SIDELINK MEDIA ACCESS CONTROL (MAC) DESIGNS CONTROL ELEMENT (CE) DESIGNS

Description

Field of the Disclosure

[0001] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for generating and utilizing sidelink communication related medium access control (MAC) control elements (CEs).Description of Related Art

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, 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, to name a few.

[0003] In some examples, a wireless multiple-access communication system may include a number of base stations (BSs), which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation, a new radio (NR), or 5G network), a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with a number of central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more DUs, in communication with a CU, may define an access node (e.g., which may be referred to as a BS, 5G NB, next generation NodeB (gNB or gNodeB), transmission reception point (TRP), etc.). A BS or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a BS or DU to a UE) and uplink channels (e.g., for transmissions from a UE to BS or DU).

[0004] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. NR (e.g., new radio or 5G) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL). To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0005] However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. WO 2018 / 174642 A1 discloses: a communication technique for merging, with IoT technology, a 5G communication system for supporting a data transmission rate higher than that of a 4G system; and a system therefor. US 2017 / 353819 A1 discloses a method and apparatus for a first UE for resource allocation on relay channel in a wireless communication system. US 2017 / 374579 A1 discloses methods, systems, and apparatuses for integrating a first radio access technology and a second radio access technology in a wireless transmit / receive unit (WTRU).BRIEF SUMMARY

[0006] The invention is defined in the independent claims.

[0007] After reading the section entitled "Detailed Description" one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure. FIG. 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN), in accordance with certain aspects of the present disclosure. FIG. 3 is a diagram illustrating an example physical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure. FIG. 4 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE), in accordance with certain aspects of the present disclosure. FIGs. 5A and 5B show diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure. FIG. 6 illustrate example sidelink communications modes. FIG. 7 is a flow diagram illustrating example operations that may be performed by a first node, in accordance with certain aspects of the present disclosure. FIG. 8 is a flow diagram illustrating example operations that may be performed by a second node, in accordance with certain aspects of the present disclosure. FIG. 9 is a flow diagram illustrating example operations that may be performed by a first node, in accordance with certain aspects of the present disclosure. FIG. 10 is a flow diagram illustrating example operations that may be performed by a second node, in accordance with certain aspects of the present disclosure.

[0009] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.DETAILED DESCRIPTION

[0010] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for generating and processing sideline MAC-CEs.

[0011] The techniques described herein may be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as NR (e.g. 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS).

[0012] New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and / or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

[0013] New radio (NR) access (e.g., 5G technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond), millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond), massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and / or mission critical targeting ultra-reliable low-latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.Example Wireless Communications System

[0014] FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, UEs 120 and / or BS 110 of FIG. 1 may be configured to perform operations described below with reference to FIGs. 8-12 to generate and / or process sidelink MAC-CEs.

[0015] As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipments (UEs). Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to a coverage area of a Node B (NB) and / or a NB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and next generation NodeB (gNB or gNodeB), NR BS, 5G NB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some examples, the base stations may be interconnected to one another and / or to one or more other base stations or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

[0016] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

[0017] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the BSs 110a, 110b and 110c may be macro BSs for the macro cells 102a, 102b and 102c, respectively. The BS 110x may be a pico BS for a pico cell 102x. The BSs 110y and 110z may be femto BSs for the femto cells 102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

[0018] Wireless communication network 100 may also include relay stations. A relay station is a station that receives a transmission of data and / or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and / or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 110r may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

[0019] Wireless communication network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless communication network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt).

[0020] Wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0021] A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

[0022] The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor / device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0023] Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a "resource block" (RB)) may be 12 subcarriers (or 180 kHz). Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

[0024] While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

[0025] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and / or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

[0026] In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and / or uplink. A finely dashed line with double arrows indicates interfering transmissions between a UE and a BS.

[0027] FIG. 2 illustrates an example logical architecture of a distributed Radio Access Network (RAN) 200, which may be implemented in the wireless communication network 100 illustrated in FIG. 1. A 5G access node 206 may include an access node controller (ANC) 202. ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the Next Generation Core Network (NG-CN) 204 may terminate at ANC 202. The backhaul interface to neighboring next generation access Nodes (NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or more TRPs 208 (e.g., cells, BSs, gNBs, etc.).

[0028] The TRPs 208 may be a distributed unit (DU). TRPs 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not illustrated). For example, for RAN sharing, radio as a service (RaaS), and service specific AND deployments, TRPs 208 may be connected to more than one ANC. TRPs 208 may each include one or more antenna ports. TRPs 208 may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE.

[0029] The logical architecture of distributed RAN 200 may support fronthauling solutions across different deployment types. For example, the logical architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and / or jitter).

[0030] The logical architecture of distributed RAN 200 may share features and / or components with LTE. For example, next generation access node (NG-AN) 210 may support dual connectivity with NR and may share a common fronthaul for LTE and NR.

[0031] The logical architecture of distributed RAN 200 may enable cooperation between and among TRPs 208, for example, within a TRP and / or across TRPs via ANC 202. An inter-TRP interface may not be used.

[0032] Logical functions may be dynamically distributed in the logical architecture of distributed RAN 200. The Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202).

[0033] FIG. 3 illustrates an example physical architecture of a distributed RAN 300, according to aspects of the present disclosure. A centralized core network unit (C-CU) 302 may host core network functions. C-CU 302 may be centrally deployed. C-CU 302 functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity.

[0034] A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have distributed deployment. The C-RU 304 may be close to the network edge.

[0035] A DU 306 may host one or more TRPs (Edge Node (EN), an Edge Unit (EU), a Radio Head (RH), a Smart Radio Head (SRH), or the like). The DU may be located at edges of the network with radio frequency (RF) functionality.

[0036] FIG. 4 illustrates example components of BS 110 and UE 120 (as depicted in FIG. 1), which may be used to implement aspects of the present disclosure. For example, antennas 452, processors 466, 458, 464, and / or controller / processor 480 of the UE 120 and / or antennas 434, processors 420, 430, 438, and / or controller / processor 440 of the BS 110 may be used to perform the various techniques and methods described herein with reference to FIGs. 7-10.

[0037] At the BS 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller / processor 440. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and / or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 432a through 432t. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

[0038] At the UE 120, the antennas 452a through 452r may receive the downlink signals from the base station 110 and may provide received signals to the demodulators (DEMODs) in transceivers 454a through 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all the demodulators 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 460, and provide decoded control information to a controller / processor 480.

[0039] On the uplink, at UE 120, a transmit processor 464 may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source 462 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller / processor 480. The transmit processor 464 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)). The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators in transceivers 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller / processor 440.

[0040] The controllers / processors 440 and 480 may direct the operation at the BS 110 and the UE 120, respectively. The processor 440 and / or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The memories 442 and 482 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0041] In some circumstances, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and / or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS), even though the scheduling entity may be utilized for scheduling and / or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0042] FIGs. 5A and 5B show diagrammatic representations of example vehicle to everything (V2X) systems in accordance with some aspects of the present disclosure. For example, the vehicles shown in FIGs. 5A and 5B may communicate via sidelink channels and may perform sidelink CSI reporting as described herein.

[0043] The V2X systems, provided in FIGs. 5A and 5B provide two complementary transmission modes. A first transmission mode, shown by way of example in FIG. 5A, involves direct communications (for example, also referred to as side link communications) between participants in proximity to one another in a local area. A second transmission mode, shown by way of example in FIG. 5B, involves network communications through a network, which may be implemented over a Uu interface (for example, a wireless communication interface between a radio access network (RAN) and a UE).

[0044] Referring to FIG. 5A, a V2X system 500 (for example, including vehicle to vehicle (V2V) communications) is illustrated with two vehicles 502, 504. The first transmission mode allows for direct communication between different participants in a given geographic location. As illustrated, a vehicle can have a wireless communication link 506 with an individual (V2P) (for example, via a UE) through a PC5 interface. Communications between the vehicles 502 and 504 may also occur through a PC5 interface 508. In a like manner, communication may occur from a vehicle 502 to other highway components (for example, highway component 510), such as a traffic signal or sign (V2I) through a PC5 interface 512. With respect to each communication link illustrated in FIG. 5A, two-way communication may take place between elements, therefore each element may be a transmitter and a receiver of information. The V2X system 500 may be a self-managed system implemented without assistance from a network entity. A self-managed system may enable improved spectral efficiency, reduced cost, and increased reliability as network service interruptions do not occur during handover operations for moving vehicles. The V2X system may be configured to operate in a licensed or unlicensed spectrum, thus any vehicle with an equipped system may access a common frequency and share information. Such harmonized / common spectrum operations allow for safe and reliable operation.

[0045] FIG. 5B shows a V2X system 550 for communication between a vehicle 552 and a vehicle 554 through a network entity 556. These network communications may occur through discrete nodes, such as a base station (for example, an eNB or gNB), that sends and receives information to and from (for example, relays information between) vehicles 552, 554. The network communications through vehicle to network (V2N) links 558 and 510 may be used, for example, for long range communications between vehicles, such as for communicating the presence of a car accident a distance ahead along a road or highway. Other types of communications may be sent by the node to vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability, among other examples. Such data can be obtained from cloud-based sharing services.

[0046] In some circumstances, two or more subordinate entities (for example, UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via a sidelink. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. Generally, a sidelink may refer to a direct link between one subordinate entity (for example, UE1) and another subordinate entity (for example, UE2). As such, a sidelink may be used to transmit and receive a communication (also referred to herein as a "sidelink signal") without relaying the communication through a scheduling entity (for example, a BS), even though the scheduling entity may be utilized for scheduling or control purposes. In some examples, a sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0047] Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable proximal devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configurations and other parameters used for data transmissions, and the PSSCH may carry the data transmissions.

[0048] For the operation regarding PSSCH, a UE performs either transmission or reception in a slot on a carrier. NR sidelink supports for a UE a case where all the symbols in a slot are available for sidelink, as well as another case where only a subset of consecutive symbols in a slot is available for sidelink.

[0049] PSFCH may carry feedback such as channel state information (CSI) related to a sidelink channel quality. A sequence-based PSFCH format with one symbol (not including AGC training period) may be supported. The following formats may be possible: a PSFCH format based on PUCCH format 2 and a PSFCH format spanning all available symbols for sidelink in a slot.

[0050] FIG. 6 provides an overview of sidelink communications (broadcast and groupcast device-to-device or D2D) between UEs. As noted above, with reference to FIGs. 5A and 5B, sidelink generally refers to the link between two users or user-relays can be used in different scenarios and for different applications.

[0051] For example, for applications with in-coverage operation, both users are in a gNB's coverage, but directly communicate. This can be assumed for enabling some gaming applications. For applications with partial-coverage operation, one UE is in-coverage, and acts as a relay to extend the coverage for other users. For application with out-of-coverage operation, users are outside the gNB's coverage, but still need to communicate. This type of operation is important for mission critical applications, such as V2X and public safety.

[0052] As illustrated in FIG. 6, the resource allocation for sidelink communications can be done in different ways. In a first mode, Mode 1, the gNB "schedules" the sidelink resources to be used by the UE for SL transmission.

[0053] For a second mode, Mode 2, the UE determines the sidelink resources (the gNB does not schedule SL transmission resources within SL resources configured by gNB / network). In this case, the UE autonomously selects SL resources for transmission. A UE can assist in SL resource selection for other UEs. A UE may configured with an NR configured grant for SL transmission and the UE may schedule SL transmissions for other UEs.Example Sidelink MAC-CE Designs

[0054] Certain aspects of the present disclosure provide techniques for conveying information via medium access control (MAC) control element (CEs). In some cases, the MAC-CEs may relate to sidelink communications between two user equipments (UEs).

[0055] MAC-CEs have advantages over other types of command messages, albeit at some cost. For example, MAC-CEs have increased reliability provided by hybrid automatic repeat request (HARQ), but with a correspondingly increased latency. HARQ acknowledgement (Ack) or negative-acknowledgement (Nack) respectively provides confirmation that a MAC-CE (e.g., a command) has been received or otherwise.

[0056] Alternative command messages (to MAC-CEs) include downlink control information (DCI) on DL, and uplink control information (UCI) on UL (e.g., via PUCCH or PUSCH). While these messages have no HARQ Ack / Nack, they are generally less reliable, but have a lower latency.

[0057] MAC-CEs are used in sidelink communications (e.g., per one of the modes described above with reference to FIG. 6) for various reasons. For example, a sidelink buffer status report (SL-BSR) MAC-CE may be sent on the cellular link (Uu) but indicates buffer-status of sidelink traffic (e.g., a UE has sidelink traffic to send to another UE and requests resources of a gNB per Mode 1).

[0058] Further, for NR V2X, a CSI report may be sent over a sidelink MAC-CE. This approach may avoid a UE having to implement receiver for UCI-multiplexing.

[0059] For advanced systems (e.g., in Rel-17), use cases may call for more (and different) types of sidelink-related MAC-CEs. Such MAC-CEs may include both MAC-CEs sent over Uu and MAC-CEs sent over sidelink (carrying sidelink-related information in both cases).

[0060] In the case of sidelink relaying, MAC-CEs may indicate relayed traffic or originating traffic. In the case of Uu-PC5 slot-aggregation (where both cellular and sidelinks may be used), special handling for MAC-CEs may be considered. For example, a MAC-CE may indicate which code block groups (CBGs of a transport block / TB) come from which link.

[0061] In some cases, a MAC-CE may indicate which CBGs carry other MAC-CEs. MAC-CEs may be placed at the beginning of a TB or at the end, for example, depending on urgency.

[0062] Aspects of the present disclosure provide sidelink related MAC-CE designs that may accommodate these various use cases. For example, in some cases, the MAC-CEs may including routing information that may help a recipient identify and process different types of traffic (e.g., relayed traffic / original traffic, traffic sent via sidelink / traffic sent via Uu).

[0063] FIG. 7 is a flow diagram illustrating example operations 700 that may be performed by a first node, in accordance with certain aspects of the present disclosure. For example, operations 700 may be performed by a UE or base station (e.g., either being the first node) shown in FIG. 6. In some examples, the first node may be any of the BS 556, vehicle 502, vehicle 504, vehicle 552, or vehicle 554 of FIG. 5.

[0064] Operations 700 begin, at 702, by preparing at least a first medium access control (MAC) control element (CE) related to sidelink communications between two user equipments (UEs). For example, the preparation may include appending relaying or routing information to Uu MAC-CEs. When the MAC-CEs are for the use of sidelink, the preparation may include including sidelink related content (examples provided below).

[0065] At 704, the first node sends the first MAC-CE on at least one of a sidelink (e.g., PC5) or a cellular link (e.g., Uu). At 706, the first node provides routing information for the first MAC-CE. For example, the relaying or routing information may indicate one or more of source node, destination node, and transit route. In some cases, the relaying or routing information may be separately indicated, such as in RRC, DCI, or sidelink equivalents to the RRC and DCI. In some cases, when the sidelink related content is relayed, routing information may be padded or removed for sidelink-relayed MAC-CE.

[0066] FIG. 8 is a flow diagram illustrating example operations 800 that may be performed by a second node, in accordance with certain aspects of the present disclosure. For example, operations 800 may be performed by a UE or base station (e.g., either being the second node) shown in FIG. 6. Operations 800 may be complementary to operations 700 of FIG. 7, such as when the second node is configured to communicate with the first node of operations 700 in a sidelink channel. Likewise, in some examples, the second node may be another one of any of the BS 556, vehicle 502, vehicle 504, vehicle 552, or vehicle 554 of FIG. 5.

[0067] Operations 800 begin, at 802, by receiving from a first node, such as the first node of operations 700, on at least one of a sidelink or a cellular link, at least a first medium access control (MAC) control element (CE) related to sidelink communications between two user equipments (UEs). At 804, the second node obtains routing information for the first MAC-CE. At 806, the second node processes first MAC-CE based, at least in part, on the routing information. Details of sidelink related MAC-CEs are provided below.

[0068] There are various types of sidelink related MAC-CEs. These include, for example, Uu MAC-CEs (DL or UL) relayed via sidelink, MAC-CEs sent on SL with SL-related content, and MAC-CEs sent on Uu with SL-related content (e.g., SL-BSR already in LTE).

[0069] For Uu MAC-CEs (DL or UL) relayed via sidelink, relaying / routing information may be appended. As an alternative, routing (and / or relaying) information may be provided separately (e.g., indicated via RRC / MAC-CE / DCI or their sidelink equivalents). As used herein, the term routing information includes relaying information and such information may indicate, for example, one or more of source-node, destination node, or a transit route). If the last leg of a relayed route is via cellular (Uu), then routing info may be removed at that point (or some / all may be kept, such as a source ID). In some cases, the last leg may be combined sidelink and cellular (Uu + PC5), in case of Uu+PC5 slot-aggregation. In such cases, the routing info indication may be different in this case as compared to Uu-only (e.g., routing information may indicate which link different MAC-CEs are sent on).

[0070] MAC-CEs sent on SL may convey various SL-related content. For example, a MAC-CE may include sidelink CSI (SL-CSI), sidelink timing advance (SL-TA), sidelink transmit power control (SL-TPC) command, sidelink scheduling requests (SL-SR), sidelink buffer status reports (SL-BSR), or sidelink power headroom reports (SL-PHR). In some cases, sidelink MAC-CEs may be used for activation / deactivation of resources or services, such as sidelink semi persistent scheduling (SL-SPS) or sidelink configured grants (SL-CG analogous to SPS UL) and / or aperiodic or semi-persistent CSI-RS or SRS (A / SP SL-CSIRS / SRS). In case such MAC-CEs are relayed over SL, routing info may be modified (e.g., added / removed) as noted in the above described case of SL-relayed Uu MAC-CE.

[0071] MAC-CEs may also be sent on Uu with SL-related content, such as the aforementioned SL-BSR to indicate a UE has sidelink traffic to send and requests a grant of resources from a base station. Other types of MAC-CEs sent on Uu may include SL-PHR, TPC, recommended bit-rate, CBR / CR, and the like. In some cases, the MAC-CEs may be sent as gNB-relayed versions of the types of MAC-CEs described above that might be sent on SL with SL-related content (e.g., rather than send directly to another UE, a UE may send via a base station).

[0072] In the case of MAC-CEs sent via Uu+PC5 slot-aggregation, a 'header' MAC-CE may be used to indicate which CBGs come from which link (Uu or PC5 or both). Such a MAC-CE may also indicate locations of other MAC-CEs (e.g., which CBGs have MAC-CEs) and / or on which link they are sent (Uu or PC5 or both).

[0073] In the case of MAC-CE commands, corresponding activation / deactivation of resources or services is often based on the timing of acknowledgment of the command. For example, some activation / deactivation of SPS resources may occur n subframes after a corresponding command is acknowledged (ACK'd), for example, via a HARQ Ack. In the case of relayed MAC-CEs, however, it may be difficult to determine timing due to the possible variable delay due to different routes (with different numbers of hops).

[0074] Aspects of the present disclosure, however, may help address this issue by considering routing / relaying information when determining MAC-CE activation time, thus providing sidelink related MAC-CE designs that may accommodate these various use cases. For example, in some cases, the MAC-CEs may including routing information that may help a recipient identify and process different types of traffic (e.g., relayed traffic / original traffic, traffic sent via sidelink / traffic sent via Uu).

[0075] FIG. 9 is a flow diagram illustrating example operations 900 that may be performed by a first node to determine MAC-CE activation timing, in accordance with certain aspects of the present disclosure. For example, operations 900 may be performed by a UE or base station shown in FIG. 6.

[0076] Operations 900 begin, at 902, by sending a medium access control (MAC) control element (CE) to activate or deactivate resources or a service related to sidelink communications between two user equipments (UEs). At 904, the first node determines timing for the activation or deactivation based, at least in part, on routing information for the first MAC-CE.

[0077] FIG. 10 is a flow diagram illustrating example operations 1000 that may be performed by a second node to determine MAC-CE activation timing, in accordance with certain aspects of the present disclosure. For example, operations 1000 may be performed by a UE or base station shown in FIG. 6.

[0078] Operations 1000 begin, at 1002, by receiving a medium access control (MAC) control element (CE) to activate or deactivate resources or a service related to sidelink communications between two user equipments (UEs). At 1004, the second node determines timing for the activation or deactivation based, at least in part, on routing information for the first MAC-CE.

[0079] As noted above, activation time for a sidelink MAC-CE may be adjusted based on the link and / or route on which it is sent. In some cases, SL MAC-CEs sent on Uu may not have activation times (e.g., UL MAC-CEs, DL MAC-CEs carrying TA commands and recommended bit rates may not have activation times).

[0080] As noted above, however, many have activation time based on the time of Acknowledgment (ACK) transmission (e.g., 3 ms or N slots after Ack transmission). The counting of time in such cases either includes or excludes TA commands received during the counting. In some cases, for this purpose, the Ack transmission refers to acknowledgment of the whole TB (as opposed only to the CB / CBG carrying the MAC-CE). In general, UL MAC-CEs do not have activation times, because it is up to the gNB implementation how to respond to them.

[0081] SL MAC-CEs sent to gNB with SL-related content may be treated like Uu UL MAC-CEs (e.g., and left to gNB implementation). MAC-CEs sent to a UE over SL, or over DL (with SL-related content) may be treated like Uu DL MAC-CEs. In such cases, activation time may be based on Ack transmission. As noted above, the Ack transmissions (or delivery) time, and also the function mapping this delivery time to the activation time (eg, a delay parameter such as n milliseconds or m slots) may be different for MAC-CEs sent over SL vs over DL.

[0082] Thus, routing / relaying information may be considered when determining time for activating / deactivating MAC-CEs sent with or without relaying. In some cases, the timing may also depend on whether or not the Ack transmission is relayed.

[0083] For example, if the Ack transmission is not relayed (even though the MAC-CE itself may be relayed the Ack may be direct from final destination to original sender), activation timing may follow the (conventional) Ack transmission timing.

[0084] If the Ack is relayed, there are various options for determining the activation timing. For example, according to a first option, the timing of a first hop of the Ack route may be followed. Since the final recipient may not know the first hop, separate signaling may be used (e.g., as part of the Ack, or in DCI / MAC-CE / RRC). In some cases, the timing may be, for example, 3 ms from this timing (as in Uu).

[0085] In some cases, this type of fixed timing may not be sufficient time for the Ack to reach the final destination (depending on the number of hops). Therefore, a variable time X ms may be used instead, where the value of X depends on the number of hops. Because the number of actual hops may be dynamic (e.g., as each node may select its own preferred route), a preconfigured (or "expected") number of hops may be used instead.

[0086] According to a first option, the timing of a last hop of the Ack route may be used to determine the MAC-CE activation timing. In this case, the recipient knows the timing based on when it receives the Ack. But, in this case, the sender may not know this time. Therefore, rather than a fixed time, the activation timing may be based on a preconfigured / expected timing (based on a number of hops), which effectively becomes equivalent to the option described above with X ms.

[0087] If the Ack transmission could be relayed by multiple routes, the number of hops used to determine the X ms may be based on a rule. For example, X could be based on the shortest of the multiple routes or on the longest of the multiple routes (e.g., where length is measured in terms of the number of hops).

[0088] According to the claimed invention content of the routing information depends, at least in part, on whether the first MAC-CE is sent via the sidelink, the cellular link, or an aggregation of the sidelink and the cellular link; and timing for the activation or deactivation of the resources or the service is determined based, at least in part, on an acknowledgment of the first MAC-CE and the routing information.

[0089] The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and / or software component(s) and / or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components. For example, various operations shown in FIGs. 7-10 may be performed by various processors shown in FIG. 4, such as processors 466, 458, 464, and / or controller / processor 480 of the UE 120.

[0090] The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0091] If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0092] If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and / or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and / or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

[0093] A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

[0094] Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray ®< disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0095] Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and / or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIGs. 7-10.

[0096] Further, it should be appreciated that modules and / or other appropriate means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by a user terminal and / or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and / or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

Claims

1. A method of wireless communications by a first node, comprising: preparing (702) at least a first medium access control, MAC, control element, CE, related to sidelink communications between two user equipments, UEs; sending (704, 902) the first MAC-CE on at least one of a sidelink or a cellular link, wherein the first MAC-CE is designed to activate or deactivate resources or a service; providing (706) routing information for the first MAC-CE, wherein content of the routing information depends, at least in part, on whether the first MAC-CE is sent via the sidelink, the cellular link, or an aggregation of the sidelink and the cellular link; and determining (904) timing for the activation or deactivation of the resources or the service based, at least in part, on an acknowledgment of the first MAC-CE and the routing information.

2. The method of claim 1, wherein the routing information comprises at least one of: a source node, a destination node, or a transit route through one or more nodes; or the method of claim 1, wherein the routing information indicates whether traffic sent with the first MAC-CE is relayed traffic or traffic originating at the first node; or the method of claim 1, wherein routing information is sent with the first MAC-CE.

3. The method of claim 1, wherein the first MAC-CE is included in a transport block, TB, sent via the aggregation of sidelink and cellular link.

4. The method of claim 1, wherein: the first MAC-CE originated from another node and the first node is relaying the first MAC-CE; and the routing information provided by the first node is modified relative to routing information in the first MAC-CE as received by the first node.

5. The method of claim 1, wherein the first MAC-CE indicates at least one of a sidelink timing advance command, a sidelink transmission power control command, a sidelink scheduling request, a sidelink buffer status report, a sidelink power headroom report, or a recommended bit rate.

6. A method of wireless communications by a second node, comprising: receiving (802, 1002) from a first node, on at least one of a sidelink or a cellular link, at least a first medium access control, MAC, control element, CE, related to sidelink communications between two user equipments, UEs; obtaining (804) routing information for the first MAC-CE, wherein the first MAC-CE is designed to activate or deactivate resources or a service; processing (806) the first MAC-CE based, at least in part, on the routing information, wherein content of the routing information depends, at least in part, on whether the first MAC-CE is sent via the sidelink, the cellular link, or an aggregation of the sidelink and the cellular link; and determining (1004) timing for the activation or deactivation of the resources or the service based, at least in part, on an acknowledgment of the first MAC-CE and the routing information.

7. The method of claim 6, wherein the routing information indicates whether traffic sent with the first MAC-CE is relayed traffic or traffic originating at the first node; or the method of claim 6, wherein the routing information is obtained with the first MAC-CE.

8. The method of claim 6, wherein the first MAC-CE is included in a transport block, TB, sent via the aggregation of sidelink and cellular link.

9. The method of claim 6, wherein: the routing information indicates the first MAC-CE originated from another node and was relayed by the first node.

10. The method of claim 6, wherein the first MAC-CE indicates at least one of a sidelink timing advance command, a sidelink transmission power control command, a sidelink scheduling request, a sidelink buffer status report, a sidelink power headroom report, or a recommended bit rate.

11. An apparatus for wireless communications by a first node, comprising: means for preparing at least a first medium access control, MAC, control element, CE, related to sidelink communications between two user equipments, UEs; means for sending the first MAC-CE on at least one of a sidelink or a cellular link, wherein the first MAC-CE is designed to activate or deactivate resources or a service; means for providing routing information for the first MAC-CE, wherein content of the routing information depends, at least in part, on whether the first MAC-CE is sent via the sidelink, the cellular link, or an aggregation of the sidelink and the cellular link; and means for determining timing for the activation or deactivation of the resources or the service based, at least in part, on an acknowledgment of the first MAC-CE and the routing information.

12. The apparatus for wireless communication according to claim 11, further comprising means for carrying out the method of any of claims 2 to 5.

13. An apparatus for wireless communications by a second node, comprising: means for receiving from a first node, on at least one of a sidelink or a cellular link, at least a first medium access control, MAC, control element, CE, related to sidelink communications between two user equipments, UEs; means for obtaining routing information for the first MAC-CE, wherein the first MAC-CE is designed to activate or deactivate resources or a service; means for processing the first MAC-CE based, at least in part, on the routing information, wherein content of the routing information depends, at least in part, on whether the first MAC-CE is sent via the sidelink, the cellular link, or an aggregation of the sidelink and the cellular link; and means for determining timing for the activation or deactivation of the resources or the service based, at least in part, on an acknowledgment of the first MAC-CE and the routing information.

14. The apparatus for wireless communication according to claim 13, further comprising means for carrying out the method of any of claims 7 to 10.

15. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of any of claims 1 to 5 or 6 to 10.