TECHNIQUES FOR SIDELINK RELAY HANDOVER PROCEDURE

Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may relay wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The first UE may transmit, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The first UE may receive instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The first UE may then perform the handover procedure including establishing a wireless connection with the second base station based on the instructions.

FIELD OF TECHNOLOGY

The following relates to wireless communications, including techniques for sidelink relay handover procedure.

BACKGROUND

Some wireless communications systems may support sidelink relays in which a relay UE may forward, or relay, wireless communications between a base station and a remote UE. Among other advantages, the use of sidelink relays may enable remote UEs to reduce a transmission power of uplink transmissions, thereby reducing a power consumption at the remote UE. However, the use of sidelink relays may result in complexities in the context of performing cell handover procedures.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support techniques for sidelink relay handover procedure. Generally, the described techniques which may be implemented by either relay user equipments (UEs) and/or remote UEs to identify whether target base stations support sidelink relay operations (e.g., whether the base station includes a sidelink-relay-capable base station or non-sidelink-relay-capable base station), which may help inform decisions for handover procedures. In particular, relay UEs and remote UEs may perform a handover procedure from a first base station to a second base station based on determining that the second base station supports sidelink relay operation. In some aspects, UEs (e.g., relay UEs, remote UEs) may determine whether base stations support sidelink relay operation based on system information block (SIB) messages received from the respective bases stations. In some cases, the SIB may indicate whether a base station supports sidelink relay operation explicitly (e.g., based on explicit bit fields within the SIB) and/or implicitly (e.g., based on identifying an absence of a sidelink relay configuration). In some cases, both relay UEs and remote UEs may control or influence which candidate base stations it will perform a handover procedure with based on measurement reports. For example, when transmitting measurement reports for candidate base stations, UEs may omit measurements for base stations which do not support sidelink relay operation, may indicate which base stations do not support sidelink relay operation, may indicate a preference for base stations which support sidelink relay operation, or any combination thereof.

A method for wireless communication at a first UE is described. The method may include relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE, transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation, and performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to relay wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE, transmit, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, receive instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation, and perform the handover procedure including establishing a wireless connection with the second base station based on the instructions.

Another apparatus for wireless communication at a first UE is described. The apparatus may include means for relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE, means for transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, means for receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation, and means for performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to relay wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE, transmit, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, receive instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation, and perform the handover procedure including establishing a wireless connection with the second base station based on the instructions.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a SIB message from at least one candidate base station of the one or more candidate base stations and determining, based on the SIB message, that the at least one candidate base station supports sidelink relay operation, where the first UE transmits the measurement report based on determining that the at least one candidate base station supports support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, via the SIB message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, where the determining may be based on the one or more bit field values.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that a third base station does not support sidelink relay operation, where transmitting the measurement report, performing the handover procedure, or both, may be based on determining that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the third base station, a SIB message, where determining that the third base station does not support sidelink relay operation may be based on the SIB message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the third base station does not support sidelink relay operation may be based on identifying one or more bit fields within the SIB message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the SIB message which indicates that the third base station supports sidelink relay operation, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the measurement report omits measurements for the third base station based on the third base station not supporting sidelink relay operation, and performing the handover procedure with the second base station may be based on the measurement report omitting measurements for the third base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the first base station, a radio resource control (RRC) message indicating for the first UE to omit measurements associated with base stations which do not support sidelink relay operation, where the first UE omits the measurements for the third base station based on the RRC message.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the measurement report may include operations, features, means, or instructions for transmitting measurements for the third base station via the measurement report, where the measurement report includes an indication that the third base station does not support sidelink relay operation, where performing the handover procedure with the second base station may be based on the indication that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the first base station, an indication that the third base station does not support sidelink relay operation, where the determining may be based on the indication that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a sidelink relay configuration associated with the first base station and performing a discovery procedure based on the determined sidelink relay configuration, where performing the handover procedure may be based on performing the discovery procedure.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a SIB message from the first base station, where determining the sidelink relay configuration associated with the first base station may be based on the SIB message.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more candidate base stations support sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for communicating with the second base station within a first frequency range, determining a third base station supports sidelink relay operation within a second frequency range which may be different from the first frequency range, determining a sidelink relay configuration associated with the third base station based on the third base station supporting sidelink relay operation within the second frequency range, and performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving sidelink relay configuration, communicating with the second base station within a first frequency range, determining an absence of base stations configured to communicate within a second frequency range which may be different from the first frequency range, and performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration.

A method for wireless communication at a second UE is described. The method may include communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE, receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation, and performing the handover procedure to establish wireless communications with the second base station based on the instructions.

An apparatus for wireless communication at a second UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to communicate with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE, receive instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation, and perform the handover procedure to establish wireless communications with the second base station based on the instructions.

Another apparatus for wireless communication at a second UE is described. The apparatus may include means for communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE, means for receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation, and means for performing the handover procedure to establish wireless communications with the second base station based on the instructions.

A non-transitory computer-readable medium storing code for wireless communication at a second UE is described. The code may include instructions executable by a processor to communicate with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE, receive instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation, and perform the handover procedure to establish wireless communications with the second base station based on the instructions.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the first base station via the first UE, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, where performing the handover procedure may be based on transmitting the measurement report.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a SIB message from at least one candidate base station of the one or more candidate base stations and determining, based on the SIB message, that the at least one base station supports sidelink relay operation, where the second UE transmits the measurement report based on determining that the at least one candidate base station supports support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, via the SIB message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, where the determining may be based on the one or more bit field values.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that a third base station does not support sidelink relay operation, where transmitting the measurement report, performing the handover procedure, or both, may be based on determining that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the third base station, a SIB message, where determining that the third base station does not support sidelink relay operation may be based on the SIB message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the third base station does not support sidelink relay operation may be based on identifying one or more bit fields within the SIB message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the SIB message which indicates that the third base station supports sidelink relay operation, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the measurement report omits measurements for the third base station based on the third base station not supporting sidelink relay operation, and performing the handover procedure with the second base station may be based on the measurement report omitting measurements for the third base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the first base station via the first UE, an RRC message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, where the second UE omits the measurements for the third base station based on the RRC message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a policy control function message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, where the second UE omits the measurements for the third base station based on the policy control function message.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the measurement report may include operations, features, means, or instructions for transmitting measurements for the third base station via the measurement report, where the measurement report includes an indication that the third base station does not support sidelink relay operation, where performing the handover procedure with the second base station may be based on the indication that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the first base station via the first UE, an indication that the third base station does not support sidelink relay operation, where the determining may be based on the indication that the third base station does not support sidelink relay operation.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that a third base station may be not associated with UEs which may be configured to relay wireless communions between the third base station and one or more additional UEs and transmitting the measurement report where the measurement report omits measurements for the third base station based on determining that the third base station may be not associated with UEs which may be configured to relay wireless communions between the third base station and the one or more additional UEs.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, via the measurement report, an indication of a priority associated with base stations which support sidelink relay operation, where performing the handover procedure may be based on the priority.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a sidelink relay configuration associated with the first base station and performing a discovery procedure based on the determined sidelink relay configuration, where performing the handover procedure may be based on performing the discovery procedure.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a SIB message from the first base station, where determining the sidelink relay configuration associated with the first base station may be based on the SIB message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a third base station, a handover request for a second handover procedure from the first base station to the third base station, where the third base station does not support sidelink relay operation and receiving, from the third base station, a control message rejecting the handover request, where performing the handover procedure from the first base station to the second base station may be based on receiving the control message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for performing a relay UE reselection procedure from the first UE to a third UE and communicating with the first base station via the third UE based on performing the relay UE reselection procedure, where the third UE may be configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link between the first UE and the third UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second base station supports sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for communicating with the second base station within a first frequency range, determining a third base station supports sidelink relay operation within a second frequency range which may be different from the first frequency range, determining a sidelink relay configuration associated with the third base station based on the third base station supporting sidelink relay operation within the second frequency range, and performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving sidelink relay configuration, communicating with the second base station within a first frequency range, determining an absence of base stations configured to communicate within a second frequency range which may be different from the first frequency range, and performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration.

DETAILED DESCRIPTION

Some wireless systems may support sidelink relays in which a relay user equipment (UE) may forward, or relay, wireless communications between a base station and a remote UE. Among other advantages, the use of sidelink relays may enable remote UEs to reduce a transmission power of uplink transmissions, thereby reducing a power consumption at the remote UE. However, the use of sidelink relays may result in complexities in the context of performing cell handover procedures from one base station to another.

The complexities of performing cell handover procedures with sidelink relays may be further caused by the fact that not all base stations in a wireless communications system may support sidelink relay operation. For example, some base stations may support sidelink relay operation (e.g., SL-RelayCapableBSs), while others may not support sidelink relay operation (e.g., non-SL-RelayCapableBSs). For the purposes of the present disclosure, a base station may be considered to support sidelink relay operation if the base station is associated with a sidelink relay configuration, supports sidelink relay transmissions, supports sidelink relay discovery procedures (e.g., may provide a sidelink relay discovery configuration), or any combination thereof, within a single carrier. Conversely, for the purposes of the present disclosure, a base station which does not support sidelink relay configuration may not be associated with a sidelink relay configuration, may not support sidelink relay discovery procedures and/or sidelink relay transmissions, or any combination thereof.

In some wireless communications systems, relay UEs may only connect to base stations which support sidelink relay operation (e.g., SL-RelayCapableBSs), thereby limiting a quantity of base stations with which relay UEs may perform handover procedures. Furthermore, remote UEs may prefer to perform handover procedures to base stations which support sidelink relay operation (e.g., SL-RelayCapableBSs). However, some wireless communications systems do not provide signaling or techniques which enable relay UEs and/or remote UEs to identify which base stations support sidelink relay operation, and which do not.

Accordingly, techniques described herein are directed to signaling and other configurations which may enable relay UEs and/or remote UEs to identify whether target base stations support sidelink relay operations (e.g., whether a base station includes an SL-RelayCapableBS or a non-SL-RelayCapableBS), which may help inform decisions for handover procedures. In particular, relay UEs and remote UEs may perform a handover procedure from a first base station to a second base station based on determining that the second base station supports sidelink relay operation.

In some aspects, UEs (e.g., relay UEs, remote UEs) may determine whether base stations support sidelink relay operation based on system information block (SIB) messages received from the respective bases stations. In some cases, the SIB may indicate whether a base station supports sidelink relay operation explicitly (e.g., based on explicit bit fields within the SIB) and/or implicitly (e.g., based on identifying an absence of a sidelink relay configuration). In some cases, both relay UEs and remote UEs may control or influence which candidate base stations it will perform a handover procedure with based on measurement reports. For example, when transmitting measurement reports for candidate base stations, UEs may omit measurements for base stations which do not support sidelink relay operation, may indicate which base stations are do not support sidelink relay operation, may indicate a preference for base stations which support sidelink relay operation, or any combination thereof.

Aspects of the disclosure are initially described in the context of wireless communications systems. Additional aspects of the disclosure are described in the context of an example relay configuration and example process flows. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to techniques for sidelink relay handover procedure.

In some aspects, the UEs115and the base stations105of the wireless communications system100may support signaling and other techniques which may enable relay UEs115and/or remote UEs115to identify whether target base stations105support sidelink relay operations (e.g., whether a base station105includes an SL-RelayCapableBS or a non-SL-RelayCapableBS), which may help inform decisions for handover procedures. In particular, relay UEs115and remote UEs115may perform a handover procedure from a first base station105to a second base station105based on determining that the second base station105supports sidelink relay operation.

In some aspects, UEs115(e.g., relay UEs115, remote UEs115) of the wireless communications system100may determine whether base stations105support sidelink relay operation based on SIB messages received from the respective bases stations105. In some cases, the SIB may indicate whether a base station105supports sidelink relay operation explicitly (e.g., based on explicit bit fields within the SIB) and/or implicitly (e.g., based on identifying an absence of a sidelink relay configuration). Additionally, or alternatively, UEs115may determine whether base stations105support sidelink relay operation based on policy control function (PCF) signaling received from a core network.

In some cases, both relay UEs115and remote UEs115may control or influence which candidate base stations105it will perform a handover procedure with based on measurement reports. For example, when transmitting measurement reports for candidate base stations, UEs115may omit measurements for base stations105which do not support sidelink relay operation, may indicate which base stations105do not support sidelink relay operation, may indicate a preference for base stations105which support sidelink relay operation, or any combination thereof. In some aspects, UEs115may be configured (e.g., via RRC signaling) to tailor measurement reporting based on whether base stations105do or do not support sidelink relay operation.

Techniques described herein may enable improved handover procedures for both remote UEs115and relay UEs115in the context of wireless communications systems. In particular, techniques described herein may enable UEs115(e.g., relay UEs115, remote UEs115) to determine whether base stations105support sidelink relay operation or not, which may enable more informed decisions regarding handover procedures. By enabling UEs115to determine whether base stations105support sidelink relay operation, techniques described herein may enable UEs115to perform handover procedures with base stations which support sidelink relay operation, thereby providing for more widespread use of sidelink relays and reducing power consumption at remote UEs115.

FIG.2illustrates an example of a relay configuration200that supports techniques for sidelink relay handover procedure in accordance with aspects of the present disclosure. The relay configuration200may implement, or be implemented by, aspects of the wireless communications system100.

In some aspects, the relay configuration200illustrates relay schemes205-aand205-bfor Layer 2 (L2) relay communications between a remote UE and a relay UE which is configured to relay communications between the remote UE and a base station. In particular, the relay scheme205-aillustrates a control plane protocol stack for L2 relay, and the relay scheme205-billustrates a user plane protocol stack for L2 relay. The relay schemes205illustrate various signaling carried out throughout the protocol stacks of the various devices which is used to carry out the respective handovers.

In each of the relay schemes205, a remote UE may be communicatively coupled to a relay UE via a PC5 link (e.g., sidelink communication link). The relay UE may be communicatively coupled to a base station via a Uu link (e.g., uplink/downlink communication link), and may be configured to relay wireless communications between the remote UE and the base station. The base station may be communicatively coupled to a user plane function (UPF) of a wireless communications system via an N3 interface, and the UPF may be coupled to the data network via an N6 interface.

In the context of the control plane protocol stack for L2 relay, the relay scheme205-aillustrates both the PC5 C-plane and the NR Uu C-plane at the remote UE. The PC5 C-plane may be configured for setting up unicast links with the relay UE prior to relayed communications. In some aspects, the remote UE may support NR Uu access stratum (AS) and non-access stratum (NAS) connections above the PC5 radio link control (RLC) layer. In some aspects, the base station (e.g., NG-RAN) illustrated in the relay scheme205-amay be configured to control the remote UE's PC5 link via the NR RRC layer. Additionally, an adaptation layer at the relay UE may be configured to support multiplexing traffic for multiple remote UEs on a Uu link between the relay UE and the base station.

Referring to the user plane protocol stack for L2 relay illustrated in the relay scheme205b, the relay may be performed below the PDCP layer. In particular, the relay UE may forward the PC5 bearer and the Uu bearer using an adaptation layer function. In some aspects, dedicated radio bearers (DRBs) of the remote UE may be controlled by the base station (e.g., NG-RAN). Additionally, in L2 relay, all traffic may terminate at the 5GC, and there may be no direct communication between the remote UE or to the relay UE.

FIG.3illustrates an example of a wireless communications system300that supports techniques for sidelink relay handover procedure in accordance with aspects of the present disclosure. In some aspects, aspects of the wireless communications system300may implement, or be implemented by, aspects of the wireless communications system100, relay configuration200, or both.

The wireless communications system300may include a first base station105-a, a second base station105-b, a third base station105-c, a relay UE115-a, and a remote UE115-band115-c, and a core network305, which may be examples of UEs115, base stations105, and other wireless devices as described with reference toFIGS.1and2.

In some aspects, the first base station105-a, the second base station105-b, and the third base station105-cmay communicate with the core network305using a communication links310-a,310-b, and310-c, respectively. The communication links310-a,310-b, and310-cmay be examples of an N3 interface between the base stations105and the core network305of the wireless communications system300.

The relay UE115-amay communicate with the first base station105-a(e.g., source base station105-a) using a communication link310-d. The communication link310-dmay include an example of an NR or LTE link between the relay UE115-aand the first base station105-a. In some cases, the communication link310-dmay include an example of an access link (e.g., Uu link) which may include a bi-directional link that enables both uplink and downlink communication. For example, the relay UE115-amay transmit uplink signals, such as uplink control signals or uplink data signals, to the first base station105-ausing the communication link310-d, and the first base station105-amay transmit downlink signals, such as downlink control signals or downlink data signals, to the relay UE115-ausing the communication link310-d.

In some aspects, the relay UE115-amay be communicatively coupled to a remote UE115-bvia communication link310-e. The communication link310-emay include an example of a sidelink communication link or PC5 link between the relay UE115-aand the remote UE115-b. In some aspects, the relay UE115-amay be configured to forward, or relay, wireless communications between the first base station105-aand the remote UE115-b. For example, the remote UE115-bmay be configured to transmit data to the relay UE115-avia communication link310-e, and the relay UE115-amay be configured to forward (e.g., relay) the data received from the remote UE115-bto the first base station105-avia the communication link310-d. Conversely, the first base station105-amay be configured to transmit data (e.g., downlink signals) to the relay UE115-avia communication link310-d, and the relay UE115-amay be configured to forward (e.g., relay) the data received from the first base station105-ato the remote UE115-bvia the via the communication link310-e. As noted previously herein, the use of sidelink relays (e.g., the use of the relay UE115-a) may enable the remote UE115-bto reduce a transmission power of uplink transmissions, thereby reducing a power consumption at the remote UE115-b.

As noted previously herein, the use of sidelink relays may result in complexities in the context of performing cell handover procedures from one base station105to another. The complexities of performing cell handover procedures with sidelink relays may be further caused by the fact that not all base stations105in a wireless communications system may support sidelink relay operation. For example, the first base station105-aand the second base station105-bmay support sidelink relay operation (e.g., SL-RelayCapableBSs), while the third base station105-cmay not support sidelink relay operation (e.g., non-SL-RelayCapableBSs). For the purposes of the present disclosure, a base station105may be considered to support sidelink relay operation if the base station105supports sidelink relay discovery procedures and sidelink relay communications (e.g., sidelink relay operation) within a single carrier. Conversely, for the purposes of the present disclosure, a base station105which does not support sidelink relay configuration may not support sidelink relay discovery procedures and sidelink relay communications within a single carrier. Identifying base stations which do not support sidelink relay operation (e.g., non-SL-RelayCapableBS) may be particularly important in the case where a UE115supports sidelink relays, but candidate base stations105do not.

In some wireless communications systems, relay UEs115(e.g., relay UE115-a) may only connect to base stations105which support sidelink relay operation (e.g., SL-RelayCapableBSs), thereby limiting a quantity of base stations105with which relay UEs115may perform handover procedures. For example, in the context of L2 sidelink relay, the relay UE115-amay only be able to connect to base stations105which support sidelink relay operation, including the transmission of discovery messages. Comparatively, in the context of L3 sidelink relay, the relay UE115-amay be configured to communicate with base stations105which do not support sidelink relay operation. In such cases, the relay UE115-amay be configured to transmit discovery messages in accordance with signaled or configured (e.g., pre-configured) sidelink relay configurations when it is connected to a non-SL-RelayCapableBS whose serving carrier is not shared with a sidelink carrier.

Furthermore, remote UEs115(e.g., remote UE115-b) may prefer to perform handover procedures to base stations105which support sidelink relay operation (e.g., SL-RelayCapableBSs). However, some wireless communications systems do not provide signaling or techniques which enable relay UEs115and/or remote UEs115to identify which base stations105support sidelink relay operation, and which do not. Moreover, in cases where a remote UE115(e.g., remote UE115-b) which supports L2 and/or L3 relay is directly coupled (e.g., via a Uu link) to a base station105which does not support sidelink relay (e.g., non-SL-RelayCapableBSs), the remote UE115may be configured to transmit discovery messages in accordance with signaled or configured (e.g., pre-configured) sidelink relay configurations when it is connected to a non-SL-RelayCapableBS whose serving carrier is not shared with a sidelink carrier.

Accordingly, the UEs115and the base stations105of the wireless communications system300may support signaling and other techniques which may enable the relay UE115-aand/or the remote UE115-bto identify whether base stations105support sidelink relay operations (e.g., whether a base station105includes a SL-RelayCapableBS or a non-SL-RelayCapableBS), which may help inform decisions for handover procedures. In particular, the relay UE115-aand the remote UE115-bmay perform a handover procedure from a source base station105(e.g., first base station105-a) to a target base station105(e.g., second base station105-b) based on determining that the target base station105supports sidelink relay operation.

In some aspects, the relay UE115-aand/or the remote UE115-bmay determine whether a base station105of the wireless communications system300supports sidelink relay operation based on SIB messages received from the respective bases stations105. In some cases, the SIB may indicate whether a base station105supports sidelink relay operation explicitly (e.g., based on explicit bit fields within the SIB) and/or implicitly (e.g., based on identifying an absence of a sidelink relay configuration). Additionally, or alternatively, the relay UE115-aand/or the remote UE115-bmay determine whether base stations105support sidelink relay operation based on PCF signaling received from the core network305.

In some cases, both the relay UE115-aand the remote UE115-bmay control or influence which candidate base stations105it will perform a handover procedure with based on measurement reports. For example, when transmitting measurement reports for candidate base stations, the UEs115-aand/or115-bmay omit measurements for base stations105which do not support sidelink relay operation, may indicate which base stations105do not support sidelink relay operation, may indicate a preference for base stations105which support sidelink relay operation, or any combination thereof. For instance, in cases where the second base station105-bsupports sidelink relay operation (e.g., SL-RelayCapableBS) but the third base station105-cdoes not support sidelink relay operation (e.g., non-SL-RelayCapableBS), the UEs115-aand/or115-bmay be configured to transmit measurements reports to the first base station105-a, where the measurement reports omit measurements for the third base station105-c, indicate that the third base station105-cdoes not support sidelink relay operation, indicate a preference for the second base station105-b, or any combination thereof. In some aspects, UEs115may be configured to tailor measurement reporting (e.g., omit measurements for non-SL-RelayCapableBSs, flag non-SL-RelayCapableBSs) based on RRC signaling.

As noted previously herein, the relay UE115-amay be required to be communicatively coupled to a base station105which supports sidelink relay operation (e.g., SL-RelayCapableBSs) for L2 relays, but may be communicatively coupled to a base station105which does not support sidelink relay operation (e.g., non-SL-RelayCapableBSs) for L3 relays. Moreover, the remote UE115-amay be communicatively coupled to both SL-RelayCapableBSs and non-SL-RelayCapableBSs for both L2 and L3 relays. However, there may be a preference for both the relay UE115-aand the remote UE115-bto be communicatively coupled to base stations105which support sidelink relay in order to promote more widespread use of sidelink relays.

Accordingly, techniques described herein may enable UEs115(e.g., relay UE115-a, remote UE115-b) to determine that they are communicatively coupled to a base station105which does not support sidelink relay operation, and perform a handover procedure to a base station105which does support sidelink relay operation. In some cases, the handover procedures and the determination as to whether candidate base stations105support sidelink relay may be assisted by the network via measurement reporting, as will be described in further detail herein with respect toFIGS.4and5.

In additional or alternative aspects, the relay UE115-aand/or the remote UE115-bmay trigger (e.g., initiate) discovery procedures to connect with a SL-RelayCapableBS in cases where the respective UEs115are connected with a non-SL-RelayCapableBS. For example, in some cases, the first base station105-amay not support sidelink relay operation in a first frequency range. In this example, the remote UE115-bmay be communicatively coupled to the first base station105-avia a communication link310-f, and may communicate with the first base station105-awithin the first frequency range. In this example, in order to connect with a base station105which does support sidelink relay operation, the remote UE115-bmay be configured (e.g., via upper layers) to search for base stations105(e.g., first base station105-a, second base station105-b, third base station105-c) which support sidelink relay operation on a second frequency range which is different from the first frequency range. In this regard, the remote UE115-bmay search inter-frequencies for a base station105which supports sidelink discovery procedures and a sidelink relay configuration within a given frequency range.

Continuing with the same example, in some cases, the remote UE115-bmay identify a frequency range in which a base station105supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the remote UE115-bmay camp on the respective cell with the strongest signal (e.g., strongest reference signal received power (RSRP), strongest reference signal received quality (RSRQ)) of the identified frequency, and may trigger a sidelink discovery procedure in accordance with a sidelink relay configuration associated with the cell. Comparatively, in other cases, the remote UE115-bmay not identify a frequency range which supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the remote UE115-bmay select a frequency range without cellular coverage, and may trigger a discovery procedure for a SL-RelayCapableBS in accordance with a pre-configured sidelink relay configuration. In this regard, the remote UE115-bmay be configured to trigger discovery procedures for L2 and L3 relays by searching inter-frequencies which support sidelink discovery procedures and sidelink relay configuration. Moreover, the relay UE115-amay be configured to perform similar techniques in order to trigger discovery procedures for L3 relays.

Techniques which may be used by UEs115and base stations105to identify whether base stations105support sidelink relay operation and to perform handover procedures based on the capability of base stations105to support sidelink relay operations are discussed in further detail herein with respect toFIGS.4and5.

FIG.4illustrates an example of a process flow400that supports techniques for sidelink relay handover procedure in accordance with aspects of the present disclosure. In some examples, process flow400may implement, or be implemented by, aspects of wireless communications systems100, relay configuration200, wireless communications system300, or any combination thereof. For example, the process flow400may illustrate a relay UE115-ddetermining whether candidate base stations105support sidelink relay operation, and performing a handover procedure with a candidate base station105based on the determination, as described with reference toFIGS.1-3.

In some cases, process flow400may include a remote UE115-c, a relay UE115-d, a first base station105-d, a second base station105-e, and a third base station105-f, which may be examples of corresponding devices as described herein. For example, in some cases, the remote UE115-cand the relay UE115-dillustrated inFIG.4may be examples of the remote UE115-band the relay UE115-a, respectively, as illustrated inFIG.3. Similarly, the first base station105-d, the second base station105-e, and the third base station105-fillustrated inFIG.4may be examples of the first base station105-a, the second base station105-b, and the third base station105-c, respectively, as illustrated inFIG.3.

At405, the relay UE115-dmay receive a SIB message from the first base station105-d. In some aspects, the SIB message may indicate whether or not the first base station105-bsupports sidelink relay operation or not (e.g., determine whether the first base station105-dis SL-RelayCapableBS or non-SL-RelayCapableBS). For example, in some cases, the SIB message may include one or more bit fields which explicitly indicate whether the first base station105-dsupports sidelink relay operation. In this regard, the SIB message may include one or more bit fields which indicate whether the first base station105-dsupports sidelink discovery procedures and sidelink relay within a single carrier.

In additional or alternative aspects, the SIB message may implicitly indicate whether the first base station105-dsupports sidelink relay operation. For example, if the relay UE115-ddetermines that the SIB message provides a sidelink relay configuration for sidelink relay operation, the UE115-dmay determine that the first base station105-dsupports sidelink relay operation. Conversely, if the relay UE115-ddecodes (e.g., demodulates) the SIB message and does not identify a sidelink relay configuration, the relay UE115-dmay determine that the first base station105-ddoes not support sidelink relay operation.

As noted previously herein, for L2 relay, the relay UE115-dmay only be communicatively coupled to base stations105which support sidelink relay operation (e.g., only connect to SL-RelayCapableBSs). In this regard, in the context of L2 relay, the SIB message transmitted by the first base station105-dmay indicate that the first base station105-dsupports sidelink relay operation. Moreover, in the context of handover procedures for L2 relay, both a source base station105and a target base station105for a handover procedure at the relay UE115-dmay include base stations105which support sidelink relay operation.

At410, the relay UE115-dmay receive an RRC message from the first base station105-d. The relay UE115-dmay receive the RRC message at410based on receiving the SIB message at405. In some aspects, the RRC message may indicate a measurement reporting configuration for transmitting measurement reports to the first base station105-d. In this regard, the RRC message may indicate whether the relay UE115-dis to measure and/or report measurements for SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. Additionally, or alternatively, the RRC message may indicate whether measurement reports should indicate (e.g., flag) which base stations105support sidelink relay operation or not, whether the relay UE115-dshould indicate a preference for base stations105which support sidelink relay operation, or any combination thereof.

For example, in some cases, the RRC message may indicate that measurement reports transmitted by the relay UE115-dwhich indicate measurements for candidate base stations105should omit measurements which are associated with base stations105which do not support sidelink relay operation. In other words, the RRC message may indicate that the relay UE115-dshould omit measurements for non-SL-RelayCapableBSs from measurement reports. Additionally, or alternatively, the RRC message may instruct the relay UE115-dto refrain from performing measurements on signals associated with non-SL-RelayCapableBSs.

By way of another example, the RRC message may indicate that measurement reports transmitted by the relay UE115-dshould include indications as to whether base stations105associated with the reported measurements are associated with SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. In this regard, the RRC message may instruct the relay UE115-dto flag measurements as being associated with base stations105which do or do not support sidelink relay operation.

At415, the relay UE115-dmay determine a sidelink relay configuration associated with the first base station105-d. In some aspects, the sidelink relay configuration may provide a set of rules or other configurations for performing discovery procedures at the relay UE115-d, for relaying communications between the first base station105-dand the remote UE115-c, and the like. The relay UE115-dmay determine the sidelink relay configuration based on receiving the SIB message at405, receiving the RRC message at410, or both.

At420, the relay UE115-dmay be configured to communicate with the first base station105-d. Additionally, in some aspects, the relay UE115-dmay be configured to relay (e.g., forward) wireless communications between the first base station105-dand the remote UE115-c. For example, the relay UE115-dmay be configured to relay wireless communications between the first base station105-dand the remote UE115-cvia at least a sidelink communication link between the remote UE115-cand the relay UE115-d, a Uu link between the relay UE115-dand the first base station105-d, or both. In this regard, the remote UE115-cmay communicate with the first base station105-d(e.g., exchange uplink and/or downlink signals) via at least the sidelink communication link between the remote UE115-cand the relay UE115-d.

At425, the relay UE115-dmay perform a discovery procedure. As noted previously herein, for L2 relay, the relay UE115-dmay be configured to connect only to base stations105which support sidelink relay operation. In this regard, the relay UE115-dmay be configured to perform the discovery procedure at425to identify another base station105which supports sidelink relay operation. In some aspects, the relay UE115-dmay perform the discovery procedure at425based on receiving the SIB message at405, receiving the RRC message at410, determining the sidelink relay configuration associated with the first base station105-dat415, or any combination thereof. For example, the relay UE115-dmay perform the discovery procedure based on (e.g., in accordance with) the determined sidelink relay configuration.

At430, the relay UE115-dmay receive a SIB message from at least one candidate base station105. For example, as shown inFIG.4, the relay UE115-dmay receive SIB messages from the second base station105-e, the third base station105-d, or both.

As noted previously herein, the SIB messages received from the candidate base stations may explicitly or implicitly indicate whether or not the respective base stations (e.g., second base station105-e, third base station105-f) support sidelink relay operation. For example, in some cases, a SIB messages received from the second base station105-emay include one or more bit field values which explicitly indicates whether the second base station105-esupports sidelink relay operation or not. By way of another example, a SIB message received from the third base station105-fmay or may not include data indicative of a sidelink relay configuration associated with the third base station105-f, which may serve as an implicit indication as to whether or not the third base station105-fsupports sidelink relay operation.

At435, the first base station105-dmay perform an Xn interface procedure (e.g., exchange Xn signaling) with candidate base stations105in order to determine whether or not the respective candidate base stations105support sidelink relay operation. For example, the first base station105-dmay exchange Xn signaling with the second base station105-eto determine whether or not the second base station105-esupports sidelink relay operation.

At440, the first base station105-dmay transmit a downlink transmission which indicates whether or not the respective candidate base stations105support sidelink relay operation. The first base station105-dmay transmit the indication at440based on performing the Xn procedures at435. For example, by exchanging the Xn signaling at435, the first base station105-dmay determine that the second base station105-edoes support sidelink relay operation, and the third base station105-fdoes not support sidelink relay operation. In this example, the first base station105-dmay transmit, to the relay UE115-d, an indication that the second base station105-edoes support sidelink relay operation, and the third base station105-fdoes not support sidelink relay operation.

At445, the relay UE115-dmay determine whether the candidate base stations105support sidelink relay operation or not (e.g., whether the candidate base stations105are SL-RelayCapableBSs or non-SL-RelayCapableBSs). For example, the relay UE115-dmay determine that the second base station105-esupports sidelink relay operation, and the third base station105-fdoes not support sidelink relay operation. In some aspects, the relay UE115-dmay determine whether the candidate base stations105support sidelink relay operation based on performing the discovery procedure at425, receiving the SIB messages from the candidate base stations105at430, receiving the explicit indications received from the first base station105-dat440, or both.

For example, in cases where the SIB messages received at430include one or more bit field values indicating whether or not the respective base stations105-eand105-fsupport sidelink relay operation, the relay UE115-dmay determine whether the respective base stations105-eand105-fsupport sidelink relay operation based on the one or more bit field values. By way of another example, upon receiving a SIB from the third base station105-f, the relay UE115-dmay be configured to determine that the third base station105-fdoes not support sidelink relay operation based on identifying an absence of data within the received SIB message which indicates that the third base station105-fsupports sidelink relay operation (e.g., implicit determination based on the SIB message).

At450, the relay UE115-dmay transmit one or more measurement reports to the first base station105-d. The measurement reports may indicate measurements (e.g., RSRP, RSRQ, SNR, SINR, channel quality indicator (CQI)) which were performed on signals received from one or more candidate base stations105. In this regard, the measurement report may indicate measurements which the relay UE115-dperformed on signals (e.g., reference signals) received from the second base station105-e, the third base station105-f, or both. Additionally, or alternatively, the measurement reports may indicate whether or not the respective candidate base stations105support sidelink relay operation or not.

In some aspects, the relay UE115-dmay transmit the measurement reports at450based on receiving the SIB message at405, receiving the RRC message at410, determining the sidelink relay configuration associated with the first base station105-dat415, performing the discovery procedure at425, receiving the SIB messages from the candidate base stations105at430, receiving the indications at440, determining whether the candidate base stations105support sidelink relay operation at445, or any combination thereof.

For example, the relay UE115-dmay transmit the measurement reports at450in accordance with a measurement reporting configuration received via the RRC message at410. For example, in some cases, the RRC message may indicate that measurement reports transmitted by the relay UE115-dshould omit measurements which are associated with base stations105which do not support sidelink relay operation. In this example, the relay UE115-fmay omit measurements for the third base station105-ffrom the measurement reports based on determining that the third base station105-fdoes not support sidelink relay operation.

By way of another example, the RRC message may indicate that measurement reports transmitted by the relay UE115-dshould include indications as to whether base stations105associated with the reported measurements are associated with SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. In this example, the measurement report may include measurements for both the second base station105-eand the third base station105-f, and may indicate that the second base station105-esupports sidelink relay operation, the third base station105-fdoes not support sidelink relay operation, or both.

At455, the relay UE115-dmay receive, from the first base station105-d, instructions to perform a handover procedure. The first base station105-dmay transmit the instructions for the handover procedure based on performing the Xn procedures at435, receiving the measurement reports at450, or both.

In some aspects, the instructions may instruct the relay UE115-dto perform a handover procedure from the first base station105-dto a candidate base station105which supports sidelink relay operation. For example, in cases where the measurement report indicates that the second base station105-esupports sidelink relay operation, the instructions received at455may instruct the relay UE115-dto perform a handover procedure from the first base station105-dto the second base station105-e.

At460, the relay UE115-dmay perform the handover procedure from the first base station105-dto the second base station105-f. The relay UE115-dmay perform the handover procedure based on (e.g., in accordance with) the instructions received at455. Additionally, or alternatively, the relay UE115-dmay perform the handover procedure based on receiving the SIB message from the first base station105-dat405, receiving the RRC message at410, determining the sidelink relay configuration associated with the first base station105-dat415, performing the discovery procedure at425, determining whether the candidate base stations105support sidelink relay operation at445, transmitting the measurement reports at450, receiving the instructions at455, or any combination thereof.

At465, the relay UE115-dmay communicate with the second base station105-e. In some aspects, the relay UE115-dmay communicate with the second base station105-ebased on performing the handover procedure at460. In this regard, the relay UE115-dmay exchange uplink and downlink transmissions with the second base station105-evia a Uu link between the relay UE115-dand the second base station105-f.

In some aspects, the relay UE115-dmay be configured to relay communications between the second base station105-dand the remote UE115-c. For example, in cases where the wireless communications system supports group mobility for relay and remote UEs115, the remote UE115-cmay perform the handover procedure along with the relay UE115-d, in which case the relay UE115-dmay relay communications between the respective devices, as noted previously herein. By way of another example, in cases where the wireless communications system does not support group mobility, the remote UE115-cmay perform its own handover or reselection procedure to re-establish a wireless connection with the relay UE115-dafter the relay UE115-dperforms the handover procedure at460. In this example, the relay UE115-dmay be configured to relay communications between the respective remote UE115-cand the second base station105-donce a wireless connection is re-established between the UEs115-cand115-d.

In some cases, as noted previously herein, the relay UE115-dmay be configured to search inter-frequencies and trigger (e.g., initiate) discovery procedures to connect with a SL-RelayCapableBS in cases where the relay UE115-dis connected with a non-SL-RelayCapableBS. For example, in the context of L3 relay, the relay UE115-dmay be communicatively coupled to the third base station105-fIn this example, the relay UE115-dmay communicate with the third base station105-fwithin a first frequency range, where the third base station105-fdoes not support sidelink relay operation within the first frequency range. In order to connect with a base station105which does support sidelink relay operation, the relay UE115-dmay be configured (e.g., via upper layers) to search for base stations105(e.g., first base station105-d, second base station105-e, third base station105-f) which support sidelink relay operation on a different frequency range from the first frequency range. In this regard, the remote UE115-bmay search inter-frequencies for a base station105which supports sidelink discovery procedures and a sidelink relay configuration within a given frequency range.

Continuing with the same example, in some cases, the relay UE115-dmay determine a fourth base station105(not shown) supports sidelink relay operation within a second frequency range which is different from the first frequency range. The relay UE115-dmay determine a sidelink relay configuration associated with the fourth base station105, and may perform a discovery procedure associated with the fourth base station105based on (e.g., in accordance with) the sidelink relay configuration. may identify a frequency range in which a base station105supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the relay UE115-dmay camp on the respective cell of the fourth base station105with the strongest signal (e.g., strongest RSRP, strongest RSRQ) of the second frequency range, and may trigger a sidelink discovery procedure in accordance with a sidelink relay configuration associated with the fourth base station105.

Comparatively, in other cases, the relay UE115-dmay not identify a frequency range which supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the relay UE115-dmay select a frequency range without cellular coverage, and may trigger a discovery procedure for a base station105which supports sidelink relay operation in accordance with a pre-configured sidelink relay configuration (e.g., in accordance with a sidelink relay configuration received via the RRC message at410). In this regard, the relay UE115-dmay be configured to trigger discovery procedures for L3 relays by searching inter-frequencies which support sidelink discovery procedures and sidelink relay configuration.

Techniques described herein may enable improved handover procedures for both remote UEs115and relay UEs115in the context of wireless communications systems. In particular, techniques described herein may enable the relay UE115-dto determine whether base stations105support sidelink relay operation or not, which may enable more informed decisions regarding handover procedures. By enabling the relay UE115-dto determine whether base stations105support sidelink relay operation, techniques described herein may enable the relay UE115-dto perform handover procedures with base stations105which support sidelink relay operation, thereby providing for more widespread use of sidelink relays and reducing power consumption at remote UEs115(e.g., remote UE115-c).

FIG.5illustrates an example of a process flow500that supports techniques for sidelink relay handover procedure in accordance with aspects of the present disclosure. In some examples, process flow500may implement, or be implemented by, aspects of wireless communications systems100, relay configuration200, wireless communications system300, process flow400, or any combination thereof. For example, the process flow400may illustrate a remote UE115-edetermining whether candidate base stations105support sidelink relay operation, and performing a handover procedure with a candidate base station105based on the determination, as described with reference toFIGS.1-3.

In some cases, process flow500may include a remote UE115-e, a relay UE115-f, a first base station105-g, a second base station105-h, and a third base station105-i, which may be examples of corresponding devices as described herein. For example, in some cases, the remote UE115-eand the relay UE115-fillustrated inFIG.5may be examples of the remote UE115-band the relay UE115-a, respectively, as illustrated inFIG.3. Similarly, the first base station105-g, the second base station105-h, and the third base station105-iillustrated inFIG.5may be examples of the first base station105-a, the second base station105-b, and the third base station105-c, respectively, as illustrated inFIG.3.

At505, the remote UE115-emay receive a SIB message from the first base station105-g. In some aspects, the SIB message may indicate whether or not the first base station105-bsupports sidelink relay operation or not (e.g., determine whether the first base station105-gis SL-RelayCapableBS or non-SL-RelayCapableBS). For example, in some cases, the SIB message may include one or more bit fields which explicitly indicate whether the first base station105-gsupports sidelink relay operation. In this regard, the SIB message may include one or more bit fields which indicate whether the first base station105-gsupports sidelink discovery procedures and sidelink relay within a single carrier.

In additional or alternative aspects, the SIB message may implicitly indicate whether the first base station105-gsupports sidelink relay operation. For example, if the remote UE115-edetermines that the SIB message provides a sidelink relay configuration for sidelink relay operation, the remote UE115-emay determine that the first base station105-gsupports sidelink relay operation. Conversely, if the remote UE115-edecodes (e.g., demodulates) the SIB message and does not identify a sidelink relay configuration, the remote UE115-emay determine that the first base station105-gdoes not support sidelink relay operation.

In some aspects, the SIB message transmitted by the first base station105-gmay indicate that the first base station105-gsupports sidelink relay operation. Moreover, as shown inFIG.5, the remote UE115-emay be communicatively coupled to the first base station105-gwith or without the relay UE115-f. In this regard, the remote UE115-emay receive the SIB message directly from the first base station105-g(e.g., via a Uu link between the first base station105-gand the remote UE115-e), via the relay UE115-f(e.g., via at least a sidelink communication link between the remote UE115-eand the relay UE115-f), or both.

At510, the remote UE115-emay receive an RRC message from the first base station105-g. The remote UE115-emay receive the RRC message at510based on receiving the SIB message at505. Moreover, the remote UE115-emay receive the RRC message directly from the first base station105-g(e.g., via a Uu link between the first base station105-gand the remote UE115-e), via the relay UE115-f(e.g., via at least a sidelink communication link between the remote UE115-eand the relay UE115-f), or both.

In some aspects, the RRC message may indicate a measurement reporting configuration for transmitting measurement reports to the first base station105-g. In this regard, the RRC message may indicate whether the remote UE115-eis to measure and/or report measurements for SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. Additionally, or alternatively, the RRC message may indicate whether measurement reports should indicate (e.g., flag) which base stations105support sidelink relay operation or not, whether the remote UE115-eshould indicate a preference for base stations105which support sidelink relay operation, or any combination thereof.

For example, in some cases, the RRC message may indicate that measurement reports transmitted by the remote UE115-ewhich indicate measurements for candidate base stations105should omit measurements which are associated with base stations105which do not support sidelink relay operation. In other words, the RRC message may indicate that the remote UE115-eshould omit measurements for non-SL-RelayCapableBSs from measurement reports. Additionally, or alternatively, the RRC message may instruct the remote UE115-eto refrain from performing measurements on signals associated with non-SL-RelayCapableBSs.

By way of another example, the RRC message may indicate that measurement reports transmitted by the remote UE115-eshould include indications as to whether base stations105associated with the reported measurements are associated with SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. In this regard, the RRC message may instruct the remote UE115-eto flag measurements as being associated with base stations105which do or do not support sidelink relay operation. Furthermore, by way of another example, the RRC message may indicate that measurement reports transmitted by the remote UE115-eshould include measurements for base stations105which are associated with a relay UE115, which are not associated with a relay UE115, or both. For instance, in cases where the remote UE115-eprioritizes sidelink relays, the RRC message may instruct the remote UE115-eto omit measurements associated with base stations105which are not associated with a relay UE115(e.g., omit measurements for base stations105which do not have a relay UE115).

In additional or alternative aspects, the remote UE115-emay receive measurement reporting configurations for transmitting measurement reports via a PCF message received from the first base station105-g, a core network associated with the first base station105-g, or both. For example, the remote UE115-emay receive, from a core network, a PCF message which instructs the remote UE115-eto omit measurements associated with base stations105which do not support sidelink relay operation. In this regard, the remote UE115-emay receive a measurement reporting configuration via the RRC message at510, via PCF messages received via the core network, or both.

At515, the remote UE115-emay determine a sidelink relay configuration associated with the first base station105-g. In some aspects, the sidelink relay configuration may provide a set of rules or other configurations for performing discovery procedures at the remote UE115-e, for communications which are relayed between the first base station105-gand the remote UE115-evia the relay UE115-f, and the like. The remote UE115-emay determine the sidelink relay configuration based on receiving the SIB message at505, receiving the RRC message at510, receiving a PCF message, or any combination thereof.

At520, the remote UE115-emay be configured to communicate with the first base station105-g. In some aspects, the remote UE115-emay be configured to communicate with the first base station105-gvia at the relay UE115-fwhich is configured to relay (e.g., forward) wireless communications between the first base station105-gand the remote UE115-e. For example, the relay UE115-fmay be configured to relay wireless communications between the first base station105-gand the remote UE115-evia at least a sidelink communication link between the remote UE115-eand the relay UE115-f, a Uu link between the relay UE115-fand the first base station105-g, or both. In this regard, the remote UE115-emay communicate with the first base station105-g(e.g., exchange uplink and/or downlink signals) via at least the sidelink communication link between the remote UE115-eand the relay UE115-f.

At525, the remote UE115-emay perform a discovery procedure. The relay UE115-emay be configured to perform the discovery procedure at525to identify another base station105which supports sidelink relay operation. In some aspects, the remote UE115-emay perform the discovery procedure at525based on receiving the SIB message at505, receiving the RRC message at510, determining the sidelink relay configuration associated with the first base station105-gat515, or any combination thereof. For example, the remote UE115-emay perform the discovery procedure based on (e.g., in accordance with) the determined sidelink relay configuration.

At530, the remote UE115-emay transmit a handover request to a base station105which does not support sidelink relay operation. For example, as shown inFIG.5, the remote UE115-emay transmit a handover request to the third base station105-i, where the third base station105-idoes not support sidelink relay operation. The remote UE115-emay transmit the handover request directly to the third base station105-i, via the relay UE115-f, or both. The handover request may include a request for the remote UE115-eto perform a handover procedure from the first base station105-gand/or relay UE115-fto the third base station105-e.

At535, the third base station105-imay transmit a control message to the remote UE115-i. In some aspects, the control message may reject the handover request which was received at530. In particular, the third base station105-imay reject the handover request based on the third base station105-inot supporting sidelink relay operation. In this regard, the third base station105-imay be configured to determine that the remote UE115-eis a remote UE115and/or that the remote UE115-emay prefer to handover to base stations105which support sidelink relay operation (with or without a relay UE115), and may reject the handover request based on the third base station105-inot supporting sidelink relay operation.

At540, the remote UE115-emay receive a SIB message from at least one candidate base station105. For example, as shown inFIG.5, the remote UE115-emay receive SIB messages from the second base station105-h, the third base station105-i, or both. Moreover, the remote UE115-emay be configured to receive the SIB messages via Uu links with the respective base stations105-hand105-i, via the relay UE115-f(e.g., via at least a sidelink communication link between the remote UE115-eand the relay UE115-f), or both.

As noted previously herein, the SIB messages received from the candidate base stations may explicitly or implicitly indicate whether or not the respective base stations (e.g., second base station105-h, third base station105-i) support sidelink relay operation. For example, in some cases, a SIB messages received from the second base station105-hmay include one or more bit field values which explicitly indicates whether the second base station105-hsupports sidelink relay operation or not. By way of another example, a SIB message received from the third base station105-imay or may not include data indicative of a sidelink relay configuration associated with the third base station105-i, which may serve as an implicit indication as to whether or not the third base station105-isupports sidelink relay operation.

At545, the first base station105-gmay perform an Xn interface procedure (e.g., exchange Xn signaling) with candidate base stations105in order to determine whether or not the respective candidate base stations105support sidelink relay operation. For example, the first base station105-gmay exchange Xn signaling with the second base station105-hto determine whether or not the second base station105-hsupports sidelink relay operation.

At550, the first base station105-gmay transmit a downlink transmission which indicates whether or not the respective candidate base stations105support sidelink relay operation. The first base station105-gmay transmit the indication at550based on performing the Xn procedures at545. For example, by exchanging the Xn signaling at545, the first base station105-gmay determine that the second base station105-hdoes support sidelink relay operation, and the third base station105-idoes not support sidelink relay operation. In this example, the first base station105-gmay transmit, to the remote UE115-e, an indication that the second base station105-hdoes support sidelink relay operation, and the third base station105-idoes not support sidelink relay operation. The remote UE115-emay receive the indication at550via a Uu link with the first base stations105-g, via the relay UE115-f(e.g., via at least a sidelink communication link between the remote UE115-eand the relay UE115-f), or both.

At555, the remote UE115-emay determine whether the candidate base stations105support sidelink relay operation or not (e.g., whether the candidate base stations105are SL-RelayCapableBSs or non-SL-RelayCapableBSs). For example, the remote UE115-emay determine that the second base station105-hsupports sidelink relay operation, and the third base station105-idoes not support sidelink relay operation. In some aspects, the remote UE115-emay determine whether the candidate base stations105support sidelink relay operation based on performing the discovery procedure at525, receiving the SIB messages from the candidate base stations105at540, receiving the explicit indications received from the first base station105-gat550, or both.

For example, in cases where the SIB messages received at540include one or more bit field values indicating whether or not the respective base stations105-hand105-isupport sidelink relay operation, the remote UE115-emay determine whether the respective base stations105-hand105-isupport sidelink relay operation based on the one or more bit field values. By way of another example, upon receiving a SIB from the third base station105-i, the remote UE115-emay be configured to determine that the third base station105-idoes not support sidelink relay operation based on identifying an absence of data within the received SIB message which indicates that the third base station105-isupports sidelink relay operation (e.g., implicit determination based on the SIB message).

At560, the remote UE115-emay determine whether the respective candidate base stations105are associated with relay UEs115which are configured to relay wireless communications between the respective candidate base stations105and remote UEs115. In this regard, the remote UE115-emay determine whether the candidate base stations105are communicatively coupled to relay UEs115which could facilitate (e.g., relay, forward) wireless communications between the remote UE115-eand the respective candidate base stations105. In some aspects, the remote UE115-emay determine whether candidate base stations105are associated with relay UEs115based on receiving the SIB message at505, receiving the RRC message at510, determining the sidelink relay configuration associated with the first base station105-gat515, receiving the SIB messages from the candidate base stations105at540, receiving the indications at550, determining whether the candidate base stations105support sidelink relay operation at555, or any combination thereof.

At565, the remote UE115-emay transmit one or more measurement reports to the first base station105-g. The measurement reports may be transmitted to the first base station105-gvia a Uu link with the first base stations105-g, via the relay UE115-f(e.g., via at least a sidelink communication link between the remote UE115-eand the relay UE115-f), or both. The measurement reports may indicate measurements (e.g., RSRP, RSRQ, SNR, SINR, CQI) which were performed on signals received from one or more candidate base stations105. In this regard, the measurement report may indicate measurements which the remote UE115-eperformed on signals (e.g., reference signals) received from the second base station105-h, the third base station105-i, or both. In additional or alternative aspects, the measurement reports may indicate whether or not the respective candidate base stations105support sidelink relay operation or not, indications of priority for performing handover procedures with base stations105which support sidelink relay operation, or any combination thereof.

In some aspects, the remote UE115-emay transmit the measurement reports at565based on receiving the SIB message at505, receiving the RRC message at510, receiving a PCF message from the core network, determining the sidelink relay configuration associated with the first base station105-gat515, performing the discovery procedure at525, receiving the SIB messages from the candidate base stations105at540, receiving the indications at550, determining whether the candidate base stations105support sidelink relay operation at555, determining whether the candidate base stations105are associated with relay UEs115at560, or any combination thereof.

For example, the remote UE115-emay transmit the measurement reports at565in accordance with a measurement reporting configuration received via the RRC message at510and. For instance, in some cases, the RRC message and/or a PCF message may indicate that measurement reports transmitted by the remote UE115-eshould omit measurements which are associated with base stations105which do not support sidelink relay operation. In this example, the remote UE115-emay omit measurements for the third base station105-ifrom the measurement reports based on determining that the third base station105-idoes not support sidelink relay operation.

By way of another example, the RRC message may indicate that measurement reports transmitted by the remote UE115-eshould include indications as to whether base stations105associated with the reported measurements are associated with SL-RelayCapableBSs, non-SL-RelayCapableBSs, or both. In this example, the measurement report may include measurements for both the second base station105-hand the third base station105-i, and may indicate that the second base station105-hsupports sidelink relay operation, the third base station105-idoes not support sidelink relay operation, or both. Furthermore, by way of another example, the RRC message may indicate that the remote UE115-eshould omit measurements for candidate base stations105which do not include a relay UE115. In this example, the remote UE115-emay determine that the second base station105-hincludes a relay UE115but the third base station105-edoes not include a relay UE115. Accordingly, in this example, the measurement report transmitted at565may omit measurements for the third base station105-i.

At570, the remote UE115-emay receive, from the first base station105-g, instructions to perform a handover procedure. The first base station105-gmay transmit the instructions for the handover procedure based on performing the Xn procedures at545, receiving the measurement reports at565, or both.

In some aspects, the instructions may instruct the remote UE115-eto perform a handover procedure from the first base station105-gand/or the relay UE115-fto a candidate base station105which supports sidelink relay operation. For example, in cases where the measurement report indicates that the second base station105-hsupports sidelink relay operation, the instructions received at570may instruct the remote UE115-eto perform a handover procedure from the first base station105-gand/or the relay UE115-fto the second base station105-h.

At575, the remote UE115-emay perform the handover procedure from the first base station105-gto the second base station105-h. The UE115-dmay perform the handover procedure based on (e.g., in accordance with) the instructions received at555. Additionally, or alternatively, the relay UE115-dmay perform the handover procedure based on receiving the SIB message from the first base station105-gat505, receiving the RRC message at510, determining the sidelink relay configuration associated with the first base station105-gat515, performing the discovery procedure at525, receiving the control message at535, determining whether the candidate base stations105support sidelink relay operation at555, determining whether the candidate base stations105are associated with relay UEs115at560, transmitting the measurement reports at565, receiving the instructions at570, or any combination thereof.

At580, the remote UE115-emay communicate with the second base station105-h. In some aspects, the remote UE115-dmay communicate with the second base station105-hbased on performing the handover procedure at575. In this regard, the remote UE115-emay exchange uplink and downlink transmissions with the second base station105-hvia a Uu link between the remote UE115-eand the second base station105-h. Additionally, or alternatively, the remote UE115-emay communicate with the second base station105-hvia a relay UE115which is configured to relay (e.g., forward) wireless communications between the remote UE115-eand the second base station105-h.

In additional or alternative aspects, the remote UE115-emay be configured to initiate a handover procedure in order to establish wireless communications with a different relay UE115(which may be communicatively coupled to the first base station105-gor a different base station105). In this regard, the remote UE115-emay be configured to trigger a relay reselection and/or relay handover procedure to establish wireless communications with a different relay UE115.

Moreover, as noted previously herein, the remote UE115-emay be configured to search inter-frequencies and trigger (e.g., initiate) discovery procedures to connect with a SL-RelayCapableBS in cases where the remote UE115-eis connected with a non-SL-RelayCapableBS. For example, in the context of L2 or L3 relay, the remote UE115-emay be communicatively coupled to the third base station105-i. In this example, the remote UE115-emay communicate with the third base station105-iwithin a first frequency range, where the third base station105-idoes not support sidelink relay operation within the first frequency range. In order to connect with a base station105which does support sidelink relay operation, the remote UE115-emay be configured (e.g., via upper layers) to search for base stations105(e.g., first base station105-g, second base station105-h, third base station105-i) which support sidelink relay operation on a different frequency range from the first frequency range. In this regard, the remote UE115-emay search inter-frequencies for a base station105which supports sidelink discovery procedures and a sidelink relay configuration within a given frequency range.

Continuing with the same example, in some cases, the remote UE115-emay determine a fourth base station105(not shown) supports sidelink relay operation within a second frequency range which is different from the first frequency range. The remote UE115-emay determine a sidelink relay configuration associated with the fourth base station105, and may perform a discovery procedure associated with the fourth base station105based on (e.g., in accordance with) the sidelink relay configuration. may identify a frequency range in which a base station105supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the remote UE115-emay camp on the respective cell of the fourth base station105with the strongest signal (e.g., strongest RSRP, strongest RSRQ) of the second frequency range, and may trigger a sidelink discovery procedure in accordance with a sidelink relay configuration associated with the fourth base station105.

Comparatively, in other cases, the remote UE115-emay not identify a frequency range which supports both sidelink discovery procedures and sidelink relay configuration. In such cases, the remote UE115-emay select a frequency range without cellular coverage, and may trigger a discovery procedure for a base station105which supports sidelink relay operation in accordance with a pre-configured sidelink relay configuration (e.g., in accordance with a sidelink relay configuration received via the RRC message at510). In this regard, the remote UE115-emay be configured to trigger discovery procedures for L2 and/or L3 relays by searching inter-frequencies which support sidelink discovery procedures and sidelink relay configuration.

Techniques described herein may enable improved handover procedures for both remote UEs115and relay UEs115in the context of wireless communications systems. In particular, techniques described herein may enable the remote UE115-eto determine whether base stations105support sidelink relay operation or not, which may enable more informed decisions regarding handover procedures. By enabling the remote UE115-eto determine whether base stations105support sidelink relay operation, techniques described herein may enable the remote UE115-eto perform handover procedures with base stations105which support sidelink relay operation, thereby providing for more widespread use of sidelink relays and reducing power consumption at remote UEs115(e.g., remote UE115-e).

The communications manager620, the receiver610, the transmitter615, or various combinations thereof or various components thereof may be examples of means for performing various aspects of techniques for sidelink relay handover procedure as described herein. For example, the communications manager620, the receiver610, the transmitter615, or various combinations or components thereof may support a method for performing one or more of the functions described herein.

In some examples, the communications manager620may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver610, the transmitter615, or both. For example, the communications manager620may receive information from the receiver610, send information to the transmitter615, or be integrated in combination with the receiver610, the transmitter615, or both to receive information, transmit information, or perform various other operations as described herein.

The communications manager620may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager620may be configured as or otherwise support a means for relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The communications manager620may be configured as or otherwise support a means for transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The communications manager620may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The communications manager620may be configured as or otherwise support a means for performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

Additionally, or alternatively, the communications manager620may support wireless communication at a second UE in accordance with examples as disclosed herein. For example, the communications manager620may be configured as or otherwise support a means for communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE. The communications manager620may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation. The communications manager620may be configured as or otherwise support a means for performing the handover procedure to establish wireless communications with the second base station based on the instructions.

By including or configuring the communications manager620in accordance with examples as described herein, the device605(e.g., a processor controlling or otherwise coupled to the receiver610, the transmitter615, the communications manager620, or a combination thereof) may support techniques for improved handover procedures for both remote UEs115and relay UEs115in the context of wireless communications systems. In particular, techniques described herein may enable UEs115(e.g., relay UEs115, remote UEs115) to determine whether base stations105support sidelink relay operation or not, which may enable more informed decisions regarding handover procedures. By enabling UEs115to determine whether base stations105support sidelink relay operation, techniques described herein may enable UEs115to perform handover procedures with base stations which support sidelink relay operation, thereby providing for more widespread use of sidelink relays and reducing power consumption at remote UEs115.

The device705, or various components thereof, may be an example of means for performing various aspects of techniques for sidelink relay handover procedure as described herein. For example, the communications manager720may include a sidelink relay manager725, a measurement report transmitting manager730, a handover command receiving manager735, a handover procedure manager740, a base station communicating manager745, or any combination thereof. The communications manager720may be an example of aspects of a communications manager620as described herein. In some examples, the communications manager720, or various components thereof, may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver710, the transmitter715, or both. For example, the communications manager720may receive information from the receiver710, send information to the transmitter715, or be integrated in combination with the receiver710, the transmitter715, or both to receive information, transmit information, or perform various other operations as described herein.

The communications manager720may support wireless communication at a first UE in accordance with examples as disclosed herein. The sidelink relay manager725may be configured as or otherwise support a means for relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The measurement report transmitting manager730may be configured as or otherwise support a means for transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The handover command receiving manager735may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The handover procedure manager740may be configured as or otherwise support a means for performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

Additionally, or alternatively, the communications manager720may support wireless communication at a second UE in accordance with examples as disclosed herein. The base station communicating manager745may be configured as or otherwise support a means for communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE. The handover command receiving manager735may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation. The handover procedure manager740may be configured as or otherwise support a means for performing the handover procedure to establish wireless communications with the second base station based on the instructions.

FIG.8shows a block diagram800of a communications manager820that supports techniques for sidelink relay handover procedure in accordance with aspects of the present disclosure. The communications manager820may be an example of aspects of a communications manager620, a communications manager720, or both, as described herein. The communications manager820, or various components thereof, may be an example of means for performing various aspects of techniques for sidelink relay handover procedure as described herein. For example, the communications manager820may include a sidelink relay manager825, a measurement report transmitting manager830, a handover command receiving manager835, a handover procedure manager840, a base station communicating manager845, an SIB message receiving manager850, a discovery procedure manager855, a handover request transmitting manager860, a control message receiving manager865, a reselection procedure manager870, an RRC message receiving manager875, a PCF message receiving manager880, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The communications manager820may support wireless communication at a first UE in accordance with examples as disclosed herein. The sidelink relay manager825may be configured as or otherwise support a means for relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The measurement report transmitting manager830may be configured as or otherwise support a means for transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The handover command receiving manager835may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The handover procedure manager840may be configured as or otherwise support a means for performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving a system information block message from at least one candidate base station of the one or more candidate base stations. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining, based on the system information block message, that the at least one base station supports sidelink relay operation, where the first UE transmits the measurement report based on determining that the at least one candidate base station supports support sidelink relay operation.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving, via the system information block message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, where the determining is based on the one or more bit field values.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining that a third base station does not support sidelink relay operation, where transmitting the measurement report, performing the handover procedure, or both, is based on determining that the third base station does not support sidelink relay operation.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving, from the third base station, a system information block message, where determining that the third base station does not support sidelink relay operation is based on the system information block message.

In some examples, determining that the third base station does not support sidelink relay operation is based on identifying one or more bit fields within the system information block message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the system information block message which indicates that the third base station supports sidelink relay operation, or both.

In some examples, the measurement report omits measurements for the third base station based on the third base station not supporting sidelink relay operation. In some examples, performing the handover procedure with the second base station is based on the measurement report omitting measurements for the third base station.

In some examples, the RRC message receiving manager875may be configured as or otherwise support a means for receiving, from the first base station, a radio resource control message indicating for the first UE to omit measurements associated with base stations which do not support sidelink relay operation, where the first UE omits the measurements for the third base station based on the radio resource control message.

In some examples, to support transmitting the measurement report, the measurement report transmitting manager830may be configured as or otherwise support a means for transmitting measurements for the third base station via the measurement report, where the measurement report includes an indication that the third base station does not support sidelink relay operation, where performing the handover procedure with the second base station is based on the indication that the third base station does not support sidelink relay operation.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for receiving, from the first base station, an indication that the third base station does not support sidelink relay operation, where the determining is based on the indication that the third base station does not support sidelink relay operation.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a sidelink relay configuration associated with the first base station. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure based on the determined sidelink relay configuration, where performing the handover procedure is based on performing the discovery procedure.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving a system information block message from the first base station, where determining the sidelink relay configuration associated with the first base station is based on the system information block message.

In some examples, the one or more candidate base stations support sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

In some examples, the base station communicating manager845may be configured as or otherwise support a means for communicating with the second base station within a first frequency range. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a third base station supports sidelink relay operation within a second frequency range which is different from the first frequency range. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a sidelink relay configuration associated with the third base station based on the third base station supporting sidelink relay operation within the second frequency range. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for receiving sidelink relay configuration. In some examples, the base station communicating manager845may be configured as or otherwise support a means for communicating with the second base station within a first frequency range. In some examples, the base station communicating manager845may be configured as or otherwise support a means for determining an absence of base stations configured to communicate within a second frequency range which is different from the first frequency range. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration.

Additionally, or alternatively, the communications manager820may support wireless communication at a second UE in accordance with examples as disclosed herein. The base station communicating manager845may be configured as or otherwise support a means for communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE. In some examples, the handover command receiving manager835may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation. In some examples, the handover procedure manager840may be configured as or otherwise support a means for performing the handover procedure to establish wireless communications with the second base station based on the instructions.

In some examples, the measurement report transmitting manager830may be configured as or otherwise support a means for transmitting, to the first base station via the first UE, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, where performing the handover procedure is based on transmitting the measurement report.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving a system information block message from at least one candidate base station of the one or more candidate base stations. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining, based on the system information block message, that the at least one base station supports sidelink relay operation, where the second UE transmits the measurement report based on determining that the at least one candidate base station supports support sidelink relay operation.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving, via the system information block message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, where the determining is based on the one or more bit field values.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining that a third base station does not support sidelink relay operation, where transmitting the measurement report, performing the handover procedure, or both, is based on determining that the third base station does not support sidelink relay operation.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving, from the third base station, a system information block message, where determining that the third base station does not support sidelink relay operation is based on the system information block message.

In some examples, determining that the third base station does not support sidelink relay operation is based on identifying one or more bit fields within the system information block message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the system information block message which indicates that the third base station supports sidelink relay operation, or both.

In some examples, the measurement report omits measurements for the third base station based on the third base station not supporting sidelink relay operation. In some examples, performing the handover procedure with the second base station is based on the measurement report omitting measurements for the third base station.

In some examples, the RRC message receiving manager875may be configured as or otherwise support a means for receiving, from the first base station via the first UE, a radio resource control message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, where the second UE omits the measurements for the third base station based on the radio resource control message.

In some examples, the PCF message receiving manager880may be configured as or otherwise support a means for receiving a policy control function message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, where the second UE omits the measurements for the third base station based on the policy control function message.

In some examples, to support transmitting the measurement report, the measurement report transmitting manager830may be configured as or otherwise support a means for transmitting measurements for the third base station via the measurement report, where the measurement report includes an indication that the third base station does not support sidelink relay operation, where performing the handover procedure with the second base station is based on the indication that the third base station does not support sidelink relay operation.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for receiving, from the first base station via the first UE, an indication that the third base station does not support sidelink relay operation, where the determining is based on the indication that the third base station does not support sidelink relay operation.

In some examples, the base station communicating manager845may be configured as or otherwise support a means for determining that a third base station is not associated with UEs which are configured to relay wireless communions between the third base station and one or more additional UEs. In some examples, the measurement report transmitting manager830may be configured as or otherwise support a means for transmitting the measurement report where the measurement report omits measurements for the third base station based on determining that the third base station is not associated with UEs which are configured to relay wireless communions between the third base station and the one or more additional UEs.

In some examples, the measurement report transmitting manager830may be configured as or otherwise support a means for transmitting, via the measurement report, an indication of a priority associated with base stations which support sidelink relay operation, where performing the handover procedure is based on the priority.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a sidelink relay configuration associated with the first base station. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure based on the determined sidelink relay configuration, where performing the handover procedure is based on performing the discovery procedure.

In some examples, the SIB message receiving manager850may be configured as or otherwise support a means for receiving a system information block message from the first base station, where determining the sidelink relay configuration associated with the first base station is based on the system information block message.

In some examples, the handover request transmitting manager860may be configured as or otherwise support a means for transmitting, to a third base station, a handover request for a second handover procedure from the first base station to the third base station, where the third base station does not support sidelink relay operation. In some examples, the control message receiving manager865may be configured as or otherwise support a means for receiving, from the third base station, a control message rejecting the handover request, where performing the handover procedure from the first base station to the second base station is based on receiving the control message.

In some examples, the reselection procedure manager870may be configured as or otherwise support a means for performing a relay UE reselection procedure from the first UE to a third UE. In some examples, the base station communicating manager845may be configured as or otherwise support a means for communicating with the first base station via the third UE based on performing the relay UE reselection procedure, where the third UE is configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link between the first UE and the third UE.

In some examples, the second base station supports sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

In some examples, the base station communicating manager845may be configured as or otherwise support a means for communicating with the second base station within a first frequency range. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a third base station supports sidelink relay operation within a second frequency range which is different from the first frequency range. In some examples, the sidelink relay manager825may be configured as or otherwise support a means for determining a sidelink relay configuration associated with the third base station based on the third base station supporting sidelink relay operation within the second frequency range. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

In some examples, the sidelink relay manager825may be configured as or otherwise support a means for receiving sidelink relay configuration. In some examples, the base station communicating manager845may be configured as or otherwise support a means for communicating with the second base station within a first frequency range. In some examples, the base station communicating manager845may be configured as or otherwise support a means for determining an absence of base stations configured to communicate within a second frequency range which is different from the first frequency range. In some examples, the discovery procedure manager855may be configured as or otherwise support a means for performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration.

The communications manager920may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager920may be configured as or otherwise support a means for relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The communications manager920may be configured as or otherwise support a means for transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The communications manager920may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The communications manager920may be configured as or otherwise support a means for performing the handover procedure including establishing a wireless connection with the second base station based on the instructions.

Additionally, or alternatively, the communications manager920may support wireless communication at a second UE in accordance with examples as disclosed herein. For example, the communications manager920may be configured as or otherwise support a means for communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE. The communications manager920may be configured as or otherwise support a means for receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation. The communications manager920may be configured as or otherwise support a means for performing the handover procedure to establish wireless communications with the second base station based on the instructions.

By including or configuring the communications manager920in accordance with examples as described herein, the device905may support techniques for improved handover procedures for both remote UEs115and relay UEs115in the context of wireless communications systems. In particular, techniques described herein may enable UEs115(e.g., relay UEs115, remote UEs115) to determine whether base stations105support sidelink relay operation or not, which may enable more informed decisions regarding handover procedures. By enabling UEs115to determine whether base stations105support sidelink relay operation, techniques described herein may enable UEs115to perform handover procedures with base stations which support sidelink relay operation, thereby providing for more widespread use of sidelink relays and reducing power consumption at remote UEs115.

At1005, the method may include relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The operations of1005may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1005may be performed by a sidelink relay manager825as described with reference toFIG.8.

At1010, the method may include transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation. The operations of1010may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1010may be performed by a measurement report transmitting manager830as described with reference toFIG.8.

At1015, the method may include receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The operations of1015may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1015may be performed by a handover command receiving manager835as described with reference toFIG.8.

At1020, the method may include performing the handover procedure including establishing a wireless connection with the second base station based on the instructions. The operations of1020may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1020may be performed by a handover procedure manager840as described with reference toFIG.8.

At1105, the method may include relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE. The operations of1105may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1105may be performed by a sidelink relay manager825as described with reference toFIG.8.

At1110, the method may include receiving a system information block message from at least one candidate base station of the one or more candidate base stations. The operations of1110may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1110may be performed by an SIB message receiving manager850as described with reference toFIG.8.

At1115, the method may include determining, based on the system information block message, that the at least one candidate base station supports sidelink relay operation. The operations of1115may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1115may be performed by a sidelink relay manager825as described with reference toFIG.8.

At1120, the method may include transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, where the first UE transmits the measurement report based on determining that the at least one candidate base station supports support sidelink relay operation. The operations of1120may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1120may be performed by a measurement report transmitting manager830as described with reference toFIG.8.

At1125, the method may include receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based on the measurement report, where the second base station supports sidelink relay operation. The operations of1125may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1125may be performed by a handover command receiving manager835as described with reference toFIG.8.

At1130, the method may include performing the handover procedure including establishing a wireless connection with the second base station based on the instructions. The operations of1130may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1130may be performed by a handover procedure manager840as described with reference toFIG.8.

At1205, the method may include communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE. The operations of1205may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1205may be performed by a base station communicating manager845as described with reference toFIG.8.

At1210, the method may include receiving instructions to perform a handover procedure from the first base station to a second base station based on the second base station supporting sidelink relay operation. The operations of1210may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1210may be performed by a handover command receiving manager835as described with reference toFIG.8.

At1215, the method may include performing the handover procedure to establish wireless communications with the second base station based on the instructions. The operations of1215may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1215may be performed by a handover procedure manager840as described with reference toFIG.8.

Aspect 1: A method for wireless communication at a first UE, comprising: relaying wireless communications between a first base station and a second UE via at least a sidelink communication link with the second UE; transmitting, to the first base station, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation; receiving instructions to perform a handover procedure from the first base station to a second base station of the one or more candidate base stations based at least in part on the measurement report, wherein the second base station supports sidelink relay operation; and performing the handover procedure including establishing a wireless connection with the second base station based at least in part on the instructions.

Aspect 2: The method of aspect 1, further comprising: receiving a SIB message from at least one candidate base station of the one or more candidate base stations; and determining, based at least in part on the SIB message, that the at least one candidate base station supports sidelink relay operation, wherein the first UE transmits the measurement report based at least in part on determining that the at least one candidate base station supports support sidelink relay operation.

Aspect 3: The method of aspect 2, further comprising: receiving, via the SIB message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, wherein the determining is based at least in part on the one or more bit field values.

Aspect 4: The method of any of aspects 1 through 3, further comprising: determining that a third base station does not support sidelink relay operation, wherein transmitting the measurement report, performing the handover procedure, or both, is based at least in part on determining that the third base station does not support sidelink relay operation.

Aspect 5: The method of aspect 4, further comprising: receiving, from the third base station, a SIB message, wherein determining that the third base station does not support sidelink relay operation is based at least in part on the SIB message.

Aspect 6: The method of aspect 5, wherein determining that the third base station does not support sidelink relay operation is based at least in part on identifying one or more bit fields within the SIB message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the SIB message which indicates that the third base station supports sidelink relay operation, or both.

Aspect 7: The method of any of aspects 4 through 6, wherein the measurement report omits measurements for the third base station based at least in part on the third base station not supporting sidelink relay operation, performing the handover procedure with the second base station is based at least in part on the measurement report omitting measurements for the third base station.

Aspect 8: The method of aspect 7, further comprising: receiving, from the first base station, an RRC message indicating for the first UE to omit measurements associated with base stations which do not support sidelink relay operation, wherein the first UE omits the measurements for the third base station based at least in part on the RRC message.

Aspect 9: The method of any of aspects 4 through 8, wherein transmitting the measurement report comprises: transmitting measurements for the third base station via the measurement report, wherein the measurement report comprises an indication that the third base station does not support sidelink relay operation, wherein performing the handover procedure with the second base station is based at least in part on the indication that the third base station does not support sidelink relay operation.

Aspect 10: The method of any of aspects 4 through 9, further comprising: receiving, from the first base station, an indication that the third base station does not support sidelink relay operation, wherein the determining is based at least in part on the indication that the third base station does not support sidelink relay operation.

Aspect 11: The method of any of aspects 1 through 10, further comprising: determining a sidelink relay configuration associated with the first base station; and performing a discovery procedure based at least in part on the determined sidelink relay configuration, wherein performing the handover procedure is based at least in part on performing the discovery procedure.

Aspect 12: The method of aspect 11, further comprising: receiving a SIB message from the first base station, wherein determining the sidelink relay configuration associated with the first base station is based at least in part on the SIB message.

Aspect 13: The method of any of aspects 1 through 12, wherein the one or more candidate base stations support sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

Aspect 14: The method of any of aspects 1 through 13, further comprising: communicating with the second base station within a first frequency range; determining a third base station supports sidelink relay operation within a second frequency range which is different from the first frequency range; determining a sidelink relay configuration associated with the third base station based at least in part on the third base station supporting sidelink relay operation within the second frequency range; and performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

Aspect 15: The method of any of aspects 1 through 14, further comprising: receiving sidelink relay configuration; communicating with the second base station within a first frequency range; determining an absence of base stations configured to communicate within a second frequency range which is different from the first frequency range; and performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration

Aspect 16: A method for wireless communication at a second UE, comprising: communicating with a first base station via a first UE configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link with the first UE; receiving instructions to perform a handover procedure from the first base station to a second base station based at least in part on the second base station supporting sidelink relay operation; and performing the handover procedure to establish wireless communications with the second base station based at least in part on the instructions.

Aspect 17: The method of aspect 16, further comprising: transmitting, to the first base station via the first UE, a measurement report for one or more candidate base stations, the measurement report indicating that the one or more candidate base stations support sidelink relay operation, wherein performing the handover procedure is based at least in part on transmitting the measurement report.

Aspect 18: The method of aspect 17, further comprising: receiving a SIB message from at least one candidate base station of the one or more candidate base stations; and determining, based at least in part on the SIB message, that the at least one base station supports sidelink relay operation, wherein the second UE transmits the measurement report based at least in part on determining that the at least one candidate base station supports support sidelink relay operation.

Aspect 19: The method of aspect 18, further comprising: receiving, via the SIB message, one or more bit field values indicating that the at least one candidate base station supports sidelink relay operation, wherein the determining is based at least in part on the one or more bit field values.

Aspect 20: The method of any of aspects 17 through 19, further comprising: determining that a third base station does not support sidelink relay operation, wherein transmitting the measurement report, performing the handover procedure, or both, is based at least in part on determining that the third base station does not support sidelink relay operation.

Aspect 21: The method of aspect 20, further comprising: receiving, from the third base station, a SIB message, wherein determining that the third base station does not support sidelink relay operation is based at least in part on the SIB message.

Aspect 22: The method of aspect 21, wherein determining that the third base station does not support sidelink relay operation is based at least in part on identifying one or more bit fields within the SIB message indicating that the third base station does not support sidelink relay operation, identifying an absence of data within the SIB message which indicates that the third base station supports sidelink relay operation, or both.

Aspect 23: The method of any of aspects 20 through 22, wherein the measurement report omits measurements for the third base station based at least in part on the third base station not supporting sidelink relay operation, performing the handover procedure with the second base station is based at least in part on the measurement report omitting measurements for the third base station.

Aspect 24: The method of aspect 23, further comprising: receiving, from the first base station via the first UE, an RRC message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, wherein the second UE omits the measurements for the third base station based at least in part on the RRC message.

Aspect 25: The method of any of aspects 23 through 24, further comprising: receiving a policy control function message indicating for the second UE to omit measurements associated with base stations which do not support sidelink relay operation, wherein the second UE omits the measurements for the third base station based at least in part on the policy control function message.

Aspect 26: The method of any of aspects 20 through 25, wherein transmitting the measurement report comprises: transmitting measurements for the third base station via the measurement report, wherein the measurement report comprises an indication that the third base station does not support sidelink relay operation, wherein performing the handover procedure with the second base station is based at least in part on the indication that the third base station does not support sidelink relay operation.

Aspect 27: The method of any of aspects 20 through 26, further comprising: receiving, from the first base station via the first UE, an indication that the third base station does not support sidelink relay operation, wherein the determining is based at least in part on the indication that the third base station does not support sidelink relay operation.

Aspect 28: The method of any of aspects 17 through 27, further comprising: determining that a third base station is not associated with UEs which are configured to relay wireless communions between the third base station and one or more additional UEs; and transmitting the measurement report where the measurement report omits measurements for the third base station based at least in part on determining that the third base station is not associated with UEs which are configured to relay wireless communions between the third base station and the one or more additional UEs.

Aspect 29: The method of any of aspects 17 through 28, further comprising: transmitting, via the measurement report, an indication of a priority associated with base stations which support sidelink relay operation, wherein performing the handover procedure is based at least in part on the priority.

Aspect 30: The method of any of aspects 16 through 29, further comprising: determining a sidelink relay configuration associated with the first base station; and performing a discovery procedure based at least in part on the determined sidelink relay configuration, wherein performing the handover procedure is based at least in part on performing the discovery procedure.

Aspect 31: The method of aspect 30, further comprising: receiving a SIB message from the first base station, wherein determining the sidelink relay configuration associated with the first base station is based at least in part on the SIB message.

Aspect 32: The method of any of aspects 16 through 31, further comprising: transmitting, to a third base station, a handover request for a second handover procedure from the first base station to the third base station, wherein the third base station does not support sidelink relay operation; and receiving, from the third base station, a control message rejecting the handover request, wherein performing the handover procedure from the first base station to the second base station is based at least in part on receiving the control message.

Aspect 33: The method of any of aspects 16 through 32, further comprising: performing a relay UE reselection procedure from the first UE to a third UE; and communicating with the first base station via the third UE based at least in part on performing the relay UE reselection procedure, wherein the third UE is configured to relay wireless communications between the second UE and the first base station via at least a sidelink communication link between the first UE and the third UE.

Aspect 34: The method of any of aspects 16 through 33, wherein the second base station supports sidelink relay operation by supporting sidelink relay discovery procedures, sidelink relay transmissions, or both.

Aspect 35: The method of any of aspects 16 through 34, further comprising: communicating with the second base station within a first frequency range; determining a third base station supports sidelink relay operation within a second frequency range which is different from the first frequency range; determining a sidelink relay configuration associated with the third base station based at least in part on the third base station supporting sidelink relay operation within the second frequency range; and performing a discovery procedure associated with the third base station in accordance with the sidelink relay configuration.

Aspect 36: The method of any of aspects 16 through 35, further comprising: receiving sidelink relay configuration; communicating with the second base station within a first frequency range; determining an absence of base stations configured to communicate within a second frequency range which is different from the first frequency range; and performing a discovery procedure within the second frequency range and in accordance with the sidelink relay configuration.

Aspect 41: An apparatus for wireless communication at a second UE, comprising at least one means for performing a method of any of aspects 16 through 36.