Beam training resource selection by fr2 sidelink ue

Abstract

This disclosure provides systems, devices, apparatuses, and methods, including a computer program encoded on a storage medium, for selecting beam training resources by a sidelink UE. A first UE can determine whether to perform beam training with a second UE in a set of beam training resources. The set of beam training resources may include a first subset of beam training resources for UEs without RRC connections and a second subset of beam training resources for UEs with RRC connections, wherein the first and second subsets of beam training resources do not overlap. The first UE can determine whether it is RRC connected to the second UE and, based on whether it is RRC connected to the second UE, perform beam training in one of the first or second subsets of beam training resources.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Patent Application No. 17 / 137,257, filed on December 29, 2020, entitled “BEAM TRAINING RESOURCESELECTION BY FR2 SIDELINK UE,” the entire contents of which are expressly incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to communication systems, and more specifically, to sidelink communication. Background Technology

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that enable communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, national, regional, and even global levels. An example telecommunications standard is 5G New Radio (NR). 5G NR is part of the Continuous Mobile Broadband Evolution program issued by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR can be based on the 4G Long Term Evolution (LTE) standard. Some aspects of wireless communication can include direct communication between devices based on sidelinks, such as in vehicle-to-everything (V2X) and / or other device-to-device (D2D) communications. There is a need for further improvements in sidelink technologies. These improvements can also be applied to other multiple access technologies and telecommunications standards that adopt these technologies. Summary of the Invention

[0006] The following is a simplified outline of one or more aspects to provide a basic understanding of them. This outline is not a comprehensive overview of all conceived aspects, nor is it intended to identify key or important elements of all aspects, nor to define the scope of any aspect or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as an introduction to the more detailed descriptions that follow.

[0007] In a distributed network, each User Equipment (UE) can be configured to establish a beampair link (BPL) with another UE to perform point-to-point / unicast communication. When a UE's beam quality degrades, the UE can perform beam training procedures to improve beam quality. Some beam training procedures can occur after the Random Access Channel (RACH) procedure, while others can occur before the RACH procedure. Therefore, different UEs performing different types of beam training procedures may select the same beam training resources from the beam training resource set, which can lead to interference between different UEs.

[0008] Therefore, when a UE determines to perform a beam training procedure with another UE, the UE can select beam training resources from the beam training resource set during a network-wide / system-wide beam training opportunity. The beam training resource set can be divided into a first subset and a second subset. The first subset can be used to execute beam training procedures that occur before the RACH procedure. For example, the first subset can be used for initial BPL establishment. The second subset can be used to execute beam training procedures that occur after the RACH procedure. For example, the second subset can be used for beam refinement or beam switching. Based on whether the UE has already executed the RACH procedure, the UE can select beam training resources from either the first or second subset to execute the determined beam training procedure.

[0009] In this disclosure, methods, computer-readable media, and apparatus are provided. The apparatus may be associated with a first UE and may be configured to determine whether to perform beamtraining with a second UE in a beamtraining resource set, the beamtraining resource set including a first subset of beamtraining resources for UEs without Radio Resource Control (RRC) connections with the UE associated with the beamtraining and a second subset of beamtraining resources for UEs with RRC connections with the UE associated with the beamtraining, the first and second subsets of beamtraining resources not overlapping; determine whether the first UE is RRC connected to the second UE; and, based on the determination of whether the first UE is RRC connected to the second UE, perform beamtraining in one of the first or second subset of beamtraining resources.

[0010] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and drawings set forth certain illustrative features of the one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of the various aspects can be employed, and this description is intended to include all such aspects and their equivalents. Attached Figure Description

[0011] Figure 1 This is a schematic diagram illustrating an example of a wireless communication system and an access network.

[0012] Figure 2A This is a schematic diagram illustrating an example of the first frame according to various aspects of this disclosure.

[0013] Figure 2B This is a schematic diagram illustrating examples of intra-frame DL channels according to various aspects of this disclosure.

[0014] Figure 2C This is a schematic diagram illustrating an example of a second frame according to various aspects of this disclosure.

[0015] Figure 2D This is a schematic diagram illustrating examples of intra-frame UL channels according to various aspects of this disclosure.

[0016] Figure 3 This is a schematic diagram illustrating an example of a first device and a second device involving wireless communication based on, for example, a side link.

[0017] Figure 4 This is a schematic diagram illustrating the call flow between the first UE and the second UE.

[0018] Figure 5 This is a schematic diagram illustrating the resources used to perform beam training procedures.

[0019] Figure 6 A schematic diagram is shown of beam training timing, which is divided into a first subset of beam training resources for non-RRC connected UEs and a second subset of beam training resources for RRC connected UEs.

[0020] Figure 7 This is a flowchart of the UE's wireless communication method.

[0021] Figure 8 This is a schematic diagram illustrating an example hardware implementation of the example device. Detailed Implementation

[0022] The following detailed description, relating to the accompanying drawings, is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein can be practiced. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in the form of block diagrams to avoid obscuring these concepts.

[0023] Several aspects of a telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in detail below and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively, “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0024] For example, an element, or any part of an element, or any combination of elements, can be implemented as a “processing system” including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in a processing system can execute software. Software should be understood broadly as meaning instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or otherwise.

[0025] Therefore, in one or more exemplary embodiments, the described functionality can be implemented in hardware, software, or a combination thereof. If implemented in software, these functions can be stored on a computer-readable medium or encoded as one or more instructions or code on a computer-readable medium. A computer-readable medium includes a computer storage medium. The storage medium can be any available medium accessible by a computer. By way of example, and not limitation, such a computer-readable medium can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of computer-readable media of the foregoing types, or any other medium that can be used to store computer-executable code in the form of computer-accessible instructions or data structures.

[0026] Figure 1 This is a schematic diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a user interface unit (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femtocells, picocells, and microcells.

[0027] The link between User Equipment (UE) 104 and Base Station 102 or 180 can be established as an access link (e.g., using a Uu interface). Other communications can be exchanged between wireless devices based on sidelinks. For example, some UEs 104 can communicate directly with each other using Device-to-Device (D2D) communication link 158. In some examples, D2D communication link 158 can use DL / ULWWAN spectrum. D2D communication link 158 can use one or more sidelink channels, such as Physical Sidelink Broadcast Channel (PSBCH), Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Control Channel (PSCCH). D2D communication can be conducted through various wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0028] Some examples of sidelink communication can include vehicle-based communication devices that can communicate from vehicle to vehicle (V2V), vehicle to infrastructure (V2I) (e.g., from a vehicle-based communication device to a road infrastructure node, such as a roadside unit (RSU)), vehicle to network (V2N) (e.g., from a vehicle-based communication device to one or more network nodes, such as a base station), vehicle to pedestrian (V2P), cellular vehicle to everything (C-V2X), and / or combinations thereof and / or with other devices, collectively referred to as vehicle to everything (V2X) communication. Sidelink communication can be based on V2X or other D2D communication, such as proximity services (ProSe), etc. In addition to the UE, sidelink communication can also be sent and received by other transmitting and receiving devices (e.g., roadside unit (RSU) 107, etc.). Sidelink communication can be exchanged using a PC5 interface, as described in relation to the example in Figure 2. Although the following description, including the example time slot structure of Figure 2, can provide an example of sidelink communication related to 5G NR, the concepts described herein can be applied to other similar fields such as LTE, LTE-A, CDMA, GSM and other wireless technologies.

[0029] Refer again Figure 1 In some aspects, UE 104 or other devices based on sidelink communication may include a beam training component 198 configured to determine whether to perform beam training with a second UE in a beam training resource set, the beam training resource set including a first subset of beam training resources for UEs without radio resource control (RRC) connections with the UE associated with the beam training and a second subset of beam training resources for UEs with RRC connections with the UE associated with the beam training, the first subset of beam training resources and the second subset of beam training resources not overlapping; determine whether the first UE is RRC connected to the second UE; and perform beam training in one of the first subset of beam training resources or the second subset of beam training resources based on the determination of whether the first UE is RRC connected to the second UE.

[0030] Base station 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with EPC 160 via a first backhaul link 132 (e.g., S1 interface). Base station 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can interface with core network 190 via a second backhaul link 184. Among other functions, base station 102 can perform one or more of the following functions: user data transmission, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, location, and warning message delivery. Base station 102 can communicate with each other directly or indirectly (e.g., via EPC 160 or core network 190) via third backhaul link 134 (e.g., X2 interface). First backhaul link 132, second backhaul link 184 and third backhaul link 134 can be wired or wireless.

[0031] Base station 102 can communicate wirelessly with UE 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. Overlapping geographic coverage areas 110 may exist. For example, small cell 102' may have a coverage area 110' that overlaps with the coverage areas 110 of one or more macro base stations 102. A network that includes both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network may also include a Home Evolution Node B (eNB) (HeNB), which can provide services to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between base station 102 and UE 104 may include uplink (UL) (also known as reverse link) transmission from UE 104 to base station 102 and / or downlink (DL) (also known as forward link) transmission from base station 102 to UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technologies, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may use one or more carriers. Base station 102 / UE104 may use spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) per carrier, each carrier being allocated in carrier aggregation for transmission in each direction up to a total of Yx MHz (x component carriers). Carriers may or may not be adjacent to each other. Carrier allocation may be asymmetrical relative to DL and UL (e.g., more or fewer carriers may be allocated to DL than to UL). Component carriers may include primary component carriers and one or more secondary component carriers. The primary component carrier may be referred to as the primary cell (PCell), and the secondary component carriers may be referred to as secondary cells (SCells).

[0032] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154, for example, in an unlicensed spectrum such as 5 GHz. When communicating in unlicensed spectrum, the STA 152 / AP 150 may perform a free channel assessment (CCA) before communication to determine whether the channel is available.

[0033] Small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cell 102' can employ NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as used by Wi-Fi AP 150. Small cell 102' employing NR in unlicensed spectrum can enhance coverage of the access network and / or increase the access network's capabilities.

[0034] The electromagnetic spectrum is typically subdivided into various classes, bands, channels, etc., based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been designated as frequency range names FR1 (410MHz-7.125GHz) and FR2 (24.25GHz-52.6GHz). The frequencies between FR1 and FR2 are generally referred to as the intermediate frequency band. Although a portion of FR1 is greater than 6GHz, FR1 is often (interchangeably) referred to as the "sub-6GHz" band in various documents and articles. Similar naming issues sometimes occur with FR2, although FR2 is different from the Extremely High Frequency (EHF) band (30GHz-300GHz) designated as the "millimeter wave" band by the International Telecommunication Union (ITU), it is often (interchangeably) referred to as the "millimeter wave" band in documents and articles.

[0035] In light of the foregoing, unless otherwise specifically stated, it should be understood that the terms "sub-6GHz" and the like (if used herein) can broadly refer to frequencies that may be less than 6GHz, may be within FR1, or may include mid-band frequencies. Furthermore, unless otherwise specifically stated, it should be understood that the terms "millimeter wave" and the like (if used herein) can broadly refer to frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band.

[0036] Base station 102 (whether it is a small cell 102' or a large-area (e.g., a macro base station)) may include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations (e.g., gNB 180) may operate in conventional sub-6 GHz spectrum, millimeter wave frequencies, and / or near-millimeter wave frequencies in communication with UE 104. When gNB 180 operates at millimeter wave or near-millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. Millimeter wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short range. Base station 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming. Similarly, beamforming may be applied to sidelink communication (e.g., between UEs).

[0037] Base station 180 may transmit beamforming signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamforming signals from base station 180 in one or more receive directions 182'. UE 104 may also transmit beamforming signals to base station 180 in one or more transmit directions. Base station 180 may receive beamforming signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beamforming training to determine the optimal receive and transmit directions for each of base station 180 / UE 104. The transmit and receive directions of base station 180 may be the same or different. The transmit and receive directions of UE 104 may be the same or different. Although this example is described with respect to base station 180 and UE 104, these aspects can be similarly applied to sidelink communication between first and second devices (e.g., first and second UEs).

[0038] EPC 160 may include Mobility Management Entity (MME) 162, other MMEs 164, Serving Gateway 166, Multimedia Broadcast Multicast Service (MBMS) Gateway 168, Broadcast Multicast Service Center (BM-SC) 170, and Packet Data Network (PDN) Gateway 172. MME 162 may communicate with Home Subscriber Server (HSS) 174. MME 162 is the control node that handles signaling between UE 104 and EPC 160. Typically, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are delivered through Serving Gateway 166, which is itself connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP Service 176. IP Service 176 may include the Internet, intranet, IP Multimedia Subsystem (IMS), PS streaming service, and / or other IP services. The BM-SC 170 provides functions for MBMS user service provisioning and delivery. The BM-SC 170 can serve as an entry point for content provider MBMS transmissions, authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and schedule MBMS transmissions. The MBMS gateway 168 can distribute MBMS services to base stations 102 belonging to Multicast-Broadcast Single Frequency Network (MBSFN) areas belonging to broadcast-specific services, and can be responsible for session management (start / stop) and collecting billing information related to eMBMS.

[0039] The core network 190 may include Access and Mobility Management Functions (AMF) 192, other AMFs 193, Session Management Functions (SMF) 194, and User Plane Functions (UPF) 195. AMF 192 may communicate with Unified Data Management (UDM) 196. AMF 192 is the control node that handles signaling between UE 104 and the core network 190. Typically, AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are delivered through UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 connects to IP services 197. IP services 197 may include the Internet, intranets, IP Multimedia Subsystem (IMS), Packet Switched (PS) Streaming (PSS) services, and / or other IP services.

[0040] Base stations may include and / or be referred to as gNB, Node B, eNB, access point, base transceiver station, radio base station, radio transceiver, transceiver function, Basic Services Set (BSS), Extended Services Set (ESS), Transmitter Receiver Point (TRP), or some other suitable terminology. Base station 102 provides UE 104 with access to EPC 160 or core network 190. Examples of UE 104 include cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, GPS devices, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similarly functional devices. Some of UE 104 may be referred to as IoT devices (e.g., parking timers, air pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, radio terminal, remote terminal, handheld device, user agent, mobile client, client, or some other suitable term.

[0041] Figure 2A This is a schematic diagram 200 showing an example of the first subframe within a 5G NR frame structure. Figure 2B This is a schematic diagram 230 illustrating an example of a DL channel within a 5G NR subframe. Figure 2C This is a schematic diagram 250 showing an example of a second subframe within a 5G NR frame structure. Figure 2DThis is a schematic diagram 280 illustrating an example of a UL channel within a 5G NR subframe. The 5G NR frame structure can be Frequency Division Duplex (FDD), where subframes within a specific set of subcarriers (carrier system bandwidth) are dedicated to either DL or UL, or it can be Time Division Duplex (TDD), where subframes within a specific set of subcarriers (carrier system bandwidth) are dedicated to both DL and UL. Figure 2A , Figure 2C In the provided example, it is assumed that the 5G NR frame structure is TDD, where subframe 4 is configured with slot format 28 (primarily DL), where D is DL, U is UL, and F is the flexibility used between DL / UL, and subframe 3 is configured with slot format 1 (all UL). Although subframes 3 and 4 are shown with slot formats 1 and 28 respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are all DL and all UL, respectively. Other slot formats 2-61 include a mixture of DL, UL, and flexible symbols. The UE configures the slot format via the received Slot Format Indicator (SFI) (dynamically via DL Control Information (DCI) or semi-statically / statically via Radio Resource Control (RRC) signaling). Note that the following description also applies to the TDD 5G NR frame structure.

[0042] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) can be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. Subframes may also include mini-time slots, which may contain 7, 4, or 2 symbols. Each time slot may contain 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may contain 14 symbols, while for time slot configuration 1, each time slot may contain 7 symbols. Symbols on the DL can be Cyclic Prefix (CP) Orthogonal Frequency Division Multiplexing (OFDM) (CP-OFDM) symbols. Symbols on the UL can be CP-OFDM symbols (for high-throughput scenarios) or Discrete Fourier Transform (DFT) Extended OFDM (DFT-s-OFDM) symbols (also known as Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the time slot configuration and parameter set (numerology). For slot configuration 0, different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Therefore, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2... μ Each time slot / subframe. Subcarrier spacing and symbol length / duration are functions of the parameter set. Subcarrier spacing can be equal to 2.μ *15kHz, where μ is the parameter set from 0 to 4. Therefore, parameter set μ = 0 has a subcarrier spacing of 15kHz, and parameter set μ = 4 has a subcarrier spacing of 240kHz. The symbol length / duration is inversely proportional to the subcarrier spacing. Figures 2A-2D Examples of frequency division multiplexing (FDM) configurations (CP) with 14 symbols per slot and slot configuration 0 with a parameter set μ=2 for 4 slots per subframe are provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within the set of frames, one or more different bandwidth portions (BWPs) can exist (see [link to relevant documentation]). Figure 2B Each BWP can have a specific set of parameters.

[0043] A resource grid can be used to represent the frame structure. Each time slot consists of a resource block (RB) extending for 12 consecutive subcarriers (also known as a physical RB (PRB)). The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0044] like Figure 2A As shown, some of the reference (pilot) signals (RS) in the RE carry the UE. The RS may include a demodulation RS (DM-RS) for channel estimation at the UE (indicated as R for a particular configuration, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS). The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0045] Figure 2BExamples of various DL channels within a subframe of a frame are shown. The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE comprising six RE Groups (REGs), each REG comprising 12 consecutive REs in the OFDM symbols of an RB. A PDCCH within a BWP can be referred to as a Control Resource Set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., a general search space, a UE-specific search space) during PDCCH monitoring timing on the CORESET, where PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs can be located at higher and / or lower frequencies across the entire channel bandwidth. The Primary Synchronization Signal (PSS) can be within symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identity. The Secondary Synchronization Signal (SSS) can be within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the Physical Layer Cell Identity Group Number and radio frame timing. Based on the Physical Layer Identity and Physical Layer Cell Identity Group Number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The Physical Broadcast Channel (PBCH), carrying the Master Information Block (MIB), can be logically grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also known as an SS block (SSB)). The MIB provides the number of RBs and the System Frame Number (SFN) in the system bandwidth. The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as System Information Block (SIB)), and paging information.

[0046] like Figure 2C As shown, some REs carry DM-RS for channel estimation at the base station (indicated as R for a specific configuration, but other DM-RS configurations are possible). The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and DM-RS for the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the first or second symbol of the PUSCH. The PUCCH DM-RS can be transmitted in different configurations depending on whether a short or long PUCCH is transmitted and the specific PUCCH format used. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of the subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The SRS can be used by the base station for channel quality estimation to implement frequency-dependent scheduling on the UL.

[0047] Figure 2DExamples of various UL channels within a subframe of a frame are shown. The PUCCH can be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), pre-decoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) information (ACK / NACK (NACK)) feedback. The PUCCH carries data and may additionally be used to carry buffer status reports (BSR), power headroom reports (PHR), and / or UCI.

[0048] Figure 3 This is a block diagram 300 illustrating sidelink-based communication between a first wireless communication device 310 and a second wireless communication device 350. In some examples, devices 310 and 350 may communicate based on V2X or other D2D communication. Communication may be based on a sidelink using a PC5 interface. Devices 310 and 350 may include UEs, RSUs, base stations, etc. Packets may be provided to a controller / processor 375 implementing Layer 3 and Layer 2 functions. Layer 3 includes the RRC layer, and Layer 2 includes the Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and Media Access Control (MAC) layer.

[0049] Transmit (TX) processor 316 and receive (RX) processor 370 implement Layer 1 functions associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include error detection of the transport channel, forward error correction (FEC) decoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The decoded and modulated symbols can then be divided into parallel streams. Each data stream can then be mapped to OFDM subcarriers, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domains, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially pre-decoded to generate multiple spatial streams. Channel estimation from channel estimator 374 can be used to determine the decoding and modulation scheme, as well as for spatial processing. The channel estimation can be derived from a reference signal and / or channel condition feedback transmitted by device 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier with the corresponding spatial stream for transmission.

[0050] At device 350, each receiver 354RX receives a signal via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides this information to the receive (RX) processor 356. The TX processor 368 and RX processor 356 implement Layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for device 350. If multiple spatial streams are destined for device 350, they can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses a Fast Fourier Transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal consists of a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signal on each subcarrier are recovered and demodulated by determining the most probable signal constellation point transmitted by device 310. These soft decisions can be based on a channel estimate calculated by the channel estimator 358. The soft decision is then decoded and deinterleaved to recover the data and control signals originally transmitted by device 310 on the physical channel. The data and control signals are then provided to controller / processor 359 that implements Layer 3 and Layer 2 functions.

[0051] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. The controller / processor 359 can provide demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between transport and logical channels. The controller / processor 359 is also responsible for error detection to support HARQ operations using ACK and / or NACK protocols.

[0052] Similar to the functions described in relation to the transmission of device 310, controller / processor 359 can provide RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with the transmission of upper-layer PDUs, error correction via ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs on TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority processing, and logical channel priority.

[0053] The channel estimate derived by the channel estimator 358 from the reference signal or feedback transmitted by the device 310 can be used by the TX processor 368 to select an appropriate decoding and modulation scheme and facilitate spatial processing. The spatial stream generated by the TX processor 368 can be provided to different antennas 352 via individual transmitters 354TX. Each transmitter 354TX can modulate an RF carrier with the corresponding spatial stream for transmission.

[0054] The transmission at device 310 is processed in a manner similar to that described in relation to the receiver function at device 350. Each receiver 318RX receives a signal via its corresponding antenna 320. Each receiver 318RX recovers the information modulated on the RF carrier and provides this information to the RX processor 370.

[0055] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. The controller / processor 375 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel. The controller / processor 375 is also responsible for error detection to support HARQ operations using ACK and / or NACK protocols.

[0056] At least one of the TX processor 368, RX processor 356, and controller / processor 359 can be configured to perform operations related to... Figure 1 The beam training component 198 is related to the following aspects.

[0057] Figure 4 This is a call flow diagram 400 illustrating communication between a first UE 402 and a second UE 404. The first UE 402 can perform a beamforming procedure with the second UE 404 based on a set of resources allocated by time and / or frequency. This allocation can provide a first subset of resources to be used by UEs with non-RRC connections and a second subset of resources to be used by UEs with RRC connections. Therefore, the first UE 402 can determine at 406 to perform a beamforming procedure with the second UE 404 within the time- and / or frequency-allocated beamforming resource set. This beamforming procedure can be used for beam link (BPL) establishment, beam refinement, beam switching, etc., with the second UE 404.

[0058] At 408, the first UE 402 can determine whether it is connected to the second UE 404 RRC. If the first UE 402 is not connected to the second UE 404 RRC, the first UE 402 can determine the beam training procedure for its Tx or Rx beam at 412a. When the first UE 402 is not connected to the second UE 404 RRC, the beam training procedure performed by the first UE 402 can be based on the BPL established with the second UE 404. In the configuration, the first UE 402 can attempt to recover from a radio link failure (RLF).

[0059] The partitioning of the beam training resource set can be initially determined by the first UE 402 based on the default configuration. However, if the procedure indicates that more resources should be included in the first or second resource subset, the first UE 402 can adjust the resource partitioning accordingly at 418a. That is, the first UE 402 can adjust the resource partitioning of the beam training resource set at 418a to increase or decrease the size of the first or second resource subset. At 420a, the first UE 402 can select beam training resources from the first beam training resource subset when the first UE 402 is not connected to the second UE 404 RRC, and at 422a, a determined beam training procedure is executed with the second UE 404 based on the resources selected from the first beam training resource subset.

[0060] Alternatively, at 408, the first UE 402 may establish an RRC connection with the second UE 404. At 410, measurement reports between the first UE 402 and the second UE 404 may trigger a specific type of beam training procedure. For example, when the first UE 402 is RRC connected to the second UE 404, the beam training procedure performed by the first UE 402 may be based on beam refinement or beam switching. Beam refinement may be performed by the first UE 402 when the BPL with the second UE 404 can be improved but can continue to be used; however, beam searching may be performed by the first UE 402 when the first UE 402 wants to abandon a beam and select a different beam. Measurement reports communicated at 410 may be based on self-measurements sent from the first UE 402 to the second UE 404 or measurements performed by the second UE 404 and received by the first UE 402 from the second UE 404.

[0061] When the first UE 402 is not RRC connected to the second UE 404, the first UE 402 can determine the beam training procedure (e.g., beam refinement procedure or beam switching procedure) for its Tx or Rx beam at 412b. At 414, the first UE 402 can send a BPL RRC reconfiguration message to the second UE 404. This RRC reconfiguration message may indicate the determined beam training procedure, one or more Transmission Configuration Indicators (TCI)-Status IDs (e.g., via the Quasi-Co-location (QCL) assumption of the reference signal) for the beam to be monitored, and a second subset of resources. At 416, the first UE 402 can receive an RRC reconfiguration response message from the second UE 404, indicating whether the second UE 404 accepts the RRC reconfiguration.

[0062] The partitioning of the beam training resource set can be initially determined by the first UE 402 based on the default configuration, but can be adjusted by the first UE 402 based on an indication that more resources should be included in the first or second resource subset. That is, the first UE 402 can adjust the resource partitioning of the beam training resource set at 418b to increase or decrease the size of the first or second resource subset. At 420b, when the first UE 402 is RRC connected to the second UE 404, the first UE 402 can select beam training resources from the second beam training resource subset, and at 422b, a determined beam training procedure is performed with the second UE 404 based on the resources selected from the second beam training resource subset.

[0063] Figure 5 This is a schematic diagram 500 illustrating resources used to perform beamforming procedures. Millimeter-wave (mmW) communication in frequency range 2 (FR2) can be based on frequencies from 24.25 GHz to 52.6 GHz. Communication transmitted in FR2 can be beamformed based on the path loss that may occur during such transmission. That is, high-frequency waves associated with FR2 may attenuate more rapidly with increasing distance than low-frequency waves (e.g., frequencies corresponding to 410 MHz to 7,125 MHz for frequency range 1 (FR1) waves). Beamforming operations performed for sidelink communication (e.g., V2X, D2D, etc.) may have increased complexity compared to beamforming operations performed between a base station and a UE, because each UE in a distributed network may have to establish a BPL with a peer UE to perform point-to-point (e.g., unicast) communication. In a distributed network, central entities such as base stations, RSUs, APs, etc., may not be used to coordinate sidelink communication. Therefore, establishing and maintaining mmW links in a distributed network may be more expensive than establishing and maintaining links in FR1 and / or establishing and maintaining millimeter-wave links with resources scheduled by a central entity.

[0064] For sidelink communication via FR2 in a distributed network, the network-wide / system-wide periodic beam training resources (e.g., beam training resource 506) can be semi-statically configured for beam search and beam training procedures. Beam training resource 506 of beam training timing 504 can have extended time periods to allow multiple nodes in the distributed network to create and maintain links with each other. The extended time periods of beam training resource 506 / beam training timing 504 can provide reduced system overhead. For example, a 100ms beam training timing 504 can be configured to provide 10% overhead every 1,000ms. Each of the network-wide / system-wide periodic resources for creating and maintaining links (e.g., based on beam search, RACH procedures, etc.) for distributed nodes in the network within the semi-statically configured resources can be tens or hundreds of milliseconds. Because this resource may be associated with extended time periods, beam training resource 506 can occur less frequently than resources associated with reduced time periods. For example, unlike the Uu link, where resources can be synchronized every 20ms (e.g., based on 5ms beam training resources), 100ms beam training resources (e.g., 506) can provide longer beam training opportunities (e.g., 504). In various aspects, each beam training opportunity 504 can include multiple beam training resources 506. The UE can select beam training resources 506 for beam training procedures 508 / 510 to reduce resource conflicts with other UEs attempting to use the same beam training resources 506.

[0065] The semi-static beam training resource 506 of beam training timing 504 can occur periodically in sidelink frames 502. That is, the beam training timing 504 for the entire network / system can be based on... The beam training is configured periodically. Each beam training opportunity 504 may include multiple beam training resources 506. Beam training resources 506 may be multiplexed in time and / or frequency based on time division multiplexing (TDM) and / or frequency division multiplexing (FDM). Beam training resources 506 may be used for initial BPL establishment based on the first beam training procedure 508, or for beam refinement / beam switching based on the second beam training procedure 510. In various respects, after establishing the BPL based on the first beam training procedure 508, the connected UE may also need to maintain the BPL based on the second beam training procedure 510.

[0066] Beam training resource 506 can be of different types, including beam training resource 506 associated with RACH procedure 512c and beam training resource not associated with RACH procedure (e.g., RACH-free beam training based on second beam training procedure 510). Beam training resource 506 associated with RACH procedure 512 can also be associated with beam training reference signal (BTRS) 512a, which may be followed by processing period 512b, which may also be followed by RACH procedure 512c. Beam training resource 506 associated with RACH-free beam training can include BTRS 514a, which may be followed by one or more guard symbols 514b. In all aspects, beam training resource 506 associated with RACH procedure 512c can be used to establish a BPL with a peer UE. However, beam training resource 506 associated with no RACH beam training can be used when the UE has discovered a peer UE and is performing RACH procedure 512c with the peer UE, but is attempting to perform procedures such as beam refinement and beam switching. The UE can select beam training resource 506 to perform beam training procedures 508-510 in a manner that reduces conflicts between beam training resources 506.

[0067] BPL management can be based on whether the UE is a standalone or non-standalone device. Standalone devices can be configured to operate in FR2, while non-standalone devices can be configured to operate in FR2 and other frequency ranges (e.g., sub-6GHz frequency ranges, LTE frequency ranges, etc.). BPL establishment in a standalone configuration can be based on sending BTRS 512a via the network-wide / system-wide beam training resource 506. The peer UE can be configured to listen for BTRS 512a and send RACH at a predetermined RACH timing. Beam training resource 506, access time, RACH timing, etc., can occur based on the default configuration, allowing the RRC connection to be established after the device discovery procedure. For example, after beam training timing 504, a discovery message can be sent based on beam training procedures 508 / 510. For BPL establishment in a non-standalone configuration, device discovery and RRC connection may have already occurred (e.g., via FR1) for performing beam training / scanning without RACH in FR2, and beam reports can be sent via the existing RRC connection.

[0068] The beam refinement and beam switching procedures for FR2 can be based on the RRC connection between the UE and its peer UE. Therefore, the RRC indication of the dominant beam direction can follow the beam training without RACH in FR2. Thus, the beam training resource 506 associated with the RACH procedure 512c can be used for independent configuration, while the beam training resource 506 associated with the beam training without RACH can be used for a non-independent configuration including the beam refinement / beam switching procedure.

[0069] Sidelink transmission via FR2 can be based on network-wide / system-wide beam training resources 506. Resources can be semi-statically configured for beam training opportunities 504, such that each beam training opportunity 504 can include multiple beam training resources 506 for beam training, beam alignment, beam refinement, BPL establishment, etc. In various aspects, the same beam training resources selected by peer UEs may lead to degraded measurements via interference that causes beam misalignment or discovery failure. Therefore, by configuring the UE to select beam training resources 506 from the beam training resource pool of beam training opportunity 504, the UE's sidelink performance can be improved (e.g., in FR2). For example, the partitioning of the beam training resource pool can separate a first subset of beam training resources for initial BPL establishment for independent UEs from a second subset of beam training resources for BPL establishment and beam refinement / beam search for UEs with existing RRC connections. The UE can select beam training resources 506 from the resource pool based on the partitioning. The UE can also determine subsequent partitioning locations based on network conditions. For example, if the program indicates that more nearby UEs are non-independent UEs, the partitioning can be adjusted to provide more beam training resources for non-independent UEs. 506 In other examples, when the program indicates that more nearby UEs are independent UEs, the partitioning can be adjusted in the opposite direction. In a further example, based on whether all nearby UEs are independent or non-independent UEs, the partitioning can be completely eliminated.

[0070] Figure 6 A schematic diagram 600 illustrates a first subset 604 of beam training resources for non-RRC connected UEs and a second subset 606 of beam training resources for RRC connected UEs. The network-wide / system-wide beam training resources 604-606 can be initially determined based on a default configuration. For example, the UE can determine that beam training timing 602 can be divided into a predefined number of beam training resources, including the first subset 604 and the second subset 606. Beam training resource subsets 604-606 can be used for beam training without RACH or beam training associated with a RACH procedure. Furthermore, each beam training resource in the subsets 604-606 can be a time duration t0, which can be a predefined time duration indicating the number of beams that can be scanned by the UE. Based on the length of beam training timing 602 and the number of symbols determined for performing a single scan, the UE can determine the maximum number of beams that can be scanned during beam training timing 602. Scanning can be based on an automatic gain control (AGC) symbol followed by one or more pre-configured BTRS symbols. Beam training associated with the RACH procedure can also be based on determining the number of RACH timings via a predefined mapping between BTRS and RACH timings.

[0071] Beam training timing 602 can be partitioned from [0, T1] to provide a first beam training resource subset 604, and from [T1, T2] to provide a second beam training resource subset 606. In a configuration where the UE is an independent device without an existing RRC connection to a peer UE, the independent UE can determine that the first beam training resource subset 604 extends from [0, T1] based on a default configuration, and can select one or more beam training resources during a time period from [0, T1]. To establish a BPL in independent mode or restore a BPL from an RLF, the UE can enumerate the first beam training resource subset 604 partitioned from [0, T1] in a predetermined order. Based on the number of beams to be scanned, the UE can select one or more beam training resources from the first beam training resource subset 604 corresponding to [0, T1]. Additionally or alternatively, the UE can select M beam training resources from a total of N resource sets in a uniformly random manner, where M corresponds to the number of resources used to scan a defined number of beams. In a further aspect, the UE can select M resources based on the UE's identity (ID) (e.g., Layer 2 ID) via a predetermined protocol.

[0072] A first subset 604 of beam training resources, divided from [0, T1], can be used for initial BPL establishment (e.g., RACH timing) in an independent configuration, and a second subset 606 of beam training resources, divided from [T1, T2], can be used for UEs with RRC connections (e.g., no RACH timing). The resources for beam training timing 602 can be temporally segmented, allowing non-independent UEs that determine the transmissions of independent UEs to perform beam training on different resources than the independent UEs. Therefore, non-independent UEs can avoid transmitting during times corresponding to the time period [0, T1] unless the non-independent UE includes enhanced capabilities (e.g., multiple panels for transmitting and receiving signals).

[0073] In some cases, the UE may have an existing RRC connection with a peer UE. For example, a non-independent UE may have already established an RRC connection via FR1, or an independent UE may have already established an RRC connection via FR2 based on an existing BPL, where the independent UE may be intended to perform beam refinement, beam alignment / realignment, etc. The UE may perform self-measurement or receive measurement reports that trigger the beam training procedure. The UE that determines to transmit BTRS may perform Rx beam scanning / alignment based on sending an RRC reconfiguration message to the peer UE via a side link during the time period [0, T1]. The RRC reconfiguration message may indicate the beam training procedure, indicate a set of TCI-state IDs of the beams to be monitored (e.g., via the QCL assumption of the reference signal), and select M resources from the time period [T1, T2] of the beam training timing 602. In a further aspect, the RRC reconfiguration message may indicate the beam training procedure, indicate a TCI-state ID of the transport beam to be trained, and select M resources from the time period [T1, T2] of the beam training timing 602. Upon receiving an RRC reconfiguration message, the peer UE can accept the RRC reconfiguration message based on an RRC reconfiguration response message sent to the UE via a side link. The peer UE can also be configured to update the resources indicated for the beam training procedure in the RRC reconfiguration message based on internal sensing technology. The UE and peer UE can communicate round-trip (e.g., negotiate beam training resources) until the proposed set of beam training resources is accepted for the time period [T1, T2] for executing the beam training procedure.

[0074] Based on network message load and the presence / number of independent and non-independent devices, the UE can adjust the initial determination of beam training resource allocation (e.g., determined via default configuration). When the UE is not transmitting BTRS, the UE can listen on beam training opportunity 602 (e.g., the UE can initiate discovery / search operations when the UE is idle). The UE can determine that a subset of resources (e.g., 604 or 606) relative to the UE's resource allocation (e.g., 606 or 604) includes a fraction of resources higher than a predefined fraction α, which are unused on n consecutive beam training opportunities 602, or that some time-frequency resources of the resource subset relative to the UE's allocation are available for k consecutive beam training opportunities 602, where parameters n and k can be default parameters. In this case, the UE can determine that the resource should be removed from the resource subset relative to the allocation and added to the resource subset on the allocation side associated with the UE, where the UE can use such resources to perform beam training procedures.

[0075] In the example, a UE with an RRC connection can determine that a portion of the resources in the first beam training resource subset 604 for a non-RRC connected UE have been unused for consecutive beam training opportunities 602. The UE can then determine to remove the unused resources from the first beam training resource subset 604 and add them to the second beam training resource subset 606. The determination of whether beam training resources are used or unused can be based on the measured RSRP on the beam training resources and / or the direction in which the transmission of the beam training resources is received. Therefore, beam refinement / beam alignment can be performed in orthogonal / non-interference directions.

[0076] Figure 7 This is a flowchart 700 of a wireless communication method. The method can be executed by a UE (e.g., UE 104 / 402; device 802; etc.), which may include a memory 360 and may be the entire UE 104 / 402 or a component of UE 104 / 402, such as a TX processor 368, an RX processor 356, and / or a controller / processor 359.

[0077] At point 702, the UE can determine that beam training is performed with the second UE in the beam training resource set. The beam training resource set includes a first subset of beam training resources for UEs without an RRC connection to the UE associated with the beam training, and a second subset of beam training resources for UEs with an RRC connection to the UE associated with the beam training, which does not overlap with the first subset of beam training resources. For example, refer to... Figure 4 and Figure 6 The first UE 402 can determine at 406 that it will perform beam training with the second UE 404 in a beam training resource set. The beam training resource set includes a first beam training resource subset 604 for initial independent BPL establishment and a second beam training resource subset 606 for UEs using RRC connections. The first beam training resource subset 604 may not overlap with the second beam training resource subset 606 in beam training timing 602. The first beam training resource subset 604 and the second beam training resource subset 606 may be either TDM or FDM. In various aspects, the beam training resource set may be based on a partition between the first beam training resource subset 604 and the second beam training resource subset 606, wherein the partition may be adjusted based on the RSRP determined on each of the first and second beam training resource subsets 604 and 606.

[0078] At point 704, the UE can determine whether the first UE is RRC connected to the second UE. For example, refer to... Figure 4 The first UE 402 can determine at 408 whether the first UE 402 is connected to the second UE 404RRC.

[0079] At point 706, when the first UE is determined not to have an RRC connection with the second UE, the UE may determine that beam training is required to determine either a transmit beam or a receive beam for communication with the second UE. For example, refer to Figure 4 When the first UE 402 is not connected to the second UE 404 RRC, the first UE 402 can determine a beam training procedure for its Tx or Rx beam at 412a. In various respects, this beam training procedure can be used to establish a BPL with the second UE 404.

[0080] At point 708, if the first subset of beam training resources includes N beam training resources, the UE can select M beam training resources from the N beam training resources in the first subset of beam training resources—beam training is performed through the M selected beam training resources. For example, refer to... Figures 4-6 The first UE 402 may select beam training resources from a first subset of beam training resources (e.g., first subset 604 of beam training resources) at 420a to perform a beam training procedure with the second UE 404 at 422a. The beam training procedure (e.g., beam training procedure 510) may be based on selecting a subset of beam training resources 506 included in beam training time 504. The M beam training resources may be randomly selected uniformly from N beam training resources, or selected based on an identifier of the first UE 402, at least one of these methods.

[0081] At point 710, when the first UE is determined to have an RRC connection with the second UE, the UE can communicate measurement reports with the second UE. For example, refer to... Figure 4 At 410, when the first UE 402 is connected to the second UE 404 RRC, measurement reports can be communicated between the first UE 402 and the second UE 404.

[0082] At point 712, the UE can determine, based on the communication measurement report, that beam training is required to determine either a transmit beam or a receive beam for communication with the second UE. For example, refer to... Figure 4 The first UE 402 can determine the beam training procedure for its Tx or Rx beam at 412b based on the measurement report communicated at 410. In various respects, this beam training procedure can be used for the beam refinement procedure or beam switching procedure of the first UE 402.

[0083] At point 714, the UE can send an instruction request to reconfigure the sidelink message of the second UE's BPL based on the determination that beam training is required. For example, refer to Figure 4The first UE 402 may, at 414, send an RRC reconfiguration message for the BPL of the second UE 404, based on the determination of the beam training procedure at 412b. The sent RRC reconfiguration sidelink message (e.g., transmitted at 414) may indicate at least one TCI state, which indicates a QCL assumption for a reference signal associated with at least one transmitted beam used to perform beam training, which is performed based on the sent at least one TCI state ID.

[0084] At point 716, when the second beam training resource subset includes N beam training resources, the UE can select M beam training resources from the N beam training resources in the second beam training resource subset—beam training is performed through the M selected beam training resources in the second beam training resource subset. For example, refer to... Figures 4-6 The first UE 402 may select beam training resources from a second subset of beam training resources (e.g., second subset of beam training resources 606) at 420b to perform a beam training procedure with the second UE 404 at 422b. The beam training procedure (e.g., beam training procedure 508) may be based on the selection of a subset of beam training resources 506 included in beam training time 504.

[0085] At point 718, the UE can receive an RRC reconfiguration sidelink response message from the second UE based on the sent RRC reconfiguration sidelink message—and select M beam training resources based on the received RRC reconfiguration sidelink response message. For example, refer to... Figure 4 and Figure 6 The first UE 402 can receive an RRC reconfiguration response message from the second UE 404 at 416 based on the RRC reconfiguration message transmitted for BPL at 414. Based on the RRC reconfiguration response message received from the second UE 404 at 416, the first UE 402 can select beam training resources from the second beam training resource subset (e.g., second beam training resource subset 606) at 420b.

[0086] At 720, the UE can perform beam training in either the first beam training resource subset or the second beam training resource subset based on whether the first UE is RRC connected to the second UE. For example, refer to Figure 4 and Figure 6 The first UE 402 may perform a beam training procedure in the first beam training resource subset 604 at 422a, or the first UE 402 may perform a beam training procedure in the second beam training resource subset 606 at 422b based on whether the first UE 402 is connected to the second UE 404 RRC at 408.

[0087] Figure 8 Schematic diagram 800 illustrates an example hardware implementation of device 802. Device 802 is a UE and includes a cellular baseband processor 804 (also referred to as a modem) coupled to a cellular RF transceiver 822 and one or more Subscriber Identity Module (SIM) cards 820, an application processor 806 coupled to a Secure Digital Card (SD) card 808 and a screen 810, a Bluetooth module 812, a Wireless Local Area Network (WLAN) module 814, a Global Positioning System (GPS) module 816, and a power supply 818. Cellular baseband processor 804 communicates with UE 104 and / or BS 102 / 180 via cellular RF transceiver 822. Cellular baseband processor 804 may include computer-readable medium / memory. This computer-readable medium / memory may be non-transitory. Cellular baseband processor 804 is responsible for general processing, including executing software stored on the computer-readable medium / memory. When executed by cellular baseband processor 804, this software causes cellular baseband processor 804 to perform the various functions described above. Computer-readable media / memory can also be used to store data manipulated by the cellular baseband processor 804 during software execution. The cellular baseband processor 804 also includes a receiving component 830, a communication manager 832, and a transmission component 834. The communication manager 832 includes one or more of the components shown. Components within the communication manager 832 can be stored in computer-readable media / memory and / or configured as hardware within the cellular baseband processor 804. The cellular baseband processor 804 can be a component of the UE 350 and can include a memory 360 and / or at least one of a TX processor 368, an RX processor 356, and a controller / processor 358. In one configuration, the device 802 can be a modem chip and includes only the baseband processor 804, while in another configuration, the device 802 can be the entire UE (e.g., see...). Figure 3 (350) and includes the above-mentioned additional module of device 802.

[0088] The communication manager 832 includes a beam training component 840 configured (e.g., as described in relation to 702, 704, and 720) to determine whether to perform beam training with a second UE in a beam training resource set—the beam training resource set including a first subset of beam training resources for UEs without RRC connections to the UE associated with the beam training, and a second subset of beam training resources that does not overlap with the first subset of beam training resources for UEs with RRC connections to the UE associated with the beam training; determine whether the first UE is RRC connected to the second UE; and perform beam training in either the first or second subset of beam training resources based on the determination of whether the first UE is RRC connected to the second UE.

[0089] The communication manager 832 also includes a RACH resource component 842 configured to: communicate measurement reports with the second UE, such as those described in relation to 710, 712, 714, 716, and 718; determine, based on the communicated measurement reports, that beam training is required to determine one of the transmit or receive beams for communication with the second UE; based on the determination that beam training is required, send an RRC reconfiguration sidelink message indicating a request to reconfigure the BPL with the second UE; select M beam training resources from N beam training resources in a subset of second beam training resources—perform beam training using the M selected beam training resources in the subset of second beam training resources; and receive an RRC reconfiguration sidelink response message from the second UE based on the sent RRC reconfiguration sidelink message—select M beam training resources based on the received RRC reconfiguration sidelink response message. The communication manager 832 also includes a no-RACH resource component 844, which is configured, for example, as described in relation to 706 and 708, to determine that beam training is required to determine one of a transmit beam or a receive beam for communication with the second UE; and to select M beam training resources from N beam training resources in a first subset of beam training resources and perform beam training through the selected M beam training resources.

[0090] The apparatus may include the device that performs the aforementioned Figure 7 The flowchart shows the algorithm's additional components in each block. Therefore, the aforementioned Figure 7 Each block in the flowchart can be executed by a component, and the apparatus can include one or more of these components. These components can be one or more hardware components specifically configured to execute the process / algorithm, implemented by a processor configured to execute the process / algorithm, stored in a computer-readable medium for implementation by the processor, or some combination thereof.

[0091] In one configuration, apparatus 802, particularly cellular baseband processor 804, includes components for determining whether to perform beam training with a second UE in a beam training resource set, the beam training resource set including a first subset of beam training resources for UEs without RRC connections to the UE associated with the beam training and a second subset of beam training resources for UEs with RRC connections to the UE associated with the beam training, the first and second subsets of beam training resources not overlapping; components for determining whether the first UE is RRC connected to the second UE; and components for performing beam training in one of the first or second subsets of beam training resources based on the determination of whether the first UE is RRC connected to the second UE. When it is determined that the first UE is not RRC connected to the second UE and the first beam training resource subset includes N beam training resources, the apparatus 802 may further include a component for determining that beam training needs to be performed to determine one of the transmit beam or receive beam for communication with the second UE; and a component for selecting M beam training resources from the N beam training resources in the first beam training resource subset, wherein beam training is performed through the selected M beam training resources.

[0092] When the first UE is determined to be RRC-connected to the second UE, apparatus 802 may further include components for communicating measurement reports with the second UE; and components for determining, based on the communicated measurement reports, that beam training is required to determine one of a transmit beam or a receive beam for communication with the second UE. When the second beam training resource subset includes N beam training resources, apparatus 802 may further include components for sending an indication request to reconfigure the RRC reconfiguration sidelink message with the second UE's BPL based on the determination that beam training is required; and components for selecting M beam training resources from the N beam training resources in the second beam training resource subset, wherein the beam training is performed using the M selected beam training resources in the second beam training resource subset. Apparatus 802 may further include components for receiving an RRC reconfiguration sidelink response message from the second UE based on the sent RRC reconfiguration sidelink message, wherein the M beam training resources are selected based on the received RRC reconfiguration sidelink response message. The apparatus 802 may further include components for adjusting the partitioning of the first and second beam training resource subsets based on correspondingly determined RSRPs on each of the first and second beam training resource subsets.

[0093] The aforementioned components may be one or more of the aforementioned components of the device 802 configured to perform the functions described therein. As described above, the device 802 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Therefore, in one configuration, the aforementioned components may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions described therein.

[0094] Therefore, when a UE determines to perform a beam training procedure with another UE, the UE can select beam training resources from the beam training resource set during the network-wide / system-wide beam training period. The beam training resource set can be divided into a first subset and a second subset. The first subset can be used to execute beam training procedures that occur before the RACH procedure. For example, the first subset can be used for initial BPL establishment. The second subset can be used to execute beam training procedures that occur after the RACH procedure. For example, the second subset can be used for beam refinement or beam switching. Based on whether the UE has already executed the RACH procedure, the UE can select beam training resources from either the first or second subset to execute the determined beam training procedure.

[0095] It is understood that the specific order or hierarchy of blocks in the disclosed process / flowchart is illustrative of the example method. Based on design preferences, it is understood that the specific order or hierarchy of blocks in the process / flowchart can be rearranged. Furthermore, some blocks can be combined or omitted. The appended method claims present the elements of various blocks in a sample order and are not intended to limit one to the specific order or hierarchy presented.

[0096] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may also be applied to other aspects. Therefore, the claims are not intended to limit the aspects shown herein, but rather to be given the full scope consistent with the language of the claims, wherein references to singular elements are not intended to mean “one and only one,” but rather “one or more,” unless specifically stated otherwise. Terms such as “if,” “when,” and “at the time of,” should be interpreted as meaning “under the condition of,” rather than implying an immediate temporal relationship or reaction. That is, these phrases (e.g., “when”) do not imply immediate action in response to an action or during the occurrence of an action, but only that if a condition is met, then the action will occur, without requiring a specific or immediate time limit for the occurrence of the action. The word “exemplary” is used herein to mean “as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as more preferred or advantageous than other aspects. Unless otherwise specifically stated, the term “some” means one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be only A, only B, only C, A and B, A and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of elements throughout the aspects described in this disclosure that are known to or subsequently known to those skilled in the art are expressly incorporated herein by reference and are intended to be included by the claims. Furthermore, nothing disclosed herein is intended to be contributed to the public, whether or not such disclosure is expressly recited in the claims. The terms “module,” “mechanism,” “element,” “device,” etc., cannot replace the term “component.” Therefore, unless an element is explicitly stated using the phrase "for a component of," no claim element can be understood as a component plus a function.

[0097] The following aspects are illustrative only and may be combined with, but not limited to, other aspects or teachings described herein.

[0098] Aspect 1 is a method for wireless communication of a first UE, comprising: determining to perform beam training with a second UE in a beam training resource set, the beam training resource set including a first subset of beam training resources for UEs without RRC connections to the UE associated with the beam training and a second subset of beam training resources for UEs with RRC connections to the UE associated with the beam training, the first subset of beam training resources and the second subset of beam training resources not overlapping; determining whether the first UE is RRC connected to the second UE; and performing beam training in one of the first subset of beam training resources or the second subset of beam training resources based on the determination of whether the first UE is RRC connected to the second UE.

[0099] Aspect 2 can be combined with aspect 1 and includes determining that the first UE is not RRC connected to the second UE, and that the first subset of beam training resources includes N beam training resources. This aspect further includes: determining that beam training is required to determine one of a transmit beam or a receive beam for communication with the second UE; and selecting M beam training resources from the N beam training resources in the first subset of beam training resources, wherein the beam training is performed through the selected M beam training resources.

[0100] Aspect 3 may be combined with any of Aspects 1-2 and includes M beam training resources being uniformly and randomly selected from N beam training resources, or selected based on the identifier of the first UE, at least one of the following.

[0101] Aspect 4 may be combined with aspect 1 and includes the first UE being determined to be connected to the second UE via RRC. The aspect further includes: communicating measurement reports with the second UE; and, based on the communicated measurement reports, determining that beam training is required to determine one of the transmit beam or receive beam for communicating with the second UE.

[0102] Aspect 5 may be combined with any one of Aspect 1 or 4, and includes the second beam training resource subset comprising N beam training resources. The aspect further includes: based on determining that beam training is required, sending an indication request to reconfigure the RRC reconfiguration side link message of the BPL of the second UE; and selecting M beam training resources from the N beam training resources in the second beam training resource subset, wherein the beam training is performed through the M selected beam training resources in the second beam training resource subset.

[0103] Aspect 6 may be combined with aspect 1 or any of aspects 4-5, and includes a transmitted RRC reconfiguration sidelink message indicating at least one TCI status ID, which indicates a QCL hypothesis of a reference signal associated with at least one transmitted beam for performing the beam training, and performing the beam training based on the transmitted at least one TCI status ID.

[0104] Aspect 7 may be combined with aspect 1 or any of aspects 4-6, and further includes receiving an RRC reconfiguration sidelink response message from the second UE based on the transmitted RRC reconfiguration sidelink message, wherein the M beam training resources are selected based on the received RRC reconfiguration sidelink response message.

[0105] Aspect 8 can be combined with any of aspects 1-7, and includes the first beam training resource subset and the second beam training resource subset being one of time division multiplexing or frequency division multiplexing.

[0106] Aspect 9 may be combined with any of aspects 1-8, and further includes adjusting the partitioning of the first beam training resource subset and the second beam training resource subset based on the corresponding RSRP determined on each of the first beam training resource subset and the second beam training resource subset.

[0107] Aspect 10 is an apparatus for wireless communication, including at least one processor coupled to a memory, and configured to implement any one of the methods in aspects 1-9.

[0108] Aspect 11 is an apparatus for wireless communication, including components for implementing any one of the methods in aspects 1-9.

[0109] Aspect 12 is a computer-readable medium storing computer-executable code that, when executed by the at least one processor, causes the at least one processor to perform any one of the methods of aspects 1-9.

Claims

1. A method for wireless communication of a first user equipment (UE), comprising: A beam training resource set is determined to be performed with a second UE in a beam training resource set that is semi-statically configured as part of the beam training timing. The beam training resource set includes a first subset of beam training resources for UEs that do not have a Radio Resource Control (RRC) connection with the UE associated with the beam training and a second subset of beam training resources for UEs that have an RRC connection with the UE associated with the beam training. The first subset of beam training resources and the second subset of beam training resources are non-overlapping and are semi-statically configured. Determine whether the first UE is RRC connected to the second UE; as well as Based on the determination that the first UE is not connected to the second UE via RRC, beam training is performed in the first beam training resource subset, or based on the determination that the first UE is connected to the second UE via RRC, beam training is performed in the second beam training resource subset.

2. The method according to claim 1, wherein the first UE is determined not to be connected to the second UE RRC, and the first subset of beam training resources includes N beam training resources, the method further comprising: The beam training is to be used to determine one of the transmit beam or receive beam for communicating with the second UE; as well as M beam training resources are selected from the N beam training resources in the first subset of beam training resources, and the beam training is performed using the selected M beam training resources.

3. The method according to claim 2, wherein the M beam training resources are uniformly and randomly selected from the N beam training resources, or selected based on the identifier of the first UE, at least one of the following.

4. The method of claim 1, wherein the first UE is determined to be connected to the second UE via RRC, the method further comprising: Communication measurement report with the second UE; as well as Based on the communication measurement report, it is determined that beam training will be used to determine one of the transmit or receive beams for communication with the second UE.

5. The method according to claim 4, wherein the second beam training resource subset comprises N beam training resources, and the method further comprises: Based on the determination that beam training is to be used, a radio resource control (RRC) reconfiguration side link message is sent to request reconfiguration of the beam pair link (BPL) of the second UE. as well as M beam training resources are selected from the N beam training resources in the second beam training resource subset, and the beam training is performed using the M selected beam training resources in the second beam training resource subset.

6. The method of claim 5, wherein the transmitted RRC reconfiguration sidelink message indicates at least one Transmission Configuration Indicator (TCI) State Identifier ID, the TCI State Identifier ID indicating a quasi-in-place QCL assumption of a reference signal associated with at least one transmitted beam for performing beam training, and the beam training is performed based on the transmitted at least one TCI State Identifier ID.

7. The method of claim 5 further includes receiving an RRC reconfiguration sidelink response message from the second UE based on the sent RRC reconfiguration sidelink message, wherein the M beam training resources are selected based on the received RRC reconfiguration sidelink response message.

8. The method according to claim 1, wherein the first beam training resource subset and the second beam training resource subset are one of time division multiplexing or frequency division multiplexing.

9. The method of claim 1, further comprising adjusting the partitioning of the first beam training resource subset and the second beam training resource subset based on the corresponding determined reference signal received power (RSRP) on each of the first beam training resource subset and the second beam training resource subset.

10. An apparatus for wireless communication of a first user equipment (UE), comprising: At least one memory containing instructions; as well as At least one processor is configured to execute the instructions to cause the device to: A beam training resource set is determined to be performed with a second UE in a beam training resource set that is semi-statically configured as part of the beam training timing. The beam training resource set includes a first subset of beam training resources for UEs that do not have a Radio Resource Control (RRC) connection with the UE associated with the beam training and a second subset of beam training resources for UEs that have an RRC connection with the UE associated with the beam training. The first subset of beam training resources and the second subset of beam training resources are non-overlapping and are semi-statically configured. Determine whether the first UE is RRC connected to the second UE; as well as Based on the determination that the first UE is not connected to the second UE via RRC, beam training is performed in the first beam training resource subset, or based on the determination that the first UE is connected to the second UE via RRC, beam training is performed in the second beam training resource subset.

11. The apparatus of claim 10, wherein the at least one processor is configured to cause the apparatus to determine that the first UE is not RRC connected to the second UE, and the first subset of beam training resources includes N beam training resources, and the at least one processor is further configured to cause the apparatus to: The beamforming training is to be used to determine one of the transmit or receive beams for communication with the second UE; and In the first subset of beam training resources, M beam training resources are selected from the N beam training resources, wherein, in order to perform the beam training, the at least one processor is configured to cause the device to perform the beam training through the selected M beam training resources.

12. The apparatus of claim 11, wherein, in order to select the M beam training resources, the at least one processor is configured to cause the apparatus to select based on at least one of uniformly random selection from the N beam training resources or an identifier of the first UE.

13. The apparatus of claim 10, wherein the at least one processor is configured to cause the apparatus to determine that the first UE and the second UE are RRC connected, and the at least one processor is further configured to cause the apparatus to: Communication measurement report with the second UE; and Based on the communication measurement report, it is determined that beam training will be used to determine one of the transmit or receive beams for communication with the second UE.

14. The apparatus of claim 13, wherein the second subset of beam training resources comprises N beam training resources, and the at least one processor is further configured to cause the apparatus to: Based on the determination that beam training is to be used, a radio resource control (RRC) reconfiguration sidelink message is sent to request reconfiguration of the beam pair link (BPL) with the second UE; and In the second subset of beam training resources, M beam training resources are selected from N beam training resources, wherein, in order to perform the beam training, the at least one processor is configured to cause the device to perform the beam training through the M selected beam training resources in the second subset of beam training resources.

15. The apparatus of claim 14, wherein the transmitted RRC reconfiguration sidelink message indicates at least one Transmission Configuration Indicator (TCI) State Identifier ID, the TCI State Identifier ID indicating a quasi-co-location QCL assumption of a reference signal associated with at least one transmitted beam for performing beam training, and wherein, in order to perform the beam training, the at least one processor is configured to cause the apparatus to perform the beam training based on the transmitted at least one TCI State Identifier ID.

16. The apparatus of claim 14, wherein the at least one processor is further configured to cause the apparatus to receive an RRC reconfiguration sidelink response message from the second UE based on the transmitted RRC reconfiguration sidelink message, wherein in order to select the M beam training resources, the at least one processor is further configured to cause the apparatus to select the M beam training resources based on the received RRC reconfiguration sidelink response message.

17. The apparatus of claim 10, wherein the first beam training resource subset and the second beam training resource subset are one of time division multiplexing or frequency division multiplexing.

18. The apparatus of claim 10, wherein the at least one processor is further configured to cause the apparatus to adjust the partitioning of the first beam training resource subset and the second beam training resource subset based on a correspondingly determined Reference Signal Received Power (RSRP) on each of the first beam training resource subset and the second beam training resource subset.

19. An apparatus for wireless communication of a first user equipment (UE), comprising: Components for determining a beam training resource set and performing beam training with a second UE in a beam training timing that is semi-statically configured as part of a beam training event, the beam training resource set including a first subset of beam training resources for UEs that do not have a Radio Resource Control (RRC) connection with the UE associated with the beam training and a second subset of beam training resources for UEs that have an RRC connection with the UE associated with the beam training, the first subset of beam training resources and the second subset of beam training resources being non-overlapping and semi-statically configured; A component used to determine whether the first UE is RRC connected to the second UE; as well as A component for performing beam training in the first beam training resource subset based on the determination that the first UE is not connected to the second UE RRC, or for performing beam training in the second beam training resource subset based on the determination that the first UE is connected to the second UE RRC.

20. The apparatus of claim 19, wherein the first UE is determined not to be RRC connected to the second UE, and the first subset of beam training resources comprises N beam training resources, the apparatus further comprising: The component used to determine the beam training to be used to determine one of the transmit beam or receive beam for communicating with the second UE; as well as A component for selecting M beam training resources from the N beam training resources in the first subset of beam training resources, wherein beam training is performed using the selected M beam training resources.

21. The apparatus of claim 20, wherein the M beam training resources are uniformly and randomly selected from the N beam training resources, or selected based on the identifier of the first UE, at least one of the following.

22. The apparatus of claim 19, wherein the first UE is determined to be RRC connected to the second UE, the apparatus further comprising: Components used for communicating measurement reports with the second UE; as well as Based on the measurement report being communicated, a component is used to determine which of the beam training beams will be used to determine one of the transmit or receive beams for communication with the second UE.

23. The apparatus of claim 22, wherein the second subset of beam training resources comprises N beam training resources, and the apparatus further comprises: The component used to send an indication request to reconfigure the radio resource control (RRC) reconfiguration side link message with the second UE's beam pair link BPL based on the determination of the beam training to be used; as well as A component for selecting M beam training resources from N beam training resources in the second beam training resource subset, wherein beam training is performed using the M selected beam training resources in the second beam training resource subset.

24. The apparatus of claim 23, wherein the transmitted RRC reconfiguration sidelink message indicates at least one Transmission Configuration Indicator (TCI) State Identifier ID, the TCI State Identifier ID indicating a quasi-in-place QCL assumption of a reference signal associated with at least one transmitted beam for performing beam training, and the beam training is performed based on the transmitted at least one TCI State Identifier ID.

25. The apparatus of claim 23, further comprising means for receiving an RRC reconfiguration sidelink response message from the second UE based on the transmitted RRC reconfiguration sidelink message, wherein the M beam training resources are selected based on the received RRC reconfiguration sidelink response message.

26. The apparatus of claim 19, wherein the first beam training resource subset and the second beam training resource subset are one of time division multiplexing or frequency division multiplexing.

27. The apparatus of claim 19, further comprising a component for adjusting the partitioning of the first beam training resource subset and the second beam training resource subset based on a correspondingly determined reference signal received power (RSRP) on each of the first beam training resource subset and the second beam training resource subset.

28. A computer-readable medium storing computer-executable code, said computer-executable code, when executed by at least one processor of a first user equipment (UE), causing said at least one processor to: A beam training resource set is determined to be performed with a second UE in a beam training resource set that is semi-statically configured as part of the beam training timing. The beam training resource set includes a first subset of beam training resources for UEs that do not have a Radio Resource Control (RRC) connection with the UE associated with the beam training and a second subset of beam training resources for UEs that have an RRC connection with the UE associated with the beam training. The first subset of beam training resources and the second subset of beam training resources are non-overlapping and are semi-statically configured. Determine whether the first UE is RRC connected to the second UE; as well as Based on the determination that the first UE is not connected to the second UE via RRC, beam training is performed in the first beam training resource subset; or based on the determination that the first UE is connected to the second UE via RRC, beam training is performed in the second beam training resource subset.

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