TRANSMITTING SIDELINK CSI USING AN UPLINK CHANNEL

Apparatuses, methods, and systems are disclosed for communicating SL CSI using an uplink channel. One method includes receiving, from a Transmitting User Equipment (Tx UE), a Medium Access Control-Control Element (MAC-CE) including a Sidelink (SL) Channel State Information (CSI) report. In some implementations, the SL CSI report comprises a first SL CSI value. In some implementations, the first SL CSI value is tagged with an identifier that identifies a Receiving User Equipment (Rx UE).

TECHNICAL FIELD

The subject matter disclosed herein relates generally to wireless communications and more particularly relates to reporting sidelink (SL) channel state information (CSI), e.g., to a gNB or RAN node.

BACKGROUND

The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project (3GPP), Fifth Generation Core Network (5GC), Fifth Generation System (5GS), 5G QoS Indicator (5QI), Authentication, Authorization and Accounting (AAA), Positive-Acknowledgment (ACK), Application Function (AF), Access and Mobility Management Function (AMF), Access Point (AP), Application Programming Interface (API), Access Stratum (AS), Base Station (BS), Bandwidth Part (BWP), Code Block Group (CBG), Code Division Multiplexing (CDM), Code Division Multiple Access (CDMA), Control Element (CE), Core Network (CN), Control Plane (CP), Channel Quality Indicator (CQI), Channel State Information (CSI), CSI Reference Signal (CSI-RS), Downlink Control Information (DCI), Downlink (DL), Discontinuous Transmission (DTX), Evolved Node-B (eNB), Evolved Packet Core (EPC), Evolved Packet System (EPS), New Generation (i.e., 5G) Node-B (gNB), General Packet Radio Service (GPRS), Global System for Mobile Communications (GSM), Hybrid Automatic Repeat Request (HARQ), Home Subscriber Server (HSS), Identifier (ID), Information Element (IE), Layer-1 (L1) (also known as the Physical Layer), Layer-2 (L2) (also known as the Link Layer), Layer-3 (L3) (also known as the Network Layer), Logical Channel (LCH), LCH Prioritization (LCP), Long Term Evolution (LTE), Medium Access Control (MAC), MAC Control Element (MAC-CE), Mobility Management Entity (MME), Negative-Acknowledgment (NACK) or (NAK), Non-Access Stratum (NAS), Network Exposure Function (NEF), Network Slice Selection Assistance Information (NSSAI) (e.g., a vector value including one or more S-NSSAI values), New Radio (NR) (a 5G radio access technology; also referred to as “5G NR), Packet Delay Budget (PDB), Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Packet Data Unit (PDU) (used in connection with ‘PDU Session’), Packet Data Network Gateway (P-GW), PC5 Link Identifier (PLI), Public Land Mobile Network (PLMN), Precoding Matrix Indicator (PMI), PC5 5QI (PQI) (i.e., corresponds to QoS for NR V2X communication over the PC5 interface), Physical Random Access Channel (PRACH), Physical Resource Block (PRB), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), QoS Flow Indicator (QFI), Quality of Service (QoS), Random Access Channel (RACH), Radio Access Network (RAN), Radio Access Technology (RAT), Rank Indicator (RI), Radio Link Control (RLC), Radio Resource Control (RRC), Reference Signal (RS), Received Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), Receive (RX), Sidelink Control Information (SCI), Sidelink CSI RS (S-CSI-RS), Serving Gateway (S-GW), Signal-to-Interference-and-Noise Ratio (SINR), Sidelink (SL), Sidelink CSI (SL-CSI), Sidelink Reference Signal (SL-RS), Session Management (SM), Session Management Function (SMF), Single Network Slice Selection Assistance Information (S-NSSAI), Scheduling Request (SR), Sidelink Received Signal Received Power (S-RSRP), Transport Block (TB), Transmit (TX), Uplink Control Information (UCI), Unified Data Management (UDM), User Data Repository (UDR), User Entity/Equipment (Mobile Terminal) (UE), Uplink (UL), User Plane (UP), Universal Mobile Telecommunications System (UMTS), User Plane (UP), UMTS Terrestrial Radio Access Network (UTRAN), Vehicle-to-everything (V2X) (V2X communication encompasses both V2V and V2I), Vehicle-to-Infrastructure (V2I), Vehicle-to-Vehicle (V2V), a UE capable of vehicular communications using 3GPP protocols (V2X UE), and Worldwide Interoperability for Microwave Access (WiMAX). As used herein, “HARQ-ACK” refers to HARQ feedback may represent collectively the Positive Acknowledge (ACK) and the Negative Acknowledge (NACK) and Discontinuous Transmission (DTX). ACK means that a TB is correctly received while NACK (or NAK) means a TB is erroneously received. DTX means that no TB was detected.

In certain wireless communication systems, V2X CQI/RI (channel quality indicator/rank indicator) is reported from Rx UE to Tx UE for unicast via higher layer signaling. In some embodiments, a MAC-CE is used to report CQI/RI from Rx UE to Tx UE. V2X communication allows vehicles to communicate with moving parts of the traffic system around them. Two resource allocation modes are used in LTE V2X communication which are also considered as a baseline for corresponding resource allocation modes in NR V2X communication.

BRIEF SUMMARY

Disclosed are procedures for transmitting SL CSI using an uplink channel. Said procedures may be implemented by apparatus, systems, methods, or computer program products.

One method of a base station includes receiving, from a Transmitting User Equipment (Tx UE), a Medium Access Control-Control Element (MAC-CE) including a Sidelink (SL) Channel State Information (CSI) report. In certain embodiments, the SL CSI report comprises a first SL CSI value. In certain embodiments, the first SL CSI value is tagged with an identifier that identifies a Receiving User Equipment (Rx UE).

One method of a UE includes receiving a first SL-CSI value from a Rx UE via one of a plurality of unicast links and generating a SL-CSI report containing the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The method includes transmitting a MAC-CE to a RAN node using an uplink channel, the MAC-CE containing the SL-CSI report.

Another method of a UE includes receiving a first SL-CSI value from a Rx UE via one of a plurality of unicast links and generating a SL-CSI report comprising the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The method includes transmitting the SL-CSI report to a RAN node using a Layer-1 (L1) uplink (UL) control channel.

DETAILED DESCRIPTION

Generally, the present disclosure describes systems, methods, and apparatus for reporting SL-CSI, e.g., of UEs engaged in V2X communication. In some embodiments, a transmitting UE (Tx UE) reports SL-CSI from plurality of the unicast links to a gNB. In certain embodiments, the Tx UE reports SL-CSI for each unicast links is tagged with an additional field to report the SL unicast link ID or SL unicast destination ID, SL-CSI measurement configuration, SL BWP ID, SL carrier ID or panel ID, SL Slot number. SL-CSI reporting to gNB may be beneficial for the Tx UE to report SL channel quality to the gNB so that the gNB scheduler is aware of the sideline channel and can schedule SL resources appropriately. SL CSI comprises of SL CQI, SL RI values, SL PMI and SL beam measurement reports. These solutions are discussed in greater detail below.

NR V2X communication may use one of the following SL resource allocation modes. In Mode-1, the RAN node (e.g., gNB) schedules SL resource(s) to be used by UE for SL transmission(s). One example of Mode-1 resource allocation is described in 3GPP technical report (TR) 38.885, section 6.2.1. In Mode-2, the network does not schedule the SL resources; rather, the UE determines SL transmission resource(s) within SL resources configured by BS/network or pre-configured SL resources. As such, Mode-2 covers the cases of: a) the UE autonomously selecting SL resource for transmission; b) the UE being configured with NR configured grant (Type-1 like) for SL transmission; c) the UE scheduling SL transmissions of other UEs; and d) the UE assisting in SL resource selection for other UE(s), a functionality which may be part of any of the above cases.

In 3GPP Rel-16 standards for V2X, CQI/RI is reported from a Rx UE to a Tx UE for unicast via higher layer signaling. In certain embodiments, a MAC-CE may be used to report CQI/RI from the Rx UE to the Tx UE. Additionally, the Tx UE may report sidelink channel quality to the gNB so that the gNB scheduler is aware of the sidelink channel. As noted above, SL CSI reporting to gNB supports SL QoS monitoring and SL scheduling enhancement.

Discussed herein are solutions to report SL CSI to a gNB either via L1 signaling via PUCCH or higher layer signaling such as MAC-CE or RRC signaling. Moreover, one Tx UE may have multiple unicast links with multiple Rx UEs and the reporting of SL CSI identifies a corresponding unicast link, as described in greater detail below. For the case of L1 signaling being used to send the SL CSI report to the gNB, the below solutions also provide timing of periodic PUCCH resource to prevent misalignment which may be caused by the Tx UE receiving aperiodic SL-CSI report from Rx UE using higher layer signaling such as MAC-CE. For the case of higher layer signaling being used to report the SL CSI to gNB, the below solutions define MAC-CE formats for carrying to carry SL CSI values in Uu signaling.

For reporting SL-CSI, currently (e.g., in Rel-16) SL-CSI is exchanged between the Rx UE and Tx UE, but not with the gNB. Thus, the gNB is not aware of the SL channels. However, information on SL channel condition may be valuable for the gNB scheduler for a Mode-1 scheduling. The present disclosure presents solutions for reporting SL-CSI to the gNB either using higher layer signaling—such as MAC-CE or RRC signaling—or using L1 signaling via PUCCH.

In some embodiments, L1 signaling is used to report the SL-CSI report to gNB. However, the timing of periodic PUCCH resource may be mis-aligned because of Tx UE receiving aperiodic SL-CSI report from Rx UE using higher layer signaling such as MAC-CE. Therefore, it is not trivial on how/when to trigger or request the UL PUSCH resource to do aperiodic SL-CSI reporting. In other embodiments, higher layer signaling is used to report the SL-CSI to gNB.

In addition, one Tx UE may have multiple unicast links with Rx UEs and the reporting of SL-CSI may take into account corresponding to a unicast link ID and gNB requires additional information apart from the CSI values to help associate the SL-CSI values to a SL carrier/BWP, PRB(s), panels, slot number, SL CSI-RS, etc. Because the SL CSI-RS is being transmitted along with the SL data, the gNB does not know when the CSI-RS was transmitted by the Tx UE if the destination ID was selected by the Tx UE itself.

Various solutions disclosed herein use higher layer signaling to report gNB on CSI reports received on the PC5 interface from Rx UE(s). Such solutions enable the gNB scheduler to be aware of the sidelink channel conditions. In addition, SL-CSI reporting helps it in SL QoS monitoring, predictions and thus enables/disables advanced SL QoS fulfillment. SL-CSI report received.

Various solutions disclosed herein enable Tx UE to form MAC-CE to report SL-CSI via UL signaling which contains SL link ID, SL BWP ID, panel ID to help associate SL-CSI reporting to particular SL link ID or destination ID (Tx UE may have one or more unicast link with one or more Rx UE(s)) and additional information fields to help associate SL-CSI report from Tx UE.

The disclosed solutions also optimize the SL-CSI reporting procedures to reduce latency in transmitting SL-CSI report to gNB by requesting UL resources before the available of CSI report at the Tx UE. Various solutions also optimize the overhead of CSI reporting to the gNB including CSI reports from multiple unicast links belonging to the same TX-Rx UE pairs.

FIG.1depicts a wireless communication system100for transmitting SL CSI using an uplink channel for wireless devices communicating V2X messages115, according to embodiments of the disclosure. In one embodiment, the wireless communication system100includes at least one remote unit105, a radio access network (RAN)120, and a mobile core network140. The RAN120and the mobile core network140form a mobile communication network. The RAN120may be composed of a base unit121with which the remote unit105communicates using wireless communication links123. Even though a specific number of remote units105, base units121, wireless communication links123, RANs120, and mobile core networks140are depicted inFIG.1, one of skill in the art will recognize that any number of remote units105, base units121, wireless communication links123, RANs120, and mobile core networks140may be included in the wireless communication system100.

In one implementation, the RAN120is compliant with the 5G system specified in the 3GPP specifications. In another implementation, the RAN120is compliant with the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system100may implement some other open or proprietary communication network, for example WiMAX, among other networks. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

The remote units105may communicate directly with one or more of the base units121in the RAN120via uplink (UL) and downlink (DL) communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links123. Here, the RAN120is an intermediate network that provides the remote units105with access to the mobile core network140.

In some embodiments, the remote units105communicate with an application server151via a network connection with the mobile core network140. For example, an application107(e.g., web browser, media client, telephone/VoIP application) in a remote unit105may trigger the remote unit105to establish a PDU session (or other data connection) with the mobile core network140via the RAN120. The mobile core network140then relays traffic between the remote unit105and the application server151in the packet data network150using the PDU session. The PDU session represents a logical connection between the remote unit105and the user plane function (UPF)141. In order to establish the PDU session, the remote unit105must be registered with the mobile core network. Note that the remote unit105may establish one or more PDU sessions (or other data connections) with the mobile core network140. As such, the remote unit105may concurrently have at least one PDU session for communicating with the packet data network150and at least one PDU session for communicating with another data network (not shown).

The base units121may be distributed over a geographic region. In certain embodiments, a base unit121may also be referred to as an access terminal, an access point (AP), a base, a base station (BS), a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a RAN node, or by any other terminology used in the art. The base units121are generally part of a radio access network (RAN), such as the RAN120, that may include one or more controllers communicably coupled to one or more corresponding base units121. These and other elements of radio access network are not illustrated but are well known generally by those having ordinary skill in the art. The base units121connect to the mobile core network140via the RAN120.

The base units121may serve a number of remote units105within a serving area, for example, a cell or a cell sector, via a wireless communication link123. The base units121may communicate directly with one or more of the remote units105via communication signals. Generally, the base units121transmit DL communication signals to serve the remote units105in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links123. The wireless communication links123may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links123facilitate communication between one or more of the remote units105and/or one or more of the base units121.

In one embodiment, the mobile core network140is a 5G core (5GC) or the evolved packet core (EPC), which may be coupled to a packet data network150, like the Internet and private data networks, among other data networks. A remote unit105may have a subscription or other account with the mobile core network140. Each mobile core network140belongs to a single public land mobile network (PLMN). The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

The mobile core network140includes several network functions (NFs). As depicted, the mobile core network140includes one or more user plane functions (UPFs)141. The mobile core network140also includes multiple control plane functions including, but not limited to, an Access and Mobility Management Function (AMF)143that serves the RAN120, a Session Management Function (SMF)145, a Policy Control Function (PCF)147, and a Unified Data Management function (UDM)149. In various embodiments, the mobile core network140may also include an Authentication Server Function (AUSF), a Network Repository Function (NRF) (used by the various NFs to discover and communicate with each other over APIs), a Network Exposure Function (NEF), or other NFs defined for the 5GC.

In various embodiments, the mobile core network140supports different types of mobile data connections and different types of network slices, wherein each mobile data connection utilizes a specific network slice. Here, a “network slice” refers to a portion of the mobile core network140optimized for a certain traffic type or communication service. Each network slice includes a set of CP and/or UP network functions. A network instance may be identified by a S-NSSAI, while a set of network slices for which the remote unit105is authorized to use is identified by NSSAI. In certain embodiments, the various network slices may include separate instances of network functions, such as the SMF145and UPF141. In some embodiments, the different network slices may share some common network functions, such as the AMF143. The different network slices are not shown inFIG.1for ease of illustration, but their support is assumed.

Although specific numbers and types of network functions are depicted inFIG.1, one of skill in the art will recognize that any number and type of network functions may be included in the mobile core network140. Moreover, where the mobile core network140is an EPC, the depicted network functions may be replaced with appropriate EPC entities, such as an MME, S-GW, P-GW, HSS, and the like. In certain embodiments, the mobile core network140may include an AAA server.

In various embodiments, the remote units105may communicate directly with each other (e.g., device-to-device communication) using V2X communication signals115. Here, V2X transmissions may occur on V2X resources. As discussed above, a remote unit105may be provided with different V2X communication resources for different V2X modes. Mode-1 corresponds to an NR-based network-scheduled V2X communication mode. Mode-2 corresponds to an NR-based UE-scheduled V2X communication mode.

WhileFIG.1depicts components of a 5G RAN and a 5G core network, the described embodiments for transmitting SL CSI using an uplink channel apply to other types of communication networks and RATs, including Institute of Electrical and Electronics Engineers (IEEE) 802.11 variants, GSM, GPRS, UMTS, LTE variants, CDMA 2000, Bluetooth, ZigBee, Sigfox, and the like. For example, in an LTE variant involving an EPC, the AMF143may be mapped to an MME, the SMF145may be mapped to a control plane portion of a packet gateway (PGW) and/or to an MME, the UPF141may be mapped to a serving gateway (SGW) and a user plane portion of the PGW, the UDM/UDR149may be mapped to an HSS, etc.

In the following descriptions, the term RAN node is used for the base station, but it is replaceable by any other radio access node, e.g., BS, eNB, gNB, AP, NR, etc. Further the operations are described mainly in the context of 5G NR. However, the proposed solutions/methods are also equally applicable to other mobile communication systems supporting serving cells/carriers being configured for sidelink communication, e.g., over PC5 interface.

FIG.2depicts a procedure200for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. The procedure200may be implemented by a Tx UE201that communicates with at least one Rx UE205using sidelink communications. The Tx UE201and Rx UE205may be embodiments of the remote units105, described above. While a single Rx UE205is depicted for ease of illustration, in other embodiments the Tx UE201may engage in sidelink communications with multiple Rx UEs205concurrently. Moreover, at a later point in time the Tx UE201and Rx UE205may swap roles. Still further, the depicted Tx UE201may itself be a receiving UE with respect to other SL UEs (not depicted).

In various embodiments, the Tx UE201sends a SL-CSI request215to the Rx UE205. The Rx UE205responds by sending an SL-CSI value220to the Tx UE201. Here, the SL-CSI value220is based on the physical layer measurements from Rx UE205to Tx UE201. The Tx UE201reports SL CSI230to the RAN node210. Here, the RAN node210may be one implementation of the base unit121, described above.

Regarding the SL CSI reporting230, a MAC-CE may be used to carry a SL-CSI report. In one embodiment, the MAC-CE is generated only when there is UL data to be transmitted and the MAC-CE is multiplexed with the UL data transmission in a TB, i.e., the generated UL TB contains UL data and MAC-CE containing SL CSI report. In this case, the priority of transmitting the MAC-CE is same as that of the UL data. In another embodiment, the MAC-CE is generated immediately without UL data and in this case, a UL TB is generated for the physical (PHY) layer only containing the MAC-CE carrying the SL-CSI report. The MAC-CE is associated with certain UL priority (PQI value and/or PDB). The MAC-CE itself triggers SL resource (re)selection mechanism for Mode-2. This MAC-CE may be configured with either Mode-1 or Mode-2 transmission—or both—and the corresponding HARQ feedback option may be enabled or disabled, and accordingly specified or (pre)configured.

For Mode-1, separate SR resource is configured by RAN node210for MAC-CE carrying SL-CSI to all SL-UEs. This MAC-CE used to carry SL-CSI may trigger SR requesting resource from RAN node210for Mode-1 SL grant. This MAC-CE may be configured with SL-HARQ enabled or not, blind (re)transmission and number of blind (re)transmission. However, the number of blind re-transmissions may be same or different compared with that of SL data transmission.

The LCP procedure for transmitting the MAC-CE for SL-CSI reporting is based on the defined priority value (for e.g., PQI value). The generated TB containing the MAC-CE may also include a source ID of the received CSI-RS transmission, e.g., for the L2 source ID of the Tx UE unicast session that transmitted the CSI-RS or requested SL-CSI report. For Mode-2, candidate resource selection/transmission procedure may take into account the PDB value of this MAC-CE (e.g., UE selects the T2 value for candidate resource selection based on the priority value defined for this MAC-CE) and indicate the same in the QoS priority field in the SCI.

Note that a Rx UE205may start/restart a timer whenever it receives CSI-RS transmission or SL-CSI reporting request and may find the candidate resource for transmission within this time window. When the timer expires and if there is no SL resource selected or available for transmission then the MAC-CE is not transmitted. The timer is re-started whenever CSI-RS is received, or SL-CSI measurement is received from lower layers. As long as the CSI report is considered pending for transmission (pending flag is defined), UE generates SL-CSI report based on the latest CSI-RS transmission received from the same source. The pending flag is cleared or cancelled when the SL-CSI report is transmitted. Alternatively, the RX-UE205may include the time-slot number in a radio frame when the CSI report was generated, and the Tx UE may choose to accept or ignore the report from RX-UE.

Solutions for the Tx UE201reporting SL-CSI to the RAN node210are described in greater detail below. In certain embodiments, the Tx UE201may multiplex SL-CSI values from multiple SL carriers or BWP, panels from one unicast link or destination ID in a MAC-CE. In various embodiments, only SL LCHs that are allowed to transmit SL data with Mode-1 configurations are allowed to multiplex SL-CSI reports in a MAC-CE.

Note that the Tx UE201and Rx UE205may have a plurality of UE panels225. A “UE panel” may be a logical entity with physical UE antennas mapped to the logical entity. How to map physical UE antennas to the logical entity may be up to UE implementation. Depending on UE's own implementation, a “UE panel” can have at least one of the following functionalities as an operational role: Unit of antenna group to control its Tx beam independently, Unit of antenna group to control its transmission power independently, Unit of antenna group to control its transmission timing independently. The “UE panel” may be transparent to RAN node210.

For certain condition(s), RAN node210or network can assume the mapping between UE's physical antennas to the logical entity “UE panel” will not be changed. For example, the condition may include until the next update or report from the Tx UE201or comprise a duration of time over which the RAN node210assumes there will be no change to the mapping. The Tx UE201may report its UE capability with respect to the “UE panel” to the RAN node210or network. The UE capability may include at least the number of “UE panels.”

In various embodiments, the Tx UE201and Rx UE205may support SL transmission from one beam within a panel; with multiple panels, more than one beam (one beam per panel) may be used for SL transmission. In another implementation, more than one beam per panel may be supported/used for SL transmission.

For certain condition(s), RAN node210can assume the mapping between UE's physical antennas to the logical entity “UE panel” will not be changed. For example, the condition may include until the next update or report from UE or comprise a duration of time over which the RAN node210assumes there will be no change to the mapping. UE may report its UE capability with respect to the “UE panel” to the RAN node210or network. The UE capability may include at least the number of “UE panels.” In one implementation, the UE may support UL transmission from one beam within a panel; with multiple panels, more than one beam (one beam per panel) may be used for UL transmission. In another implementation, more than one beam per panel may be supported/used for UL transmission.

According to a first solution, the Tx UE201uses a new MAC-CE format is defined to report SL-CSI to the RAN node210(e.g., via UL signaling) which contains additional information other than the SL-CSI values. Such additional information may include, but is not limited to, SL link ID, SL BWP ID, panel ID, CSI measurement configuration to help associate SL-CSI reporting to particular SL link ID or destination ID (Tx UE may have one or more unicast link with one or more Rx UE(s)). One implementation of the MAC-CE formation is explained below with reference toFIGS.4A-4D. Another implementation of the MAC-CE formation is explained below with reference toFIGS.6A-6D.

In various embodiments, the Tx UE201implements pre-emptive SR transmission to reduce latency in transmitting SL-CSI report to RAN node210by requesting UL resources before the available of CSI report at the Tx UE. In some embodiments, SL-CSI report triggering conditions are now event triggered based on the availability of SL-CSI report at the Tx UE201.

In various embodiments, the Tx UE201reduces the overhead of CSI reporting to the RAN node210including identifying and combining CSI reports from multiple unicast links belonging to the same TX-Rx UE pairs. The multiplexing of CSI reports from multiple unicast links in the same CSI report to RAN node210may be undertaken by the Tx UE201based on certain factors. These factors may include the latency bound of the SL-CSI reports and number of Receiver UEs, etc. as discussed in greater detail below.

FIG.3depicts a first scenario300of a transmitting UE (e.g., the Tx UE201) reporting SL-CSI, e.g., to a RAN node210. Here, it is assumed that the Tx UE201has received multiple SL-CSI values from one or more Rx UEs (e.g., the Rx UE(s)205). As shown inFIG.3, the Tx UE201transmits a SL-CSI report301to the RAN node210. In various embodiments, the SL-CSI report301may multiplex SL-CSI values for different SL BWP and/or SL carrier belonging to the same or different unicast link ID (or destination ID). In the example depicted, the SL-CSI report301includes a first SL-CSI value303that is tagged with a first unicast link ID305and with at least one BWP ID and/or SL carrier ID307. The depicted SL-CSI report301also includes a second SL-CSI value309that is tagged with a second unicast link ID311and with at least one BWP ID and/or SL carrier ID313. The depicted SL-CSI report301further includes a third SL-CSI value315that is tagged with a third unicast link ID317and with at least one BWP ID and/or SL carrier ID319. Note that the SL-CSI value303,309and315may be tagged with multiple BWP/carrier ID(s). Further, each SL-CSI value is tagged with their respective carrier IDs or BWP IDs, which may be the same or different carrier/BWP IDs as tagged in other SL-CSI values.

According to the first solution, the SL-CSI Report301is transmitted using a new MAC-CE is defined in the Uu interface (Uplink signaling) for carrying SL-CSI value from Tx UE201to RAN node210. Said MAC-CE has a new field to report SL-CSI values from one or more SL BWP/Carrier received from one or more Rx UEs. The MAC-CE includes a new field for a unicast link ID (where the link ID uniquely denotes the source-destination pair)—alternatively, for a destination ID—to help associate SL-CSI values reported by the Tx UE201to a particular unicast link ID (or destination ID) which may belong to same or different Rx UE(s)205.

In certain embodiments, the RAN node210may require one or more additional measurement information from Tx UE201to help associate the SL-CSI report to a measured SL CSI value. Thus, the Tx UE201may also tag a SL CSI value with one or more of: sidelink carrier frequency, sidelink BWP, sidelink CSI-RS measurement configuration, SL CSI-RS scheduling information for each SL unicast link(s) measurement, SL latency bound, SL slot number corresponding to the SL-CSI estimated, etc.

In some embodiments, SL LCHs that are allowed to transmit SL data with Mode-1 configurations are allowed to multiplex SL-CSI reports in a MAC-CE. In another example, the RAN node210may configure, via RRC signaling, whether the Mode-1 SL LCH(s) should send SL-CSI reports to the RAN node210; the RAN node210may also enable/disable SL-CSI reporting for each unicast link(s) or destination ID(s).

In various embodiments, the priority of SL LCH(s) and/or the minimum latency bound for the SL-CSI reporting from Rx UE(s) may also be used as a selection criterion if there are limited resources. If there are multiple unicast link(s) or destination ID(s) with the same priority, then Tx UE201may select using rules defined below with reference to the fifth solution.

FIGS.4A-4Ddepict a MAC-CE400, according to embodiments of the first solution.FIG.4Adepicts the MAC-CE400containing a plurality of SL fields, including a first field405, a second field410, and a third field415. Here, the first field405provides information for a first SL Link and the second field410provides information for a second SL Link.

FIG.4Bdepicts one embodiment of the first field405. As depicted, the first field405may begin with a SL link ID presence/absence flag420(e.g., 1-bit flag) where, for example, the value ‘1’ indicates the presence of SL link ID. The presence bit/flag420is followed by first SL link ID (or destination ID) sub-field425and then followed by first SL BWP ID or SL carrier ID sub-field430, and then followed by first SL CQI435and first SL RI440values. Here, SL CQI/RI measurement and derivation may be based on the existing physical layer procedure for Uu (e.g., 4-bit Channel Quality Indicator and 1-bit or 2-bit Rank Indicator, depending on number of transmission layers and/or antenna ports). Note that it is possible to extend the first field405with other SL-CSI values like PMI (precoding matrix indicator), SL beam measurement reports etc.

FIG.4Cdepicts one embodiment of the second field410. As depicted, the second field410may begin with a SL link ID presence/absence flag445(e.g., 1-bit flag) and is followed by second SL link ID (or destination ID) sub-field450and then followed by second SL BWP ID or SL carrier ID sub-field455, and then followed by second SL CQI460and second SL RI465values. Again, SL CQI/RI measurement and derivation may be based on the existing physical layer procedure for Uu. Additionally, the second field410may be extended with other SL-CSI values like PMI, SL beam measurement reports etc.

FIG.4Ddepicts one embodiment of the third field415. In the third field415, the value of ‘0’ in the SL link ID absence flag470indicates the absence of SL link information which is followed by padding475. In the above implementation, the MAC-CE400may also be formed with one or more field(s) absent. In another example, a flag may be added in front of every sub-field to indicate its presence or absence. Where the flag indicates absence of a field or sub-field, padding bits may be added to ensure consistent bit-length of the field or sub-field.

In various embodiments, in order to avoid end-to-end delay, the Tx UE201may implement a pre-emptive Scheduling Request (SR) mechanism. In one embodiment, the pre-emptive SR mechanism includes transmitting SR as soon as the Tx UE201receives DCI with SL-CSI request from. In another embodiment, the pre-emptive SR mechanism includes transmitting SR as soon as the Tx UE201transmits the SL-CSI request in SCI, it transmits a SR message to RAN node210to request for UL resource before the available of CSI report at the Tx UE.

A separate SR resource may be configured for this purpose. RAN node210may provide UL grant for PUSCH for SL-CSI report transmission within the configured latency bound. RAN node210may enable/disable pre-emptive SR transmission for Tx UE based on the SL-LCH priority from QoS of data and it may be independently configured per SL-LCH. In another method, the pre-emptive SR may also be enabled based on the configuration of the end-to-end latency bound of SL-CSI reporting to RAN node210.

In various embodiments, the Tx UE201may reduce the overhead of CSI reporting to the RAN node210including identifying and combining/merging CSI reports from multiple unicast links belonging to the same TX-Rx UE pairs. In one example, along with the merged CSI values the Tx UE may transmit individual unicast link ID that contains the same CSI values in the MAC-CE400.

In various embodiments, the conditions triggering the SL-CSI report301may be event triggered, e.g., based on the availability of SL-CSI report at the Tx UE201. As long as the SL-CSI reporting event is considered pending for transmission (e.g., a pending flag is defined) for a certain unicast link or destination ID, the Tx UE201may generate a MAC-CE400based on the latest SL CSI-RS report received from the Rx UE(s)205for the same unicast link ID or destination ID. Here, the pending flag may be cleared (or cancelled) for that unicast link or destination ID after the MAC-CE400of the corresponding SL-CSI report301is transmitted to RAN node210.

In various embodiments, the multiplexing of SL-CSI value from multiple unicast links in the same SL-CSI report301to the RAN node210may be undertaken by the Tx UE201based on certain factors. These factors may include the latency bound of the SL-CSI reports, number of Rx UEs205, etc. The latency bound for reporting the SL-CSI value to the RAN node210may be configured via RRC signaling and the value of the latency bound configuration may be different considering different service type associated with different unicast link ID or destination ID.

In one embodiment, the latency bound signaled (e.g., via RRC) from RAN node210may be an end-to-end latency bound that includes both Rx UE(s)-to-Tx UE reporting and Tx UE-to-RAN node reporting. In another embodiment, the signaled latency bound is separately provided for Rx UE(s)-to-Tx UE reporting and for Tx UE-to-RAN node reporting.

In certain embodiments, if RAN node210receives SL-CSI report with a SL_CSI value that is outside the latency bound, then RAN node210may choose to ignore or drop the SL-CSI value (or the entire report). In certain embodiments, if the Tx UE201determines that a SL-CSI value does not meet the configured latency bound for transmitting to RAN node210, then it does not transmit the SL-CSI value and may inform RAN node210in the UL signaling about the cause for the same. In one example, the cause value may be SL link failure or SL-CSI late arrival from Rx UE205to Tx UE201, etc. Note that in the case of multiplexing multiple SL-CSI values into the SL-CSI report301, the expired SL-CSI values may be dropped (i.e., not multiplexed into the report301).

In various embodiments, RAN node210may indicate in the DCI to request SL-CSI report(s) from Tx UE201. In one embodiment, the SL-CSI request in the DCI may also include unicast link ID(s) or destination ID(s) and—in that case—the Tx UE201is only allowed to transmit/multiplex SL-CSI values for the specified unicast link ID(s) or destination ID(s). In such embodiments, the Tx UE201may form a MAC-CE containing SL-CSI values only for that unicast link ID(s) or destination ID(s).

In another embodiment, the SL-CSI request in the DCI does not include any unicast link or destination ID. In this case, the Tx UE201is not restricted by unicast link(s)/destination ID(s) and is thus allowed to transmit/multiplex SL-CSI values in a MAC-CE for SL LCHs that belong to any of the one or more unicast links or destination IDs that are allowed to transmit SL data with Mode-1 configurations and where the SL-CSI report is available.

For the above methods, when Tx UE201receives SL CSI-RS request from RAN node210, it may start transmitting SL CSI-RS corresponding to one or more unicast links or destination IDs for SL LCHs with Mode-1 configurations and request SL-CSI values accordingly.

In some embodiments, the MAC-CE400is generated for UL by the Tx UE201only when there is SL-CSI report received from Rx UE(s)205and when the SL-CSI report is pending MAC-CE400may be multiplexed with UL data i.e., generated UL TB contains UL data and MAC-CE containing SL CSI report and in that case, the priority of transmitting the MAC-CE400is same as that of the UL data.

In some embodiments, the MAC-CE400may be generated immediately even without UL data i.e., generated UL TB contains only MAC-CE containing SL CSI report. This MAC-CE400is associated with certain UL priority and the MAC-CE400itself may trigger a SR transmission to request PUSCH resource for UL transmission. In certain embodiments, a separate SR resource may be configured by RAN node210for a MAC-CE carrying SL-CSI, e.g., to all UEs. The LCP procedure for transmitting the MAC-CE400for SL-CSI reporting may be based on the defined SL priority value, where the priority of this MAC-CE400may be same or lower or higher compared with the priority of the MAC-CE of the SL buffer status report (BSR).

According to a second solution, when transmitting the SL-CSI report301using UL PUCCH/PUSCH, each SL-CSI value (e.g.,303,309,315) is tagged or associated with corresponding SL link ID or destination ID, as described above. In various embodiments, the SL-CSI value(s) may be tagged with additional information such as the SL BWP ID or carrier ID, the SL CSI-RS measurement configuration, the SL CSI-RS scheduling information for each unicast link(s), the latency bound, the SL slot number, etc., as explained in the first solution. Here, the SL-CSI report triggering conditions may be event triggered based on the availability of SL-CSI report at the Tx UE201, as explained in the first solution.

In some implementations of the second solution, a separate SR resource may be configured to request either a PUCCH or a PUSCH resource from the RAN node210. In one embodiment, the trigger for SR transmission may be due to pending SL-CSI in MAC. In another embodiment, the trigger for SR transmission may be due to receiving a SL-CSI request in DCI from the RAN node210. In other embodiments, the trigger for SR transmission may be due to SL-CSI request transmitted by the Tx UE201in SCI to the Rx UE(s)205. In case of pre-emptive SR configured for this SL LCH, the SR message may be transmitted to request a PUCCH or PUSCH resource as soon as the DCI containing a request for SL-CSI reporting is received by the Tx UE201or as soon as the SCI containing a request for SL-CSI reporting is transmitted by the Tx UE201, as explained in the first solution.

In some embodiments, the NR DCI may contain a field for UL PUCCH resource and timing related information to report SL-CSI values. In certain embodiments, the timing information may be ‘k’, defined in number of slots from the NR DCI reception to UL PUCCH transmission. In other embodiments, the timing information may be ‘k’, defined as the number of slots from the SCI transmission to UL PUCCH transmission.

FIG.5depicts a second scenario500of a transmitting UE (e.g., the Tx UE201) reporting SL-CSI, e.g., to a RAN node210, according to a third solution. In the second scenario500, the Tx UE201includes multiple logical panels, and the SL-CSI includes SL logical panel IDs in a SL-CSI report501. The second scenario500is similar to the first scenario300, discussed above, but applies to the case of multi-panel SL transmission. Here, it is assumed that the Tx UE201has received multiple SL-CSI values from one or more Rx UEs (e.g., the Rx UE(s)205). In the second scenario500, SL-CSI reporting from the Rx UE205may also include corresponding panel ID(s) in the SL-CSI report501for which the measurement was undertaken.

According to the third solution, the SL-CSI report501sent to the RAN node210includes additional information along with the SL-CSI values such as panel ID(s) (both Tx UE panel ID(s) and Rx UE panel ID(s) used for SL transmission) used for SL-CSI measurement in both the Tx UE201and the Rx UE205.

As shown inFIG.5, the Tx UE201transmits the SL-CSI report501to the RAN node210. The SL-CSI report501may be transmitted in a MAC-CE. Alternatively, the SL-CSI report501may be transmitted via PUCCH or PUSCH transmission, as explained in the second solution.

In various embodiments, the SL-CSI report501may multiplex SL-CSI values for different SL BWP and/or SL carrier and logical panel/beam combinations that belong to the same or different unicast link ID (or destination ID). In the example depicted, the SL-CSI report501includes a first SL-CSI value503that is tagged with a first unicast link ID305and with a BWP ID and/or SL carrier ID and Panel ID505. The depicted SL-CSI report501also includes a second SL-CSI value507that is tagged with a second unicast link ID311and with a BWP ID and/or SL carrier ID and Panel ID509. The depicted SL-CSI report501further includes a third SL-CSI value511that is tagged with a third unicast link ID317and with a BWP ID and/or SL carrier ID and Panel ID513. Note that the SL-CSI value503,507and511may be tagged with multiple BWP/carrier ID(s). Further, each SL-CSI value is tagged with their respective carrier IDs or BWP IDs, which may be the same or different carrier/BWP IDs as tagged in other SL-CSI values.

FIGS.6A-6Ddepict a MAC-CE600, according to embodiments of the third solution.FIG.6Adepicts the MAC-CE600containing a plurality of SL fields, including a first field605, a second field610, and a third field615. Here, the first field605provides information for a first SL Link and panel/beam combination and the second field410provides information for a second SL Link and panel/beam combination.

FIG.6Bdepicts one embodiment of the first field605. As depicted, the first field605may begin with an SL link ID presence/absence flag620(e.g., 1-bit flag) where, for example, the value ‘1’ indicates the presence of SL link ID. The presence bit/flag620is followed by first SL link ID (or destination ID) sub-field625and then followed by first SL BWP ID or SL carrier ID and SL panel ID sub-field630, and then followed by first SL CQI635and first SL RI640values. Additionally, the first field610may contain PMI, SL beam measurement reports etc. Here, SL CQI/RI measurement and derivation may be as described above with reference toFIGS.4A-4D.

FIG.6Cdepicts one embodiment of the second field610. As depicted, the second field610may begin with a SL link ID presence/absence flag645(e.g., 1-bit flag) and is followed by second SL link ID (or destination ID) sub-field650and then followed by second SL BWP ID or SL carrier ID and panel ID sub-field655, and then followed by second SL CQI660and second SL RI665values. Again, SL CQI/RI measurement and derivation may be based on the existing physical layer procedure for Uu. Additionally, the second field610may be extended with other SL-CSI values like PMI, SL beam measurement reports etc.

In a key difference from the MAC-CE400, the MAC-CE600includes new fields for panel ID(s) to help associate SL-CSI values reported by a Rx UE(s) (for e.g., unicast link ID or destination ID belonging to the same or different Rx UE(s)) to the SL-CSI measurements performed with a panel(s). As depicted, the first SL BWP ID or SL carrier ID sub-field630is expanded to provide first panel ID(s) (alternatively, beam IDs) associated with the first SL Link. Similarly, the second SL BWP ID or SL carrier ID sub-field655is expanded to provide second panel ID(s) (alternatively, beam IDs) associated with the second SL Link.

FIG.6Ddepicts one embodiment of the third field615. In the third field615, the value of ‘0’ in the SL link ID absence flag670indicates the absence of SL link information which is followed by padding675. In the above implementation, the MAC-CE600may also be formed with one or more field(s) absent. In another example, a flag may be added in front of every sub-field to indicate its presence or absence. Where the flag indicates absence of a field or sub-field, padding bits may be added to ensure consistent bit-length of the field or sub-field.

According to a fourth solution, the SL-CSI may be reported via assistance information, e.g., with RRC signaling. Considering one or more combination of the above solutions, SL-CSI reporting may also be transmitted with UE assistance information like RRC signaling where the report of SL-CSI is transmitted to gNB along with the unicast link ID or destination ID and also panel ID(s). Triggers for requesting resource for assistance information (i.e., PUSCH resource) may be based on one or more combination of the above solutions.

The Tx UE201needs to select a single destination for data transmission among multiple destinations having data available for transmission when a grant (Mode-1 or Mode-2) appears. In certain embodiments, there may be a highest priority destination (i.e., destination ID of the highest priority logical channel among all LCHs across destinations having data available for transmission). However, if there is more than one such “highest priority destination,” current techniques offer no guidance on how the Tx UE201is to select one destination out of these destinations for data transmission.

According to a fifth solution, one destination is to be randomly selected out of these multiple competing destinations. In a variant of the fifth solution, the Tx UE201determines the “highest priority destination” as the destination corresponding to the next highest priority LCH having data available for transmission, of any of the competing destinations. So, if there are more than one destinations with one or more LCH(s) having the same priority for the highest priority logical channel with data, then the comparison is to be made based on the next highest priority LCH in the competing destinations.

In another variant of the fifth solution, when there is more than one such “highest priority destination,” another QoS attribute may be used to compare the competing logical channels in the said multiple destinations. The specific QoS attribute may be latency or reliability as examples. In this sense, a destination with the highest priority LCH is to be selected if the LCH has a lower latency (and/or higher reliability and/or smaller remaining PDB) compared with other competing LCH(s) of other destination(s).

According to a sixth solution, the Tx UE201may configure code block group (CBG)-based HARQ feedback for a Rx UE with a unicast link, e.g., using a PC5 RRC signaling, or using SCI, or using MAC-CE, or being pre-configured for out of coverage UEs. The Tx UE may also provide resources for Physical sidelink feedback channel (PSFCH) to report CBG-based ACK/NACK using a set of code division multiplexing (CDM) resources where mapping between the CBG and cyclic shifts for the CDM resources is signaled via PC5 RRC or SCI or MAC-CE. In one implementation, the mapping between CBG and CDM may have a one-to-one relationship, for example, Cyclic shifts #1may be related to CBG #1, Cyclic shifts #2may be related to CBG #2, and so on.

For a Tx UE201, only SL LCHs that are allowed to transmit SL data with Mode-1 configurations are allowed to multiplex CBG-based HARQ feedback report to the RAN node210. Here, the DCI may contain a field for PUCCH timing and resources for reporting SL CBG to the RAN node210. The cyclic shifts for the PUCCH resource to report SL CBG and its mapping rule may be semi-statically configured e.g., via RRC signaling.

FIG.7Adepicts a NR protocol stack700, according to embodiments of the disclosure. WhileFIG.7Ashows the remote unit105, the base unit121and the mobile core network140, these are representative of a set of UEs interacting with a RAN node and a NF (e.g., AMF) in a core network. As depicted, the protocol stack700comprises a User Plane protocol stack705and a Control Plane protocol stack710. The User Plane protocol stack705includes a PHY layer715, a Medium Access Control (MAC) sublayer720, a Radio Link Control (RLC) sublayer725, a Packet Data Convergence Protocol (PDCP) sublayer730, and Service Data Adaptation Protocol (SDAP) layer735. The Control Plane protocol stack710also includes a physical layer715, a MAC sublayer720, a RLC sublayer725, and a PDCP sublayer730. The Control Place protocol stack710also includes a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer745.

The AS protocol stack for the Control Plane protocol stack710consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The AS protocol stack for the User Plane protocol stack705consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The Layer-2 (L2) is split into the SDAP, PDCP, RLC and MAC sublayers. The Layer-3 (L3) includes the RRC layer740and the NAS layer745for the control plane and includes, e.g., an Internet Protocol (IP) layer or PDU Layer (note depicted) for the user plane. L1 and L2 are referred to as “lower layers” such as PUCCH/PUSCH or MAC-CE, while L3 and above (e.g., transport layer, application layer) are referred to as “higher layers” or “upper layers” such as RRC.

The physical layer715offers transport channels to the MAC sublayer720. The MAC sublayer720offers logical channels to the RLC sublayer725. The RLC sublayer725offers RLC channels to the PDCP sublayer730. The PDCP sublayer730offers radio bearers to the SDAP sublayer735and/or RRC layer740. The SDAP sublayer735offers QoS flows to the mobile core network140(e.g., 5GC). The RRC layer740provides for the addition, modification, and release of Carrier Aggregation and/or Dual Connectivity. The RRC layer740also manages the establishment, configuration, maintenance, and release of Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs). In certain embodiments, an RRC entity functions for detection of and recovery from radio link failure.

FIG.7Bdepicts a PC5 protocol stack750, according to embodiments of the disclosure. WhileFIG.7Bshows the Tx UE201and the Rx UE203, these are representative of a set of UEs communicating peer-to-peer via PC5 and other embodiments may involve different UEs. As depicted, the PC5 protocol stack includes a physical layer755, a MAC sublayer760, a RLC sublayer765, a PDCP sublayer770, and RRC and SDAP layers (depicted as combined element “RRC/SDAP”775), for the control plane and user plane, respectively.

The AS protocol stack for the control plane in the PC5 interface consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The AS protocol stack for the user plane in the PC5 interface consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The L2 is split into the SDAP, PDCP, RLC and MAC sublayers. The L3 includes the RRC sublayer and the NAS layer for the control plane and includes, e.g., an IP layer for the user plane. L1 and L2 are referred to as “lower layers”, while L3 and above (e.g., transport layer, V2X layer, application layer) are referred to as “higher layers” or “upper layers.”

FIG.8depicts a user equipment apparatus800that may be used for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. In various embodiments, the user equipment apparatus800is used to implement one or more of the solutions described above. The user equipment apparatus800may be one embodiment of the remote unit105, the Tx UE201, and/or the Rx UE205, described above. Furthermore, the user equipment apparatus800may include a processor805, a memory810, an input device815, an output device820, and a transceiver825.

In some embodiments, the input device815and the output device820are combined into a single device, such as a touchscreen. In certain embodiments, the user equipment apparatus800may not include any input device815and/or output device820. In various embodiments, the user equipment apparatus800may include one or more of: the processor805, the memory810, and the transceiver825, and may not include the input device815and/or the output device820.

As depicted, the transceiver825includes at least one transmitter830and at least one receiver835. Here, the transceiver825communicates with one or more cells supported by one or more base units121. Additionally, the transceiver825may support at least one network interface840and/or application interface845. The application interface(s)845may support one or more APIs. The network interface(s)840may support 3GPP reference points, such as Uu and PC5. Other network interfaces840may be supported, as understood by one of ordinary skill in the art.

The processor805, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor805may be a microcontroller, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processing unit, a field programmable gate array (FPGA), or similar programmable controller. In some embodiments, the processor805executes instructions stored in the memory810to perform the methods and routines described herein. The processor805is communicatively coupled to the memory810, the input device815, the output device820, and the transceiver825.

In various embodiments, the processor805controls the user equipment apparatus800to implement the above described UE behaviors. For example, the processor805receives (i.e., via the transceiver825) a first SL-CSI value from a Rx UE via one of a plurality of unicast links. The processor805generates an SL-CSI report comprising the first SL-CSI value, wherein the first SL-CSI value is tagged with an identifier that identifies the Rx UE.

In some embodiments, the processor805controls the transceiver825to transmit a MAC-CE to a RAN node using an uplink channel, the MAC-CE containing the SL-CSI report. In some embodiments, the MAC-CE further includes an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In some embodiments, generating the SL-CSI report occurs in response to the user equipment apparatus800having SL-CSI report pending flag. In such embodiments, the processor805clears the flag after the transmission of the MAC-CE. In some embodiments, the user equipment apparatus800operates in a first sidelink mode (i.e., SL Mode-1) corresponding to a network-scheduled sidelink operation. In such embodiments, generating the SL-CSI report includes forming the MAC-CE only from one or more SL logical channels configured to transmit SL data using Mode-1.

In some embodiments, the processor805triggers a SR transmission to request a PUSCH resource for the transmission of the MAC-CE. In some embodiments, the processor805controls the transceiver825to transmit a SR to request an uplink resource (i.e., PUSCH) prior to receiving the first SL-CSI value from the Rx UE, according to the preemptive SR mechanisms described above. In one embodiment of preemptive SR, the transceiver825transmits the SR in response to receiving a SL-CSI request from the RAN node in DCI, where the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE. In another embodiment of preemptive SR, the transceiver825transmits the SR in response to transmitting SCI to the Rx UE, said SCI containing a SL-CSI request, where the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE.

In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from the plurality of unicast links, each SL-CSI value being tagged with a different identifier. Here, the identifiers with which the different SL-CSI value is tagged may be a Destination ID, a Unicast Link ID, a SL BWP ID, a SL carrier ID, a SL logical panel ID, or combinations thereof as described above. In one embodiment, the identifier is a combination of the above IDs that uniquely identifies the Rx UE reporting CSI.

In some embodiments, multiplexing the plurality of SL-CSI values from the plurality of unicast links is based on a latency bound of the SL-CSI values. In one embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound configured as an end-to-end latency bound applicable to both a Rx UE-to-Tx UE reporting period and a Tx UE-to-RAN node reporting period. In another embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound including a first latency bound applicable to a Rx UE-to-Tx UE reporting period and a second latency bound applicable to a Tx UE-to-RAN node reporting period. In the above embodiments, a second SL-CSI value that exceeds the latency bound is excluded from the SL-CSI report.

In other embodiments, the processor805controls the transceiver825to transmit the SL-CSI report to a RAN node using a L1 UL control channel. In some embodiments, the L1 UL control channel is a PUCCH. In such embodiments, the transceiver825receives DCI, the DCI carrying time and frequency information for the PUCCH carrying the SL-CSI report, where transmitting the SL-CSI report comprises a PUCCH transmission. In certain embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the DCI reception and the PUCCH transmission.

In some embodiments, the processor805controls the transceiver825to transmit SCI to the Rx UE, said SCI containing a SL-CSI request, where the Rx UE transmits the first SL-CSI value in response to the SL-CSI request. In such embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the SCI transmission and the PUCCH transmission.

In some embodiments, the L1 UL control channel transmission comprises an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In various embodiments, the identifier with which a SL-CSI value is tagged comprises a link ID that uniquely denotes a source-destination pair between the user equipment apparatus800and the Rx UE. In some embodiments, the identifier with which a SL-CSI value is tagged comprises a destination ID corresponding to the Rx UE. In one embodiment, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple carriers and/or bandwidth parts for the same source-destination pair. In another embodiment, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple panels and/or beams for the same source-destination pair.

The memory810, in one embodiment, is a computer readable storage medium. In some embodiments, the memory810includes volatile computer storage media. For example, the memory810may include a RAM, including dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), and/or static RAM (SRAM). In some embodiments, the memory810includes non-volatile computer storage media. For example, the memory810may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory810includes both volatile and non-volatile computer storage media.

In some embodiments, the memory810stores data related to transmitting SL CSI using an uplink channel. For example, the memory810may store resource allocations, SL-CSI values, LCH data, MAC PDUs, TBs, and the like. In certain embodiments, the memory810also stores program code and related data, such as an operating system (OS) or other controller algorithms operating on the apparatus800.

The input device815, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device815may be integrated with the output device820, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device815includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device815includes two or more different devices, such as a keyboard and a touch panel.

In certain embodiments, the output device820includes one or more speakers for producing sound. For example, the output device820may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device820includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the output device820may be integrated with the input device815. For example, the input device815and output device820may form a touchscreen or similar touch-sensitive display. In other embodiments, the output device820may be located near the input device815.

The transceiver825includes at least transmitter830and at least one receiver835. One or more transmitters830may be used to provide UL communication signals to a base unit121, such as the UL transmissions described herein. Similarly, one or more receivers835may be used to receive DL communication signals from the base unit121, as described herein. Although only one transmitter830and one receiver835are illustrated, the user equipment apparatus800may have any suitable number of transmitters830and receivers835. Further, the transmitter(s)830and the receiver(s)835may be any suitable type of transmitters and receivers. In one embodiment, the transceiver825includes a first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and a second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum.

In certain embodiments, the first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and the second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum may be combined into a single transceiver unit, for example a single chip performing functions for use with both licensed and unlicensed radio spectrum. In some embodiments, the first transmitter/receiver pair and the second transmitter/receiver pair may share one or more hardware components. For example, certain transceivers825, transmitters830, and receivers835may be implemented as physically separate components that access a shared hardware resource and/or software resource, such as for example, the network interface840.

In various embodiments, one or more transmitters830and/or one or more receivers835may be implemented and/or integrated into a single hardware component, such as a multi-transceiver chip, a system-on-a-chip, an application-specific integrated circuit (ASIC), or other type of hardware component. In certain embodiments, one or more transmitters830and/or one or more receivers835may be implemented and/or integrated into a multi-chip module. In some embodiments, other components such as the network interface840or other hardware components/circuits may be integrated with any number of transmitters830and/or receivers835into a single chip. In such embodiment, the transmitters830and receivers835may be logically configured as a transceiver825that uses one more common control signals or as modular transmitters830and receivers835implemented in the same hardware chip or in a multi-chip module.

FIG.9depicts one embodiment of a network equipment apparatus900that may be used for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. In some embodiments, the network apparatus900may be one embodiment of a RAN node and its supporting hardware, such as the base unit121, RAN node and/or gNB, described above. Furthermore, network equipment apparatus900may include a processor905, a memory910, an input device915, an output device920, and a transceiver925. In certain embodiments, the network equipment apparatus900does not include any input device915and/or output device920.

As depicted, the transceiver925includes at least one transmitter930and at least one receiver935. Here, the transceiver925communicates with one or more remote units105. Additionally, the transceiver925may support at least one network interface940and/or application interface945. The application interface(s)945may support one or more APIs. The network interface(s)940may support 3GPP reference points, such as Uu, N1, N2 and N3. Other network interfaces940may be supported, as understood by one of ordinary skill in the art.

The processor905, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor905may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or similar programmable controller. In some embodiments, the processor905executes instructions stored in the memory910to perform the methods and routines described herein. The processor905is communicatively coupled to the memory910, the input device915, the output device920, and the transceiver925.

In various embodiments, the processor905controls the network equipment apparatus900to implement the above described RAN node behaviors. For example, the processor905may allocate SL resources to a UE, as described herein.

The memory910, in one embodiment, is a computer readable storage medium. In some embodiments, the memory910includes volatile computer storage media. For example, the memory910may include a RAM, including DRAM, SDRAM, and/or SRAM. In some embodiments, the memory910includes non-volatile computer storage media. For example, the memory910may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory910includes both volatile and non-volatile computer storage media.

In some embodiments, the memory910stores data relating to transmitting SL CSI using an uplink channel, for example storing UE identities, SL resource allocations, and the like. In certain embodiments, the memory910also stores program code and related data, such as an operating system (OS) or other controller algorithms operating on the network equipment apparatus900and one or more software applications.

The input device915, in one embodiment, may be substantially as described above with reference to the input device815. Similarly, the output device920may be substantially as described above with reference to the output device820. In some embodiments, the input device915may be integrated with the output device920, for example, as a touchscreen or similar touch-sensitive display. In other embodiments, all or portions of the output device920may be located near the input device915.

As discussed above, the transceiver925may communicate with one or more remote units and/or with one or more network functions that provide access to one or more PLMNs. The transceiver925operates under the control of the processor905to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor905may selectively activate the transceiver925(or portions thereof) at particular times in order to send and receive messages.

The transceiver925may include one or more transmitters930and one or more receivers935. In certain embodiments, the one or more transmitters930and/or the one or more receivers935may share transceiver hardware and/or circuitry. For example, the one or more transmitters930and/or the one or more receivers935may share antenna(s), antenna tuner(s), amplifier(s), filter(s), oscillator(s), mixer(s), modulator/demodulator(s), power supply, and the like. In one embodiment, the transceiver925implements multiple logical transceivers using different communication protocols or protocol stacks, while using common physical hardware.

FIG.10depicts one embodiment of a method1000for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. In various embodiments, the method1000is performed by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. In some embodiments, the method1000is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method1000begins and receives1005a first SL-CSI value from a Rx UE via one of a plurality of unicast links. The method1000includes generating1010a SL-CSI report containing the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The method1000includes transmitting1015a MAC-CE to a RAN node using an uplink channel, the MAC-CE containing the SL-CSI report. The method1000ends.

FIG.11depicts one embodiment of a method1100for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. In various embodiments, the method1100is performed by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. In some embodiments, the method1100is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method1100begins and receives1105a first SL-CSI value from a Rx UE via one of a plurality of unicast links. The method1100includes generating1110a SL-CSI report comprising the first SL-CSI value, wherein the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The method1100includes transmitting1115the SL-CSI report to a radio access network (RAN) node using a L1 UL control channel. The method1100ends.

Disclosed herein is a first apparatus for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. The first apparatus may be implemented by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. The first apparatus includes a transceiver that receives a first SL-CSI value from a Rx UE via one of a plurality of unicast links. The first apparatus includes a processor that generates an SL-CSI report comprising the first SL-CSI value, wherein the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The processor controls the transceiver to transmit a MAC-CE to a RAN node using an uplink channel, the MAC-CE containing the SL-CSI report.

In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from the plurality of unicast links, each SL-CSI value being tagged with a different identifier. In certain embodiments, multiplexing the plurality of SL-CSI values from the plurality of unicast links is based on a latency bound of the SL-CSI values, wherein a second SL-CSI value that exceeds the latency bound is excluded from the SL-CSI report. In one embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound configured as an end-to-end latency bound applicable to both a Rx UE-to-Tx UE reporting period and a Tx UE-to-RAN node reporting period. In another embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound including a first latency bound applicable to a Rx UE-to-Tx UE reporting period and a second latency bound applicable to a Tx UE-to-RAN node reporting period.

In some embodiments, the identifier comprises a link ID that uniquely denotes a source-destination pair between the Tx UE and the Rx UE. In some embodiments, the identifier comprises a destination ID corresponding to the Rx UE. In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple carriers and/or bandwidth parts and from multiple panels and/or beams for the same source-destination pair. In some embodiments, the MAC-CE further includes an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In some embodiments, generating the SL-CSI report occurs in response to the Tx UE having SL-CSI report pending flag. In such embodiments, the processor clears the flag after the transmission of the MAC-CE. In some embodiments, the Tx UE operates in a first sidelink mode (i.e., SL Mode-1) corresponding to a network-scheduled sidelink operation. In such embodiments, generating the SL-CSI report includes forming the MAC-CE only from one or more SL logical channels configured to transmit SL data using Mode-1.

In some embodiments, the processor triggers a SR transmission to request a PUSCH resource for the transmission of the MAC-CE. In some embodiments, the processor controls the transceiver to transmit a SR to request an uplink resource in response to receiving a SL-CSI request from the RAN node in DCI, wherein the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE. In some embodiments, the processor controls the transceiver to transmit a SR to request an uplink resource in response to transmitting SCI to the Rx UE, said SCI containing a SL-CSI request, wherein the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE.

Disclosed herein is a first method for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. The first method may be performed by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. The first method includes receiving a first SL-CSI value from a Rx UE via one of a plurality of unicast links and generating a SL-CSI report containing the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The first method includes transmitting a MAC-CE to a RAN node using an uplink channel, the MAC-CE containing the SL-CSI report.

In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from the plurality of unicast links, each SL-CSI value being tagged with a different identifier. In certain embodiments, multiplexing the plurality of SL-CSI values from the plurality of unicast links is based on a latency bound of the SL-CSI values, wherein a second SL-CSI value that exceeds the latency bound is excluded from the SL-CSI report. In one embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound configured as an end-to-end latency bound applicable to both a Rx UE-to-Tx UE reporting period and a Tx UE-to-RAN node reporting period. In another embodiment, the latency bound is signaled via RRC from the RAN node, the latency bound including a first latency bound applicable to a Rx UE-to-Tx UE reporting period and a second latency bound applicable to a Tx UE-to-RAN node reporting period.

In some embodiments, the identifier comprises a link ID that uniquely denotes a source-destination pair between the Tx UE and the Rx UE. In some embodiments, the identifier comprises a destination ID corresponding to the Rx UE. In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple carriers and/or bandwidth parts and from multiple panels and/or beams for the same source-destination pair. In some embodiments, the MAC-CE further includes an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In some embodiments, generating the SL-CSI report occurs in response to the Tx UE having SL-CSI report pending flag. In such embodiments, the first method further includes clearing the flag after the transmission of the MAC-CE. In some embodiments, the Tx UE operates in a first sidelink mode (i.e., SL Mode-1) corresponding to a network-scheduled sidelink operation. In such embodiments, generating the SL-CSI report includes forming the MAC-CE only from one or more SL logical channels configured to transmit SL data using Mode-1.

In some embodiments, the first method includes triggering a SR transmission to request a PUSCH resource for the transmission of the MAC-CE. In some embodiments, the first method includes transmitting a SR to request an uplink resource in response to receiving a SL-CSI request from the RAN node in DCI, wherein the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE. In some embodiments, the first method includes transmitting a SR to request an uplink resource in response to transmitting SCI to the Rx UE, said SCI containing a SL-CSI request, wherein the SR is transmitted prior to receiving the first SL-CSI value from the Rx UE.

Disclosed herein is a second apparatus for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. The second apparatus may be implemented by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. The second apparatus includes a transceiver that receives a first SL-CSI value from a Rx UE via one of a plurality of unicast links. The second apparatus includes a processor that generates an SL-CSI report comprising the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The processor controls the transceiver to transmit the SL-CSI report to a RAN node using a L1 UL control channel.

In some embodiments, the L1 UL control channel is a PUCCH. In such embodiments, the transceiver receives DCI, the DCI carrying time and frequency information for the PUCCH carrying the SL-CSI report, where transmitting the SL-CSI report comprises a PUCCH transmission. In certain embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the DCI reception and the PUCCH transmission.

In some embodiments, the processor controls the transceiver to transmit SCI to the Rx UE, said SCI containing a SL-CSI request, where the Rx UE transmits the first SL-CSI value in response to the SL-CSI request. In such embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the SCI transmission and the PUCCH transmission.

In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from the plurality of unicast links, each SL-CSI value being tagged with a different identifier. In some embodiments, the L1 UL control channel transmission comprises an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In some embodiments, the identifier comprises a destination ID corresponding to the Rx UE. In some embodiments, the identifier comprises a link ID that uniquely denotes a source-destination pair between the Tx UE and the Rx UE. In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple carriers and/or bandwidth parts and from multiple panels and/or beams for the same source-destination pair.

Disclosed herein is a second method for transmitting SL CSI using an uplink channel, according to embodiments of the disclosure. The second method may be performed by a Tx UE, such as the remote unit105, the Tx UE201and/or the user equipment apparatus800, described above. The second method includes receiving a first SL-CSI value from a Rx UE via one of a plurality of unicast links and generating a SL-CSI report comprising the first SL-CSI value, where the first SL-CSI value is tagged with an identifier that identifies the Rx UE. The second method includes transmitting the SL-CSI report to a RAN node using an L1 UL control channel.

In some embodiments, the L1 UL control channel is a PUCCH. In such embodiments, the second method includes receiving DCI, the DCI carrying time and frequency information for the PUCCH carrying the SL-CSI report, where transmitting the SL-CSI report comprises a PUCCH transmission. In certain embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the DCI reception and the PUCCH transmission.

In some embodiments, the second method includes transmitting SCI to the Rx UE, said SCI containing a SL-CSI request, where the Rx UE transmits the first SL-CSI value in response to the SL-CSI request. In such embodiments, the timing information in DCI comprises a parameter ‘k’ that defines a number of slots between the SCI transmission and the PUCCH transmission.

In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from the plurality of unicast links, each SL-CSI value being tagged with a different identifier. In some embodiments, the L1 UL control channel transmission comprises an additional field to report one or more of: a SL-CSI measurement configuration, a SL BWP ID, a SL carrier ID, a SL logical panel ID, and a SL Slot number.

In some embodiments, the identifier comprises a destination ID corresponding to the Rx UE. In some embodiments, the identifier comprises a link ID that uniquely denotes a source-destination pair between the Tx UE and the Rx UE. In some embodiments, generating the SL-CSI report comprises multiplexing a plurality of SL-CSI values from multiple carriers and/or bandwidth parts and from multiple panels and/or beams for the same source-destination pair.

Disclosed herein is a third apparatus for communicating SL CSI using an uplink channel, according to embodiments of the disclosure. The third apparatus may be implemented by a base station, such as the base unit121, the RAN Node210and/or the network equipment apparatus900, described above. The third apparatus includes a processor coupled with a memory and configured to cause the third apparatus to receive, from a Tx UE, a MAC-CE including a SL CSI report, where the SL CSI report comprises a first SL CSI value, and where the first SL CSI value is tagged with an identifier that identifies a Rx UE.

In some embodiments, the processor is further configured to cause the third apparatus to transmit an RRC message that indicates a latency bound, where the latency bound is configured as an end-to-end latency bound.

In some embodiments, the identifier comprises a link identifier that uniquely identifies a source-destination pair between the Tx UE and the Rx UE. In some embodiments, the identifier comprises a destination identifier corresponding to the Rx UE.

In some embodiments, the MAC-CE further includes a field to report one or more of: a SL CSI measurement configuration, an SL BWP identifier, a SL carrier identifier, a SL logical panel identifier, or a SL slot number.

In some embodiments, the processor is further configured to cause the third apparatus to: A) transmit a DCI that indicates a request for the SL CSI report; and B) receive an SR for an uplink resource based on the transmitted DCI.

In some embodiments, the processor is further configured to cause the third apparatus to transmit DCI indicating timing information, frequency information, or both, for a PUCCH transmission carrying the SL CSI report. In certain embodiments, the timing information comprises a parameter ‘k’ that is indicative of a number of slots between the transmitted DCI and the PUCCH transmission.

Disclosed herein is a third method for communicating SL CSI using an uplink channel, according to embodiments of the disclosure. The first method may be performed by a base station, such as the base unit121, the RAN Node210and/or the network equipment apparatus900, described above. The first method includes receiving, from a Tx UE, a MAC-CE including a SL CSI report, where the SL CSI report comprises a first SL CSI value, and where the first SL CSI value is tagged with an identifier that identifies a Rx UE.

In some embodiments, the third method further includes transmitting an RRC message that indicates a latency bound, where the latency bound is configured as an end-to-end latency bound.

In some embodiments, the identifier comprises a link identifier that uniquely identifies a source-destination pair between the Tx UE and the Rx UE. In some embodiments, the identifier comprises a destination identifier corresponding to the Rx UE.

In some embodiments, the MAC-CE further includes a field to report one or more of: a SL CSI measurement configuration, an SL BWP identifier, a SL carrier identifier, a SL logical panel identifier, or a SL slot number.

In some embodiments, the third method further includes: A) transmitting a DCI that indicates a request for the SL CSI report; and B) receiving an SR for an uplink resource based on the transmitted DCI.

In some embodiments, the third method further includes transmitting DCI indicating timing information, frequency information, or both, for a PUCCH transmission carrying the SL CSI report. In certain embodiments, the timing information comprises a parameter ‘k’ that is indicative of a number of slots between the transmitted DCI and the PUCCH transmission.