Sidelink group management for group communication with transmit power control

Abstract

Techniques for wireless communications are disclosed. In one aspect, a user equipment (UE) participating in a sidelink communication group communicates with one or more member UEs of the sidelink communication group, and based on a determination of at least a transmit power for a group presence notification message and an expectation of the UE to send a group presence notification message of the sidelink communication group according to communicating with the one or more member UEs, sends a group presence notification message of the sidelink communication group.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Application No. 63 / 003,088, filed on March 31, 2020, entitled “SIDELINK GROUP MANAGEMENT FOR TRANSMIT POWER CONTROLLED GROUP COMMUNICATIONS,” and U.S. Non-Provisional Application No. 17 / 217,836, filed on March 30, 2021, entitled “SIDELINK GROUP MANAGEMENT FOR TRANSMIT POWERCONTROLLED GROUP COMMUNICATIONS,” both of which are assigned to the assignee hereof and are expressly incorporated herein by reference in their entireties. Technical Field

[0003] Aspects of the present disclosure generally relate to wireless communications. Background Art

[0004] Wireless communication systems have evolved through generations, including first generation analog wireless telephone service (1G), second generation (2G) digital wireless telephone service (including transitional 2.5G and 2.75G networks), third generation (3G) high speed data, Internet-enabled wireless services, and fourth generation (4G) services (e.g., Long Term Evolution (LTE) or WiMax). Currently, many different types of wireless communication systems are in use, including cellular systems and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog Advanced Mobile Phone System (AMPS) and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile Communications (GSM), and the like.

[0005] The fifth generation (5G) wireless standard, called New Radio (NR), calls for higher data transfer speeds, more connections, and better coverage, among other improvements. The 5G standard according to the Next Generation Mobile Network Alliance is designed to provide data rates of tens of megabits per second to each of tens of thousands of users and 1 gigabit per second to dozens of employees in an office. To support large sensor deployments, hundreds of thousands of simultaneous connections should be supported. Therefore, the spectrum efficiency of 5G mobile communications should be significantly improved compared to the current 4G standard. In addition, signaling efficiency should be improved and latency should be significantly reduced compared to the current standard.

[0006] In other examples, vehicle-to-everything (V2X) communication technologies are being implemented to support autonomous driving applications, such as wireless communications between vehicles, between vehicles and roadside infrastructure, between vehicles and pedestrians, etc., leveraging the increased data rates and reduced latency of 5G. Summary of the invention

[0007] The following presents a simplified summary of one or more aspects disclosed herein. Therefore, the following summary should not be considered as an extensive review of all expected aspects, nor should it be considered that the following summary identifies key or important elements related to all expected aspects or delimits the scope associated with any particular aspect. Therefore, the following summary has the sole purpose of presenting certain concepts related to one or more aspects related to the mechanisms disclosed herein in a simplified form before the specific embodiments presented below.

[0008] On the one hand, a wireless communication method performed by a user equipment (UE) participating in a sidelink communication group includes communicating with one or more member UEs of the sidelink communication group, and sending a group presence announcement message of the sidelink communication group based on a determination of at least a transmit power for a group presence announcement message and an expectation by the UE to send a group presence announcement message of the sidelink communication group based on communicating with the one or more member UEs.

[0009] In one aspect, a user equipment (UE) includes a memory; a communication interface; and at least one processor communicatively coupled to the memory and the communication interface, the at least one processor being configured to: communicate with one or more member UEs of a sidelink communication group; and cause the communication interface to send a group presence notification message of the sidelink communication group based on a determination of at least a transmit power for a group presence notification message and an expectation by the UE to send a group presence notification message of the sidelink communication group according to communicating with the one or more member UEs.

[0010] In one aspect, a user equipment (UE) includes a component for communicating with one or more member UEs of a sidelink communication group; and a component for sending a group presence announcement message of a sidelink communication group based on communicating with the one or more member UEs, a determination of at least a transmit power for the group presence announcement message and an expectation by the UE to send a group presence announcement message of the sidelink communication group.

[0011] On the one hand, a non-transitory computer-readable medium stores computer-executable instructions, which, when executed by a user equipment (UE), cause the UE to: communicate with one or more member UEs of the sidelink communication group; and send a group presence notification message of the sidelink communication group based on a determination of at least a transmit power for the group presence notification message and an expectation of the UE to send a group presence notification message of the sidelink communication group according to communicating with the one or more member UEs.

[0012] Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are presented to aid in describing various aspects of the disclosure and are provided solely for illustration of the aspects and not limitation thereof.

[0014] Figure 1 An example wireless communication system in accordance with aspects of the present disclosure is illustrated.

[0015] Figure 2A and Figure 2B An example wireless network structure is illustrated in accordance with aspects of the present disclosure.

[0016] Figure 3 An example of a wireless communication system supporting unicast sidelink setup according to aspects of the present disclosure is illustrated.

[0017] Figure 4 is a block diagram illustrating various components of an example UE in accordance with aspects of the present disclosure.

[0018] Figure 5 An example wireless communication system in accordance with aspects of the present disclosure is illustrated.

[0019] Figure 6

[0013] An example method of wireless communication according to aspects of the present disclosure is illustrated. DETAILED DESCRIPTION

[0020] Various aspects of the present disclosure are provided in the following description and in the related drawings for various examples provided for illustrative purposes. Alternative aspects may be designed without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted to avoid obscuring the relevant details of the present disclosure.

[0021] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term "aspects of the disclosure" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation.

[0022] Those skilled in the art will appreciate that any of a variety of different technologies and techniques may be used to represent the information and signals described below. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0023] In addition, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be appreciated that the various actions described herein may be performed by a specific circuit (e.g., an application specific integrated circuit (ASIC)), by program instructions being executed by one or more processors, or by a combination of the two. Additionally, it may be considered that the sequence of (one or more) actions described herein is fully embodied in any form of non-transitory computer-readable storage medium having a set of corresponding computer instructions stored therein, which, when executed, will cause or instruct the associated processor of the device to perform the functionality described herein. Therefore, various aspects of the present disclosure may be embodied in many different forms, all of which are contemplated to be within the scope of the subject matter claimed. In addition, for each aspect described herein, the corresponding form of any such aspect may be described herein as, for example, "logic is configured to" perform the described actions.

[0024] As used herein, unless otherwise specified, the terms "user equipment" (UE), "vehicle UE" (V-UE), "pedestrian UE" (P-UE), and "base station" are not intended to be specific or otherwise limited to any particular radio access technology (RAT). In general, a UE can be any wireless communication device used by a user to communicate over a wireless communication network (e.g., a car computer, a vehicle navigation device, a mobile phone, a router, a tablet computer, a laptop computer, an asset locating device, a wearable device (e.g., a smart watch, glasses, augmented reality (AR) / virtual reality (VR) headsets, etc.), a vehicle (e.g., a car, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.). A UE can be mobile or (e.g., at certain times) stationary and can communicate with a radio access network (RAN). As used herein, the term "UE" can be interchangeably referred to as a "mobile device", "access terminal" or "AT", "client device", "wireless device", "subscriber device", "subscriber terminal", "subscriber station", "user terminal" or UT, "mobile terminal", "mobile station" or variations thereof.

[0025] V-UE is a type of UE and can be any vehicle-mounted wireless communication device, such as a navigation system, a warning system, a head-up display (HUD), an on-board computer, an on-board infotainment system, an automatic driving system (ADS), an advanced driver assistance system (ADAS), etc. Alternatively, the V-UE can be a portable wireless communication device (e.g., a mobile phone, a tablet computer, etc.) carried by the driver of the vehicle or a passenger in the vehicle. Depending on the context, the term "V-UE" can refer to a vehicle-mounted wireless communication device or the vehicle itself. P-UE is a type of UE and can be a portable wireless communication device carried by a pedestrian (i.e., a user who is not driving or riding in a vehicle). Typically, the UE can communicate with the core network via the RAN, and the UE can be connected to an external network such as the Internet and to other UEs through the core network. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through a wired access network, a wireless local area network (WLAN) (e.g., based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc.), etc.

[0026] A base station may operate according to one of several RATs communicating with a UE, depending on the network in which it is deployed, and may alternatively be referred to as an access point (AP), a network node, a NodeB, an evolved NodeB (eNB), a next generation eNB (ng-eNB), a new radio (NR) NodeB (also referred to as a gNB or gNodeB), etc. A base station may be primarily used to support wireless access for UEs, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, a base station may provide a pure edge node signaling function, while in other systems, a base station may provide other control and / or network management functions. A UE may signal a base station via a communication link, which is referred to as an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A base station may signal a UE via a communication link, which is referred to as a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term "traffic channel (TCH)" may refer to a UL / reverse or DL / forward traffic channel.

[0027] The term "base station" may refer to a single physical transmit-receive point (TRP) or to multiple physical TRPs, which may or may not be co-located. For example, where the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to the cell (or several cell sectors) of the base station. Where the term "base station" refers to multiple co-located physical TRPs, the physical TRP may be an antenna array of the base station (e.g., as in a multiple-input multiple-output (MIMO) system, or where the base station employs beamforming). Where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRP may be a serving base station that receives measurement reports from a UE and an adjacent base station whose reference radio frequency (RF) signal the UE is measuring. Because, as used herein, a TRP is a point at which a base station transmits and receives wireless signals, references to transmissions from a base station or receptions at a base station will be understood to refer to a specific TRP of a base station.

[0028] In some implementations of supporting UE positioning, a base station may not support wireless access by a UE (e.g., may not support data, voice, and / or signaling connections for the UE), but may send a reference RF signal to the UE for measurement by the UE and / or may receive and measure a signal sent by the UE. Such a base station may be referred to as a positioning beacon (e.g., when sending an RF signal to the UE) and / or a position measurement unit (e.g., when receiving and measuring a signal from the UE).

[0029] An "RF signal" includes an electromagnetic wave of a given frequency that transmits information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same RF signal transmitted on different paths between a transmitter and a receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal," where it is clear from the context that the term "signal" refers to either a wireless signal or an RF signal.

[0030] Figure 1 An example wireless communication system 100 according to various aspects of the present disclosure is illustrated. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 (labeled as "BS") and various UEs 104. The base stations 102 may include macro cell base stations (high power cellular base stations) and / or small cell base stations (low power cellular base stations). In one aspect, the macro cell base station 102 may include an eNB and / or ng-eNB in ​​which the wireless communication system 100 corresponds to an LTE network, or a gNB in ​​which the wireless communication system 100 corresponds to an NR network, or a combination of both, and the small cell base station may include a femto cell, a pico cell, a micro cell, etc.

[0031] The base stations 102 may collectively form a RAN and interface with a core network 174 (e.g., an evolved packet core (EPC) or a 5G core (5GC)) via backhaul links 122 and connect to one or more location servers 172 (e.g., a location management function (LMF) or a secure user plane location (SUPL) location platform (SLP)) via the core network 174. The location server(s) 172 may be part of the core network 174 or may be external to the core network 174. The base stations 102 may perform, among other functions, one or more of the following: transmitting; Delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and warning messages. The base stations 102 can communicate with each other directly or indirectly (e.g., through EPC / 5GC) over the backhaul link 134, which can be wired or wireless.

[0032] Base station 102 can communicate wirelessly with UE 104. Each of base stations 102 can provide communication coverage for a respective geographic coverage area 110. In one aspect, base station 102 in each geographic coverage area 110 can support one or more cells. A "cell" is a logical communication entity for communicating with a base station (e.g., through some frequency resources, referred to as carrier frequency, component carrier, carrier, frequency band, etc.), and can be associated with an identifier (e.g., physical cell identifier (PCI), enhanced cell identifier (ECI), virtual cell identifier (VCI), global cell identifier (CGI), etc.) for distinguishing cells operating via the same or different carrier frequencies. In some cases, different cells can be configured according to different protocol types (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or other) that can provide access to different types of UEs. Because a specific base station supports one cell, the term "cell" can refer to one or both of a logical communication entity and a base station supporting the logical communication entity, depending on the context. In some cases, the term “cell” may also refer to a geographic coverage area (eg, a sector) of a base station, as long as a carrier frequency can be detected and used for communications within certain portions of the geographic coverage area 110 .

[0033] Although the geographic coverage areas 110 of adjacent macrocell base stations 102 may partially overlap (e.g., in a handoff region), some geographic coverage areas 110 may be substantially overlapped by larger geographic coverage areas 110. For example, a small cell base station 102' (labeled "SC" for "small cell") may have a geographic coverage area 110' that substantially overlaps with the geographic coverage areas 110 of one or more macrocell base stations 102. A network that includes both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB) that may provide services to a restricted group called a closed subscriber group (CSG).

[0034] The communication link 120 between the base station 102 and the UE 104 may include uplink (also referred to as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also referred to as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna techniques including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric with respect to the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0035] The wireless communication system 100 may also include a wireless local area network (WLAN) access point (AP) 150 that communicates with a WLAN station (STA) 152 in an unlicensed spectrum (e.g., 5 GHz) via a communication link 154. When communicating in the unlicensed spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or a listen before talk (LBT) process to determine whether the channel is available before communicating.

[0036] The small cell base station 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell base station 102' can adopt LTE or NR technology and use the same 5GHz unlicensed spectrum used by the WLAN AP 150. The small cell base station 102' adopting LTE / 5G in the unlicensed spectrum can increase the coverage of the access network and / or increase its capacity. NR in the unlicensed spectrum can be referred to as NR-U. LTE in the unlicensed spectrum can be referred to as LTE-U, License Assisted Access (LAA) or MulteFire.

[0037] The wireless communication system 100 may also include a mmW base station 180 that can communicate with UE 182 at millimeter wave (mmW) frequencies and / or near mmW frequencies. Extremely high frequency (EHF) is part of RF in the electromagnetic spectrum. EHF has a range between 30 GHz and 300 GHz and a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Close to mmW may extend down to 3 GHz frequencies with a wavelength of 100 mm waves. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also known as centimeter waves. Communications using mmW / near mmW radio frequency bands have higher path losses and relatively short ranges. The mmW base station 180 and UE 182 can utilize beamforming (transmitting and / or receiving) on ​​the mmW communication link 184 to compensate for extremely high path losses and short distances. In addition, it should be understood that in alternative configurations, one or more base stations 102 may also use mmW or near mmW and beamforming for transmission. Therefore, it should be understood that the foregoing diagrams are merely examples and should not be construed as limiting the various aspects of the disclosure.

[0038] Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, the signal is broadcast in all directions (omnidirectional). Through transmit beamforming, the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal to (multiple) receiving devices. In order to change the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each transmitter of one or more transmitters that broadcast the RF signal. For example, the network node can use an antenna array (referred to as a "phased array" or "antenna array") that generates RF beams that can be "steered" to point to different directions without actually moving the antenna. Specifically, the RF current from the transmitter is fed to each antenna in the correct phase relationship so that the radio waves from the respective antennas are added together to increase the radiation in the desired direction while canceling to suppress the radiation in the undesired direction.

[0039] The transmit beams can be quasi-co-located, which means that they appear to have the same parameters in the receiver (e.g., UE) regardless of whether the transmit antennas of the network nodes themselves are physically co-located. In NR, there are four types of quasi-co-location (QCL) relationships. Specifically, a given type of QCL relationship means that certain parameters about the second reference RF signal on the second beam can be derived from information about the source reference RF signal on the source beam. Therefore, if the source reference RF signal is QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay and delay spread of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type D, the receiver can use the source reference RF signal to estimate the spatial reception parameters of the second reference RF signal sent on the same channel.

[0040] In receive beamforming, the receiver uses a receive beam to amplify the RF signal detected on a given channel. For example, the receiver may increase the gain setting and / or adjust the phase setting of the antenna array in a particular direction to amplify the RF signal received from that direction (e.g., increase the gain level of the RF signal). Therefore, when a receiver is said to be beamforming in a certain direction, it means that the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of the RF signal received from that direction.

[0041] The transmit and receive beams may be spatially correlated. The spatial relationship means that parameters of a second beam (e.g., a transmit or receive beam) of a second reference signal may be derived from information about a first beam (e.g., a receive beam or a transmit beam) of a first reference signal. For example, a UE may use a specific receive beam to receive a reference downlink reference signal (e.g., a synchronization signal block (SSB)) from a base station. The UE may then form a transmit beam for transmitting an uplink reference signal (e.g., a sounding reference signal (SRS)) to the base station based on the parameters of the receive beam.

[0042] Note that a "downlink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station is forming a downlink beam to send a reference signal to the UE, the downlink beam is a transmit beam. However, if the UE is forming a downlink beam, it is a receive beam for receiving downlink reference signals. Similarly, an "uplink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station is forming an uplink beam, it is an uplink receive beam, and if the UE is forming an uplink beam, it is an uplink transmit beam.

[0043] In 5G, the spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). The mmW band generally includes the FR2, FR3, and FR4 frequency ranges. Therefore, the terms "mmW" and "FR2" or "FR3" or "FR4" are generally used interchangeably.

[0044] In a multi-carrier system (such as 5G), one of the carrier frequencies is called the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", and the remaining carrier frequencies are called "secondary carriers" or "secondary serving cells" or "SCells". In carrier aggregation, the anchor carrier is a carrier operating on the primary frequency (e.g., FR1) used by the UE 104 / 182 and the cell in which the UE 104 / 182 performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels and can be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that can be configured once an RRC connection is established between the UE 104 and the anchor carrier, and can be used to provide additional radio resources. In some cases, the secondary carrier can be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals, for example, since the primary uplink and downlink carriers are typically UE-specific, those UE-specific information and signals may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same is true for the uplink primary carrier. The network is able to change the primary carrier of any UE 104 / 182 at any time. For example, this is done to balance the load on different carriers. Because a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency / component carrier on which some base stations are communicating, the terms "cell", "serving cell", "component carrier", "carrier frequency", etc. can be used interchangeably.

[0045] For example, still refer to Figure 1 , one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (or "PCell"), and the other frequencies utilized by the macrocell base station 102 and / or the mmW base station 180 may be secondary carriers ("SCells"). Simultaneous transmission and / or reception of multiple carriers enables the UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically result in a two-fold increase in data rate (i.e., 40 MHz) compared to the rate achieved by a single 20 MHz carrier.

[0046] exist Figure 1 In the example of FIG. 1 , one or more Earth-orbiting satellite positioning information system (SPS) spacecraft (SV) 112 (eg, satellites) may be used as any of the illustrated UEs (for simplicity, in FIG. 1 ). Figure 1104). UE 104 may include one or more dedicated SPS receivers, which are specifically designed to receive SPS signals 124 for deriving geographic location information from SV 112. SPS generally includes a transmitter system (e.g., SV 112) that is positioned so that receivers (e.g., UE 104) determine their positions on or above the earth based at least in part on signals received from the transmitter (e.g., SPS signals 124). Such transmitters generally transmit signals marked with a repetitive pseudo-random noise (PN) code of a set number of chips. Although generally located in SV 112, the transmitter may sometimes be located on a ground-based control station, base station 102, and / or other UE 104.

[0047] The use of the SPS signal 124 may be enhanced by various satellite-based augmentation systems (SBAS) that may be associated with or otherwise support use with one or more global and / or regional navigation satellite systems. For example, the SBAS may include augmentation system(s) that provide integrity information, differential corrections, etc., such as the Wide Area Augmentation System (WAAS), the European Geosynchronous Navigation Overlay Service (EGNOS), the Multifunction Satellite Augmentation System (MSAS), the Global Positioning System (GPS) Assisted Geographic Augmentation Navigation, or the GPS and Geographic Augmentation Navigation System (GAGAN), etc. Thus, as used herein, an SPS may include any combination of one or more global and / or regional navigation satellite systems and / or augmentation systems, and the SPS signal 124 may include an SPS, a SPS-like, and / or other signals associated with such one or more SPSs.

[0048] In other examples, leveraging NR's increased data rates and reduced latency, vehicle-to-everything (V2X) communication technologies are being implemented to support intelligent transportation system (ITS) applications, such as wireless communications between vehicles (vehicle-to-vehicle (V2V)), between vehicles and roadside infrastructure (vehicle-to-infrastructure (V2I)), and between vehicles and pedestrians (vehicle-to-pedestrian (V2P)). The goal is to enable vehicles to sense their surroundings and communicate that information to other vehicles, infrastructure, and personal mobile devices. Such vehicle communications will enable safety, mobility, and environmental improvements that current technology cannot provide. Once fully implemented, the technology is expected to reduce unimpaired vehicle collisions by 80%.

[0049] Still reference Figure 1, the wireless communication system 100 may include a plurality of V-UEs 160 that may communicate with a base station 102 via a communication link 120 (e.g., using a Uu interface). The V-UEs 160 may also communicate directly with each other via a wireless sidelink 162, with a roadside access point 164 (also referred to as a “roadside unit”) via a wireless sidelink 166, or with a UE 104 via a wireless sidelink 168. A wireless sidelink (or simply a “sidelink”) is an adaptation of a core cellular (e.g., LTE, NR) standard that allows direct communication between two or more UEs without communicating through a base station. Sidelink communications may be unicast or multicast and may be used for device-to-device (D2D) media sharing, V2V communications, V2X communications (e.g., cellular V2X (cV2X) communications, enhanced V2X (eV2X) communications, etc.), emergency rescue applications, etc. One or more of the group of V-UEs 160 using sidelink communication may be within the geographic coverage area 110 of the base station 102. Other V-UEs 160 in such a group may be outside the geographic coverage area 110 of the base station 102 or otherwise unable to receive transmissions from the base station 102. In some cases, the group of V-UEs 160 communicating via sidelink communication may utilize a one-to-many (1:M) system, where each V-UE 160 transmits to each other V-UE 160 in the group. In some cases, the base station 102 facilitates the scheduling of resources for sidelink communication. In other cases, sidelink communication is performed between V-UEs 160 without the involvement of the base station 102.

[0050] In one aspect, the sidelinks 162, 166, 168 can operate over an associated wireless communication medium that can be shared with other vehicles and / or infrastructure access points and other wireless communications between other RATs. A "medium" may include one or more time, frequency, and / or spatial communication resources (e.g., covering one or more channels across one or more carriers) associated with wireless communications between one or more transmitter / receiver pairs.

[0051] In one aspect, the sidelinks 162, 166, 168 may be cV2X links. The first generation of cV2X has been standardized in LTE, and the next generation is expected to be defined in NR. cV2X is a cellular technology that also supports device-to-device communications. In the United States and Europe, cV2X is expected to operate in the authorized ITS band below (sub) 6 GHz. Other bands may be allocated to other countries. Therefore, as a specific example, the associated medium used by the sidelinks 162, 166, 168 may correspond to at least a portion of the authorized ITS band below 6 GHz. However, the present disclosure is not limited to this band or cellular technology.

[0052] In one aspect, the sidelinks 162, 166, 168 may be dedicated short-range communication (DSRC) links. DSRC is a one-way or two-way short-range to medium-range wireless communication protocol that uses the Wireless Access in Vehicular Environment (WAVE) protocol, also known as IEEE 802.11p, for V2V, V2I, and V2P communications. IEEE 802.11p is an approved revision of the IEEE 802.11 standard and operates in the authorized ITS band 5.9 GHz (5.85-5.925 GHz) in the United States. In Europe, IEEE 802.11p operates in the ITSG5A band (5.875–5.905 MHz). Other bands may be allocated to other countries. The V2V communications briefly described above occur on a safety channel, which in the United States is typically a 10 MHz channel dedicated to safety purposes. The remainder of the DSRC band (75 MHz in total bandwidth) is intended for other driver-related services such as road rules, toll collection, parking automation, etc. Thus, as a specific example, the associated medium used by the sidelinks 162, 166, 168 may correspond to at least a portion of the licensed ITS band at 5.9 GHz.

[0053] Alternatively, the associated medium may correspond to at least a portion of an unlicensed frequency band shared among the various RATs. Although different licensed frequency bands have been reserved for certain communication systems (e.g., by government entities such as the Federal Communications Commission (FCC) in the United States), these systems (particularly those employing small cell access points) have recently expanded operations to unlicensed frequency bands, such as the Unlicensed National Information Infrastructure (U-NII) band used by wireless local area network (WLAN) technologies (most notably the IEEE 802.11x WLAN commonly referred to as "Wi-Fi") technologies. Example systems of this type include different variants of CDMA systems, TDMA systems, FDMA systems, orthogonal FDMA (OFDMA) systems, single carrier FDMA (SC-FDMA) systems, and the like.

[0054] Communication between V-UEs 160 is referred to as V2V communication, communication between V-UEs 160 and one or more roadside access points 164 is referred to as V2I communication, and communication between V-UEs 160 and one or more UEs 104 (where UEs 104 are P-UEs) is referred to as V2P communication. V2V communication between V-UEs 160 may include, for example, information about the position, speed, acceleration, heading, and other vehicle data of the V-UEs 160. V2I information received at the V-UEs 160 from one or more roadside access points 164 may include, for example, road rules, parking automation information, etc. V2P communication between V-UEs 160 and UEs 104 may include, for example, information about the position, speed, acceleration, and heading of the V-UEs 160 and the position, speed (e.g., the speed of a user carrying the UE 104 on a bicycle), and heading of the UEs 104.

[0055] Note that although Figure 1 Only two of the UEs are shown as V-UEs (V-UE 160), but any of the illustrated UEs (e.g., UE 104, 152, 182, 190) may be a V-UE. In addition, although only V-UE 160 and a single UE 104 are shown as connected via a sidelink, Figure 1 Any of the UEs shown in the figure (whether V-UE, P-UE, etc.) can perform sidelink communications. In addition, although only UE 182 is described as being capable of beamforming, any of the UEs shown (including V-UE 160) can perform beamforming. In the case where V-UE 160 is capable of beamforming, they can perform beamforming toward each other (i.e., toward other V-UE 160), toward roadside access points 164, toward other UEs (e.g., UE 104, 152, 182, 190), etc. Therefore, in some cases, V-UE 160 can utilize beamforming on sidelinks 162, 166, and 168.

[0056] The wireless communication system 100 may also include one or more UEs, such as UE 190, which are indirectly connected to one or more communication networks via one or more device-to-device (D2D) point-to-point (P2P) links. Figure 1In the example of , UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of base stations 102 (e.g., through which UE 190 can indirectly obtain cellular connectivity), and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which UE 190 can indirectly obtain WLAN-based network connectivity). In the example, D2D P2P links 192 and 194 can be supported by any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Etc. As another example, D2D P2P links 192 and 194 may be sidelinks, as described above with reference to sidelinks 162 , 166 , and 168 .

[0057] Figure 2A An example wireless network structure 200 is illustrated. For example, the 5GC 210 (also referred to as the Next Generation Core (NGC)) can be functionally viewed as a control plane (C-plane) function 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane (U-plane) function 212 (e.g., UE gateway function, access to data networks, IP routing, etc.), which operate in coordination to form a core network. The user plane interface (NG-U) 213 and the control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210, and specifically to the user plane function 212 and the control plane function 214, respectively. In additional configurations, the ng-eNB 224 can also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and via the NG-U 213 to the user plane function 212. In addition, the ng-eNB 224 can communicate directly with the gNB 222 via the backhaul connection 223. In some configurations, the next generation RAN (NG-RAN) 220 may have one or more gNBs 222, while other configurations include one or more of ng-eNBs 224 and gNBs 222. The gNB 222 or the ng-eNB 224 (or both the gNB 222 and the ng-eNB 224) may communicate with one or more UEs 204 (e.g., any UE described herein).

[0058] Another optional aspect may include a location server 230 that can communicate with the 5GC 210 to provide location assistance for (multiple) UEs 204. The location server 230 can be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed on multiple physical servers, etc.), or alternatively, each server can correspond to a single server. The location server 230 can be configured to support one or more location services for UEs 204, and UEs 204 can be connected to the location server 230 via the core network, the 5GC 210, and / or via the Internet (not shown). In addition, the location server 230 can be integrated into a component of the core network, or alternatively can be external to the core network (e.g., a third-party server, such as an original equipment manufacturer (OEM) server or a service host).

[0059] Figure 2B Another example wireless network structure 250 is shown. For example, 5GC 260 (which may correspond to Figure 2AThe 5GC 210 in the 5GC 210 can be functionally considered as a control plane function provided by an access and mobility management function (AMF) 264, and a user plane function provided by a user plane function (UPF) 262, which operate in cooperation to form the core network (i.e., 5GC 260). The functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transmission of session management (SM) messages between one or more UEs 204 (e.g., any UE described herein) and a session management function (SMF) 266, a transparent proxy service for routing SM messages, access authentication and access authorization, transmission of short message service (SMS) messages between UE 204 and a short message service function (SMSF) (not shown), and a security anchor function (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and UE 204, and receives an intermediate key established as a result of the UE 204 authentication process. In the case of authentication based on the UMTS (Universal Mobile Telecommunications System) Subscriber Identity Module (USIM), the AMF 264 retrieves security materials from the AUSF. The functions of the AMF 264 also include security context management (SCM). The SCM receives keys from the SEAF, which are used to derive keys for specific access networks. The functions of the AMF 264 also include location service management for regulatory services, transmission of location service messages between the UE 204 and the Location Management Function (LMF) 270 (which acts as a location server 230), transmission of location service messages between the NG-RAN 220 and the LMF 270, EPS bearer identifier allocation for interaction with the Evolved Packet System (EPS), and UE 204 mobility event notification. In addition, the AMF 264 also supports the functions of non-3GPP (Third Generation Partnership Project) access networks.

[0060] The functions of the UPF 262 include: acting as an anchor point for intra-RAT / inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point for interconnection with a data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, handling quality of service (QoS) for the user plane (e.g., uplink / downlink rate enforcement, reflective QoS marking in downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in uplink and downlink, downlink packet buffering and downlink data notification triggering, and issuing and forwarding one or more "end markers" to the source RAN node. The UPF 262 may also support the transmission of location service messages on the user plane between the UE 204 and a location server such as the SLP 272.

[0061] The functions of SMF 266 include session management, UE Internet Protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at UPF 262 to route traffic to the appropriate destination, control of QoS and partial policy enforcement, and downlink data notification. The interface through which SMF 266 communicates with AMF 264 is called the N11 interface.

[0062] Another optional aspect may include an LMF 270 that can communicate with the 5GC 260 to provide location assistance for the UE 204. The LMF 270 can be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed across multiple physical servers, etc.), or alternatively, each server can correspond to a single server. The LMF 270 can be configured to support one or more location services for the UE 204, which can be connected to the LMF 270 via the core network, the 5GC 260, and / or via the Internet (not shown). The SLP 272 can support similar functionality to the LMF 270, but the LMF 270 can communicate with the AMF 264, the NG-RAN 220, and the UE 204 via a control plane (e.g., using interfaces and protocols intended to convey signaling messages rather than voice or data), and the SLP 272 can communicate with the UE 204 and external clients ( Figure 2B ) to communicate (e.g., using protocols intended to carry voice and / or data, such as the Transmission Control Protocol (TCP) and / or IP).

[0063] The user plane interface 263 and the control plane interface 265 connect the 5GC 260 (particularly the UPF 262 and the AMF 264) to one or more gNBs 222 and / or ng-eNBs 224 in the NG-RAN 220, respectively. The interface between the gNB(s) 222 and / or ng-eNB(s) 224 and the AMF 264 is referred to as the "N2" interface, and the interface between the gNB(s) 222 and / or ng-eNB(s) 224 and the UPF 262 is referred to as the "N3" interface. The gNB(s) 222 and / or ng-eNB(s) 224 of the NG-RAN 220 may communicate directly with each other via a backhaul connection 223 referred to as an "Xn-C" interface. One or more of the gNBs 222 and / or ng-eNBs 224 may communicate with one or more UEs 204 via a wireless interface referred to as a "Uu" interface.

[0064] The functions of the gNB 222 are divided between the gNB Central Unit (gNB-CU) 226 and one or more gNB Distributed Units (gNB-DU) 228. The interface 232 between the gNB-CU 226 and one or more gNB-DUs 228 is referred to as the "F1" interface. The gNB-CU 226 is a logical node that includes base station functions for transmitting user data, mobility control, radio access network sharing, positioning, session management, etc., except for those functions specifically assigned to the gNB-DU 228. More specifically, the gNB-CU 226 hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols of the gNB 222. The gNB-DU 228 is a logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of the gNB 222. Its operation is controlled by the gNB-CU 226. One gNB-DU 228 can support one or more cells, and one cell is supported by only one gNB-DU 228. Therefore, the UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCP layers, and communicates with the gNB-DU 228 via the RLC, MAC, and PHY layers.

[0065] Figure 3 An example of a wireless communication system 300 that supports wireless unicast sidelink establishment according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 300 can implement aspects of the wireless communication systems 100, 200, and 250. The wireless communication system 300 can include a first UE 302 and a second UE 304, which can be examples of any UE described herein. As a specific example, the UEs 302 and 304 can correspond to Figure 1 V-UE 160, Figure 1 UE 190 and UE 104 connected by D2D P2P link 192, or Figure 2A and Figure 2B UE 204 in.

[0066] exist Figure 3 In the example of , UE 302 may attempt to establish a unicast connection with UE 304 on a sidelink, which may be a V2X sidelink between UE 302 and UE 304. As a specific example, the established sidelink connection may correspond to Figure 1 The sidelink connection may be established in an omni frequency range (e.g., FR1) and / or in a mmW frequency range (e.g., FR2). In some cases, UE 302 may be referred to as an initiating UE that initiates a sidelink connection procedure, and UE 304 may be referred to as a target UE that is targeted by the initiating UE for the sidelink connection procedure.

[0067] In order to establish a unicast connection, access stratum (AS) (a functional layer in the UMTS and LTE protocol stacks between the RAN and the UE, which is responsible for transmitting data over a wireless link and managing radio resources, and which is part of Layer 2) parameters may be configured and negotiated between the UE 302 and the UE 304. For example, a transmit and receive capability match may be negotiated between the UE 302 and the UE 304. Each UE may have different capabilities (e.g., transmit and receive, 64 quadrature amplitude modulation (QAM), transmit diversity, carrier aggregation (CA), (multiple) supported communication bands, etc.). In some cases, different services may be supported at the upper layers of the respective protocol stacks of the UE 302 and the UE 304. Additionally, a security association for a unicast connection may be established between the UE 302 and the UE 304. Unicast traffic may benefit from link-level security protection (e.g., integrity protection). The security requirements of different wireless communication systems may be different. For example, V2X and Uu systems may have different security requirements (e.g., Uu security does not include confidentiality protection). Additionally, IP configuration (eg, IP version, address, etc.) may be negotiated for a unicast connection between UE 302 and UE 304 .

[0068] In some cases, UE 304 may create a service announcement (e.g., a service capability message) to be sent over a cellular network (e.g., cV2X) to assist in establishing a sidelink connection. Typically, UE 302 may identify and locate candidates for sidelink communication based on an unencrypted basic service message (BSM) broadcast by a nearby UE (e.g., UE 304). The BSM may include location information, security and identity information, and vehicle information (e.g., speed, handling, size, etc.) for the corresponding UE. However, for different wireless communication systems (e.g., D2D or V2X communication), the discovery channel may not be configured to enable UE 302 to detect (multiple) BSMs. Therefore, the service announcement (e.g., discovery signal) sent by UE 304 and other nearby UEs may be an upper layer signal and broadcast (e.g., in an NR sidelink broadcast). In some cases, UE 304 may include one or more parameters of itself in the service announcement, including connection parameters and / or capabilities it possesses. UE 302 may then monitor and receive the broadcasted service announcements to identify potential UEs for the corresponding sidelink connection. In some cases, UE 302 may identify potential UEs based on the capabilities indicated by each UE in their respective service announcements.

[0069] The service announcement may include information that helps UE 302 (eg, or any initiating UE) identify the UE that sent the service announcement. Figure 3 304 in the example of ). For example, the service announcement may include channel information over which direct communication requests may be issued. In some cases, the channel information may be RAT specific (e.g., specific to LTE or NR) and may include a resource pool in which the UE 302 sends the communication request. Additionally, if the destination address is different from the current address (e.g., the address of the streaming provider or the address of the UE sending the service announcement), the service announcement may include a specific destination address of the UE (e.g., a layer 2 destination address). The service announcement may also include the network or transport layer over which the UE 302 sends the communication request. For example, the network layer (also known as "layer 3" or "L3") or the transport layer (also known as "layer 4" or "L4") may indicate the port number of the application for the UE to which the service announcement is sent. In some cases, IP addressing may not be required if the signaling (e.g., PC5 signaling) directly carries a protocol (e.g., real-time transport protocol (RTP)) or gives a locally generated random protocol. Additionally, the service announcement may include a protocol for certificate establishment and QoS-related parameters.

[0070] After identifying potential sidelink connection targets ( Figure 3 After that, the initiator UE ( Figure 3304) can send a connection request 315 to the identified target UE 304. In some cases, the connection request 315 can be a first RRC message (e.g., an "RRCDirectConnectionSetupRequest" message) sent by the UE 302 to request a unicast connection with the UE 304. For example, the unicast connection can utilize a PC5 interface for the sidelink, and the connection request 315 can be an RRC connection setup request message. Additionally, the UE 302 can use the sidelink signaling radio bearer 305 to transmit the connection request 315.

[0071] After receiving the connection request 315, the UE 304 may determine whether to accept or reject the connection request 315. The UE 304 may make this determination based on the transmit / receive capabilities, the ability to accommodate a unicast connection via the sidelink, the specific service indicated for the unicast connection, the content to be sent via the unicast connection, or a combination thereof. For example, if the UE 302 wants to use the first RAT to send or receive data, but the UE 304 does not support the first RAT, the UE 304 may reject the connection request 315. Additionally or alternatively, the UE 304 may reject the connection request 315 based on the inability to accommodate a unicast connection via the sidelink due to limited radio resources, scheduling issues, etc. Therefore, the UE 304 may send an indication of whether the request is accepted or rejected in the connection response 320. Similar to the UE 302 and the connection request 315, the UE 304 may use the sidelink signaling radio bearer 310 to transmit the connection response 320. Additionally, the connection response 320 may be a second RRC message (eg, a “RRCDirectConnectionResponse” message) sent by the UE 304 in response to the connection request 315 .

[0072] In some cases, the sidelink signaling radio bearers 305 and 310 may be the same sidelink signaling radio bearer or may be separate sidelink signaling radio bearers. Thus, a radio link control (RLC) layer acknowledgement mode (AM) may be used for the sidelink signaling radio bearers 305 and 310. A UE supporting unicast connections may monitor on a logical channel associated with the sidelink signaling radio bearer. In some cases, the AS layer (i.e., Layer 2) may deliver information directly through RRC signaling (e.g., control plane) rather than the V2X layer (e.g., data plane).

[0073] If the connection response 320 indicates that the UE 304 accepts the connection request 315, the UE 302 may then send a connection setup 325 message on the sidelink signaling radio bearer 305 to indicate that the unicast connection setup is complete. In some cases, the connection setup 325 may be a third RRC message (e.g., an "RRCDirectConnectionSetupComplete" message). Each of the connection request 315, the connection response 320, and the connection setup 325 may use basic capabilities when transmitted from one UE to another UE to enable each UE to receive and decode the corresponding transmission (e.g., RRC message).

[0074] Additionally, an identifier may be used for each of the connection request 315, the connection response 320, and the connection establishment 325. For example, the identifier may indicate which UE 302 / 304 is sending which message and / or which UE 302 / 304 the message is intended for. For a physical (PHY) layer channel, RRC signaling and any subsequent data transmission may use the same identifier (e.g., Layer 2 ID). However, for a logical channel, the identifier may be separate for RRC signaling and for data transmission. For example, on a logical channel, RRC signaling and data transmission may be handled in different ways and have different confirmation (ACK) feedback messaging. In some cases, for RRC messaging, a physical layer ACK may be used to ensure that the corresponding message is correctly sent and received.

[0075] One or more information elements may be included in the connection request 315 and / or the connection response 320 for UE 302 and / or UE 304, respectively, to enable negotiation of corresponding AS layer parameters for unicast connection. For example, UE 302 and / or UE 304 may include a packet data convergence protocol (PDCP) parameter in the corresponding unicast connection establishment message to set the PDCP context for the unicast connection. In some cases, the PDCP context may indicate whether PDCP duplication is used for the unicast connection. Additionally, UE 302 and / or UE 304 may include an RLC parameter when establishing a unicast connection to set the RLC context for the unicast connection. For example, the RLC context may indicate that AM (e.g., using a reordering timer (t-reordering)) or an unacknowledged mode (UM) is used for the RLC layer of unicast communication.

[0076] Additionally, UE 302 and / or UE 304 may include medium access control (MAC) parameters to set up a MAC context for a unicast connection. In some cases, the MAC context may implement a resource selection algorithm, a hybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK or negative ACK (NACK) feedback), parameters of the HARQ feedback scheme, carrier aggregation, or a combination thereof for a unicast connection. Additionally, UE 302 and / or UE 304 may include PHY layer parameters to set up a PHY layer context for a unicast connection when establishing a unicast connection. For example, the PHY layer context may indicate a transport format for a unicast connection (unless a transport profile is included for each UE 302 / 304) and a radio resource configuration (e.g., bandwidth part (BWP), parameter set (numerology), etc.). These information elements may support different frequency range configurations (e.g., FR1 and FR2).

[0077] In some cases, a security context may also be set for the unicast connection (e.g., after the connection establishment 325 message is sent). Before a security association (e.g., a security context) is established between UE 302 and UE 304, the sidelink signaling radio bearers 305 and 310 may not be protected. After the security association is established, the sidelink signaling radio bearers 305 and 310 may be protected. Therefore, the security context may enable secure data transmission through the unicast connection and the sidelink signaling radio bearers 305 and 310. Additionally, IP layer parameters (e.g., link-local IPv4 or IPv6 addresses) may also be negotiated. In some cases, the IP layer parameters may be negotiated by an upper layer control protocol running after RRC signaling is established (e.g., unicast connection establishment). As described above, UE 304 may decide whether to accept or reject the connection request 315 based on a specific service indicated for the unicast connection and / or content to be sent over the unicast connection (e.g., upper layer information). Specific services and / or content may also be indicated by an upper layer control protocol running after RRC signaling is established.

[0078] After establishing the unicast connection, UE 302 and UE 304 may communicate via sidelink 330 using the unicast connection, wherein sidelink data 335 is sent between the two UEs 302 and 304. Sidelink 330 may correspond to Figure 1162 and / or 168 in the sidelink. In some cases, the sidelink data 335 may include an RRC message sent between the two UEs 302 and 304. In order to maintain the unicast connection on the sidelink 330, UE 302 and / or UE 304 may send a keep alive message (e.g., a "RRCDirectLinkAlive" message, a fourth RRC message, etc.). In some cases, the keep alive message may be triggered periodically or on demand (e.g., event triggered). Therefore, the triggering and transmission of the keep alive message may be invoked by UE 302 or by both UE 302 and UE 304. Additionally or alternatively, a MAC control element (CE) (e.g., defined by the sidelink 330) may be used to monitor the state of the unicast connection on the sidelink 330 and maintain the connection. When the unicast connection is no longer needed (e.g., UE 302 travels far enough away from UE 304), UE 302 and / or UE 304 may initiate a release procedure to disconnect the unicast connection via sidelink 330. Therefore, subsequent RRC messages may not be sent between UE 302 and UE 304 on the unicast connection.

[0079] Figure 4 400 is a block diagram illustrating various components of an example UE 400 according to various aspects of the present disclosure. In one aspect, UE 400 may correspond to any UE described herein. As a specific example, UE 400 may be a V-UE, such as Figure 1 For simplicity, Figure 4 The various features and functions shown in the block diagram are connected together using a common data bus, which is intended to represent that these various features and functions are operably coupled together. Those skilled in the art will recognize that other connections, mechanisms, features, functions, etc. can be provided and adapted as needed to operably couple and configure the actual UE. In addition, it should be recognized that Figure 4 One or more of the features or functions shown in the examples may be further broken down, or Figure 4 Two or more of the illustrated features or functions may be combined.

[0080] The UE 400 may include at least one transceiver 404 connected to one or more antennas 402 and providing means (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) for communicating with other network nodes (such as V-UE (e.g., V-UE 160), infrastructure access points (e.g., roadside access points 164), P-UE (e.g., UE 104), base stations (e.g., base station 102), etc.) via at least one designated RAT (e.g., cV2X or IEEE 802.11p) over one or more communication links (e.g., communication link 120, sidelinks 162, 166, 168, mmW communication link 184). The at least one transceiver 404 may be configured differently for transmitting and encoding signals (e.g., messages, indications, information, etc.), and conversely, for receiving and decoding signals (e.g., messages, indications, information, pilots, etc.) according to the designated RAT. In an aspect, at least one transceiver 404 and antenna(s) 402 may form a (wireless) communication interface of the UE 400 .

[0081] As used herein, a "transceiver" may include at least one transmitter and at least one receiver in an integrated device (e.g., transmitter circuitry and receiver circuitry embodied as a single communication device) in some implementations, may include separate transmitter devices and separate receiver devices in some implementations, or may be embodied in other ways in other implementations. In one aspect, as described herein, a transmitter may include or be coupled to multiple antennas (e.g., antenna(s) 402), such as an antenna array, which allows the UE 400 to perform transmit "beamforming." Similarly, as described herein, a receiver may include or be coupled to multiple antennas (e.g., antenna(s) 402), such as an antenna array, which allows the UE 400 to perform receive "beamforming." In one aspect, the transmitter(s) and receiver(s) may share the same multiple antennas (e.g., antenna(s) 402), such that the UE 400 may only receive or transmit at a given time, rather than simultaneously. In some cases, a transceiver may not be able to provide both transmit and receive functionality. For example, low-function receiver circuitry (eg, a receiver chip or similar circuit that provides only low-level snooping) may be used in some designs to reduce cost when full communications need not be provided.

[0082] UE 400 may also include a satellite positioning service (SPS) receiver 406. SPS receiver 406 may be connected to one or more antennas 402 and may provide a component for receiving and / or measuring satellite signals. The SPS receiver 406 may include any suitable hardware and / or software for receiving and processing SPS signals, such as global positioning system (GPS) signals. Depending on the circumstances, the SPS receiver 406 requests information and operations from other systems and uses measurements obtained by any suitable SPS algorithm to perform calculations necessary to determine the location of UE 400.

[0083] One or more sensors 408 may be coupled to at least one processor 410 and may provide means for sensing or detecting information related to the status and / or environment of the UE 400, such as speed, heading (e.g., compass heading), headlight status, fuel consumption, etc. For example, the one or more sensors 408 may include a speedometer, a tachometer, an accelerometer (e.g., a micro-electromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), etc.

[0084] The at least one processor 410 may include one or more central processing units (CPUs), microprocessors, microcontrollers, ASICs, processing cores, digital signal processors (DSPs), field programmable gate arrays (FPGAs), etc. that provide processing functions and other computing and control functions. Thus, the at least one processor 410 may provide means for processing, such as means for determining, means for calculating, means for receiving, means for sending, means for indicating, etc. The at least one processor 410 may include any form of logic suitable for executing or causing components of the UE 400 to perform at least the techniques described herein.

[0085] The at least one processor 410 may also be coupled to a memory 414 that provides means for storing data (including means for retrieval, means for maintenance, etc.) and software instructions for executing programmed functions within the UE 400. The memory 414 may be onboard the at least one processor 410 (e.g., within the same integrated circuit (IC) package), and / or the memory 414 may be external to the at least one processor 410 and functionally coupled via a data bus.

[0086] UE 400 may include a user interface 450 that provides any suitable interface system, such as a microphone / speaker 452, a keypad 454, and a display 456 that allow a user to interact with UE 400. Microphone / speaker 452 may provide voice communication services with UE 400. Keypad 454 may include any suitable buttons for user input to UE 400. Display 456 may include any suitable display, such as, for example, a backlit liquid crystal display (LCD), and may also include a touch screen display for additional user input modes. Therefore, user interface 450 may be a component for providing indications (e.g., auditory and / or visual indications) to a user and / or for receiving user input (e.g., via a user actuation of a sensing device such as a keyboard, a touch screen, a microphone, etc.).

[0087] In one aspect, the UE 400 may include a sidelink manager 470 coupled to the at least one processor 410. The sidelink manager 470 may be a hardware, software, or firmware component that, when executed, causes the UE 400 to perform operations described herein. For example, the sidelink manager 470 may be a software module stored in the memory 414 and executable by the at least one processor 410. As another example, the sidelink manager 470 may be a hardware circuit (e.g., an ASIC, a field programmable gate array (FPGA), etc.) within the UE 400.

[0088] For sidelink communications between two or more UEs, it is sometimes necessary for the transmitting UE to increase or decrease its transmit power to improve the audibility of the transmitted signal(s) at the receiving UE(s). This is called transmit power control (TPC). The transmit power may be increased to meet a threshold signal strength at the receiver, or decreased to minimize interference with other transmitters using the spectrum. There are two types of transmit power control: open loop and closed loop. In open loop transmit power control, the transmitting UE uses its own power setting algorithm to determine its transmit power. There is no feedback input to the receiver. In closed loop transmit power control, the transmitting UE uses feedback from the receiving UE(s) to determine its transmit power. In some cases, the receiving UE may specifically request a certain transmit power. Open loop transmit power control may be used during connection establishment, before the receiving UE(s) can provide feedback to the transmitting UE. Once the sidelink has been established (e.g., as Figure 3 As shown), closed-loop power control can be used.

[0089] As described above, a UE group (e.g., Figure 1 V-UE 160 in FIG. 2 , UE 204 in FIG. 2 , Figure 3UEs 302 and 304 in the group may communicate via the sidelink. If closed-loop / open-loop transmit power control is used for sidelink group communications, the UEs in the group settle (and track) a transmit power that enables them to communicate with other UEs in the group. Typically, active (transmitting and / or receiving) group members may or may not be known to all UEs in the group. Specifically, the active group members may be known to all UEs in the group, as may be the case in a closed group. Alternatively, in the case of an open group, the active group members may not be known to all UEs in the group. As another option, the active group members may be known only to the group leader, which may be the case in both an open group and a closed group.

[0090] One issue related to the transmit power control process for sidelink group communications is how to allow new UEs to enter the group. For example, there needs to be a mechanism for non-member UEs to discover the existence of the group. If a group announcement discovery process is used, it is necessary to determine which (multiple) member UEs send the group announcement and with what transmit power. When a new UE joins the group, it will trigger a re-evaluation of the transmit power selection of the existing member UEs to reach this new member UE.

[0091] Therefore, the present disclosure provides techniques for sidelink group management for transmit power controlled group communications. The techniques of the present disclosure assume that a sidelink group communications session exists between groups of UEs. A group leader may or may not exist. In addition, it is assumed that a transmit power control process has been selected for the existing group members, and the member UEs have determined the transmit power for their sidelink transmissions that will reach all other UEs in the group (or a given subgroup of those UEs).

[0092] On the one hand, the UE group determines one or more UEs in the group to periodically send group presence notification messages, and the transmit power that one or more UEs should use for those group presence notifications. The group presence notification message should include at least an identifier specific to the group. On the one hand, the group identifier can be a layer 2 (i.e., access stratum layer) group identifier. Alternatively, on the other hand, the group identifier can be an application layer group identifier. The group presence notification message can be an application layer message, a NAS layer (e.g., V2X layer) message, or an RRC layer message. More specifically, the type of message depends on which layer is controlling the group notification and / or group management. For example, if the sidelink communication group is an open group, the group presence notification message can be an RRC layer message, because in this case, RRC may be more efficient. As another example, if the sidelink communication group is a closed group, the group presence notification message can be an application layer message, because in this case, group management can be controlled at the application layer level. The group presence announcement message may be transmitted via a physical sidelink discovery channel (PSDCH) or one or more sidelink communication physical channels (eg, a physical sidelink control channel (PSCCH) and / or a physical sidelink shared channel (PSSCH)).

[0093] On the one hand, all UEs in the sidelink communication group can send a group presence announcement message. For example, if there is no group leader, each UE can send a group presence announcement message. On the one hand, the group presence announcement message can be a synchronous transmission between all UEs. For example, the group presence announcement message can be aligned on the system frame number (SFN). And when there is no specific requirement for the spatial directionality of the transmission (for example, in FR1), this helps to reduce the resource overhead associated with the transmission of the group presence announcement message.

[0094] In one aspect, instead of having some or all of the group members send the group presence announcement message, only the group leader sends the group presence announcement message.

[0095] On the one hand, the group leader may select a subgroup of UEs in the sidelink communication group to send a group presence notification message. The group leader may also provide a configuration for the transmission of the group presence notification message, including at least a period and a time offset between the selected (multiple) UEs. The group leader may stagger the (multiple) time offset configurations of the selected (multiple) UEs so that from the perspective of the group, the equivalent period of the group presence notification message transmission is reduced by a factor of the number of selected UEs. For example, if the group leader determines that a group presence notification message should be sent every second and selects two UEs to send the group presence notification message, each selected UE will send a group presence notification message every two seconds.

[0096] On the one hand, the UE subgroup selected to send the group presence announcement message can be based at least in part on signal strength measurements (e.g., RSRP, RSRQ) between UEs in the sidelink communication group. On the one hand, if the signal strength of the transmission from the UE to one or more other UEs in the group is lower than a configured threshold, the group leader can select the UE. Specifically, if the UE is well connected to all or most of the other UEs in the group, as indicated by the high RSRP associated with the UE, it may not be at the edge of the group, but at a more central location. However, if the signal strength associated with the UE or UE subgroup is low (i.e., below a certain threshold), the UE or UE subgroup may be at the edge of the group. In this case, it would be beneficial for the UE / UE subgroup to broadcast the group presence announcement message because they are more likely to be heard by non-group UEs outside or farther away from the geographical location of the sidelink communication group.

[0097] On the one hand, similar to the above, if the signal strength of the transmission from the UE to one or more other UEs in the group on one or more transmit beams is below a configured threshold, the group leader may select a UE or a UE subgroup to broadcast a group presence announcement message. The signal strength of the transmission from the UE can be determined by the receiving UE using any receive beam or the best receive beam for receiving such transmission. If the sidelink communication group operates in millimeter wave (e.g., FR2), the selected (multiple) UEs may use multiple transmit beams to transmit the group presence announcement message in a beamforming manner. In this case, the selected UE should not be based solely on the signal strength of a given transmit beam, but should be based on the signal strength of multiple transmit beams.

[0098] In one aspect, a UE sending a group presence announcement message may determine a transmit power for transmitting the group presence announcement message based at least in part on: (1) a transmit power configuration used by the UE to transmit other sidelink physical channels to group members; (2) a downlink path loss measurement to a serving base station; (3) a sidelink path loss to a group leader (if there is one); (4) a transmit power configuration received from the group leader (if there is one); and / or (5) a maximum transmit power configuration of the UE that does not exceed the maximum transmit power capability of the UE.

[0099] The transmit power configuration received from the group leader (option (4) above) may include a maximum transmit power to be used for group presence announcement message transmissions and / or an upper limit on the incremental transmit power increase that a UE may use beyond the transmit power that the UE is using for sidelink transmissions to other group members. This option may be used in the following example scenario. In this example scenario, sidelink transmit power control is used within a sidelink communication group. In addition, the group leader determines the maximum transmit power that may be used by members in the group based on path loss measurements of a serving base station (which may serve all or at least most of the member UEs). That is, interference from uplink UE transmissions at the base station is being managed only by the group leader, rather than by each member individually. Since the sidelink communication group is local (i.e., the member UEs are within wireless communication range of each other and may therefore be a relatively small geographic area), it should be sufficient to use only measurements from the group leader, as they may be almost identical to all other member UEs. In such an example scenario, the group leader may determine how much the incremental increase in transmit power that a selected (multiple) UE may use exceeds the transmit power used for normal sidelink communications within the group.

[0100] On the one hand, the UE that sends the group presence announcement message can determine one or more transmit spatial configurations (i.e., transmit beams) for the group presence message. The selected transmit spatial configuration can include at least transmit beams that have been determined to be "bad" for communicating with other group members. In particular, the UE can determine the transmit beam set (transmit spatial configuration) for which the signal strength measured by one or more other member UEs is lower than a configured threshold, which means that the transmit beam set includes beams that may not be directed to member UEs. The UE can use one or more transmit beams in the determined set to send the group presence announcement message. It is assumed that by selecting one or more transmit beams that are not directed to other UEs in the sidelink communication group, the one or more transmit beams are more likely to be detected by UEs that are not members of the group.

[0101] Figure 5 An example wireless communication system 500 is illustrated in accordance with aspects of the present disclosure. Figure 5 In the example of FIG. 5 , a group of UEs (illustrated as UEs 502, 504, and 506) have formed a sidelink communication group. The member UEs may communicate with each other via various sidelinks, as indicated by dashed arrows, which may correspond to Figure 1 sidelinks 162 and / or 168, or Figure 3 The sidelink 330 in Figure 5In the example of , UE 502 is the group leader, and UE 506 has been selected or otherwise determined as the UE that sends the group presence notification message. The remaining UEs 504-1, 504-2, and 504-3 (collectively referred to as UE 504) are member UEs that are not group leaders and do not send group presence notification messages. However, please note that there may be no group leader, or the group leader but not any other UE can send the group presence notification message.

[0102] To distinguish Figure 5 Of the UEs shown, UE 502 may be referred to herein as a group leader UE 502, UE 504 may be referred to as a regular member UE 504, and UE 506 may be referred to as a transmitting UE 506. As will be appreciated, there may be more than one UE. Figure 5 There may be more or fewer than three regular member UEs 504 as shown, and there may be more than Figure 5 More transmitting UE 506 are shown.

[0103] In an aspect, the transmitting UE 506 may be selected / determined based on having a signal strength to one or more other UEs 504 / 502 that is less than a threshold value (which may be configured by the group leader UE 502, a serving base station, a network entity, an applicable standard, etc.). For example, given its distance from the regular member UE 504-1, the signal strength of the sidelink transmission received at the regular member UE 504-1 may be less than a threshold value, and based on this determination, the transmitting UE 506 is selected to send the group presence announcement message. Figure 5 As can be seen in the example of , the lower signal strength of the transmission from the transmitting UE 506 to the regular member UE 504-1 indicates that the transmitting UE 506 is at the edge of the sidelink communication group.

[0104] On the one hand, Figure 5 UEs 502, 504, and 506 in the group may operate in a mmW frequency range (e.g., FR2) and may therefore use beamforming (transmit and receive) to communicate via the sidelink shown. In this case, the transmitting UE 506 may be selected / determined based on the signal strength of the beamformed transmission from the transmitting UE 506 to one or more of the other UEs 502 / 506 being below a threshold. As described above, the threshold may be configured by the group leader UE 502, the serving base station, the network entity, applicable standards, etc. For example, given its distance from the regular member UE 504-1, the signal strength of the beamformed sidelink transmission received at the regular member UE 504-1 may be less than the threshold. The signal strength may be determined by the regular member UE 504-1 using any receive beam or the best receive beam to receive the sidelink transmission from the transmitting UE 506.

[0105] Once selected / determined, the transmitting UE 506 periodically transmits the group presence announcement message 510. If operating in FR1, the transmitting UE 506 may transmit the group presence announcement message 510 omni-directionally. Alternatively, if operating in the mmW frequency range, the transmitting UE 506 may transmit the group presence announcement message in a beamforming manner using one or more transmit beams. The one or more transmit beams may include at least one transmit beam having a received signal strength at one or more other UEs 502 / 504 in the group that is below a threshold determined to be acceptable for communicating with other group members. For example, the transmitting UE 506 may select a transmit beam 516 to transmit the group presence announcement message 510. As shown in FIG. Figure 5 As shown, transmit beam 516 would be a poor choice for communicating with other UEs in the sidelink communication group, which is why it is selected, but it can provide a sufficiently large received signal strength at non-member UE 508 to be detected by non-member UE 508.

[0106] Figure 6 An example method 600 of wireless communication according to aspects of the present disclosure is illustrated. In one aspect, the method 600 may be performed by a UE (e.g., any UE described herein) participating in a sidelink communication group. In a specific example, the UE may correspond to Figure 5 The sending UE 506 in.

[0107] At 610, the UE communicates with one or more member UEs (eg, Figure 5 In one aspect, operation 610 may be performed by at least one transceiver 404, at least one processor 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing this operation.

[0108] At 620, the UE transmits a group presence announcement message for the sidelink communication group based on at least a transmit power for the group presence announcement message and a determination that the UE expects to transmit the group presence announcement message for the sidelink communication group according to communicating with one or more member UEs. In an aspect, operation 620 may be performed by at least one transceiver 404, at least one processor 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing this operation.

[0109] As will be appreciated, a technical advantage of method 600 is improved efficiency for determining transmit power control within a group of UEs connected via a sidelink.

[0110] It can be seen in the detailed description above that different features are combined together in the examples. This disclosure should not be understood as an intention that the example clauses have more features than those explicitly mentioned in each clause. On the contrary, various aspects of the present disclosure may include less than all the features of the disclosed single example clauses. Therefore, the following clauses should be considered to be combined in the description, where each clause itself can be used as a separate example. Although each subordinate clause can be referenced in each clause to a specific combination with one of the other clauses, the (multiple) aspects of the subordinate clause are not limited to a specific combination. It should be understood that other example clauses may also include a combination of (multiple) subordinate clause aspects with the subject matter of any other subordinate clause or independent clause, or any combination of features with other subordinate and independent clauses. Various aspects disclosed herein explicitly include these combinations, unless it is clearly expressed or can be easily inferred that a specific combination is not intended (for example, contradictory aspects, such as defining an element as both an insulator and a conductor). In addition, even if the clause is not directly dependent on the independent clause, it may be intended to include various aspects of the clause in any other independent clause.

[0111] Examples of implementations are described in the following numbered clauses:

[0112] Clause 1: A wireless communication method for performance by a user equipment (UE) participating in a sidelink communication group, comprising: communicating with one or more member UEs of the sidelink communication group; determining, based on communicating with the one or more member UEs, that the UE should send a group presence notification message for the sidelink communication group and at least one transmission power of the group presence notification message; and sending the group presence notification message based on the determination.

[0113] Clause 2: A method according to clause 1, wherein determining comprises: receiving an indication from a group leader UE of the sidelink communication group to send the group existence announcement message.

[0114] Clause 3: The method of clause 2, wherein the indication comprises a period and a time offset of the group presence announcement messages.

[0115] Clause 4: A method according to clause 3, wherein the time offset is staggered with the time offset of group presence announcement message transmissions from other member UEs of the sidelink communication group.

[0116] Clause 5: A method as described in any of clauses 3 to 4, wherein the UE periodically sends the group presence notification message based on the received periodicity.

[0117] Clause 6: A method according to any of clauses 1 to 5, wherein the UE is a leader UE of the sidelink communication group, and the determination that the UE should send a group presence announcement message is based on the UE being the leader UE.

[0118] Clause 7: A method according to any one of clauses 1 to 6, wherein all member UEs of a sidelink communication group send a group existence notification message, and the determination that a UE should send the group existence notification message is based on the UE being a member of the sidelink communication group.

[0119] Clause 8: A method as described in any of clauses 1 to 7, wherein the determination that the UE should send a group presence announcement message is based on a received signal strength measurement of transmissions from the UE to one or more member UEs being less than a threshold.

[0120] Clause 9: A method according to clause 8, wherein the threshold is received from a leader UE of the sidelink communication group or a base station serving the UE, or is specified in a cell communication standard.

[0121] Clause 10: A method as described in any of clauses 1 to 9, wherein the transmission from the UE to the one or more member UEs is a beamformed transmission.

[0122] Clause 11: The method according to any one of clauses 1 to 10 further includes: determining a set of transmit beams having a received signal strength measurement at one or more member UEs that is less than a threshold; and selecting at least one transmit beam from the set of transmit beams for sending the group existence notification message, wherein sending the group existence notification message includes sending the group existence notification message on at least one transmit beam.

[0123] Clause 12: The method of clause 11, wherein the transmit beam set having a received signal strength measurement less than the threshold indicates that the transmit beam set is not suitable for communicating with one or more member UEs.

[0124] Clause 13: A method according to any one of clauses 1 to 12, wherein the transmit power is determined based on: the transmit power configuration of the UE for sending other sidelink physical channels to one or more member UEs, a downlink path loss measurement of the serving base station, a sidelink path loss to the leader UE of the sidelink communication group, the transmit power configuration received from the leader UE, the maximum transmit power configuration of the UE that does not exceed the maximum transmit power capability of the UE, or any combination thereof.

[0125] Clause 14: A method according to clause 13, wherein the transmit power configuration received from the group leader UE includes: a maximum transmit power for a group presence notification message, and / or an upper limit on an incremental transmit power increase that the UE expects to use beyond the transmit power configuration that the UE is using to send other sidelink physical channels to one or more member UEs.

[0126] Clause 15: A method as described in any of clauses 1 to 14, wherein the group presence announcement message includes a group identifier of the sidelink communication group.

[0127] Clause 16: The method of clause 15, wherein the group identifier is an access layer group identifier, or the group identifier is an application layer group identifier.

[0128] Clause 17: A method as described in any of clauses 1 to 16, wherein the set existence notification message comprises: an application layer message, a non-access stratum layer message, or a radio resource control (RRC) message.

[0129] Clause 18: A method according to any one of clauses 1 to 17, wherein the group presence announcement message is sent via a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).

[0130] Clause 19: An apparatus comprising a memory and at least one processor communicatively coupled to the memory, the memory and the at least one processor configured to perform the method of any of clauses 1 to 18.

[0131] Clause 20: An apparatus comprising means for performing the method according to any one of clauses 1 to 18.

[0132] Clause 21: A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising at least one instruction for causing a computer or a processor to perform the method according to any one of clauses 1 to 18.

[0133] Additional implementation examples are described in the following numbered clauses:

[0134] Clause 1: A wireless communication method for execution by a user equipment (UE) participating in a sidelink communication group, comprising: communicating with one or more member UEs of the sidelink communication group; and sending a group existence announcement message of the sidelink communication group based on a determination of at least a transmission power of the group existence announcement message and an expectation by the UE to send a group existence announcement message of the sidelink communication group according to communicating with the one or more member UEs.

[0135] Clause 2: The method according to clause 1 further comprises: receiving an indication from a group leader UE of the sidelink communication group to send the group existence announcement message.

[0136] Clause 3: The method of clause 2, wherein the indication comprises a period and a time offset of the group presence announcement messages.

[0137] Clause 4: A method according to clause 3, wherein the time offset is staggered with the time offset of group presence announcement message transmissions from other member UEs of the sidelink communication group.

[0138] Clause 5: A method as described in any of clauses 3 to 4, wherein the UE periodically sends the group presence notification message based on a period.

[0139] Clause 6: A method according to any one of clauses 1 to 5, wherein the UE is a leader UE of the sidelink communication group, and the determination that the UE is expected to send a group existence announcement message is also based on the UE being the leader UE.

[0140] Clause 7: A method according to any one of clauses 1 to 6, wherein all member UEs of a sidelink communication group send a group existence notification message, and the determination that a UE is expected to send the group existence notification message is also based on the UE being a member of the sidelink communication group.

[0141] Clause 8: A method according to any one of clauses 1 to 7, wherein the determination that the UE expects to send the group presence notification message is also based on a received signal strength measurement of a transmission from the UE to one or more member UEs being less than a threshold, or a received signal strength measurement of a transmission from one or more member UEs to the UE being less than the threshold, or both.

[0142] Clause 9: The method according to clause 8 further includes: receiving the threshold from a leader UE of the sidelink communication group or a base station serving the UE.

[0143] Clause 10: A method as described in any of clauses 1 to 9, wherein the transmission from the UE to the one or more member UEs is a beamformed transmission.

[0144] Clause 11: The method according to any one of clauses 1 to 10 further includes: determining a set of transmit beams having a received signal strength measurement at one or more member UEs that is less than a threshold; and selecting at least one transmit beam from the set of transmit beams for sending the group existence notification message, wherein the sending includes sending the group existence notification message on at least one transmit beam.

[0145] Clause 12: The method of clause 11, wherein the transmit beam set having a received signal strength measurement less than the threshold indicates that the transmit beam set is not suitable for communicating with one or more member UEs.

[0146] Clause 13: A method according to any one of clauses 1 to 12, wherein the transmit power is determined based on: the transmit power configuration of the UE used to transmit other sidelink physical channels to one or more member UEs, a downlink path loss measurement of the serving base station, a sidelink path loss to a leader UE of the sidelink communication group, a transmit power configuration received from the leader UE, a maximum transmit power configuration of the UE that does not exceed the maximum transmit power capability of the UE, or any combination thereof.

[0147] Clause 14: A method according to clause 13, wherein the transmit power configuration received from the group leader UE includes: a maximum transmit power for a group presence announcement message, an upper limit on an incremental transmit power increase that the UE expects to use, exceeding a transmit power configuration that the UE is using to send other sidelink physical channels to one or more member UEs, or any combination thereof.

[0148] Clause 15: A method as described in any of clauses 1 to 14, wherein the group presence announcement message includes a group identifier of the sidelink communication group.

[0149] Clause 16: The method of clause 15, wherein the group identifier is an access layer group identifier, or the group identifier is an application layer group identifier.

[0150] Clause 17: A method as described in any of clauses 1 to 16, wherein the group existence notification message comprises: an application layer message, a non-access stratum (NAS) layer message, or a radio resource control (RRC) message.

[0151] Clause 18: A method according to any one of clauses 1 to 17, wherein the UE sends the group presence notification message via a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).

[0152] Clause 19: An apparatus comprising a memory and at least one processor communicatively coupled to the memory, the memory and the at least one processor configured to perform the method of any of clauses 1 to 18.

[0153] Clause 20: An apparatus comprising means for performing the method according to any one of clauses 1 to 18.

[0154] Clause 21: A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising at least one instruction for causing a computer or a processor to perform the method according to any one of clauses 1 to 18.

[0155] Those skilled in the art will appreciate that any of a variety of different technologies and techniques may be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0156] In addition, it will be appreciated by those skilled in the art that the various illustrative logic blocks, modules, circuits and algorithmic steps described in conjunction with the various aspects disclosed herein can all be implemented as electronic hardware, computer software or a combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various illustrative components, frames, modules, circuits and steps have been generally described in terms of their functions above. Whether this function is implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. Those skilled in the art can implement the described functions in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0157] The various illustrative logical blocks, modules, and circuits described in conjunction with the various aspects disclosed herein may be implemented or executed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0158] The methods, sequences and / or algorithms described in conjunction with the aspects disclosed herein may be directly embodied in hardware, in a software module executed by a processor, or in a combination of the two. The software module may be present in a random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. An example storage medium is coupled to a processor so that the processor can read information from and write information to the storage medium. In alternative aspects, the storage medium may be integrated with the processor. The processor and storage medium may be present in an ASIC. The ASIC may be present in a user terminal (e.g., UE). In alternative aspects, the processor and storage medium may be present in a user terminal as discrete components.

[0159] In one or more example aspects, the described functions can be implemented in hardware, software, firmware or any combination thereof. If implemented in software, the functions can be stored on a computer-readable medium or sent via the computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, and the communication media include any media that facilitates the transfer of computer programs from one place to another. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other media that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer. Moreover, any connection is properly referred to as a computer-readable medium. For example, if software is sent from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwave, coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and micro are all included in the definition of medium. As used herein, disk and disc 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 should also be included within the scope of computer-readable media.

[0160] Although the foregoing disclosure shows the illustrative aspects of the present disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps and / or actions of the method claims according to the aspects of the present disclosure described herein do not need to be performed in any particular order. In addition, although the elements of the present disclosure may be described or claimed in the singular, the plural may be contemplated unless limitation to the singular is explicitly stated.

Claims

1. A wireless communication method for a user equipment UE participating in a sidelink communication group, comprising: Communicating with one or more member UEs of the sidelink communication group; as well as Based on a determination of at least a transmission power for a group presence announcement message and that the UE expects to send the group presence announcement message of the sidelink communication group according to communication with the one or more member UEs, a group presence announcement message of the sidelink communication group is sent, wherein the UE is one of a subset of members of the sidelink communication group that sends the group presence announcement message of the sidelink communication group.

2. The method according to claim 1, further comprising: An instruction for sending the group existence announcement message is received from a group leader UE of the sidelink communication group.

3. The method according to claim 2, wherein: The indication includes a period and a time offset of the group presence announcement message.

4. The method according to claim 3, wherein: The time offset is staggered with the time offset of group presence announcement message transmission from other member UEs of the sidelink communication group.

5. The method according to claim 3, wherein: The UE periodically sends the group existence announcement message based on the period.

6. The method according to claim 1, wherein: The UE is a leader UE of the sidelink communication group, and The determination that the UE is expected to send the group presence announcement message is also based on the UE being the group leader UE.

7. The method according to claim 1, wherein: All member UEs of the sidelink communication group send the group existence notification message, and The determination that the UE is expected to send the group presence announcement message is also based on the UE being a member of the sidelink communication group.

8. The method according to claim 1, wherein: The determination that the UE is expected to send the group presence announcement message is also based on a received signal strength measurement of transmissions from the UE to the one or more member UEs being less than a threshold, or a received signal strength measurement of transmissions from the one or more member UEs to the UE being less than the threshold, or both.

9. The method according to claim 8, further comprising: The threshold is received from a leader UE of the sidelink communication group or a base station serving the UE.

10. The method according to claim 1, wherein: The transmission from the UE to the one or more member UEs is a beamformed transmission.

11. The method according to claim 1, further comprising: determining a set of transmit beams having received signal strength measurements at the one or more member UEs that are less than a threshold; as well as selecting at least one transmission beam from the transmission beam set for transmitting the group existence announcement message, Wherein, sending the group existence announcement message includes sending the group existence announcement message on the at least one transmission beam.

12. The method according to claim 11, wherein: The transmit beam set having a received signal strength measurement less than the threshold indicates that the transmit beam set is not suitable for communicating with the one or more member UEs.

13. The method according to claim 1, wherein: The transmit power is determined based on: The UE is used to send the transmit power configuration of other sidelink physical channels to the one or more member UEs, Downlink path loss measurement for the serving base station, a sidelink path loss to a leader UE of the sidelink communication group, a transmit power configuration received from the group leader UE, a maximum transmit power configuration of the UE that does not exceed the maximum transmit power capability of the UE, or Any combination thereof.

14. The method according to claim 13, wherein: The transmit power configuration received from the group leader UE includes: a maximum transmit power for the group presence announcement message, an upper limit on an incremental transmit power increase that the UE is expected to use beyond a transmit power configuration that the UE is using to transmit the other sidelink physical channel to the one or more member UEs, or Any combination thereof.

15. The method according to claim 1, wherein: The group presence announcement message includes a group identifier of the sidelink communication group.

16. The method of claim 15, wherein: The group identifier is an access stratum group identifier, or The group identifier is an application layer group identifier.

17. The method according to claim 1, wherein: The group existence notification message includes: Application layer messages, Non-access stratum NAS layer message, or Radio Resource Control RRC message.

18. The method according to claim 1, wherein: The UE sends the group existence announcement message through a physical sidelink discovery channel PSDCH, a physical sidelink control channel PSCCH or a physical sidelink shared channel PSSCH.

19. A user equipment UE, comprising: Memory; Communication interface; as well as at least one processor communicatively coupled to the memory and the communication interface, the at least one processor configured to: communicating with one or more member UEs of a sidelink communication group in which the UE is participating; and The communication interface sends a group existence announcement message of the sidelink communication group based on a determination of at least a transmission power for a group existence announcement message and that the UE expects to send the group existence announcement message of the sidelink communication group according to communication with the one or more member UEs, wherein the UE is one of a subset of members of the sidelink communication group that sends the group existence announcement message of the sidelink communication group.

20. The UE according to claim 19, wherein: The at least one processor is further configured to: An instruction for sending the group existence announcement message is received from a group leader UE of the sidelink communication group via the communication interface.

21. The UE according to claim 20, wherein: The indication includes a period and a time offset of the group presence announcement message.

22. The UE according to claim 21, wherein: The time offset is staggered with the time offset of group presence announcement message transmission from other member UEs of the sidelink communication group.

23. The UE according to claim 19, wherein: The UE is a leader UE of the sidelink communication group, and The determination that the UE is expected to send the group presence announcement message is also based on the UE being the group leader UE.

24. The UE according to claim 19, wherein: All member UEs of the sidelink communication group send the group existence notification message, and The determination that the UE is expected to send the group presence announcement message is also based on the UE being a member of the sidelink communication group.

25. The UE according to claim 19, wherein: The determination that the UE is expected to send the group presence announcement message is also based on a received signal strength measurement of transmissions from the UE to the one or more member UEs being less than a threshold, or a received signal strength measurement of transmissions from the one or more member UEs to the UE being less than the threshold, or both.

26. The UE according to claim 19, wherein: The at least one processor is further configured to: determining a set of transmit beams having received signal strength measurements at the one or more member UEs that are less than a threshold; and selecting at least one transmission beam from the transmission beam set for transmitting the group existence announcement message, The at least one processor configured to send the group presence announcement message includes at least one processor configured to send the group presence announcement message on the at least one transmit beam.

27. The UE according to claim 19, wherein: The transmit power is determined based on: The UE is used to send the transmit power configuration of other sidelink physical channels to the one or more member UEs, Downlink path loss measurement for the serving base station, a sidelink path loss to a leader UE of the sidelink communication group, a transmit power configuration received from the group leader UE, a maximum transmit power configuration of the UE that does not exceed the maximum transmit power capability of the UE, or Any combination thereof.

28. The UE according to claim 27, wherein: The transmit power configuration received from the group leader UE includes: a maximum transmit power for the group presence announcement message, an upper limit on an incremental transmit power increase that the UE is expected to use beyond a transmit power configuration that the UE is using to transmit other sidelink physical channels to the one or more member UEs, or Any combination thereof.

29. A user equipment UE, comprising: means for communicating with one or more member UEs of a sidelink communication group; as well as A component for sending a group presence announcement message of the sidelink communication group based on communicating with the one or more member UEs, determining at least a transmission power for the group presence announcement message and an expectation by the UE to send the group presence announcement message of the sidelink communication group, wherein the UE is one of a subset of the members of the sidelink communication group that sends the group presence announcement message of the sidelink communication group.

30. A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by a user equipment (UE), cause the UE to: communicating with one or more member UEs of a sidelink communication group; and Based on at least a transmit power for a group presence notification message and a determination that the UE expects to send a group presence notification message for the sidelink communication group according to communicating with the one or more member UEs, a group presence notification message for the sidelink communication group is sent, wherein, The UE is one of a subset of members of the sidelink communication group that sends a group presence announcement message of the sidelink communication group.

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