Activate sidelink relay medium access control (MAC)-control element (CE)

Abstract

The wireless communication device can be a UE configured to activate a MAC-CE transmitted through a SL relay after waiting a period of time by receiving an activation request of a command associated with a third UE, the activation request received in a first MAC-CE relayed from a second UE, sending a second MAC-CE to the second UE in response to the activation request, the second MAC-CE including an activation response to the third UE, and activating the command after sending the activation response. The UE can activate the command after waiting a period of time after sending the activation response. The UE can receive a HARQ ACK from the third UE in response to the sent activation response or receive a HARQ ACK from the second UE in response to the sent activation response, and activate the command after waiting a period of time after receiving the HARQ ACK.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 059,503, filed July 31, 2020, entitled “Method and Apparatus for Activating Sidelink Relay MAC-CE”, and U.S. Patent Application No. 17 / 379,342, filed July 19, 2021, entitled “Activation Sidelink Relay MAC-CE”, 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 methods and apparatus for activating a Media Access Control (MAC) Control Element (CE) (MAC-CE) transmitted via a sidelink relay after a waiting activation period. 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 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 universal protocol enabling different wireless devices to communicate at the city, national, regional, and even global levels. An exemplary telecommunications standard is 5G New Radio (NR). 5G NR is part of the Continuous Evolution of Mobile Broadband (CLE) program issued by the 3rd Generation Partnership Project (3GPP), designed to meet new requirements related to latency, reliability, security, scalability (e.g., the Internet of Things (IoT)), and other requirements. 5G NR includes services related to enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Some aspects of wireless communication may include direct communication between devices based on sidelinks. Sidelink technologies require further improvement. These improvements may also apply to other multiple access technologies and telecommunications standards that employ these technologies. Summary of the Invention

[0006] The following is a simplified summary of one or more aspects to provide a basic understanding of these aspects. This summary is not a broad overview of all anticipated aspects, nor is it intended to identify all important or key elements of all aspects, nor to depict the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0007] In some aspects of this disclosure, a method, a computer-readable medium, and an apparatus are provided. The wireless communication apparatus may include a user equipment (UE) configured to activate a MAC-CE transmitted via an SL relay after a waiting period, by: receiving an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from a second UE; transmitting a second MAC-CE to the second UE in response to the activation request, the second MAC-CE including an activation response to the third UE; and activating the command after transmitting the activation response. In one example, the UE may be further configured to receive a Hybrid Automatic Request (HARQ) Acknowledgment (ACK) associated with the third UE from the second UE in response to a transmitted activation response, wait a waiting period after receiving the HARQ ACK associated with the third UE before activating the command, and determine a waiting period from receiving the HARQ ACK associated with the third UE to activating the command. In one example, the UE may receive a HARQ ACK associated with the second UE from the second UE in response to a sent activation response, wait for a period of time after receiving the HARQ ACK associated with the second UE before activating the command, and determine the waiting period between receiving the HARQ ACK associated with the second UE and activating the command. In another example, the UE may be activated after a period of time from the sending of the second MAC-CE including the activation response, based on the number of hops between the third UE and the first UE through which the activation request passes, wherein the hop number is greater than or equal to 1, and receive a HARQ ACK associated with the third UE from the second UE in response to the sent activation response. Here, the command may be activated before or after receiving the HARQ ACK. Here, the activation request is received via the Physical Side Link Shared Channel (PSSCH), and the activation response is sent via the PSSCH. The UE may include an ACK in the activation response.

[0008] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and drawings set forth certain illustrative features of one or more aspects in detail. However, these features represent only a few of the various ways in which the principles of each aspect can be employed, and this description is intended to include all such aspects and their equivalents. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating an example of a wireless communication system and an access network.

[0010] Figure 2A This is a diagram illustrating an example of the first frame according to various aspects of this disclosure.

[0011] Figure 2B This is a diagram illustrating an example of a DL channel within a subframe according to various aspects of this disclosure.

[0012] Figure 2C This is an illustration showing an example of a second frame according to various aspects of this disclosure.

[0013] Figure 2D This is a diagram illustrating an example of a UL channel within a subframe according to various aspects of this disclosure.

[0014] Figure 3 This is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

[0015] Figure 4 An exemplary aspect of the side link time slot structure is shown.

[0016] Figure 5 An exemplary aspect of sidelink communication between devices is shown according to the aspects presented herein.

[0017] Figure 6 An example of wireless communication is shown.

[0018] Figure 7 This is a wireless communication call flow diagram.

[0019] Figure 8 This is a flowchart of a wireless communication method.

[0020] Figure 9 This is a flowchart of a wireless communication method.

[0021] Figure 10 This is a flowchart of a wireless communication method.

[0022] Figure 11 This is a flowchart of a wireless communication method.

[0023] Figure 12This is a diagram illustrating an example of a hardware implementation for an exemplary device. Detailed Implementation

[0024] The detailed description below, illustrated with reference to the accompanying drawings, is intended as a description of various configurations and not as representing the only configuration in which the concepts described herein can be practiced. This detailed description includes specific details intended to provide a thorough 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 cases, well-known structures and components are presented in the form of block diagrams to avoid confusion regarding these concepts.

[0025] Several aspects of a telecommunications system will now be described with reference to various apparatuses and methods. These apparatuses and methods will be described in detail below and shown 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 these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole.

[0026] For example, an element, any part of an element, or any combination of elements may 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 (ISC) 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 may execute software. Software should be interpreted broadly as representing instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, application programs, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, programs, functions, etc., whether referring to software, firmware, middleware, microcode, hardware description languages, or otherwise.

[0027] Accordingly, in one or more examples, the described functionality can be implemented in hardware, software, or any combination thereof. If implemented in software, these functions can be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium that is accessible to a computer. By way of example and not limitation, such computer-readable media 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 types described above, or any other medium that can be used to store computer-executable code in the form of computer-accessible instructions or data structures.

[0028] Figure 1 This is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also known 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.

[0029] The link between UE 104 and base station 102 or 180 can be established as an access link, for example, using the Uu interface. Other communications can be exchanged between wireless devices based on sidelinks. For example, some UEs 104 can communicate with each other using device-to-device (D2D) communication link 158. In some examples, D2D communication link 158 can use DL / UL WWAN 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 achieved through various wireless D2D communication systems, such as WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0030] Examples of sidelink communication may include vehicle-based communication devices that can communicate via 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 combinations 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). In addition to the UE, sidelink communication can also be sent and received by other transmitting and receiving devices, such as roadside units (RSUs). Sidelink communication can be exchanged using the PC5 interface, for example, in combination with… Figure 4 The examples described herein are as follows. While the following description (including the exemplary timeslot structure of Figure 2) can provide an example of sidelink communication related to 5G NR, the concepts described herein can also be applied to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0031] Refer again Figure 1 In some aspects, UE 104 or other devices communicating via a sidelink may include a sidelink relay MAC-CE component 198, which is configured to: receive an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from a second UE; send a second MAC-CE to the second UE in response to the activation request, including an activation response for the third UE; and activate the command after sending the activation response.

[0032] 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: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, non-access stratum (NAS) message distribution, 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 directly or indirectly with each other (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.

[0033] Base station 102 can wirelessly communicate with UE 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. Overlapping geographic coverage areas 110 may exist. For example, a 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 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 referred to as 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 / UE 104 may use the spectrum of a maximum Y MHz bandwidth (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) allocated for each carrier in carrier aggregation for a maximum total Y x MHz (x component carriers) for transmission in each direction. Carriers may or may not be adjacent to each other. Carrier allocation may be asymmetric for DL ​​and UL (e.g., more or fewer carriers may be allocated for DL ​​relative to UL). Component carriers may include primary component carriers and one or more auxiliary component carriers. The primary component carrier may be referred to as the primary cell (PCell) and the auxiliary component carriers may be referred to as secondary cells (SCell).

[0034] 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 in, for example, 5 GHz unlicensed spectrum. When communicating in unlicensed spectrum, the STA 152 / AP 150 may perform a free channel assessment (CCA) to determine channel availability before communication.

[0035] 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) as the Wi-Fi AP 150. Small cell 102' employing NR in unlicensed spectrum can improve the coverage and / or increase the capacity of the access network.

[0036] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc., based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as the frequency ranges FR1 (410MHz–7.125GHz) and FR2 (24.25GHz–52.6GHz). The frequencies between FR1 and FR2 are generally referred to as the mid-band frequencies. Although a portion of FR1 is greater than 6GHz, in various documents and articles, FR1 is often (interchangeably) referred to as the “sub-6GHz” band. A similar naming issue sometimes arises with FR2, which is often (interchangeably) referred to as the “millimeter wave” band in various documents and articles, although this is different from the extremely high frequency (EHF) band (30GHz–300GHz) defined as a “millimeter wave” band by the International Telecommunication Union (ITU).

[0037] In light of the foregoing, unless otherwise explicitly stated, it should be understood that the term "sub-6GHz" as used herein can be broadly interpreted to mean a frequency that may be less than 6GHz, may be within FR1, or may include an intermediate frequency band. Furthermore, unless otherwise specifically stated, it should be understood that the term "millimeter wave" as used herein can be broadly interpreted to mean a frequency that may include an intermediate frequency band or be within FR2, or may be within the EHF band.

[0038] Base station 102, whether a small cell 102' or a large cell (e.g., a macro base station), may include and / or be referred to as an eNB, gNodeB (gNB), or other type of base station. Some base stations, such as gNB 180, may operate in the conventional sub-6 GHz spectrum, millimeter wave frequencies, and / or near-millimeter wave frequencies in communication with UE 104. When gNB 180 operates in 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 of 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 can be applied, for example, to sidelink communication between UEs.

[0039] 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 between a first device and a second device (e.g., a first UE and a second UE) for sidelink communication.

[0040] 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 can 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 transmitted 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. BM-SC 170 can provide 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 station 102 within a Multicast-Broadcast Single Frequency Network (MBSFN) area belonging to a broadcast-specific service, and can be responsible for session management (start / stop) and collecting billing information related to eMBMS.

[0041] 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 can 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 transmitted 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 Stream (PSS) services, and / or other IP services.

[0042] Base stations may include and / or be referred to as gNB, Node B, eNB, access point, base transceiver, radio base station, radio transceiver, transceiver function, Basic Service Set (BSS), Extended Service Set (ESS), Transmit-Receive Point (TRP), or some other appropriate 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 devices, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similar functional devices. Some UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, mobile phone, user agent, mobile client, client, or some other appropriate term.

[0043] Figure 2A This is illustration 200, showing an example of the first subframe within a 5G NR frame structure. Figure 2B This is illustration 230, showing an example of a DL channel within a 5G NR subframe. Figure 2C This is illustration 250, showing an example of a second subframe within a 5G NR frame structure. Figure 2DIllustration 280 illustrates an example of a UL channel within a 5G NR subframe. The 5G NR frame structure can be Frequency Division Duplex (FDD), where, for a given set of subcarriers (carrier system bandwidth), subframes within that set are dedicated to either DL or UL, or it can be Time Division Duplex (TDD), where, for a given set of subcarriers (carrier system bandwidth), subframes within that set are dedicated to both DL and UL. Figure 2A , 2C In the provided example, it is assumed that the 5G NR frame structure is TDD, subframe 4 is configured with slot format 28 (mostly DL), where D is DL, U is UL, and F can be flexibly used between DL / UL, and subframe 3 is configured with slot format 1 (fully 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 both DL and UL, respectively. Other slot formats 2-61 include combinations 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.

[0044] Figures 2A to 2D The frame structure is illustrated, and aspects of this disclosure are applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include micro-time slots, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each time slot may include 14 symbols, while for extended CP, each time slot may include 12 symbols. Symbols on the DL can be 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 CP and parameter set. The parameter set defines the subcarrier spacing (SCS) and effectively defines the symbol length / duration as equal to 1 / SCS.

[0045] μ <![CDATA[SCSΔf=2 μ ·15[kHz]]]> Cyclic prefix 0 15 conventional 1 30 conventional 2 60 Regular, Extended 3 120 conventional 4 240 conventional

[0046] For a standard CP (14 symbols / slot), different parameter sets μ0 through 4 allow 1, 2, 4, 8, 16, and 16 slots per subframe, respectively. For an extended CP, parameter set 2 allows 4 slots per subframe. Correspondingly, for a standard CP and parameter set μ, there are 14 symbols / slots and 2 slots per subframe. μ One time slot / subframe. The 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. Figure 2A-2D An example parameter set μ=2 is provided, consisting of a regular CP with 14 symbols per slot and 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within the frame set, there may be one or more different frequency division multiplexing bandwidth portions (BWPs) (see [link to example]). Figure 2B Each BWP may have a specific set of parameters and CP (regular or extended).

[0047] 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.

[0048] like Figure 2A As shown, some REs carry reference (pilot) signals (RS) for the UE. RSs may include demodulation RS (DM-RS) (denoted as R for a particular configuration, but other DM-RS configurations are also possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. RSs may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0049] 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 symbol of the 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 common search space, a UE-specific search space) during PDCCH monitoring on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs can reside at higher and / or lower frequencies on the channel bandwidth. The Primary Synchronization Signal (PSS) can be located 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 identification. The Secondary Synchronization Signal (SSS) can be located within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the Physical Layer Cell Identifier Group Number and radio frame timing. Based on the Physical Layer Identifier and Physical Layer Cell Identifier Group Number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the 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 such as System Information Blocks (SIBs) that are not transmitted via the PBCH, and paging messages.

[0050] like Figure 2C As shown, some REs carry DM-RS for channel estimation at the base station (denoted 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 one or two symbols preceding the PUSCH. The PUCCH DM-RS can be transmitted in different configurations depending on whether a short or long PUCCH is being transmitted, and depending on the specific PUCCH format used. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of a 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 enable frequency-dependent scheduling on the UL.

[0051] Figure 2DExamples of various UL channels within a subframe of a frame are shown. The PUCCH can be positioned as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) feedback (i.e., one or more HARQ ACK bits indicate one or more ACKs and / or negative ACKs (NACK)). The PUCCH carries data and can also be used to carry buffer status reports (BSR), power headroom reports (PHR), and / or UCI.

[0052] Figure 3 This is a block diagram 300 of a first wireless communication device 310 that communicates with a second wireless communication device 350 via a sidelink. In some examples, devices 310 and 350 may communicate based on V2X or other D2D communication. The 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 Radio Resource Control (RRC) layer, and Layer 2 includes the Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and Media Access Control (MAC) layer.

[0053] Transmit (TX) processor 316 and receive (RX) processor 370 implement Layer 1 functions associated with various signal processing functions. Layer 1 includes a physical (PHY) layer, which may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, physical channel modulation / demodulation, 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-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols can then be split into parallel streams. Each 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 the time-domain OFDM symbol stream. The OFDM streams are spatially precoded to produce multiple spatial streams. The channel estimate from channel estimator 374 can be used to determine coding and modulation schemes, as well as for spatial processing. The channel estimate can be derived from a reference signal transmitted by device 350 and / or channel condition feedback. 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.

[0054] At device 350, each receiver 354RX receives a signal via its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides that 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 comprises 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 the controller / processor 359 that implements layer 3 and layer 2 functions.

[0055] 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 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0056] Similar to the functions described in the transmission description of the combined device 310, the 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 upper-layer PDU transmission, 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 to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority processing, and logical channel priority.

[0057] The TX processor 368 can use a reference signal transmitted from the device 310 by the channel estimator 358 or a feedback-derived channel estimate to select an appropriate coding and modulation scheme and facilitate spatial processing. The spatial stream generated by the TX processor 368 can be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX can modulate an RF carrier with the corresponding spatial stream for transmission.

[0058] Transmissions are processed in device 310 in a manner similar to that described for the receiver function at device 350. Each receiver 318RX receives a signal via its respective antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides that information to the RX processor 370.

[0059] 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 using ACK and / or NACK protocols to support HARQ operation.

[0060] At least one of the TX processor 368, RX processor 356, and controller / processor 359 can be configured to perform and Figure 1 The relevant aspects of 198. At least one of the TX processor 316, RX processor 370, and controller / processor 375 can be configured to perform actions related to... Figure 1 The 198-related aspects.

[0061] Figure 4 Illustrations 400 and 410 illustrate exemplary aspects of a time-slot structure that can be used for sidelink communication (e.g., between UE 104, RSU 107, etc.). In some examples, the time-slot structure may be within a 5G / NR frame structure. In other examples, the time-slot structure may be within an LTE frame structure. Although the following description may focus on 5G NR, the concepts described herein are applicable to other similar domains, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. Figure 4The exemplary time slot structure shown is merely one example; other sidelink communications may have different frame structures and / or different channels for sidelink communication. A frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include micro-time slots, which may include 7, 4, or 4 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, while for time slot configuration 1, each time slot may include 7 symbols. A single resource block for single-time slot transmission is shown in Diagram 400, which may correspond to a Transmission Time Interval (TTI) of 0.5 ms. The Physical Sidelink Control Channel can be configured to occupy multiple Physical Resource Blocks (PRBs), for example, 10, 12, 15, 40, or 45 PRBs. The PSCCH may be limited to a single subchannel. For example, the PSCCH duration may be configured to 4 or 3 symbols. For example, a subchannel may include 10, 15, 40, 45, 50, 75, or 100 PRBs. Resources for sidelink transmission can be selected from a resource pool that includes one or more subchannels. As a non-limiting example, a resource pool may include 1-27 subchannels. A PSCCH size can be established for the resource pool, for example, between 10-100% of a subchannel, lasting 4 or 3 symbols. Figure 4 Figure 410 shows an example of PSCCH occupying approximately 50% of a subchannel, serving as an example to illustrate the concept of PSCCH occupying a portion of a subchannel. PSSCH occupies at least one subchannel. In some examples, PSCCH may include a first part of Side Link Control Information (SCI), and PSSCH may include a second part of the SCI.

[0062] A resource grid can be used to represent the frame structure. Each time slot can include 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. Figure 4 As shown, some REs may include control information from the PSCCH, and some REs may include demodulated RSs (DMRS). At least one symbol may be used for feedback. Figure 4 An example with two symbols for a Physical Side Link Feedback Channel (PSFCH) with adjacent gap symbols is shown. Symbols before and / or after feedback can be used for transitions between data reception and feedback transmission. The gap allows the device to switch from operating as a transmitting device to preparing to operate as a receiving device, for example, in the next time slot. As shown, data can be transmitted in the remaining RE. Data may include the data messages described herein. The positions of any of the data, DMRS, SCI, feedback, gap symbols, and / or LBT symbols may differ. Figure 4 The example shown illustrates this. In some respects, multiple time slots can be aggregated together.

[0063] Figure 5 Example 500 of sidechain communication between devices is shown. The communication may be based on a combination of... Figure 4 The time slot structure described. For example, UE 502 can transmit sidelink transmission 514, including, for example, a control channel (e.g., PSCCH) and / or a corresponding data channel (e.g., PSSCH) that can be received by UEs 504, 506, and 508. The control channel may include information for decoding the data channel (e.g., sidelink control information (SCI)), and the data channel includes reservation information, such as information about time and / or frequency resources reserved for data channel transmission. For example, the SCI may indicate the number of TTIs and the RBs to be occupied by the data transmission. The receiving device may also use the SCI to avoid interference by avoiding transmissions on reserved resources. In addition to sidelink reception, each of UEs 502, 504, 506, and 508 is capable of sidelink transmission. Therefore, UEs 504, 506, and 508 are illustrated as transmitting sidelink transmissions 513, 515, 516, and 520. Sidelink transmissions 513, 514, 515, 516, and 520 can be unicast, broadcast, or multicast to nearby devices. For example, UE 504 can send sidelink transmissions 513 and 515 intended to be received by other UEs within range 501 of UE 504, and UE 506 can send sidelink transmission 516. Additionally or alternatively, RSU 507 can receive communications from UEs 502, 504, 506, and 508 and / or send communications 518 to UEs 502, 504, 506, and 508. One or more of UEs 502, 504, 506, 508, or RSU 507 can include, as in combination Figure 1 The sidelink relay MAC-CE component 198 is described.

[0064] MAC-CE is a command transmitted from one network device to another. Network devices can be UEs and base stations. Therefore, UEs and base stations can send command messages to each other via MAC-CE. Specifically, MAC-CE between UEs can be transmitted via sidelink communication. MAC-CE can provide feedback through HARQ messaging, thereby providing improved reliability and increased latency. The receiver can provide a HARQ ACK to the transmitter to acknowledge that the command has been successfully received via MAC-CE. Alternatively, the command message can be transmitted via DCI on the DL or UCI on the UL (via PUCCH or PUSCH). Transmitting the command message via DCI on the DL or UCI on the UL does not provide a HARQ message (e.g., ACK / NACK). Therefore, command messages transmitted via DCI on the DL or UCI on the UL may have lower latency but may have lower reliability.

[0065] MAC-CE can be sent via sidelink communication. In LTE communication, a Sidelink (SL) Buffer Status Report (BSR) MAC-CE (SL-BSR MAC-CE) can be sent on the Uu link to indicate the buffer status of sidelink services. For NR Vehicle-to-Everything (V2X) networks, CSI reports can be sent via sidelink MAC-CE. By sending a sidelink MAC-CE that includes a CSI report, the UE can avoid implementing a receiver for UCI multiplexing.

[0066] To implement more advanced use cases, more sidelink-related MAC-CEs may be required. For example, MAC-CEs sent via Uu links or sidelink communication can carry sidelink-related information. In the case of sidelink relay, the MAC-CE can indicate the relayed service and / or the originating service. In the case of Uu-PC5 timeslot aggregation, special processing can be provided for the MAC-CE, and the MAC-CE can indicate which code block groups (CBGs) were sent via which link.

[0067] Uu link MAC-CE (DL or UL) relayed via sidelink communication can include additional relay / routing information. This relay / routing information can be individually indicated for RRC / MAC-CE / DCI or their sidelink equivalents. The relay information can include one or more of the source node, destination node, or transit route.

[0068] If the last segment of the relay is a Uu link, the routing information may be deleted, or some or all of it may be retained in the last segment (e.g., the source ID). In the case of Uu+PC5 timeslot aggregation, the last segment may be a Uu+PC5 link, and the routing information indication may differ from that of a Uu-only link.

[0069] The content of a MAC-CE may include commands to perform or activate specific functions on a target network device (e.g., a receiving UE). A MAC-CE transmitted on an SL may include SL-related content such as SL-CSI, SL Timing Advance (SL-TA) (e.g., for Out-of-Coverage (OOC)), SL Transmit Power Control (TPC) (SL-TPC), SL Scheduling Request (SR) / Buffer Status Report (BSR) / Power Headroom Report (PHR), SL Semi-Persistent Scheduling (SL-SPS) / Carrier Class (CG), and / or activation / deactivation of Aperiodic / Semi-Persistent (A / SP) SL-CSI-RS / SRS (A / SP SL-CSI-RS / SRS). When a MAC-CE including the content provided above is relayed on an SL, routing information may be filled / removed according to the Uu MAC-CE provided regarding SL relay.

[0070] A MAC-CE transmitted on a Uu link with SL-related content (e.g., SL-BSR for LTE) may include SL-PHR, TPC, recommended bit rate, channel busy rate (CBR) / channel occupancy rate (CR), and a MAC-CE for base station relay provided by a MAC-CE with SL-related content transmitted on an SL.

[0071] The MAC-CE header can indicate which CBGs are sent through which link (Uu link or PC5 link). The MAC-CE header can also indicate the location of other MAC-CEs, specifically whether they originate from a Uu link or a PC5 link.

[0072] MAC-CEs can have an activation time. On Uu links, some MAC-CEs, such as UL MAC-CEs, DL TAs, and recommended bit rates, may not have an activation time, but many MAC-CEs can have an activation time based on the ACK transmission time. For example, the activation time could be 3ms or N time slots after sending an ACK. Time counting can include or exclude TA commands received during the counting period. ACK Tx can refer to the ACK for the entire TB. Generally, UL MAC-CEs may not have an activation time because how to respond to a UL MAC-CE can be determined by the base station implementation.

[0073] In SL communication, a MAC-CE containing SL-related content sent to the base station can be treated similarly to a Uu UL MAC-CE, and the base station implementation can determine how to respond to the MAC-CE. MAC-CEs sent to the UE via SL or via DL (containing SL-related content) can be treated as Uu DL MAC-CEs. Therefore, the activation time can be based on ACK. The activation times of MAC-CEs sent via SL and MAC-CEs sent via DL may differ. Furthermore, MAC-CEs relayed from one UE to another via a relay UE may require special consideration.

[0074] MAC-CE can be relayed to the receiving UE via the relay UE, and different activation times can be configured for the receiving UE. An ACK can be sent in response to successful reception of the MAC-CE. If the ACK is not relayed, it can be sent directly from the receiving UE to the initiating UE, i.e., the UE that initiated the MAC-CE. The receiving UE can follow ACK timing and can have an activation time based on the ACK transmission time. For example, the receiving UE can wait 3ms after sending an ACK to the initiating UE before activating the MAC-CE.

[0075] When an ACK is relayed back to the originating UE via a relay UE, the receiving UE may follow timing that depends on the time delay caused by the hops of the relayed MAC-CE, because the predetermined time delay may not be sufficient compared to an ACK that was sent directly. For example, the receiving UE may use X ms as the activation time, where X depends on the number of hops. Since the number of hops may be dynamic and the receiving UE may not know the signal hop count, this information may be indicated to the receiving UE separately (e.g., as part of the ACK or in DCI / MAC-CE / RRC). For example, the receiving UE may use a pre-configured "expected" number of hops.

[0076] In another example, the receiving UE may follow the timing of the last hop of the ACK. The receiving UE may know this timing based on the time it takes to receive the ACK. However, the originating UE may not know this timing. Similarly, the receiving UE may use a pre-configured / expected timing based on the number of hops, and the pre-configured / expected timing may be equivalent to configuring an activation time of X ms. When the ACK may be relayed by multiple routes, the number of hops for "X ms" can be determined based on the shortest route or the longest route, where the length of the route refers to the number of hops.

[0077] When the originating UE sends a MAC-CE containing commands to the receiving UE via a relay UE, the receiving UE can determine the activation time to activate the commands in the MAC-CE received from the originating UE via the relay UE.

[0078] In one example, when the receiving UE sends an ACK directly back to the originating UE, the receiving UE can follow the methods provided for the Uu link. In another example, when the receiving UE sends an ACK relayed via a relay UE to the originating UE, the receiving UE can determine the activation time. First, the receiving UE can wait for an activation period of X milliseconds corresponding to the number of hops between the receiving UE and the originating UE. Second, the receiving UE can increase the activation period by adding an additional Y millisecond offset, which is configured to allow time for the ACK to be relayed from the relay UE to the originating UE. Third, when the ACK for the originating UE itself is sent in a packet (e.g., a PSSCH carrying a second MAC-CE), the second MAC-CE can also be acknowledged (e.g., the relay UE can send an ACK to the receiving UE to indicate the reception of the second MAC-CE), and the relay UE can send an ACK to the receiving UE to indicate that the second MAC-CE was successfully relayed to the originating UE. Fourth, the MAC-CE from the originating UE can be activated X' milliseconds after the receiving UE transmits a PSSCH carrying an ACK based on the MAC-CE (for the MAC-CE received from the originating UE). Fifth, the MAC-CE from the originating UE can be activated X” milliseconds after successfully receiving the HARQ-ACK for the successful transmission of the PSSCH sent to the originating UE.

[0079] Figure 6 Example 600 of wireless communication is illustrated. Example 600 includes a first UE 602, a second UE 604, and a third UE 606. The third UE 606 (or UE3) can use the second UE 604 (or UE2) as a relay UE to send a MAC-CE to the first UE 602 (or UE1). Instead of a HARQ ACK or in addition to a HARQ ACK, the MAC-CE from the third UE 606 can request the first UE 602 to send an ACK based on the response MAC-CE to the third UE 606. The response MAC-CE sent by the first UE 602 to the third UE 606 does not need to be an ACK.

[0080] First, in 608, the third UE 606 can send a first MAC-CE (or MAC-CE1) intended for use by the first UE 602 to the second UE 604. In 610, the second UE 604 can then relay the first MAC-CE to the first UE 602.

[0081] After successfully receiving the first MAC-CE from the third UE 606 via the second UE 604, the first UE 602 may send a second MAC-CE (or MAC-CE2) to the third UE 606 in response to the first MAC-CE. Here, the second MAC-CE may include an ACK for the first MAC-CE, indicating the successful reception of the first MAC-CE.

[0082] PSSCH 620 illustrates an example of a PSSCH sent from a first UE 602 that includes a second MAC-CE, wherein the second MAC-CE includes a MAC-CE-based ACK for the first MAC-CE, indicating successful reception of the first MAC-CE.

[0083] In 612, the first UE 602 can transmit a PSSCH with the second MAC-CE to the third UE 606 via the second UE 604 relaying the second MAC-CE. In 614, the second UE 604 can relay the PSSCH with the second MAC-CE to the third UE 606.

[0084] After successfully receiving the second MAC-CE from the first UE 602 via the second UE 604, the third UE 606 may send a HARQ ACK indicating successful reception of the second MAC-CE. In 616, the third UE 606 may send a HARQ ACK indicating successful reception of the second MAC-CE to the second UE 604. In 618, the second UE 604 may relay the HARQ ACK indicating successful reception of the second MAC-CE to the first UE 602.

[0085] Figure 7 This is a call flow diagram 700 for wireless communication. The call flow diagram 700 may include a first UE 702, a second UE 704, and a third UE 706. The first UE 702 may receive an activation request relayed via the second UE 704 from the third UE 706, send an activation response to the third UE 706, and activate the received activation request after a period of time.

[0086] A third UE 706 (or UE3; for example, a first UE 602) may use a second UE 704 (or UE2; for example, a second UE 604) as a relay UE to send a first MAC-CE (i.e., MAC-CE1) to a first UE 702 (or UE1; for example, a third UE 606). Instead of a HARQ ACK or in addition to a HARQ ACK, the first MAC-CE from the third UE 706 may instruct UE 702 to send a MAC-CE-based ACK to the third UE 706. In 710, the third UE 706 may send a first MAC-CE (or MAC-CE1) to the second UE 704 intended for use by the first UE 702 (e.g., in step 608). The first MAC-CE may include an activation request for a command associated with the first UE 702.

[0087] In step 712, the second UE 704 can relay a first MAC-CE (e.g., in step 610) from the third UE 706 to the first UE 702, including an activation request for a command associated with the first UE 702. The first UE 702 can receive the activation request for a command associated with the third UE 706, which is received in the first MAC-CE relayed from the second UE 704 (e.g., in step 610). The activation request can be received via PSSCH.

[0088] After successfully receiving the first MAC-CE from the third UE 706, in step 714, the first UE 702 may, in response to an activation request, send a second MAC-CE 706 to the second UE 704, including an activation response to the third UE (e.g., in step 612). The activation response may be sent via a PSSCH. The PSSCH may include a MAC-CE-based ACK intended for use by the third UE 706 (e.g., PSSCH 620). That is, the PSSCH sent from the first UE 702 may include a second MAC-CE, which includes a MAC-CE-based ACK for the first MAC-CE indicating successful reception of the first MAC-CE intended for use by the third UE 706.

[0089] In 716, the second UE 704 can send a HARQ ACK indicating that it has successfully received the PSSCH from the first UE 702. The first UE 702 can receive the HARQ ACK associated with the second UE 704 in response to the activation response sent in 714.

[0090] In 718, the second UE 704 can relay the second MAC-CE received in 714 from the first UE 702 to the third UE 706, wherein the second MAC-CE includes an activation response to the third UE 706 (e.g., in step 614).

[0091] After successfully receiving a PSSCH including a MAC-CE-based ACK from the first UE 702 via the second UE 704, the third UE 706 may send a HARQ ACK indicating successful reception of the PSSCH including the MAC-CE-based ACK. In 720, the third UE 706 may send a HARQ ACK for the first UE 702 in response to successfully receiving the PSSCH relayed by the second UE 704 from the first UE 702 (e.g., in step 616).

[0092] In step 722, the second UE 704 may, in response to an activation response, relay the HARQ ACK associated with the third UE 706 from the third UE 706 to the first UE 702 (e.g., in step 618). In response to the activation response sent in step 714, the first UE 702 may receive the HARQ ACK associated with the third UE 706 from the second UE 704 (e.g., in step 618).

[0093] In 730, the first UE 702 can determine the time period prior to activating the first MAC-CE received in 712. In one aspect, the first UE 702 can determine the time period to wait after receiving a HARQ ACK associated with the third UE 706 and before activating the command. In another aspect, the first UE 702 can determine the time period to wait after receiving a HARQ ACK associated with the second UE 704 and before activating the command. In yet another aspect, the first UE 702 can determine the time period after the transmission of the second MAC-CE, including the activation response, and before command activation based on the number of hops between the third UE 706 and the first UE 702 through which the activation request passes, wherein the hop number is greater than or equal to 1.

[0094] In one aspect, the time period during which the first UE 702 waits before activating the first MAC-CE can be determined based on the PSSCH sent for the third UE 706 in 714. That is, the first UE 702 can determine the time period as X milliseconds based on the hop count from the first UE 702 to the third UE 706. The first UE 702 can activate the command sent in the first MAC-CE after a time period of X milliseconds following the sending of the PSSCH containing the MAC-CE-based ACK to the third UE 706 in 714.

[0095] In another scenario, the time period during which the first UE 702 waits before activating the first MAC-CE can be determined based on the reception of a HARQ ACK in response to the PSSCH, wherein the HARQ ACK is sent from the third UE 706 via the second UE 704 in 722. That is, the first UE 702 can define the time period as Y milliseconds. The first UE 702 can activate the command sent in the first MAC-CE after a Y millisecond time period following receiving the HARQ ACK from the third UE 706 via the second UE 704 in 722, wherein the HARQ ACK indicates successful reception of the PSSCH at the third UE 706.

[0096] In another scenario, the time period during which the first UE 702 waits before activating the first MAC-CE can be determined based on the reception of a HARQ ACK in response to the PSSCH, wherein the HARQ ACK is sent from the second UE 704 in 716. That is, the first UE 702 can define the time period as Z milliseconds. The first UE 702 can activate the command sent in the first MAC-CE after a Z millisecond time period following receiving the HARQ ACK from the second UE 704 in 716, wherein the HARQ ACK indicates successful reception of the PSSCH at the second UE 704.

[0097] In 732, the first UE 702 can activate the command after sending an activation response. That is, the first UE 702 can activate the first MAC-CE received from the third UE 706 in 712 after a time period determined in 730. In one aspect, the command can be activated after a time period of receiving a HARQ ACK associated with the third UE in 722. In another aspect, the command can be activated after a time period of receiving a HARQ ACK associated with the second UE in 716. In yet another aspect, the command can be activated after a period of time following the sending of the second MAC-CE including the activation response in 714. The command can be activated before or after receiving the HARQ ACK.

[0098] Figure 8 This is a flowchart 800 of a wireless communication method. The method can be performed by a UE (e.g., UE 104; first UE 602 / 702; device 1202). The UE can receive an activation request relayed via a second UE from a third UE, send an activation response to the third UE, and activate the received activation request after a period of time.

[0099] In 802, the UE can receive an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from the second UE. The activation request can be received via PSSCH. For example, in 712, the first UE 702 can receive an activation request for a command associated with a third UE 706, the activation request being received in a first MAC-CE relayed from the second UE 704. Furthermore, 802 can be performed by component 1240 managed by the MAC-CE.

[0100] In 804, after successfully receiving the first MAC-CE from the third UE, the UE may, in response to the activation request, send a second MAC-CE to the second UE including an activation response to the third UE. That is, the PSSCH sent from the UE may include the second MAC-CE, which includes a MAC-CE-based ACK for the first MAC-CE, indicating successful reception of the first MAC-CE intended for the third UE. For example, in 714, after successfully receiving the first MAC-CE from the third UE in 802, the first UE 702 may, in response to the activation request, send a second MAC-CE to the second UE 704 including an activation response to the third UE 706. Furthermore, 804 may be performed by the MAC-CE management component 1240.

[0101] In step 806, the UE can receive a HARQ ACK associated with the second UE in response to the activation response sent in step 804. For example, in step 716, the first UE 702 can receive a HARQ ACK associated with the second UE 704 in response to the activation response sent in step 714. Furthermore, step 806 can be performed by the HARQ management component 1242.

[0102] In step 808, the UE can receive a HARQ ACK associated with the third UE from the second UE 704 in response to the activation response sent in step 804. For example, in step 722, the first UE 702 can receive a HARQ ACK associated with the third UE 706 from the second UE 704 in response to the activation response sent in step 714. Furthermore, step 808 can be performed by the HARQ management component 1242.

[0103] In 810, the UE can determine the time period prior to activating the first MAC-CE received in 802. In one aspect, the UE can determine the time period to wait after receiving a HARQ ACK associated with a third UE and before activating the command. In another aspect, the UE can determine the time period to wait after receiving a HARQ ACK associated with a second UE and before activating the command. In yet another aspect, the UE can determine the time period after sending the second MAC-CE including the activation response and before the activation command based on the number of hops between the third UE and the UE through which the activation request traverses, wherein the hop number is greater than or equal to 1. For example, in 730, the first UE 702 can determine the time period prior to activating the first MAC-CE received in 802. Furthermore, 810 can be performed by the activation time period component 1244.

[0104] In one aspect, in 804, the time period during which the UE waits before activating the first MAC-CE can be determined based on the PSSCH sent for the third UE. That is, the UE can determine the time period as X milliseconds based on the hop count from the UE to the third UE. The UE can activate the command sent in the first MAC-CE X milliseconds after sending the PSSCH containing the MAC-CE-based ACK to the third UE in 804.

[0105] In another scenario, the time period the UE waits before activating the first MAC-CE can be determined based on the reception of a HARQ ACK in response to the PSSCH, wherein the HARQ ACK is sent from the third UE via the second UE in step 808. That is, the UE can define the time period as Y milliseconds. The UE can activate the command sent in the first MAC-CE after a Y-millisecond time period following receiving the HARQ ACK from the third UE via the second UE in step 808, wherein the HARQ ACK indicates successful reception of the PSSCH at the third UE.

[0106] In another scenario, the time period the UE waits before activating the first MAC-CE can be determined based on the reception of a HARQ ACK in response to the PSSCH, wherein the HARQ ACK is sent from the second UE in step 806. That is, the UE can define the time period as Z milliseconds. The UE can activate the command sent in the first MAC-CE after a Z millisecond time period following receiving the HARQ ACK from the second UE in step 806, wherein the HARQ ACK indicates successful reception of the PSSCH at the second UE.

[0107] In 812, the UE can activate the command after sending an activation response. That is, the UE can activate the first MAC-CE received from the third UE in 802 after a time period determined in 810. In one aspect, the command can be activated after a time period of receiving a HARQ ACK associated with the third UE in 808. In another aspect, the command can be activated after a time period of receiving a HARQ ACK associated with the second UE in 806. In yet another aspect, the command can be activated after a period of time following the sending of the second MAC-CE including the activation response in 804. The command can be activated before or after receiving the HARQ ACK. For example, in 732, the first UE 702 can activate the command after sending an activation response. Furthermore, 812 can be executed by command component 1246.

[0108] Figure 9 This is a flowchart 900 of a wireless communication method. The method can be performed by a UE (e.g., UE 104; first UE 602 / 702; device 1202). The UE can receive an activation request relayed via a second UE from a third UE, send an activation response to the third UE, and activate the received activation request after a period of time.

[0109] In 902, the UE can receive an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from the second UE. The activation request can be received via PSSCH. For example, in 712, the first UE 702 can receive an activation request for a command associated with a third UE 706, the activation request being received in a first MAC-CE relayed from the second UE 704. Furthermore, 902 can be executed by the MAC-CE management component 1240.

[0110] In step 904, after successfully receiving the first MAC-CE from the third UE, the UE may, in response to the activation request, send a second MAC-CE to the second UE, including an activation response to the third UE. That is, the PSSCH sent from the UE may include the second MAC-CE, which includes a MAC-CE-based ACK for the first MAC-CE, indicating successful reception of the first MAC-CE intended for the third UE. For example, in step 714, after successfully receiving the first MAC-CE from the third UE in step 902, the first UE 702 may, in response to the activation request, send a second MAC-CE to the second UE 704, including an activation response to the third UE 706. Furthermore, step 904 may be performed by the MAC-CE management component 1240.

[0111] In 912, the UE can activate the command after sending an activation response. That is, the UE can activate the first MAC-CE received from the third UE in 902 after a defined time period. In one aspect, the command can be activated after a time period starting from receiving a HARQ ACK associated with the third UE. In another aspect, the command can be activated after a time period starting from receiving a HARQ ACK associated with the second UE. In yet another aspect, the command can be activated after a period of time starting from sending a second MAC-CE including an activation response in 904. The command can be activated before or after receiving a HARQ ACK. For example, in 732, the first UE 702 can activate the command after sending an activation response. Furthermore, 912 can be executed by command component 1246.

[0112] Figure 10 This is a flowchart 1000 of a wireless communication method. The method can be performed by a UE (e.g., UE 104; second UE 604 / 704; device 1202). The UE can relay an activation request from a third UE to a first UE, and relay an activation response from the first UE to a third UE.

[0113] In 1002, the UE can receive a first MAC-CE intended for use by the first UE from a third UE. The first MAC-CE may include an activation request for a command associated with the first UE. For example, in 710, the second UE 704 can receive a first MAC-CE 702 intended for use by the first UE 702 from the third UE 706. Furthermore, 1002 can be performed by the MAC-CE management component 1240.

[0114] In 1004, the UE can relay a first MAC-CE, including an activation request for a command associated with the first UE, from a third UE to the first UE. The activation request can be received via PSSCH. For example, in 712, the second UE 704 can relay a first MAC-CE, including an activation request for a command associated with the first UE 702, from a third UE 706 to the first UE 702. Furthermore, 1004 can be performed by the MAC-CE management component 1240.

[0115] In 1006, the UE can receive a second MAC-CE including an activation response to the third UE from the first UE. The activation response can be sent via PSSCH. The PSSCH can include an ACK based on the MAC-CE intended for the third UE. That is, the PSSCH sent from the first UE can include a second MAC-CE including an ACK based on the first MAC-CE indicating successful reception of the first MAC-CE intended for the third UE. For example, in 714, the second UE 704 can receive a second MAC-CE including an activation response to the third UE 706 from the first UE 702. Furthermore, 1006 can be performed by the MAC-CE management component 1240.

[0116] In step 1008, the UE can send a HARQ ACK indicating successful receipt of the PSSCH from the first UE. For example, in step 716, the second UE 704 can send a HARQ ACK indicating successful receipt of the PSSCH from the first UE 702. Furthermore, step 1008 can be performed by the HARQ management component 1242.

[0117] In 1010, the UE can relay the second MAC-CE received in 1006 from the first UE to the third UE, wherein the second MAC-CE includes an activation response to the third UE. For example, in 718, the second UE 704 can relay the second MAC-CE received in 714 from the first UE 702 to the third UE 706, wherein the second MAC-CE includes an activation response to the third UE 706. Furthermore, 1010 can be performed by the MAC-CE management component 1240.

[0118] In 1012, the UE can receive a HARQ ACK for the first UE in response to successfully receiving a PSSCH relayed by the second UE from the first UE. For example, in 720, the second UE 704 can receive a HARQ ACK for the first UE 702 in response to successfully receiving a PSSCH relayed by the second UE 704 from the first UE 702. Furthermore, 1012 can be performed by the HARQ management component 1242.

[0119] In 1014, the UE can relay the HARQ ACK associated with the third UE to the first UE from the third UE in response to the activation response. For example, in 722, the second UE 704 can relay the HARQ ACK associated with the third UE 706 to the first UE 702 from the third UE 706 in response to the activation response. Furthermore, 1014 can be performed by the HARQ management component 1242.

[0120] Figure 11 This is a flowchart 1100 of a wireless communication method. The method can be performed by a UE (e.g., UE 104; second UE 604 / 704; device 1202). The UE can relay an activation request from a third UE to a first UE, and relay an activation response from the first UE to a third UE.

[0121] In 1104, the UE can relay a first MAC-CE, including an activation request for a command associated with the first UE, from a third UE to the first UE. The activation request can be received via PSSCH. For example, in 712, the second UE 704 can relay a first MAC-CE, including an activation request for a command associated with the first UE 702, from a third UE 706 to the first UE 702. Furthermore, 1104 can be performed by the MAC-CE management component 1240.

[0122] In 1110, the UE can relay the second MAC-CE received in 1106 from the first UE to the third UE, wherein the second MAC-CE includes an activation response to the third UE. For example, in 718, the second UE 704 can relay the second MAC-CE received in 714 from the first UE 702 to the third UE 706, wherein the second MAC-CE includes an activation response to the third UE 706. Furthermore, 1110 can be performed by the MAC-CE management component 1240.

[0123] Figure 12This is a diagram 1200 illustrating an example hardware implementation for device 1202. Device 1202 may be a UE, or another device configured to transmit and / or receive side-link communication. Device 1202 includes a baseband processor 1204 (also referred to as a modem) coupled to an RF transceiver 1222. In some aspects, the baseband processor 1204 may be a cellular baseband processor and / or the RF transceiver 1222 may be a cellular RF transceiver. Device 1202 may also include one or more Subscriber Identity Module (SIM) cards 1220, an application processor 1206 coupled to a Secure Digital Card (SD) card 1208 and a screen 1210, a Bluetooth module 1212, a Wireless Local Area Network (WLAN) module 1214, a Global Positioning System (GPS) module 1216, and / or a power supply 1218. The baseband processor 1204 communicates with the UE 104 and / or BS 102 / 180 via the RF transceiver 1222. Baseband processor 1204 may include computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. Baseband processor 1204 is responsible for general processing, including executing software stored on the computer-readable medium / memory. When executed by baseband processor 1204, the software causes baseband processor 1204 to perform various functions described in this application. The computer-readable medium / memory may also be used to store data manipulated by baseband processor 1204 during software execution. Baseband processor 1204 may include receiving component 1230, communication manager 1232, and transmitting component 1234. Communication manager 1232 includes one or more of the components shown. Components within communication manager 1232 may be stored in computer-readable medium / memory and / or configured as hardware within baseband processor 1204. Baseband processor 1204 may be a component of device 350 and may include memory 360 and / or at least one of TX processor 368, RX processor 356, and controller / processor 359. In one configuration, device 1202 may be a modem chip and include only baseband processor 1204, while in another configuration, device 1202 may be the entire UE (e.g., see...). Figure 3 (350) and includes an additional module of device 1202.

[0124] The communication manager 1232 includes a MAC-CE management component 1240 configured to: receive an activation request for a command associated with a third UE; send a second MAC-CE including an activation response to the third UE; receive a first MAC-CE from the third UE intended to be used by a first UE; relay the first MAC-CE from the third UE to the first UE, wherein the first MAC-CE includes an activation request for a command associated with the first UE; receive a second MAC-CE from the first UE including an activation response to the third UE; and relay the second MAC-CE from the first UE to the third UE, wherein the second MAC-CE includes an activation response to the third UE, for example, as described in conjunction with 802, 804, 902, 904, 1002, 1004, 1006, 1010, 1104, and 1110. The communication manager 1232 also includes a HARQ management component 1242 configured to: receive a HARQ ACK associated with the second UE from the second UE in response to an activation response; receive a HARQ ACK associated with the third UE from the second UE in response to a sent activation response; send a HARQ ACK indicating successful reception of a PSSCH from the first UE; receive a HARQ ACK for the first UE in response to successful reception of a PSSCH relayed via the second UE from the first UE; and relay a HARQ ACK associated with the third UE in response to the activation response, for example, as described in conjunction with 806, 808, 1008, 1012, and 1014. The communication manager 1232 also includes an activation time period component 1244 configured to determine a time period prior to the activation of the received first MAC-CE, for example, as described in conjunction with 810. The communication manager 1232 also includes a command component 1246 configured to activate the command after sending the activation response, for example, as described in conjunction with 812 and 912.

[0125] The device may include additional components that perform the above-described functions. Figure 7 , 8 Each algorithm block in the flowcharts for steps 9, 10, and 11. Therefore, Figure 7 , 8 Each block in flowcharts 9, 10, and 11 can be executed by a component, and the apparatus can include one or more of these components. The component 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 processor implementation, or a particular combination thereof.

[0126] In one configuration, apparatus 1202, specifically baseband processor 1204, includes: components for receiving an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from a second UE; components for sending a second MAC-CE including an activation response to the third UE to the second UE in response to the activation request; and components for activating the command after sending the activation response. Apparatus 1202 includes: components for receiving a HARQ acknowledgment (ACK) associated with the third UE from the second UE in response to the sent activation response; and components for determining a time period to wait after receiving the HARQ ACK associated with the third UE and before the activation command; components for receiving a HARQ acknowledgment (ACK) associated with the second UE from the second UE in response to the sent activation response; and components for determining a time period to wait after receiving the HARQ ACK associated with the second UE and before the activation command. Apparatus 1202 includes components for determining a waiting period between sending a second MAC-CE including the activation response and activating the command, based on the number of hops between the third UE and the first UE through which the activation request traverses, wherein the number of hops is greater than or equal to 1, and apparatus 1202 includes components for receiving a HARQ acknowledgment (ACK) associated with the third UE from the second UE in response to the sent activation response. Apparatus 1202 includes components for relaying a first Media Access Control (MAC) Control Element (CE) (MAC-CE) including an activation request for a command associated with the first UE from the third UE to the first UE, components for relaying a second MAC-CE including an activation response for the third UE from the first UE to the third UE, and components for relaying a HARQ ACK associated with the third UE from the third UE to the first UE in response to the relayed activation response. The components may be one or more components of apparatus 1202 configured to perform the listed component functions. As described herein, apparatus 1202 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Therefore, in one configuration, the components may be TX processor 368, RX processor 356, and controller / processor 359, configured to perform the listed component functions.

[0127] The wireless communication device may include a UE configured to activate a MAC-CE transmitted via an SL relay after waiting for a period of time by: receiving an activation request for a command associated with a second UE, the activation request being received in a first MAC-CE relayed from a third UE; sending a second MAC-CE to the third UE in response to the activation request, the second MAC-CE including an activation response to the second UE; and activating the command after sending the activation response. In one example, the UE may be further configured to receive a HARQ ACK associated with the second UE from the third UE in response to the sent activation response, wait for a period of time after receiving the HARQ ACK associated with the second UE and before the activation command, and determine the waiting period after receiving the HARQ ACK associated with the second UE and before the activation command. In one example, the UE may receive a HARQ ACK associated with the third UE from the third UE in response to a sent activation response, wait for a period of time after receiving the HARQ ACK associated with the third UE and before the activation command, and determine the waiting period from receiving the HARQ ACK associated with the third UE to activating the command. In another example, the UE may wait for a period of time after sending a second MAC-CE including the activation response and before the activation command, based on the number of hops between the second UE and the first UE through which the activation request traverses, where the hop number is greater than or equal to 1, and receive a HARQ ACK associated with the second UE from the third UE in response to the sent activation response. Here, the command may be activated before or after receiving the HARQ ACK. Here, the activation request is received via PSSCH, and the activation response is sent via PSSCH. The UE may include an ACK in the activation response.

[0128] It should be understood that the specific order or hierarchy of the boxes in the disclosed process / flowchart is illustrative of the method. Based on design preferences, it should be understood that the specific order or hierarchy of the boxes in the process / flowchart may be rearranged. Furthermore, some boxes may be combined or omitted. The appended method claims present the elements of various boxes in a sample order and are not intended to limit one to the specific order or hierarchy presented.

[0129] The foregoing description is intended to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to limit them to the aspects shown herein, but are to conform to the full scope consistent with the language of the claims, wherein, unless specifically stated otherwise, elements referred to in the singular are not intended to mean “one and only one,” but rather “one or more.” Terms such as “if,” “when,” and “while,” should be interpreted as “under the condition of,” rather than implying a direct temporal relationship or reaction. That is, these phrases, such as “when,” do not imply action taken in response to an action or immediately during the occurrence of an action, but merely imply that if the condition is met, then the action will occur, without requiring a specific or immediate time constraint on 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 preferred or superior to other aspects. Unless expressly stated otherwise, the term “some” means one or more. Combinations or any combination thereof 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,” or any combination thereof include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of 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, B 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 the elements of each aspect described herein, known to or to be understood by one of ordinary skill in the art, are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended for public viewing, whether or not such disclosure is expressly stated in the claims. Terms such as “module,” “mechanism,” “element,” and “device” may not be alternatives to the term “part.” Therefore, no claim element shall be construed as a component plus a function unless the element is explicitly referenced using the phrase "the component is used for".

[0130] The following aspects are illustrative only and may be combined with other examples or teachings described herein without limitation.

[0131] Aspect 1 is an apparatus for wireless communication at a first UE, the apparatus comprising at least one processor coupled to a memory and configured to: receive an activation request for a command associated with a third UE, the activation request being received in a first MAC-CE relayed from a second UE; transmit a second MAC-CE including an activation response to the third UE to the second UE in response to the activation request; and activate the command after transmitting the activation response.

[0132] Aspect 2 is the apparatus according to aspect 1, wherein the at least one processor and the memory are further configured to receive a HARQ ACK associated with the third UE from the second UE in response to a sent activation response.

[0133] Aspect 3 is the apparatus according to aspect 2, wherein the command is activated after a period of time following the receipt of the HARQ ACK associated with the third UE.

[0134] Aspect 4 is the apparatus described in aspect 3, wherein the at least one processor and the memory are further configured to determine a waiting period after receiving the HARQ ACK associated with the third UE and before activating the command.

[0135] Aspect 5 is the apparatus according to aspect 1, wherein the at least one processor and the memory are further configured to receive a HARQ ACK associated with the second UE from the second UE in response to a sent activation response.

[0136] Aspect 6 is the apparatus according to aspect 5, wherein the command is activated after a period of time from the receipt of the HARQ ACK associated with the second UE.

[0137] Aspect 7 is the apparatus described in aspect 6, wherein the at least one processor and the memory are further configured to determine a waiting period after receiving the HARQ ACK associated with the second UE and before activating the command.

[0138] Aspect 8 is the apparatus according to aspect 1, wherein the command is activated after a period of time from the sending of the second MAC-CE including the activation response.

[0139] Aspect 9 is the apparatus according to aspect 8, wherein the at least one processor and the memory are further configured to determine the time period from after the transmission of the second MAC-CE including the activation response and before the activation command based on the number of hops between the third UE and the first UE through which the activation request passes, wherein the number of hops is greater than or equal to 1.

[0140] Aspect 10 is an apparatus according to either aspect 8 or 9, wherein the at least one processor and the memory are further configured to receive a HARQ ACK associated with the third UE from the second UE in response to a sent activation response.

[0141] Aspect 11 is the apparatus according to aspect 10, wherein the command is activated before the HARQ ACK is received.

[0142] Aspect 12 is the apparatus according to aspect 10, wherein the command is activated upon receiving the HARQ ACK.

[0143] Aspect 13 is an apparatus according to any one of aspects 1 to 12, wherein the activation request is received via PSSCH and the activation response is sent via PSSCH.

[0144] Aspect 14 is an apparatus according to any one of aspects 1 to 13, further comprising a transceiver coupled to the at least one processor, wherein the activation response includes an ACK.

[0145] Aspect 15 is a wireless communication method for implementing any of aspects 1 to 14.

[0146] Aspect 16 is a wireless communication device including components for implementing any of aspects 1 to 14.

[0147] Aspect 17 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any of aspects 1 to 14.

[0148] Aspect 18 is a wireless communication device including at least one processor coupled to a memory and configured to: relay a first MAC-CE from the third UE to the first UE, the first MAC-CE including an activation request for a command associated with the first UE; and relay a second MAC-CE from the first UE to the third UE, the second MAC-CE including an activation response to the third UE.

[0149] Aspect 19 is an apparatus according to aspect 18, wherein the at least one processor and the memory are further configured to relay a HARQ ACK associated with the third UE from the third UE to the first UE in response to a relayed activation response.

[0150] Aspect 20 is the apparatus according to either aspect 18 or 19, wherein the activation request is received via PSSCH and the activation response is sent via PSSCH.

[0151] Aspect 21 is an apparatus according to any one of aspects 18 to 20, further comprising a transceiver coupled to the at least one processor, wherein the activation response includes an ACK.

[0152] Aspect 22 is a wireless communication method for implementing any of aspects 18 to 21.

[0153] Aspect 23 is a wireless communication device including components for implementing any of aspects 18 to 21.

[0154] Aspect 24 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any of aspects 18 to 21.

Claims

1. An apparatus for wireless communication at a first user equipment (UE), the apparatus comprising: Memory; as well as At least one processor coupled to the memory, the at least one processor and the memory being configured to: Receive an activation request for a command associated with a third UE, the activation request being received in a first Media Access Control (MAC) control element CE MAC-CE relayed from a second UE; In response to the activation request, a second MAC-CE is sent to the second UE, the second MAC-CE including an activation response to the third UE; and The command is activated after the activation response is sent and after a time period from the time the second MAC-CE including the activation response is sent, wherein the time period is based on the number of hops between the third UE and the first UE through which the activation request passes, the number of hops being greater than or equal to 1.

2. The apparatus of claim 1, wherein the at least one processor and the memory are further configured to receive a Hybrid Automatic Request (HARQ) acknowledgment (ACK) associated with the third UE from the second UE in response to a sent activation response.

3. The apparatus according to claim 2, wherein, In order to activate the command, the at least one processor and the memory are configured to activate the command after a period of time from the receipt of the HARQ ACK associated with the third UE.

4. The apparatus of claim 3, wherein the at least one processor and the memory are further configured to determine a waiting period after receiving the HARQ ACK associated with the third UE and before activating the command.

5. The apparatus of claim 1, wherein the at least one processor and the memory are further configured to receive a Hybrid Automatic Request (HARQ) Acknowledgment (ACK) associated with the second UE in response to a sent activation response.

6. The apparatus according to claim 5, wherein, In order to activate the command, the at least one processor and the memory are configured to activate the command after a period of time from the receipt of the HARQ ACK associated with the second UE.

7. The apparatus of claim 6, wherein the at least one processor and the memory are further configured to determine a waiting period after receiving the HARQ ACK associated with the second UE and before activating the command.

8. The apparatus of claim 1, wherein the at least one processor and the memory are further configured to determine the time period after the transmission of the second MAC-CE including the activation response and before the activation command, based on the number of hops between the third UE and the first UE through which the activation request passes.

9. The apparatus of claim 1, wherein the at least one processor and the memory are further configured to receive a Hybrid Automatic Request (HARQ) Acknowledgment (ACK) associated with the third UE from the second UE in response to a sent activation response.

10. The apparatus according to claim 9, wherein, In order to activate the command, the at least one processor and the memory are configured to activate the command before receiving a HARQ ACK.

11. The apparatus according to claim 9, wherein, In order to activate the command, the at least one processor and the memory are configured to activate the command after receiving a HARQ ACK.

12. The apparatus according to claim 1, wherein, In order to receive the activation request, the at least one processor and the memory are configured to receive the activation request via the Physical Side Link Shared Channel (PSSCH), and wherein, in order to send the activation response, the at least one processor and the memory are configured to send the activation response via the PSSCH.

13. The apparatus of claim 1, further comprising a transceiver coupled to the at least one processor, wherein the activation response includes an acknowledgment (ACK).

14. A method for wireless communication at a first user equipment (UE), the method comprising: Receive an activation request for a command associated with a third UE, the activation request being received in a first Media Access Control (MAC) control element CE MAC-CE relayed from a second UE; In response to the activation request, a second MAC-CE is sent to the second UE, the second MAC-CE including an activation response to the third UE; as well as The command is activated after the activation response is sent and after a time period from the time the second MAC-CE including the activation response is sent, wherein the time period is based on the number of hops between the third UE and the first UE through which the activation request passes, the number of hops being greater than or equal to 1.

15. The method of claim 14, further comprising receiving a Hybrid Automatic Request (HARQ) acknowledgment (ACK) associated with the third UE from the second UE in response to the sent activation response.

16. The method of claim 15, wherein the command is activated after a period of time following the receipt of the HARQACK associated with the third UE.

17. The method of claim 16, further comprising determining a waiting period after receiving the HARQ ACK associated with the third UE and before activating the command.

18. The method of claim 14, further comprising receiving a Hybrid Automatic Request (HARQ) acknowledgment (ACK) associated with the second UE in response to the sent activation response.

19. The method of claim 18, wherein the command is activated after a period of time following the receipt of the HARQACK associated with the second UE.

20. The method of claim 19, further comprising determining a waiting period after receiving the HARQ ACK associated with the second UE and before activating the command.

21. The method of claim 14, further comprising determining the time period after the transmission of the second MAC-CE including the activation response and before the activation command based on the number of hops between the third UE and the first UE through which the activation request passes.

22. The method of claim 14, further comprising receiving a Hybrid Automatic Request (HARQ) acknowledgment (ACK) associated with the third UE from the second UE in response to the sent activation response.

23. The method of claim 22, wherein the command is activated before receiving a HARQ ACK.

24. The method of claim 22, wherein the command is activated after receiving a HARQ ACK.

25. The method of claim 14, wherein the activation request is received via the Physical Side Link Shared Channel (PSSCH), and the activation response is sent via the PSSCH.

26. A non-transitory computer-readable medium storing computer-executable code at a first user equipment (UE), the code, when executed by at least one processor, causing the at least one processor to: Receive an activation request for a command associated with a third UE, the activation request being received in a first Media Access Control (MAC) control element CE MAC-CE relayed from a second UE; In response to the activation request, a second MAC-CE is sent to the second UE, the second MAC-CE including an activation response to the third UE; and The command is activated after the activation response is sent and after a time period from the time the second MAC-CE including the activation response is sent, wherein the time period is based on the number of hops between the third UE and the first UE through which the activation request passes, the number of hops being greater than or equal to 1.

27. An apparatus for wireless communication at a first user equipment (UE), comprising: A component for receiving an activation request for a command associated with a third UE, the activation request being received in a first media access control (MAC) control element (CE) MAC-CE relayed from a second UE; A component for sending a second MAC-CE to the second UE in response to the activation request, the second MAC-CE including an activation response to the third UE; and A component for activating the command after sending the activation response and after a time period from the sending of the second MAC-CE including the activation response, wherein the time period is based on the number of hops between the third UE and the first UE through which the activation request passes, the number of hops being greater than or equal to 1.

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