit SLSSs over a SL channel, and where the synchronizing component 252 can detect the SLSSs, it can synchronize timing and/or frequency for the UE 104 based on the received SLSSs. In this example, synchronizing component 252 synchronizes with a device source as a reference synchronization device instead of directly synchronizing to GNSS. As described, device sources may have associating timing and/or frequency drift, and thus UEs that are synchronized using device sources may have more disparity in timing or frequency than UEs synchronized using GNSS.

In method 300, at Block 304, one or more parameters for transmitting the signals can be selected based at least in part on a type of the synchronization source. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals. For example, the one or more parameters can include a MCS (e.g., a maximum MCS that can be used by the UE 104 to send or receive SL communications) , a number of HARQ retransmissions, etc. For example, the type of the synchronization source may include a type of node from which the synchronizing component 252 receives a signal for synchronizing timing or frequency, as described above, such as a satellite system source, which may include a GNSS, a device source where the device can transmit SLSSs used as a reference for synchronization, etc. In some examples, device sources can be classified into different device groups, where the one or more parameters can be further selected based on device group.

In one example, a device group may include a priority group for the device, which may be correlated to a distance between the device and a GNSS or other primary synchronization source, where the distance may include a location-based distance or a distance correlated to a number of devices that are in a synchronization chain between the device and the GNSS or other primary synchronization source. In some examples, the priority group may be defined based on, or determined dependent on, other parameters of the UE that transmits the SLSSs. In one example, a configuration of the UE can define the priority group. In another example, the priority group of the UE can be dependent on a resource, SLSS ID, PSBCH content, in-coverage (INC) bit in the PSBCH content, number of synchronization resources configured for transmitting the SLSS, etc.

FIG. 4 illustrates an example of a synchronization chain 400. In the synchronization chain 400, a GNSS 402 can be a primary synchronization source, and UE-1 404 directly synchronize timing and/or frequency to GNSS 402. UE-1 404 can transmit SLSSs over a SL broadcast channel, which UE-2 406 can receive and use to synchronize timing and/or frequency to UE-1 404. Similarly, UE-2 406 can transmit SLSSs over a SL broadcast channel, which UE-3 408 can receive and use to synchronize timing and/or frequency to UE-2 406, and UE-3 408 can transmit SLSSs over a SL broadcast channel, which UE-4 410 can receive and use to synchronize timing and/or frequency to UE-3 408, etc. As UEs continue to synchronize with one another, the timing and/or frequency can drift due to propagation delay or other radio environment conditions. In addition, in an example, the UEs can have a priority group assigned based on their distance to the GNSS 402, as described. For example, UE-1 404 can be priority group 1 as being directly synchronized to GNSS 402, whereas UE-2 406, UE-3 408, and UE-4 410 can be priority group 2, or additional priority groups can be used, etc. In any case, for example, parameter selecting component 254 can select different SL communication parameter values when synchronized to UEs in different priority groups.

Referring back to FIG. 3, in selecting the one or more parameters at Block 304, optionally at Block 308, a higher MCS can be selected where the type of the synchronization source includes a satellite source than where the type of synchronization source includes a device source. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select the higher MCS (e.g., a higher maximum MCS) where the type of synchronization source includes a satellite source (e.g., GNSS) than where the type of synchronization source includes a device source (e.g., another UE, which can be a RSU, another OBU, etc., in V2X) . For example, parameter selecting component 254 can select a high MCS, MCS_1 = 11, where synchronizing component 252 synchronizes to GNSS (e.g., UE-1 404 in FIG. 4 can select MCS_1 based on being synchronized with GNSS 402) , or can select a lower MCS, MCS_2 = 7, where synchronizing component 252 synchronizes to another UE (e.g., UE-2 406, UE-3 408, and UE-4 410 in FIG. 4 can select MCS_2 based on being synchronized to another UE) .

In another example, in selecting the one or more parameters at Block 304, and where the synchronization source is a device source (e.g., another UE) , optionally at Block 310, a MCS can be selected based on a priority group identified for the device source. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select the MCS (e.g., a maximum MCS) based on the priority group identified for the device source. For example, parameter selecting component 254 can select a higher MCS, MCS_2 = 8, where synchronizing component 252 synchronizes to a UE in priority group P1 (e.g., UE-2 406 in FIG. 4 can select MCS_2 based on being synchronized with UE-1 404) , or can select a lower MCS, MCS_3 = 7, where synchronizing component 252 synchronizes to another UE in priority group P2 (e.g., UE-3 408 in FIG. 4 can select MCS_3 based on being synchronized to UE-2-406) , etc.

In another example, in selecting the one or more parameters at Block 304, and where the synchronization source is a device source (e.g., another UE) , optionally at Block 312, a MCS can be selected based on a signal measurement of a signal received from the device source. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select the MCS (e.g., maximum MCS) based on the signal measurement of the signal received from the device source. For example, communicating component 242 can receive the signal, which can include the SLSS or other signal transmitted by the device source, such as a PSBCH demodulation reference signal (DMRS) . The signal measurement, for example, can include RSSI, RSRP, RSRQ, SNR, etc. of the SLSS or other signal. Where the signal measurement achieve a first threshold, a higher MCS can be selected than where the signal measurement does not achieve the first threshold. Where the signal achieves a second threshold but not the first threshold, a MCS that is lower than the higher MCS but is higher than a lower MCS can be selected than where the signal measurement does not achieve the second threshold. Said differently, for example, UE directly synced to GNSS can use max MCS = MCS_1, whereas UE synced to SLSS with RSRP > Threshold 1 can use max MCS = MCS_2, UE synced to SLSS with Threshold 1 > RSRP > Threshold 2 can use max MCS = MCS_3, and UE synced to SLSS with Threshold 2 > RSRP > Threshold 3 can use max MCS =MCS_4, etc., where MCS_1 > MCS_2 > MCS_3 > MCS_4.

For example, RSRP can be a filtered RSRP measurement on PSBCH DMRS as defined by third generation partnership project (3GPP) . This RSRP can measure how “far away” from a synchronization source is the UE in radio frequency (RF) terms. Lower RSRP can me the UE is further away. For example, Threshold 1 = -40 decibel-milliwatts (dBm) , Threshold 2 = -60dBm, Threshold 3 = -80dBm; MCS_1 = 11, MCS_2 = 8, MCS_3 = 7, MCS_4 = 5 for a configured MCS table. More generally, max MCS can be dependent on UE priority group (P1, P2, etc. ) as well as RSRP measurement, and parameter selecting component 254 can select the MCS based on the UE priority group of the UE from which the SLSSs are received and based on comparing the RSRP measurement to the threshold (s) .

In another example, the one or more parameters selected at action 304 can include a number of HARQ retransmissions (e.g., a maximum number of HARQ retransmissions that can be configured for the UE 104) , which may include an initial transmission. For example, in LTE V2X, number of HARQ N is either 1 (single transmission) or 2 (2 times blind transmission, e.g., not feedback-based retransmission) . More HARQ retransmissions can lead to more reliable reception at the cost of more system resource or channel loading. The UE can typically be configured to conserve resource, but if timing/frequency error is too large, a limited number of retransmission can be used to improve poor reception performance. In this regard, for example, parameter selecting component 254 can select the maximum number of HARQ retransmission to transmit data as a function of synchronization source. For example, UE directly synced to GNSS can select HARQ N = 1. UE synced to SLSS with RSRP > Threshold 1 (e.g., -60dBm) can select HARQ N = 1. UE synced to SLSS with Threshold 1 > RSRP can select HARQ N = 2. In another example, parameter selecting component 254 can select, for each synchronization condition, a combination of maximum MCS and number of HARQ retransmissions.

In an example in method 300, optionally at Block 314, a configuration can be received from a network node indicating a first MCS range to use in transmitting signals using one or more channel busy ratios (CBRs) and a second MCS range to use in transmitting the signals using the one or more CBRs where the type of synchronization source includes a device source. In an aspect, communicating component 242, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, etc., can receive, from the network node (e.g., a base station 102, another UE in SL communications, etc. ) a configuration indicating a first MCS range to use in transmitting signals using one or more channel busy ratios (CBRs) and a second MCS range to use in transmitting the signals using the one or more CBRs where the type of synchronization source includes a device source. In one example, communicating component 242 can receive the configuration in a system information block (SIB) from the base station 102, such as SIB26. In an example, SIB26, as defined in 3GPP, can include MCS ranges configured for each of multiple CBR levels (configured in SIB21 cbr-pssch-TxConfigList) . This SIB26 can be extended to further indicating the second MCS range to use for synchronization source as device source. For example, SIB26 defined in 3GPP may have a format similar to the following:

In this example, SIB26 can be extended to include another information element: MCS-PSSCH-Range-IND-r18, which can include includes minMCS and maxMCS for each CBR level. Considering the existing MCS range indication is applied to the normal cases, e.g., where UE is synchronized with GNSS, the additional MCS range list can be defined for the case when frequency/timing error is large due to absence of GNSS, e.g., UE is synchronized with SLSS.

In this example, in selecting the one or more parameters at Block 304, and where the synchronization source is a device source (e.g., another UE) , optionally at Block 316, a MCS can be selected based on the second MCS range where the type of synchronization source includes the device source. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select the MCS based on the second MCS range where the type of synchronization source includes the device source, as described above. In one example, parameter electing component 254 can select a CBR level correlated to the synchronization source type, and can select the maximum MCS associated with the selected CBR level.

In another example in method 300, optionally at Block 318, a number of subchannels to use in transmitting the signals can be selected based at least in part on the one or more parameters. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can select, based at least in part on the one or more parameters, the number of subchannels to use in transmitting the signals. For example, parameter selecting component 254 can select the number of subchannels to use in transmitting the signals based on the MCS, number of HARQ retransmissions, etc., and/or based on an estimated TB size. The TB size, when taken with the MCS and/or number of retransmissions, can impact the channel ratio (CR) of the number of subchannels the UE occupies in a window of time (e.g., 1 second) . The CR may be limited for the UE, and thus selecting different MCSs and/or number of retransmissions based on the synchronization source type may impact the CR for a given TB size. Accordingly, in some examples, parameter selecting component 254 can also modify other parameters to avoid exceeding the CR limit.

For example, when resources are reserved using semi-persistent scheduling (SPS) , further TB sizes can be estimated based on actual TB sizes arriving in the past. In an example, parameter selecting component 254 can select a number of subchannels to be able to support the maximum estimated future RB size using a maximum MCS. For same packet arrival time and packet size, transmitting with lower MCS (e.g., a greater number of subchannels) can result in higher CR. Thus, for example, where the selected MCS causes the UE to exceed (or meet) the CR limit, parameter selecting component 254 can select a smaller subchannel size to comply with the CR limit. This, however, may result in a higher MCS than the determined MCS.

Accordingly, in one example in method 300, optionally at Block 320, a notification can be sent to an application where the number of selected subchannels causes a CR to achieve a limit. In an aspect, parameter selecting component 254, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, communicating component 242, etc., can send, to the application (e.g., application 275 executing on UE 104 to communicate packets using wireless signal transmission) , the notification where the number of selected subchannels causes the CR to achieve the limit. In method 300, optionally at Block 322, packets based on an adjustment to a TB size, packet segmentation, or packet frequency can be received from the application and based at least in part on the notification. In an aspect, communicating component 242, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, etc., can receive, from the application and based at least in part on the notification, packets based on the adjustment to the TB size, packet segmentation, or packet frequency. For example, the application 275 can throttle the rate of packets being provided to lower layers for transmission based on the notification. In one example, application 275 can reduce packet size or packet segmentation. In another example, application 275 can reduce packet intensity or enlarge packet periodicity to result in less packets sent.

In method 300, at Block 306, the signals can be transmitted, based on the timing or frequency and the one or more parameters, to one or more other devices. In an aspect, communicating component 242, e.g., in conjunction with processor (s) 212, memory 216, transceiver 202, etc., can transmit, based on the timing or frequency and the one or more parameters, the signals to one or more other devices. For example, communicating component 242 can transmit the signals using a maximum MCS as selected based on the synchronization source type, priority group, signal measurement, etc., as described above. In one example, the signals can include sidelink transmissions, such as PSCCH transmissions, PSSCH transmissions, and/or the like, transmitted to other devices (e.g., other UEs) .

FIG. 5 is a block diagram of a MIMO communication system 500 including UEs 104-a, 104-b. The MIMO communication system 500 may illustrate aspects of the wireless communication access network 100 described with reference to FIG. 1. The UE 104-a may be an example of aspects of the UE 104 described with reference to FIGS. 1 and 3. The UE 104-a may be equipped with

antennas

534 and 535, and the UE 104-b may be equipped with

antennas

552 and 553. In the MIMO communication system 500, the UEs 104-a, 104-b may be able to send data over multiple communication links at the same time. Each communication link may be called a “layer” and the “rank” of the communication link may indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system where UE 104-a transmits two “layers, ” the rank of the communication link between the UE 104-a and the UE 104-b is two.

At the UE 104-a, a transmit (Tx) processor 520 may receive data from a data source. The transmit processor 520 may process the data. The transmit processor 520 may also generate control symbols or reference symbols. A transmit MIMO processor 530 may perform spatial processing (e.g., precoding) on data symbols, control symbols, or reference symbols, if applicable, and may provide output symbol streams to the transmit modulator/

demodulators

532 and 533. Each modulator/demodulator 532 through 533 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator/demodulator 532 through 533 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. In one example, DL signals from modulator/

demodulators

532 and 533 may be transmitted via the

antennas

534 and 535, respectively.

The UE 104-b may be an example of aspects of the UEs 104 described with reference to FIGS. 1 and 3. At the UE 104-b, the

UE antennas

552 and 553 may receive the signals from the UE 104-a (e.g., over a sidelink) and may provide the received signals to the modulator/

demodulators

554 and 555, respectively. Each modulator/demodulator 554 through 555 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator/demodulator 554 through 555 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 556 may obtain received symbols from the modulator/

demodulators

554 and 555, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive (Rx) processor 558 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE 104-b to a data output, and provide decoded control information to a processor 580, or memory 582.

At the UE 104-b, a transmit processor 564 may receive and process data from a data source. The transmit processor 564 may also generate reference symbols for a reference signal. The symbols from the transmit processor 564 may be precoded by a transmit MIMO processor 566 if applicable, further processed by the modulator/demodulators 554 and 555 (e.g., for SC-FDMA, etc. ) , and be transmitted to the UE 104-a in accordance with the communication parameters received from the UE 104-a. At the UE 104-a, the signals from the UE 104-b may be received by the

antennas

534 and 535, processed by the modulator/

demodulators

532 and 533, detected by a MIMO detector 536 if applicable, and further processed by a receive processor 538. The receive processor 538 may provide decoded data to a data output and to the processor 540 or memory 542.

The processor 540 and/or 580 may in some cases execute stored instructions to instantiate a communicating component 242 (see e.g., FIGS. 1 and 3) .

The components of the UEs 104-a, 104-b may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the MIMO communication system 500. Similarly, the components of the UE 104-a may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted components may be a means for performing one or more functions related to operation of the MIMO communication system 500.

The following aspects are illustrative only and aspects thereof may be combined with aspects of other embodiments or teaching described herein, without limitation.

Aspect 1 is a method for wireless communication including synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network, selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, where the type of the synchronization source includes a satellite source or a device source, and transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.

In Aspect 2, the method of Aspect 1 includes where the one or more parameters includes a maximum MCS to use for transmitting the signals.

In Aspect 3, the method of Aspect 2 includes where selecting the maximum MCS includes selecting a higher maximum MCS where the type of synchronization source includes the satellite source than where the type of synchronization source includes the device source.

In Aspect 4, the method of any of

Aspects

2 or 3 includes where the type of synchronization source is the device source, and where selecting the maximum MCS is further based on a priority group identified for the device source.

In Aspect 5, the method of Aspect 4 includes where selecting the maximum MCS is further based on at least one of a SLSS ID, PSBCH content, an in-coverage bit indicator in the PSBCH, or number of configured synchronization resources associated with the priority group.

In Aspect 6, the method of any of Aspects 2 to 5 includes where the type of synchronization source is the device source, and where selecting the maximum MCS is further based at least in part on a signal measurement of a signal received from the device source.

In Aspect 7, the method of Aspect 6 includes where the signal is a PSBCH DMRS, and where the signal measurement is a filtered reference signal received power measurement on the PSBCH DMRS.

In Aspect 8, the method of any of Aspects 6 or 7 includes where selecting the maximum MCS is further based on a priority group identified for the device source.

In Aspect 9, the method of any of Aspects 1 to 8 includes where the one or more parameters includes a number of hybrid automatic repeat/request retransmissions to use for transmitting the signals.

In Aspect 10, the method of Aspect 9 includes where the one or more parameters further includes a maximum MCS to use for transmitting the signals.

In Aspect 11, the method of any of Aspects 1 to 10 includes selecting, based at least in part on the one or more parameters, a number of subchannels to use in transmitting the signals.

In Aspect 12, the method of Aspect 11 includes where the one or more parameters include an estimated transport block size, a maximum MCS, and a number of hybrid automatic repeat/request retransmissions to use for transmitting the signals.

In Aspect 13, the method of any of Aspects 11 or 12 includes sending, to an application, a notification where the number of selected subchannels causes a channel ratio to exceed a limit.

In Aspect 14, the method of Aspect 13 includes where the application at least one of reduces a transport block size, reduces a packet segmentation, or reduces a packet frequency, based on the notification.

In Aspect 15, the method of any of Aspects 1 to 14 includes receiving, from a network node, a configuration indicating a first MCS range to use in transmitting the signals using one or more CBRs, and a second MCS range to use in transmitting the signals using the one or more CBRs where the type of the synchronization source includes the device source.

In Aspect 16, the method of Aspect 15 includes where selecting the one or more parameters includes selecting the MCS for transmitting the signals based on the second MCS range where the type of the synchronization source includes the device source.

Aspect 17 is an apparatus for wireless communication including a transceiver, a memory configured to store instructions, and one or more processors communicatively coupled with the memory and the transceiver, where the one or more processors are configured to execute the instructions to cause the apparatus to perform one or more of the methods of any of Aspects 1 to 16.

Aspect 18 is an apparatus for wireless communication including means for performing one or more of the methods of any of Aspects 1 to 16.

Aspect 19 is a computer-readable medium including code executable by one or more processors for wireless communications, the code including code for performing one or more of the methods of any of Aspects 1 to 16.

The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example, ” when used in this description, means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a specially programmed device, such as but not limited to a processor, a digital signal processor (DSP) , an ASIC, a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A specially programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A specially programmed processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, software, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a specially programmed processor, hardware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or. ” That is, unless specified otherwise, or clear from the context, the phrase, for example, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, for example the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (A and B and C) .

Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

An apparatus for wireless communication, comprising:

a memory configured to store instructions; and

one or more processors coupled with the memory, wherein the one or more processors are configured to:

synchronize, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network;

select, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source; and

transmit, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.
The apparatus of claim 1, wherein the one or more parameters includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.
The apparatus of claim 2, wherein the one or more processors are configured to select a higher maximum MCS where the type of synchronization source includes the satellite source than where the type of synchronization source includes the device source.
The apparatus of claim 2, wherein the type of synchronization source is the device source, and wherein the one or more processors are configured to select the maximum MCS further based on a priority group identified for the device source.
The apparatus of claim 4, wherein the one or more processors are configured to select the maximum MCS further based on at least one of a sidelink synchronization signal (SLSS) ID, primary sidelink broadcast channel (PSBCH) content, an in-coverage bit indicator in the PSBCH, or number of configured synchronization resources associated with the priority group.
The apparatus of claim 2, wherein the type of synchronization source is the device source, and wherein the one or more processors are configured to select the maximum MCS further based at least in part on a signal measurement of a signal received from the device source.
The apparatus of claim 6, wherein the signal is a PSBCH demodulation reference signal (DMRS) , and wherein the signal measurement is a filtered reference signal received power measurement on the PSBCH DMRS.
The apparatus of claim 6, wherein the one or more processors are configured to select the maximum MCS further based on a priority group identified for the device source.
The apparatus of claim 1, wherein the one or more parameters includes a number of hybrid automatic repeat/request retransmissions to use for transmitting the signals.
The apparatus of claim 9, wherein the one or more parameters further includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.
The apparatus of claim 1, wherein the one or more processors are configured to select, based at least in part on the one or more parameters, a number of subchannels to use in transmitting the signals.
The apparatus of claim 11, wherein the one or more parameters include an estimated transport block size, a maximum modulation and coding scheme (MCS) , and a number of hybrid automatic repeat/request retransmissions to use for transmitting the signals.
The apparatus of claim 11, wherein the one or more processors are configured to send, to an application, a notification where the number of selected subchannels causes a channel ratio to exceed a limit.
The apparatus of claim 13, wherein the application at least one of reduces a transport block size, reduces a packet segmentation, or reduces a packet frequency, based on the notification.
The apparatus of claim 1, wherein the one or more processors are configured to receive, from a network node, a configuration indicating a first modulation and coding scheme (MCS) range to use in transmitting the signals using one or more channel busy ratios (CBRs) , and a second MCS range to use in transmitting the signals using the one or more CBRs where the type of the synchronization source includes the device source.
The apparatus of claim 15, wherein the one or more processors are configured to select the one or more parameters including selecting a MCS for transmitting the signals based on the second MCS range where the type of the synchronization source includes the device source.
A method for wireless communication, comprising:

synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network;

selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source; and

transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.
The method of claim 17, wherein the one or more parameters includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.
The method of claim 18, wherein selecting the maximum MCS includes selecting a higher maximum MCS where the type of synchronization source includes the satellite source than where the type of synchronization source includes the device source.
The method of claim 18, wherein the type of synchronization source is the device source, and wherein selecting the maximum MCS is further based on a priority group identified for the device source.
The method of claim 20, wherein selecting the maximum MCS is further based on at least one of a sidelink synchronization signal (SLSS) ID, primary sidelink broadcast channel (PSBCH) content, an in-coverage bit indicator in the PSBCH, or number of configured synchronization resources associated with the priority group.
The method of claim 18, wherein the type of synchronization source is the device source, and wherein selecting the maximum MCS is further based at least in part on a signal measurement of a signal received from the device source.
The method of claim 17, wherein the one or more parameters includes a number of hybrid automatic repeat/request retransmissions to use for transmitting the signals.
The method of claim 23, wherein the one or more parameters further includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.
The method of claim 24, further comprising selecting, based at least in part on the one or more parameters, a number of subchannels to use in transmitting the signals.
The method of claim 17, further comprising receiving, from a network node, a configuration indicating a first modulation and coding scheme (MCS) range to use in transmitting the signals using one or more channel busy ratios (CBRs) , and a second MCS range to use in transmitting the signals using the one or more CBRs where the type of the synchronization source includes the device source.
An apparatus for wireless communication, comprising:

means for synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network;

means for selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source; and

means for transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.
The apparatus of claim 27, wherein the one or more parameters includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.
A computer-readable medium, comprising code executable by one or more processors for wireless communication, the code comprises code for:

synchronizing, with a synchronization source, a timing or frequency for transmitting signals in a wireless communication network;

selecting, based at least in part on a type of the synchronization source, one or more parameters for transmitting the signals, wherein the type of the synchronization source includes a satellite source or a device source; and

transmitting, based on the timing or frequency and the one or more parameters, the signals to one or more other devices.
The computer-readable medium of claim 29, wherein the one or more parameters includes a maximum modulation and coding scheme (MCS) to use for transmitting the signals.