Mobility handling for multi-hop relay connections

Abstract

Methods, systems, and devices for wireless communication are described. The described technology provides a mobility handling mechanism for supporting management of multi-hop relay connections. In some cases, a first wireless device of a multi-hop relay connection may perform relay reselection in response to a trigger being satisfied. For example, a first wireless device may perform relay reselection based on identifying better link quality, reducing the opportunity of hop count in a multi-hop relay connection, an occurrence of radio link failure (RLF) between two devices of a multi-hop relay connection, or any combination thereof. In some cases, a first wireless device may select a new wireless device for a multi-hop relay connection, establish connectivity with the new wireless device, and may terminate a link with a particular wireless device of the multi-hop relay connection. The first wireless device may relay communications via the newly established connection.

Description

TECHNICAL FIELD

[0001] The following relates to wireless communications, including mobility handling for multi-hop relay connections. BACKGROUND

[0002] Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems can be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple- access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which can be referred to as New Radio (NR) systems. These systems can employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system can include one or more base stations, each simultaneously supporting communication with multiple communication devices, which can be otherwise known as user equipment (UE).

[0003] In some cases, a UE can relay communications between a source device and a destination device. For example, a UE can receive a message from a source device intended for a destination device, and can forward the message to the destination device. SUMMARY

[0004] The described techniques relate to improved methods, systems, devices, and apparatuses that support mobility handling for multi-hop relay connections. For example, the described techniques provide mobility handling mechanisms for supporting management of multi-hop relay wireless connections. In some cases, a first wireless device relaying communications via a multi-hop relay connection established between a source device and a destination device can perform relay reselection to replace a particular wireless device in the multi-hop relay connection with a new wireless device in response to a trigger being satisfied. For example, the first wireless device can perform relay reselection to replace the particular wireless device with the new wireless device based on identifying a better sidelink (e.g., PC5 link) link quality between the first wireless device and the new wireless device, an opportunity to reduce a number of hops in the multi-hop relay connection between the source device and the destination device, a radio link failure (RLF) occurring between two devices of the multi-hop relay connection, or any combination thereof. In some cases, after identifying the trigger, the first wireless device can select the new wireless device, establish connectivity with the new wireless device, and can terminate the link with the particular wireless device, whereby communications of the multi-hop relay connection can traverse between the source device and the destination device via the new wireless device instead of via the particular wireless device.

[0005] A method for wireless communication by a first wireless device is described. The method can include transmitting or receiving a link setup message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link is to replace a second wireless link of the multi-hop wireless connection, transmitting or receiving a link release message via the second wireless link and based on establishing the first wireless link to terminate a second wireless link of the multi-hop wireless connection between the first wireless device and a third wireless device, and relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0006] A first wireless device for wireless communication is described. The first wireless device can include one or more memories storing processor-executable code and one or more processors coupled with the one or more memories. The one or more processors are individually or collectively configured to execute the code to cause the first wireless device to transmit or receive a link setup message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link is to replace a second wireless link of the multi-hop wireless connection, transmit or receive a link release message via the second wireless link and based on establishing the first wireless link to terminate a second wireless link of the multi-hop wireless connection between the first wireless device and a third wireless device, and relay one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0007] Another first wireless device for wireless communication is described. The first wireless device can include means for transmitting or receiving a link setup message, based on a trigger to perform a relay reselection procedure and a selection of a second wireless device as part of the relay reselection procedure, to establish a first wireless link between the first wireless device and the second wireless device, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection; means for transmitting or receiving a link release message, via the second wireless link and based on establishing the first wireless link, to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection; and means for relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0008] A non-transitory computer-readable medium storing code for wireless communication is described. The code can include instructions executable by a processor to transmit or receive a link setup message, based on a trigger to perform a relay reselection procedure and a selection of a second wireless device as part of the relay reselection procedure, to establish a first wireless link between the first wireless device and the second wireless device, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection; transmit or receive a link release message, via the second wireless link and based on establishing the first wireless link, to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection; and relay one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0009] Some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein can further include operations, features, means, or instructions for discovering at least the second wireless device based on the trigger, where transmitting or receiving the link setup message can be based on discovering at least the second wireless device.

[0010] In some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein, the trigger can be based on a quality of the second wireless link, a radio link failure associated with at least one wireless link of the multi-hop wireless connection, a number of the group of multiple wireless devices, or any combination thereof.

[0011] In some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein, the link setup message can be transmitted based on a trigger corresponding to an expiration of a timer.

[0012] Some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein can further include operations, features, means, or instructions for transmitting, to the source wireless device, an indication of a trigger to perform a relay reselection procedure.

[0013] Some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein can further include operations, features, means, or instructions for receiving, from a third wireless device, an indication that a third wireless link between the third wireless device and a fourth wireless device can have experienced radio link failure, where the link establishment message can be transmitted based on the indication.

[0014] Some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein can further include operations, features, means, or instructions for transmitting, to the source wireless device via a fourth wireless link between the first wireless device and the source wireless device, the indication; receiving, via the fourth wireless link and based on transmitting the indication, a second link release message to terminate the fourth wireless link; and receiving, from the source wireless device, a second link establishment message to reestablish the fourth wireless link.

[0015] Some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein can further include operations, features, means, or instructions for transmitting or receiving an indication that a third wireless link between the fourth wireless device and a destination wireless device can have been terminated and a fourth wireless link between a fifth wireless device and the destination wireless device can have been established; and transmitting, to the source wireless device via the multi-hop wireless connection, the indication.

[0016] In some examples of the method, the first wireless device, and the non-transitory computer-readable medium described herein, the destination wireless device can be a second user equipment (UE); or the destination wireless device can be a network entity. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 An example of a wireless communications system that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure.

[0018] Figure 2A And Figure 2B An example of a wireless communications system that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure.

[0019] Figure 3 An example of a wireless communications system that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure.

[0020] Figure 4A and Figure 4B An example of a process flow that supports mobility handling for multi-hop relay connections is shown.

[0021] Figure 5 An example of a process flow that supports mobility handling for multi-hop relay connections is shown.

[0022] Figure 6 An example of a process flow that supports mobility handling for multi-hop relay connections is shown.

[0023] Figure 7 An example of a process flow that supports mobility handling for multi-hop relay connections is shown.

[0024] Figure 8 and Figure 9 A block diagram of a device that supports mobility handling for multi-hop relay connections is shown.

[0025] Figure 10 A block diagram of a communications manager that supports mobility handling for multi-hop relay connections is shown.

[0026] Figure 11 A diagram illustrating a system including a device that supports mobility handling for multi-hop relay connections is shown.

[0027] Figure 12 A flow diagram illustrating a method that supports mobility handling for multi-hop relay connections is shown. DETAILED DESCRIPTION

[0028] In some wireless communications systems, communications between two wireless devices can be facilitated via one or more relay wireless devices. For example, a user equipment (UE) can relay communications between a source device and a destination device, which can improve a range of the communications (e.g., if the source device and the destination device are not within coverage of each other). Such techniques can support relaying communications between a source UE and a destination UE (e.g., UE-to-UE (U2U) relaying), relaying communications between a remote UE and a network entity (e.g., UE-to-Network (U2N) relaying), or both. In some cases, a single intervening wireless device can relay communications between a source device and a destination device, which can be an example of a single-hop relay connection (e.g., a wireless device receives a signal from the source device and directly forwards the signal to the destination device). Additionally, or alternatively, multiple wireless devices can relay communications between a source device and a destination device, which can be an example of a multi-hop relay connection (e.g., multiple wireless devices relay a signal from the source device to the destination device via respective sidelink links). However, techniques for relay mobility management (e.g., adjusting a relay path, handling radio link failure (RLF) between relay devices) in a single-hop relay connection can not scale to multi-hop relay connections, limiting flexibility of multi-hop relay connections.

[0029] According to examples disclosed herein, a wireless device of a U2U or U2N multi-hop relay can implement one or more mobility handling mechanisms to support management of a multi-hop relay connection. In some cases, a first wireless device relaying communications via a multi-hop relay connection established between a source device and a destination device can perform relay reselection to replace a particular wireless device in the multi-hop relay connection with a new wireless device in response to a trigger being satisfied. For example, the first wireless device can perform relay reselection based on identifying a better sidelink (e.g., PC5) link quality between the first wireless device and the new wireless device (e.g., as compared to a currently established PC5 link), an opportunity to reduce a number of hops in the multi-hop relay connection between the source device and the destination device, an RLF occurring between two devices of the multi-hop relay connection, or any combination thereof. In some cases, after identifying the trigger, the first wireless device can select the new wireless device, establish connectivity with the new wireless device, and can terminate a link with the particular wireless device (e.g., a wireless device being replaced in the multi-hop relay connection by the new wireless device). Such techniques can improve communications via a multi-hop relay connection by enabling dynamic reselection of wireless devices for a multi-hop relay connection to avoid poor link quality, reduce a large number of hops, recover from an RLF, or any combination thereof.

[0030] Aspects of the disclosure are first described in the context of wireless communications systems. Aspects of the disclosure are further illustrated by and described in connection with process flows, which are schematically illustrated in diagrammatic form in the drawings. Aspects of the disclosure are further illustrated by and described in connection with apparatus diagrams, system diagrams, and flowcharts related to mobility handling for multi-hop relay connections.

[0031] Figure 1 An example of a wireless communications system 100 that supports mobility handling for multi-hop relay connections is shown in accordance with one or more aspects of the present disclosure. The wireless communications system 100 can include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 can be a Long Term Evolution (LTE) network, a LTE-Advanced (LTE-A) network, a LTE-A Pro network, a New Radio (NR) network, or a network operating according to some other wireless communications technology including future iterations of the aforementioned systems and radio technologies, including future systems and radio technologies not expressly mentioned herein.

[0032] The network entities 105 can be dispersed throughout the geographic area of the wireless communications system 100, and can each include devices that can be of different form factors and have different capabilities. In various examples, a network entity 105 can be referred to as a network element, a mobility element, a radio access network (RAN) node, or network equipment, among other examples. In some examples, the network entities 105 and the UEs 115 can wirelessly communicate with one another via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, a network entity 105 can support a coverage area 110 (e.g., a geographic coverage area) within which UEs 115 and network entities 105 can establish one or more communication links 125. The coverage area 110 can be an example of a geographic area over which network entities 105 and UEs 115 can support communication in accordance with one or more radio access technologies (RATs).

[0033] The UEs 115 can be dispersed throughout the coverage areas 110 of the wireless communications system 100, and each UE 115 can be stationary or mobile, or both at different times. The UEs 115 can be devices in different forms or having different capabilities. Figure 1 Some example UEs 115 are illustrated. The UEs 115 described herein can be able to communicate with various types of devices, such as other UEs 115 or network entities 105 as shown. Figure 1

[0034] ​As described herein, nodes of the wireless communication system 100 (which may be referred to as network nodes or wireless nodes) may be network entity 105 (e.g., any network entity described herein), UE 115 (e.g., any UE described herein), network controller, apparatus, device, computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, a node may be UE 115. Alternatively, a node may be network entity 105. Alternatively, a first node may be configured to communicate with a second or third node. In one aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be UE 115. In another aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different from these examples. Similarly, references to UE 115, network entity 105, device, equipment, computing system, etc., may include disclosures of UE 115, network entity 105, device, equipment, computing system, etc., as nodes. For example, a disclosure that UE 115 is configured to receive information from network entity 105 also discloses that a first node is configured to receive information from a second node.

[0035] In some examples, network entity 105 may communicate with core network 130, communicate with each other, or both. For example, network entity 105 may communicate with core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, network entities 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entities 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. Backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be or include one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof. UE 115 can communicate with core network 130 via communication link 155.

[0036] One or more of the network entities 105 described herein can include or can be referred to as a base station 140 (e.g., a base transceiver station, a radio base station, a NR base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB, or a giga-NodeB (either of which can be referred to as a gNB), a 5G NB, a next-generation eNB (ng-eNB), a Home NodeB, a Home eNodeB, or other suitable terminology). In some examples, the network entity 105 (e.g., base station 140) can be implemented in an aggregated (e.g., monolithic, standalone) base station architecture that can be configured to utilize a protocol stack integrated physically or logically within a single network entity 105 (e.g., a single RAN node such as a base station 140).

[0037] In some examples, the network entity 105 can be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture) that can be configured to utilize a protocol stack distributed physically or logically between two or more network entities 105 such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, the network entity 105 can include one or more of a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near-real-time RIC (near-RT RIC), a non-real-time RIC (non-RT RIC)), a service management and orchestration (SMO) 180 system, or any combination thereof. The RU 170 can also be referred to as a radio head, an intelligent radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmission reception point (TRP). One or more components of the network entity 105 in the disaggregated RAN architecture can be co-located, or one or more components of the network entity 105 can be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of the disaggregated RAN architecture can be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)).

[0038] The functional split between the CU 160, the DU 165, and the RU 170 is flexible and can support different functionality depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at the CU 160, the DU 165, or the RU 170. For example, a functional split of a protocol stack can be employed between the CU 160 and the DU 165, such that the CU 160 can support one or more layers of the protocol stack, and the DU 165 can support one or more different layers of the protocol stack. In some examples, the CU 160 can host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functionality and signaling (e.g., radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP)). The CU 160 can connect to one or more DUs 165 or RUs 170, and the one or more DUs 165 or RUs 170 can host lower protocol layers, such as layer 1 (LI) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and can each be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of a protocol stack can be employed between the DU 165 and the RU 170, such that the DU 165 can support one or more layers of the protocol stack, and the RU 170 can support one or more different layers of the protocol stack. The DU 165 can support one or more different cells (e.g., via one or more RUs 170). In some cases, the functional split between the CU 160 and the DU 165 or between the DU 165 and the RU 170 can be within a protocol layer (e.g., some functions of a protocol layer can be performed by one of the CU 160, the DU 165, or the RU 170, while other functions of that protocol layer are performed by a different one of the CU 160, the DU 165, or the RU 170). The CU 160 can be further split in functionality into a CU control plane (CU-CP) function and a CU user plane (CU-UP) function. The CU 160 can connect to one or more DUs 165 via a backhaul communication link 162 (e.g., Fl, Fl-c, Fl-u), and the DU 165 can connect to one or more RUs 170 via a front-haul communication link 168 (e.g., open front-haul (FH) interface). In some examples, the backhaul communication link 162 or the front-haul communication link 168 can be implemented in accordance with an interface (e.g., channel) between layers of a protocol stack supported by the respective network entities 105 that communicate via such communication links.

[0039] In a wireless communication system (e.g., wireless communication system 100), infrastructure and spectrum resources for radio access can support wireless backhaul link capabilities to supplement wired backhaul connections to provide an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB nodes 104) can be partially controlled by one another. One or more IAB nodes 104 can be referred to as a donor entity or IAB donor. One or more DUs 165 or one or more RUs 170 can be partially controlled by one or more CUs 160 associated with a donor network entity 105 (e.g., a donor base station 140). One or more donor network entities 105 (e.g., IAB donors) can communicate with one or more additional network entities 105 (e.g., IAB nodes 104) via supported access and backhaul links (e.g., backhaul communication links 120). An IAB node 104 can include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a coupled DU 165 of an IAB donor. The IAB-MT can include a separate set of antennas for relaying communications with UEs 115 or can share the same antennas (e.g., of a RU 170) of the IAB node 104 for accessing via the DU 165 of the IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, an IAB node 104 can include a DU 165 that supports a communication link with an additional entity (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of an access network. In such cases, one or more components of the disaggregated RAN architecture (e.g., one or more IAB nodes 104 or components of an IAB node 104) can be configured to operate according to the techniques described herein.

[0040] In cases where the techniques described herein apply in the context of a disaggregated RAN architecture, one or more components of the disaggregated RAN architecture can be configured to support mobility handling for multi-hop relay connections as described herein. For example, some operations described as being performed by a UE 115 or a network entity 105 (e.g., base station 140) can additionally or alternatively be performed by one or more components of the disaggregated RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0041] A UE 115 can include or can be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” can also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 can also include or can be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 can include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which can be implemented in various objects such as appliances or vehicles, among other examples.

[0042] The UEs 115 described herein can be able to communicate with various types of devices, such as other UEs 115 that can sometimes act as relays or network entities 105 and Figure 1 network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown.

[0043] The UEs 115 and the network entities 105 can wirelessly communicate with each other using resources associated with one or more carriers via one or more communication links 125 (e.g., access links). The term “carrier” can refer to a set of RF spectrum resources having a defined physical layer structure for supporting communication links 125. For example, a carrier used for a communication link 125 can include a portion of an RF spectrum band (e.g., a bandwidth part (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel can carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating carrier operation, user data, or other signaling. The wireless communications system 100 can support communication with UEs 115 using carrier aggregation or multi-carrier operation. According to a carrier aggregation configuration, a UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers. Communications between a network entity 105 and other devices can refer to communications between these devices and any part of the network entity 105 (e.g., an entity, sub-entity). For example, the terms “transmit,” “receive,” or “communicate” can refer to any part of a network entity 105 (e.g., a base station 140, a CU 160, a DU 165, a RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0044] Signal waveforms transmitted over a carrier can be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element can refer to a resource comprising a symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and the subcarrier spacing can be inversely related. A number of bits carried by each resource element can depend on the modulation scheme (e.g., the order of the modulation scheme, a coding rate of the modulation scheme, or both), such that a relatively higher resource element number (e.g., in a transmission duration) and a relatively higher modulation scheme order can correspond to a relatively high data rate. A wireless communications resource can refer to a combination of a RF spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial resources can increase the data rate or data

[0045] A time interval for a network entity 105 or UE 115 can be expressed in multiples of a basic time unit, which can refer to a sampling period of 1 second, for example, where may represent supported subcarrier spacings, and may represent supported discrete fourier transform (DFT) sizes. Time intervals of a communications resource can be organized as radio frames, each

[0046] Each frame can include a plurality of consecutive numbered subframes or slots, and each subframe or slot can have the same duration. In some examples, a frame can be divided (e.g., in the time domain) into subframes, and each subframe can be further divided into a number of slots. Alternatively, each frame can include a variable number of slots, and the number of slots can depend on the subcarrier spacing. Each slot can include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). In some wireless communications systems 100, a slot can be further divided into multiple mini-slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period can be associated with one or more (e.g., sampling periods. The duration of each symbol period can depend on the subcarrier spacing or the frequency band of operation.

[0047] A subframe, a slot, a mini-slot, or a symbol can be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and can be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) can be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 (e.g., in the time domain) can be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0048] According to various techniques, physical channels can be multiplexed for communication using carriers. Physical control channels and physical data channels can be multiplexed for signaling via a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) of a physical control channel can be defined by a set of symbol periods and can extend across the system bandwidth or a subset thereof of a carrier. One or more control regions (e.g., CORESETs) can be configured for a set of UEs 115. For example, one or more of the UEs 115 can monitor or search control regions according to one or more search space sets for control information, and each search space set can include one or more control channel candidates arranged in one or more aggregation levels in a cascaded manner. An aggregation level of a control channel candidate can refer to a quantity of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. A search space set can include common search space sets configured for transmission of control information to a plurality of UEs 115 and UE-specific search space sets configured for transmission of control information to a specific UE 115.

[0049] In some examples, network entities 105 (e.g., base stations 140, RUs 170) can be mobile and thus provide communication coverage for a moving coverage area 110. In some examples, different coverage areas 110 associated with different technologies can overlap, but different coverage areas 110 can be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies can be supported by different network entities 105. Wireless communications system 100 can include, for example, a heterogeneous network in which different types of network entities 105 provide coverage for various coverage areas 110 using the same or different radio access technologies.

[0050] The wireless communications system 100 can be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 can be configured to support ultra-reliable low-latency communications (URLLC). UEs 115 can be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communications can include private communication or group communication, and can be supported by one or more services such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions can include prioritization of services, and such services can be used for public safety or general commercial applications. The terms “ultra-reliable,” “low-latency,” and “ultra-reliable low- latency” can be used interchangeably herein.

[0051] In some examples, UEs 115 can be configured to communicate directly with other UEs 115 via device-to-device (D2D) communication link 135 (e.g., according to a peer-to-peer (P2P) or D2D or sidelink protocol). In some examples, one or more UEs 115 in a group that is performing D2D communication can be within the coverage area 110 of a network entity 105 (e.g., base station 140, RU 170) that can support aspects of such D2D communication configured by the network entity 105 (e.g., scheduled by the network entity). In some examples, one or more UEs 115 in such a group can be outside the coverage area 110 of a network entity 105 or can otherwise be unable to receive transmissions from the network entity 105. In some examples, a group of UEs 115 communicating via D2D communication can support a one-to-many (1:M) system, where each UE 115 transmits to every other UE 115 in the group. In some examples, a network entity 105 can facilitate scheduling of resources for D2D communication. In some other examples, D2D communication can be carried out between UEs 115 without involvement of a network entity 105.

[0052] In some systems, D2D communication link 135 can be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115). In some examples, vehicles can communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle can signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to V2X systems. In some examples, vehicles in a V2X system can communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., network entities 105, base stations 140, RUs 170) using vehicle-to-network (V2N) communications, or both.

[0053] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC) or 5G core (5GC), which can include at least one control plane entity that can manage access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that can route packets or interconnect to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity can manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for UEs 115 served by network entities 105 (e.g., base stations 140) associated with the core network 130. User IP packets can be transferred through the user plane entity, which can provide IP address allocation as well as other functions. The user plane entity can be connected to the IP services 150 of the one or more network operators. The IP services 150 can include access to the Internet, Intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0054] The wireless communications system 100 can operate using one or more frequency bands, in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves can be blocked or redirected by buildings and environmental features, but the waves can penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. The use of UHF frequencies, however, can support relatively large cells, and can enable use of smaller antennas than those used for the higher frequencies.

[0055] The wireless communications system 100 can utilize both licensed and unlicensed RF spectrum bands. For example, the wireless communications system 100 can employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed frequency spectrum band, such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed frequency spectrum bands, access points 105 and UEs 115, such as base stations 140 and UEs 115, can employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed frequency spectrum bands can be based on a carrier aggregation configuration in which a component carrier used for transmissions in the unlicensed spectrum band is combined with a component carrier used for transmissions in a licensed spectrum band (e.g., LAA). Operations in the unlicensed spectrum band can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0056] The network entity 105 (e.g., base station 140, RU 170) or UE 115 can be equipped with multiple antennas, which can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of a network entity 105 or UE 115 can be located in one or more antenna arrays or antenna panels, which can support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays can be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a network entity 105 can be located at different geographic locations. A network entity 105 can include an antenna array with a set of multiple rows and multiple columns of antenna ports that the network entity 105 can use to support beamforming of transmissions to or from a UE 115. Similarly, a UE 115 can include one or more antenna arrays, which can support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel can support RF beamforming for signals transmitted via the antenna ports.

[0057] Beamforming, which can also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., a network entity 105, a UE 115) to shape or steer the beam over the space. Beamforming can be achieved by combining the signals communicated by antennas of an antenna array such that signals at particular orientations experience constructive interference while others experience destructive interference. The adjustments to signals communicated by each of the antennas of the antenna array can include applying amplitude shifts, phase shifts, or both. The adjustments associated with each of the antennas of the antenna array can be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation).

[0058] The wireless communications system 100 can be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or PDCP layer can be IP -based. A RLC layer can perform packet segmentation and reassembly to communicate over logical channels. The MAC layer can perform priority handling and multiplexing of logical channels into transport channels. The MAC layer can also use error detection techniques, error correction techniques, or both, to support retransmissions to improve link efficiency. In the control plane, the RRC layer can provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a network entity 105 or core network 130 supporting radio bearers for user plane data. The PHY layer can map transmission channels to physical channels.

[0059] In some cases, wireless communications system 100 can support relay communications between devices. For example, a source device can transmit a message intended for a destination device to a relay device, which can forward the message to the destination device. Such techniques can be supported to relay communications between a source UE 115 and a destination UE 115 (e.g., UE-to-UE (U2U) relay) or a remote UE 115 and a network entity 105 (e.g., UE-to-Network (U2N) relay). In some cases, multiple relay devices can be used to relay communications, which can be referred to as a multi-hop relay connection. In such cases, end-to-end (E2E) traffic can be relayed via multiple wireless link pairs of devices (e.g., per-hop connections) of the multi-hop relay connection. For example, a pair of UEs 115 can communicate via a unicast PC5 link (e.g., a sidelink interface), and a UE 115 and a network entity 105 can communicate via a Uu interface.

[0060] To establish a relay connection, a source UE 115 can discover one or more candidate relay UEs 115 and can select one of the candidate relay UEs 115. For example, a source UE 115 can perform one or more radio measurements (e.g., sidelink discovery reference signal received power (SD-RSRP) measurements) at a PC5 interface and can select a relay UE 115 if a PC5 link quality toward the relay UE 115 measured by the source UE 115 satisfies a threshold (e.g., configured by a network entity 105) and the source UE 115 identifies a relay route to a destination device. The source UE 115 can transmit a link establishment message to the selected relay UE 115 to establish a unicast PC5 link. Additionally, the relay UE 115 can perform a relay selection (or reselection) procedure to discover and select a subsequent device (e.g., a destination device or another relay UE 115) for relaying.

[0061] In some cases, a wireless device of a U2U or U2N multi-hop relay connection can detect a per-hop, E2E connected, or both, RLF of the relay. For example, to detect a per-hop RLF (e.g., a sidelink RLF), a UE 115 can receive an indication from a sidelink RLC entity that a threshold number of retransmissions for a particular destination has been reached, can receive an indication from a MAC entity that a threshold number of consecutive HARQ DTX cycles has been reached, or both. To detect an E2E connected RLF, a UE 115 can identify that a response message for a transmitted RRC configuration signal (e.g., RRCReconfigurationSidelink) has not been received, can receive an integrity check failure indication from a sidelink PDCP entity (e.g., for SL-SRB2 or SL-SRB3), or both.

[0062] In some cases, a wireless device of a U2U or U2N multi-hop relay connection can implement one or more mobility handling mechanisms to support management of the multi-hop relay connection. In some cases, a UE 115 of a multi-hop relay connection can perform relay reselection in response to satisfying a trigger. For example, a UE 115 can perform relay reselection based on identifying a better sidelink (e.g., PC5) link quality (e.g., as compared to a currently established sidelink or PC5 link), an opportunity to reduce a number of hops in the multi-hop relay connection, an RLF occurring between two devices of the multi-hop relay connection, or any combination thereof. In some cases, after identifying the trigger, the UE 115 can select a new relay UE 115, establish a sidelink (e.g., PC5) connection with the new relay UE 115, and can terminate the link with the previous relay UE 115. Such techniques can improve communications via a multi-hop relay connection by enabling dynamic reselection of a relay UE 115 to avoid poor link quality, reduce a large number of hops, recover from an RLF, or any combination thereof.

[0063] Figure 2A and Figure 2B Wireless communications systems 201 and 202, which support mobility handling for multi-hop relay connections, are shown in accordance with one or more aspects of the present disclosure. Wireless communications systems 201 and 202 can implement one or more aspects of wireless communications system 100. For example, wireless communications systems 201 and 202 can include an S-UE (e.g., source UE, remote UE), a D-UE (e.g., destination UE, donor UE), and one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, R-UE5, and R-UE5), each of which can be an example of a UE 115 as described with reference to FIG. 1. Additionally, wireless communications systems 201 and 202 can include a network entity 105-a, which can be an example of a network entity 105 as described with reference to FIG. 1. Figure 1 Figure 1

[0064] ​​Wireless communications systems 201 and 202 can support relay reselection techniques for multi-hop relay connections for communications in a relay U2U framework (e.g., between a S-UE and a D-UE) or a U2N framework (e.g., between a S-UE and a network entity 105-a). For example, wireless communications systems 201 and 202 can support local U2U relay reselection techniques, relay reselection for multi-hop U2N relay connections, or both. In a U2U framework, a S-UE can be referred to as a source UE and a D-UE can be referred to as a destination UE. In a U2N framework, a S-UE can be referred to as a remote UE and a D-UE can be referred to as a donor UE (e.g., a UE connected to a network entity 115-a via a Uu communication link 205). It should be noted that wireless communications systems 201 and 202 can support any number of relay devices and are not limited to the examples illustrated in FIGS. 1-3. Figure 2A and 2B FIGS. 1-3.

[0065] Wireless communications system 201 can support relay reselection initiated by a relay UE. As part of a multi-hop relay connection, signals can be relayed by R-UE1, R-UE2, R-UE3, and R-UE4 via respective existing sidelink (e.g., PC5 link or per-hop wireless link) links 210 (e.g., unicast sidelink communication links, per-hop wireless links). In some cases, one of the plurality of relay UEs (e.g., R-UE2) can identify a trigger to perform a relay reselection procedure. The trigger can be due to identifying better sidelink (e.g., PC5) link quality (e.g., compared to a current existing sidelink link 210), an opportunity to reduce the number of hops in the multi-hop relay connection, a radio link failure (RLF) occurring between a pair of relay UEs (e.g., as described below with reference to FIGS. 4-6), or a combination thereof. In some cases, based on the trigger, R-UE2 can discover one or more candidate relay UEs and can select one of the discovered UEs. For example, R-UE2 can identify that channel quality between R-UE2 and R-UE5 is better than channel quality between R-UE2 and R-UE3 and can select R-UE5 as part of a relay reselection procedure. Additionally or alternatively, a timer can be set for R-UE2 such that expiration of the timer triggers the relay reselection procedure. In such cases, R-UE2 can be referred to as a migrating UE (e.g., a UE that triggers a change in a multi-hop relay connection). Figure 4A and Figure 4B FIGS. 4-6.

[0066] In some cases, the migrating UE can inform the S-UE of the relay reselection. For example, R-UE2 can send a message to the S-UE (e.g., the message is relayed via R-UE1) indicating a cause of the relay reselection (e.g., an indication of the trigger), information about the selected candidate relay UE (e.g., information associated with R-UE5), a relay service code (RSC) associated with the candidate relay UE (e.g., a code to indicate a related service such as public safety), or any combination thereof. Based on the message, the S-UE can determine whether to perform the relay reselection, and can indicate to the migrating UE an approval or rejection of the reselection.

[0067] After selecting a new relay UE as part of the relay reselection procedure, the migrating UE can establish a new sidelink (e.g., PC5) link 210 between the migrating UE and the selected relay UE. For example, R-UE2 can send a link establishment message to R-UE5 to establish the new sidelink link 210 based on selecting R-UE5 during the relay reselection procedure. In some cases, after receiving the link establishment message from R-UE2, R-UE5 can perform a relay selection (or reselection) procedure to select a next relay UE for the multi-hop relay connection. For example, R-UE5 can discover one or more candidate UEs for the multi-hop relay connection, and can select a discovered UE to establish a new sidelink link 215 (e.g., by sending a link establishment message). In some cases, R-UE5 can select a relay UE that is part of the original multi-hop relay connection, such as R-UE4. In such cases, R-UE4 can be referred to as an anchor UE (e.g., a UE at which a path switch terminates).

[0068] In some cases, the anchor UE (e.g., R-UE 4) can initiate link release between relay UEs of the original multi-hop relay connection (e.g., after establishing a new sidelink (e.g., PC5) link 215 with R-UE 5) until reaching the migrating UE (e.g., R-UE 2). For example, R-UE 4 can send a link release message to R-UE 3 to terminate the existing sidelink (e.g., PC5) link 210 between R-UE 4 and R-UE 3. R-UE 3 can then send a link release message to R-UE 2 to terminate the existing sidelink (e.g., PC5) link 210 between R-UE 3 and R-UE 2 (e.g., terminate the existing sidelink link 210 between the anchor UE and the migrating UE). To determine the direction of the link release, the anchor UE can identify a direction indication in the received link establishment message. For example, R-UE 4 can receive a link establishment message from R-UE 5 including identifiers of the source device, the destination device, and the relay UEs of the multi-hop relay connection, and can identify that the new sidelink (e.g., PC5) link 215 established between R-UE 4 and R-UE 5 is to be part of the existing multi-hop relay connection (e.g., replace one or more existing sidelink links 210). R-UE 4 can then identify the migrating UE (e.g., from the link establishment message) to determine the link release path.

[0069] By initiating the multi-hop relay connection path switch at the migrating UE and terminating the path switch at the anchor UE, the relay reselection can avoid impacting hops that are not between the migrating UE and the anchor UE (e.g., the existing sidelink link 210 between S-UE and R-UE 1 can remain unaffected). Thus, the E2E connection between the source device and the destination device (e.g., for L2 relay) can not be impacted by the relay reselection procedure. Additionally, by establishing the new sidelink (e.g., PC5) link 215 before releasing the existing sidelink (e.g., PC5) link 210 (e.g., make-before-break framework), the interruption time, signaling overhead, or both of the multi-hop relay connection can be reduced.

[0070] The wireless communications system 202 can support relay reselection initiated by a remote UE (e.g., S-UE or D-UE). As an example, the S-UE can identify a trigger to perform a relay reselection procedure, which can be associated with identifying a better PC5 link quality, an opportunity to reduce the number of hops in the multi-hop relay connection, an RLF occurring between a pair of relay UEs, or a combination thereof, as referenced to FIG. 1. Figure 2AAs described. For example, the S-UE may identify an opportunity to reduce the number of hops in a multi-hop trunk connection between the S-UE and the destination device (e.g., the D-UE or network entity 105-a), and initiate a trunk reselection procedure. As part of the trunk reselection procedure, the S-UE may discover R-UE5 and may select R-UE5 to replace one or more hops in the multi-hop trunk connection. In some cases, R-UE5 may be able to connect directly to the D-UE, thereby reducing the number of hops between the S-UE and the D-UE (e.g., from 5 hops to 2 hops). After R-UE5 is selected, the S-UE, D-UE, and trunk UEs (e.g., R-UE1, R-UE2, R-UE3, R-UE4, and R-UE5) may perform reference... Figure 2A The described relay reselection technique (e.g., conveying link establishment and link release messages to replace the existing side link link 210 with a new side link link 215) is used to establish a new multi-hop relay connection between the source device and the destination device.

[0071] Figure 3 An example of a wireless communication system 300 supporting mobility handling for multi-hop relay connections according to one or more aspects of this disclosure is shown. Wireless communication system 300 may implement one or more aspects of wireless communication systems 100, 201, and 202. For example, wireless communication system 300 may include a remote UE (e.g., S-UE), one or more donor UEs (e.g., D-UE1 and D-UE2), one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, and R-UE4), and network entity 105-a, each of which may be a reference. Figure 1 , Figure 2A and Figure 2B Examples of the corresponding devices described. In some cases, when the donor UE (e.g., a relay UE communicating with network entity 105-a via Uu communication link 305) changes as part of relay reselection, the wireless communication system 300 can support relay reselection for multi-hop U2N relays. It should be noted that the wireless communication system 300 can support any number of relay devices and is not limited to them. Figure 3 Examples illustrated in .

[0072] In some examples, a remote UE (e.g., an S-UE) or a relay UE (e.g., R-UE2) may initiate a relay reselection process based on an identifier. For example, a remote UE or a relay UE may trigger a relay reselection based on identifying a better sidelink (e.g., PC5) link quality (e.g., compared to the existing sidelink 310), a reduced chance of hop count in a multi-hop relay connection, or both. Additionally or alternatively, a remote UE may trigger a relay reselection process to reselect a candidate relay UE (e.g., an intermediate relay UE or a donor UE) that supports a different RSC.

[0073] In some cases, such as when the donor UE does not change as part of the relay reselection procedure, the techniques associated with U2U relays (as discussed above in Figure 2A Relay Reselection” can be used to perform relay reselection. In such cases, the migrating UE (e.g., R-UE2) can trigger the relay reselection procedure and can perform relay reselection without notifying the remote UE (e.g., S-UE). For example, R-UE2 can select R-UE4 and R-UE4 can select D-UE1 (e.g., an existing donor UE), which can be an example of local U2U relay reselection using the techniques described. Figure 2A

[0074] In some other cases, such as when the donor UE changes as part of the relay reselection procedure, the S-UE can be notified of the change. For example, R-UE2 can trigger the relay reselection procedure and can select R-UE4. As part of the relay reselection procedure, R-UE4 can discover D-UE2, which can be a new donor UE (e.g., replacing D-UE1 to connect with network entity 105-a via Uu communication link 305). R-UE2 can identify that the donor UE has changed from D-UE1 to D-UE2 and can notify the S-UE of the change. For example, R-UE2 can send information associated with D-UE2 (e.g., an identifier of D-UE2, an RSC of D-UE2, or both) to the S-UE (e.g., which is relayed by R-UE1).

[0075] After receiving the information associated with D-UE2, the S-UE can send a measurement report to network entity 105-a (e.g., via the existing multi-hop relay connection), which can indicate candidate donor UE information. For example, the measurement report can include a measured PC5 link quality (e.g., between D-UE2 and R-UE4), an identifier of D-UE2, an RSC of D-UE2, or any combination thereof. In some cases, network entity 105-a can determine whether to switch donor UEs after receiving the measurement report from the S-UE. For example, network entity 105-a can send an RRC reconfiguration message to the S-UE via the existing multi-hop relay connection indicating approval to switch from D-UE1 to D-UE2.

[0076] ​In some cases, based on the RRC reconfiguration message from the network entity 105-a, the S-UE can initiate a relay reselection procedure to switch the multi-hop relay connection path. For example, the R-UE2 can establish a new PC5 link 315 with the R-UE4, the R-UE4 can establish a new PC5 link 315 with the D-UE2 (e.g., via a link establishment message), and the D-UE2 can establish a Uu communication link 305 with the network entity 105-a. In some examples, after establishing the new PC5 link 315, the S-UE can send an RRC reconfiguration complete message to the network entity 105-a via the existing multi-hop relay connection. Additionally, the network entity 105-a can release the Uu communication link 305 with the D-UE1, the D-UE1 can release the existing PC5 link 310 with the R-UE3, and the R-UE3 can release the existing PC5 link 310 with the R-UE2 (e.g., via a link release message). In some cases, depending on the state of the S-UE (e.g., L3-based relay where the remote UE is in idle or inactive state), the S-UE and the network entity 105-a can avoid conveying RRC configuration (or reconfiguration) messages, which are also depicted as operations 620, 625, and 640 in FIG. 6. Figure 6

[0077] Figure 4A Figure 4B Wireless communications systems 401 and 402, which each include one or more aspects of the present disclosure, support mobility handling for multi-hop relay connections. For example, wireless communications systems 401 and 402 each include a source UE (e.g., a source UE or a remote UE), a destination UE (e.g., a destination UE or a donor UE), one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, R-UE5, R-UE5, and R-UE6), and a network entity 105-a, each of which can be examples of the corresponding devices described with reference to FIGs. 1-6. In some examples, wireless communications systems 401 and 402 can support RLF handling techniques for U2U multi-hop relay connections (e.g., between a source UE and a destination UE) and U2N multi-hop relay connections (e.g., between a source UE and a network entity 105-a). It should be noted that wireless communications systems 401 and 402 can support any number of relay devices and are not limited to the examples illustrated in FIGs. 7 and 8. Figure 1 to Figure 3 Figure 4A 4B

[0078] ​​​​​Wireless communications system 401 can support S-UE triggering RLF recovery for a multi-hop relay connection, which can be a first example of RLF handling for multi-hop U2U and multi-hop U2N relays. In such examples, at least one relay UE of a multi-hop relay connection can use one or more RLF detection mechanisms to detect per-hop sidelink RLF (e.g., a threshold number of retransmissions via a link, a threshold number of consecutive HARQ DTX cycles, etc.). For example, R-UE2 can detect that an RLF has occurred between R-UE2 and R-UE4, which can indicate a failed sidelink link 410 between R-UE2 and R-UE4. After identifying the failed sidelink link 410, R-UE2 can send a message to the S-UE indicating that an RLF has occurred within the multi-hop relay connection (e.g., which is relayed by R-UE1).

[0079] In some cases, the S-UE can initiate relay UE selection based on identifying that an RLF has occurred within the multi-hop relay connection (e.g., indicated by R-UE2). For example, the S-UE can restart a relay UE selection procedure (e.g., which can include initiating per-hop link establishment for L2 relays and E2E link establishment), and can release the existing sidelink link 405 with R-UE1. As part of relay UE selection, the S-UE can discover one or more candidate relay UEs, and can select a relay UE from the candidate relay UEs (e.g., based on radio measurements at the PC5 interface). For example, the S-UE can reselect R-UE1, and can reestablish the existing sidelink link 405 between the S-UE and R-UE1. Additionally or alternatively, for a U2N multi-hop relay connection, the S-UE can initiate an RRC reestablishment procedure to inform the network entity 105-a of the relay reselection.

[0080] In some examples, a timer can be set on one or more relay UEs to keep the existing sidelink link 405 active despite the occurrence of an RLF (e.g., to avoid another link release and establishment procedure). For example, upon occurrence of an RLF, R-UE1 and R-UE2 can initiate respective timers, and can refrain from releasing the existing sidelink link 405 between R-UE1 and R-UE2 until expiration of the timer (e.g., so that in the case of selection by the S-UE prior to expiration of the timer, R-UE1 is able to skip per-hop link release and establishment procedures).

[0081] Wireless communication system 402 can support relay UEs initiating local RLF recovery, which can be a second example of RLF handling for multi-hop U2U and U2N relays. In such an example, at least one relay UE in a multi-hop relay connection can use one or more RLF detection mechanisms to detect per-hop sidelink RLFs (e.g., reaching a threshold number of retransmissions via the link, a threshold number of consecutive HARQDTX cycles, etc.) and can attempt to perform local RLF recovery. For example, R-UE2 can detect that an RLF has occurred between R-UE2 and R-UE3, which can indicate a failed sidelink link 410 between R-UE2 and R-UE3. R-UE2 can perform local RLF recovery by releasing the failed sidelink link 410 between R-UE2 and R-UE3 and performing a relay reselection process (e.g., discovering one or more candidate relay UEs for selection).

[0082] If the local relay RLF recovery process fails (e.g., R-UE2 cannot find a suitable relay UE), the RLF recovery can be extended to a wider scope. For example, R-UE2 can indicate to R-UE1 that an RLF has occurred between R-UE2 and R-UE3 in response to the local RLF recovery failure. R-UE1 can then perform local RLF recovery by releasing the existing sidelink link 405 between R-UE1 and R-UE2 and performing a relay reselection procedure. For example, R-UE1 can find R-UE5, select R-UE5, and establish a new sidelink link 415 between R-UE1 and R-UE5. The relay UE can continue to perform the corresponding relay reselection procedure until a new PC5 link 415 is established with a relay UE (e.g., anchor UE) with an existing multi-hop relay connection. For example, R-UE5 can establish a new PC5 link 415 with R-UE6, and R-UE6 can establish a new PC5 link 415 with R-UE4. Therefore, since RLF is detected between R-UE2 and R-UE3, new per-hop links (e.g., new side link links 415) can be established between R-UE1, R-UE5 and R-UE6 respectively (e.g., adjusting the multi-hop relay connection path to avoid the failure of side link links 410).

[0083] In some cases, local RLF recovery can support a relay device handling RLF within a multi-hop relay connection without notifying a source device or a destination device. For example, in a U2U multi-hop relay connection, R-UE1 can avoid notifying the S-UE of a path switch. As another example, in a U2N multi-hop relay connection, if the local RLF recovery is successful without a change in the donor UE (e.g., D-UE), R-UE1 can avoid notifying the S-UE of a path switch (e.g., avoid triggering RRC reestablishment). Alternatively, if the local RLF recovery is successful and the donor UE is changed (e.g., a different D-UE (not illustrated) is selected), R-UE1 can notify the S-UE of a path switch, and the S-UE can initiate RRC reestablishment with the network entity 105-a.

[0084] Figure 5 A process flow 500 that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure. The process flow 500 can be implemented by one or more aspects of the wireless communications system 100, 201, 202, 300, 401, and 402. For example, the process flow 500 can include signaling between a S-UE (e.g., source UE), a D-UE (e.g., destination UE), and one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, R-UE4, and R-UE5) (which can be the reference Figure 1 to Figure 4B The described examples of corresponding devices). The process flow 500 can support techniques for managing U2U multi-hop relay connections, which can include one or more UEs performing a local relay reselection procedure to modify a path of a multi-hop relay connection. Alternative examples can be implemented in which some of the processes are performed in a different order than described or are not performed at all. In some cases, processes can include additional features not mentioned below, or further processes can be added.

[0085] At 505, E2E traffic can be communicated between a S-UE and a D-UE via a multi-hop relay connection. For example, the S-UE can transmit one or more messages intended for the D-UE, and the one or more messages can be relayed by R-UE1, R-UE2, R-UE3, and R-UE4 (e.g., an existing multi-hop relay connection path) to reach the D-UE.

[0086] At 510, R-UE2 (e.g., migrating UE) can perform a relay reselection procedure. In some cases, R-UE2 can perform the relay reselection procedure in response to identifying a trigger to perform the relay reselection procedure. The trigger can be due to identifying better PC5 link quality, an opportunity to reduce the number of hops in the multi-hop relay connection, an RLF occurring between a pair of relay UEs, or a combination thereof. As part of the relay reselection procedure, R-UE2 can discover one or more candidate relay UEs and can select a candidate relay UE for the multi-hop relay connection. For example, R-UE2 can discover and select R-UE5 (e.g., based on radio measurements).

[0087] At 515, one or more unicast links can be established between relay UEs to establish a new path for the multi-hop relay connection. For example, after selecting R-UE5 as part of the relay reselection procedure, R-UE2 can transmit a link establishment message to establish a new wireless link (e.g., PC5 link, first wireless link, per-hop link, unicast sidelink connection) between R-UE2 and R-UE5. In some cases, the link establishment message can indicate a direction of the path (e.g., towards the D-UE). Additionally, R-UE5 can select R-UE4 as part of the relay reselection procedure and can establish a new PC5 link between R-UE5 and R-UE4, which can terminate the path switch (e.g., since R-UE4 is part of the existing path).

[0088] At 520, R-UE4 can decide to release links based on the new multi-hop relay connection path being established. For example, R-UE4 (e.g., anchor UE that terminates the path switch) can trigger old PC5 connection release after receiving the link establishment message from R-UE5. In some cases, R-UE4 can determine which hops to release according to the path direction included in the link establishment message. For example, R-UE4 can trigger old S-UE and D-UE pair PC5 connection (e.g., per-hop link of the multi-hop connection between the S-UE and the D-UE) for previous hops indicated by the path direction indication.

[0089] At 525, one or more unicast links between relay UEs can be released to terminate the old path of the multi-hop relay connection. For example, after deciding to release the existing PC5 link with R-UE3, R-UE4 can send a link release message to R-UE3. R-UE3 can then send a link release message to R-UE2 (e.g., migrating UE) to release the existing PC5 link between R-UE2 and R-UE3, which can complete the path switch of the multi-hop relay connection. Thus, relay UEs on the existing path release the old S-UE and D-UE pair PC5 connection up to R-UE2 (e.g., migrating UE).

[0090] At 530, E2E traffic can be communicated between the S-UE and the D-UE via the new multi-hop relay connection path. For example, the S-UE can transmit one or more messages intended for the D-UE, and the one or more messages can be relayed by R-UE1, R-UE2, R-UE5, and R-UE4 to reach the D-UE.

[0091] Figure 6 A process flow 600 that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure. The process flow 600 can be implemented by one or more aspects of wireless communication systems 100, 201, 202, 300, 401, and 402. For example, the process flow 600 can include signaling between an S-UE (e.g., a remote UE), one or more D-UEs (e.g., donor UEs), one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, and R-UE4), and a network entity 105-a (which can be the network entity 105 described with reference to the corresponding devices described herein). The process flow 600 can support techniques for managing U2N multi-hop relay connections, which can include one or more UEs performing a relay reselection procedure to modify a path of a multi-hop relay connection. Alternative examples can implement the following, where some processes are performed in a different order than described or are not performed at all. In some cases, processes can include additional features not mentioned below, or additional processes can be added. Figure 1 to Figure 4B The described examples of corresponding devices) are described. The process flow 600 can support techniques for managing U2N multi-hop relay connections, which can include one or more UEs performing a relay reselection procedure to modify a path of a multi-hop relay connection. Alternative examples can implement the following, where some processes are performed in a different order than described or are not performed at all. In some cases, processes can include additional features not mentioned below, or additional processes can be added.

[0092] At 605, E2E traffic can be communicated between the S-UE and the network entity 105-a via a multi-hop relay connection. For example, the S-UE can transmit one or more messages intended for the network entity 105-a, and the one or more messages can be relayed by R-UE1, R-UE2, R-UE3, and D-UE1 (e.g., an existing multi-hop relay connection path) to reach the network entity 105-a.

[0093] At 610, R-UE2 (e.g., a migrating UE) can perform a relay reselection procedure. In some cases, R-UE2 can perform the relay reselection procedure in response to identifying a trigger to perform the relay reselection procedure. The trigger can be due to identifying a better PC5 link quality, an opportunity to reduce the number of hops in the multi-hop relay connection, an RLF occurring between a pair of relay UEs, or a combination thereof. As part of the relay reselection procedure, R-UE2 can discover one or more candidate relay UEs and candidate donor UEs, and can select a candidate relay UE, a candidate donor UE, or both for the multi-hop relay connection. For example, R-UE2 can discover and select R-UE4 and D-UE2 (e.g., based on radio measurements).

[0094] At 615, R-UE2 can indicate information associated with the selected candidate UE to S-UE. For example, R-UE2 can send a message (e.g., relayed by R-UE1) to S-UE including respective identifiers of R-UE4 and D-UE2, respective RSCs of R-UE4 and D-UE2, or a combination thereof.

[0095] At 620, S-UE can send a measurement report to network entity 105-a to indicate candidate UE information. For example, S-UE can send a measurement report to network entity 105-a via the existing multi-hop relay connection, which can indicate information associated with R-UE4 and D-UE2.

[0096] At 625, network entity 105-a can decide to hand over the donor UE (e.g., from D-UE1 to D-UE2) upon receiving the measurement report and can send an RRC reconfiguration message to configure S-UE. In some cases, the RRC reconfiguration message can be relayed via the existing multi-hop relay connection.

[0097] At 630, one or more unicast links between relay UEs can be established or modified to establish a new path for the multi-hop relay connection. For example, R-UE2 can send a link establishment message to R-UE4 to establish a new PC5 link between R-UE2 and R-UE5. In some cases, the link establishment message can indicate a direction of the path (e.g., towards the D-UE). Additionally, R-UE4 can send a link establishment message to D-UE2 to establish a new PC5 link between R-UE4 and D-UE2.

[0098] At 635, D-UE2 and network entity 105-a can establish an access (e.g., Uu) communication link. For example, D-UE2 can establish an RRC connection with network entity 105-a.

[0099] At 640, S-UE can send an RRC reconfiguration complete message to network entity 105-a via the new multi-hop relay connection path. For example, the message can be relayed by R-UE1, R-UE2, R-UE4, and D-UE2 to reach network entity 105-a. In some cases, the RRC reconfiguration complete message can indicate that the path switch for the multi-hop relay connection is complete.

[0100] At 645, one or more unicast links between relay UEs can be released or modified to terminate an old path of the multi-hop relay connection. For example, D-UE1 can send a link release message to R-UE3 to release the PC5 link between R-UE3 and D-UE1. Additionally, R-UE3 can send a link release message to R-UE2 to release the PC5 link between R-UE2 and R-UE3.

[0101] At 650, D-UE1 and the network entity 105-a can release the Uu communication link. For example, D-UE1 can terminate an RRC connection with the network entity 105-a.

[0102] At 655, E2E traffic can be communicated between the S-UE and the D-UE via the new multi-hop relay connection path. For example, the S-UE can send one or more messages intended for the network entity 105-a, and the one or more messages can be relayed by R-UE1, R-UE2, R-UE4, and D-UE2 to reach the network entity 105-a.

[0103] Figure 7 A process flow 700 that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure. The process flow 700 can implement, or be implemented by, one or more aspects of the wireless communication systems 100, 201, 202, 300, 401, and 402, as well as the process flows 500 and 600. For example, the process flow 700 can include signaling between a source wireless device 705 (which can be an example of the source UE or remote UE described with reference to Figure 1 to Figure 6 the destination wireless device 710 (which can be an example of the destination UE or network entity 105 described with reference to Figure 1 to Figure 6 Additionally, the communication between the source wireless device 705 and the destination wireless device 710 can be facilitated by one or more relay UEs (e.g., R-UE1, R-UE2, R-UE3, and R-UE4), which can be examples of the corresponding devices described with reference to Figure 1 to Figure 6 The process flow 700 can support techniques for managing a U2U multi-hop relay connection or a U2N multi-hop relay connection. For example, in a U2U relay, the source wireless device 705 can be a first UE 115 and the destination wireless device 710 can be a second UE 115, and in a U2N relay, the source wireless device 705 can be a UE 115 and the destination wireless device 710 can be a network entity 105. Alternative examples can be implemented in which some processes are performed in a different order than described, or not at all. In some cases, processes can include additional features not mentioned below, or additional processes can be added.

[0104] At 715, the first wireless device (e.g., source wireless device 705, relay UE) can identify a trigger to perform a relay reselection procedure. The first wireless device can be one of a plurality of wireless devices that relay communications via a multi-hop wireless connection established between the source wireless device 705 and the destination wireless device 710. For example, R-UE1 can identify a trigger. In some cases, R-UE1 can perform a relay reselection procedure in response to the trigger to replace a wireless link of the multi-hop relay connection. The trigger can be based on a quality of an existing wireless link (e.g., between R-UE1 and R-UE2), an RLF associated with at least one wireless link of the multi-hop wireless connection, a number of wireless devices of the multi-hop relay connection, a timer initiated at the wireless device, or any combination thereof.

[0105] At 720, R-UE1 can receive an indication that a wireless link of the multi-hop relay connection has experienced an RLF. For example, R-UE1 can receive the indication from R-UE3 (e.g., a third wireless device) due to an RLF occurring on a third wireless link between R-UE3 and another relay UE (e.g., a fourth wireless device). In some cases, receiving the RLF indication can trigger the relay reselection procedure.

[0106] At 725, R-UE1 can transmit an indication of the trigger to the source wireless device 705. For example, R-UE1 can indicate a cause of the relay reselection procedure to the source wireless device 705. As another example, R-UE1 can forward the RLF indication to the source wireless device 705.

[0107] At 730, the source wireless device 705 can release and reestablish a wireless link with R-UE1. For example, if R-UE1 transmits the RLF indication to the source wireless device 705, the source wireless device 705 can initiate a relay reselection procedure (e.g., to reestablish the multi-hop relay connection in response to the RLF occurrence). In some cases, as part of the relay reselection procedure, the source wireless device 705 can transmit a link release message to R-UE1 to terminate the wireless link and can select a relay UE for the multi-hop relay connection. In some cases, the source wireless device can select (e.g., reselect) R-UE1 and can transmit a link establishment message to R-UE1 to reestablish the wireless link.

[0108] At 735, as part of the relay reselection procedure, R-UE1 can discover and select one or more candidate relay devices. For example, R-UE1 can initiate the relay reselection procedure in response to identifying the trigger, in response to receiving the link establishment message from the source wireless device 705, or both. In some cases, R-UE1 can discover R-UE2 (e.g., a second wireless device) and can select R-UE2. In some cases, R-UE2 can replace R-UE3 in the multi-hop relay connection.

[0109] At 740, R-UE1 can transmit a link setup message to R-UE2 based on discovering and selecting R-UE2. For example, R-UE1 can transmit a link setup message to establish a wireless link (e.g., a PC5 link, a per-hop link, a unicast sidelink connection) between R-UE1 and R-UE2. In some cases, the wireless link between R-UE1 and R-UE2 can replace the wireless link between R-UE1 and R-UE3.

[0110] At 745, R-UE1 can receive a link release message from R-UE3 based on establishing the wireless link between R-UE1 and R-UE2. For example, R-UE3 can transmit a link release message to terminate the wireless link between R-UE1 and R-UE3.

[0111] At 750, R-UE1 can receive an indication that a donor UE (e.g., a UE connected to a destination network entity 105 via a Uu link) of the multi-hop relay connection has changed. For example, R-UE1 can receive an indication that the wireless link between the original donor UE (e.g., a fourth wireless device) and the destination wireless device 710 has been terminated and a new wireless link between a new donor UE (e.g., a fifth wireless device) and the destination wireless device 710 has been established. In some examples, R-UE1 can transmit the indication to the source wireless device 705 via the multi-hop relay connection to inform the source wireless device 705 of the change (e.g., the source wireless device can initiate an RRC reestablishment with the destination wireless device 710).

[0112] At 755, E2E traffic can be communicated between the source wireless device 705 and the destination wireless device 710 via the new multi-hop relay connection. For example, R-UE1 can relay traffic using the wireless link established between R-UE1 and R-UE2.

[0113] Figure 8 A block diagram 800 of a device 805 that supports mobility handling for multi-hop relay connections in accordance with one or more aspects of the present disclosure is shown. The device 805 can be an example of aspects of a UE 115 as described herein. The device 805 can include a receiver 810, a transmitter 815, and a communications manager 820. The device 805, or one or more components of the device 805 (e.g., the receiver 810, the transmitter 815, and the communications manager 820), can include at least one processor that can be coupled to at least one memory to individually or collectively support or implement at least one of the described techniques. Each of these components can be in communication with one another (e.g., via one or more buses).

[0114] The receiver 810 can provide means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to mobility handling for multi-hop relay connections). Information can be passed on to other components of the device 805. The receiver 810 can utilize a single antenna or a set of multiple antennas.

[0115] The transmitter 815 can provide means for transmitting signals generated by other components of the device 805. For example, the transmitter 815 can transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to mobility handling for multi-hop relay connections). In some examples, the transmitter 815 can be collocated with the receiver 810 in a transceiver module. The transmitter 815 can utilize a single antenna or a set of multiple antennas.

[0116] The communication manager 820, the receiver 810, the transmitter 815, or various combinations thereof or various components thereof can be examples of means for performing various aspects of mobility handling for multi-hop relay connections as described herein. For example, the communication manager 820, the receiver 810, the transmitter 815, or various combinations or components thereof can be capable of performing one or more of the functions described herein.

[0117] In some examples, the communication manager 820, the receiver 810, the transmitter 815, or various combinations or components thereof can be implemented in hardware (e.g., in communication management circuitry). The hardware can include at least one of the following: a processor, a digital signal processor (DSP), a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a microcode circuit, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting the components described throughout the present disclosure to perform the functions described herein. In some examples, at least one processor and at least one memory coupled with the at least one processor can be configured to perform one or more of the functions described herein (e.g., the at least one processor executing instructions stored in the at least one memory).

[0118] Additionally or alternatively, the communications manager 820, the receiver 810, the transmitter 815, or various combinations thereof or components thereof, can be implemented in code (e.g., as communications management software or firmware) executed by at least one processor. If implemented in code executed by at least one processor, the functions of the communications manager 820, the receiver 810, the transmitter 815, or various combinations thereof or components thereof, can be executed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting the components described in this disclosure to perform the functions described in this disclosure).

[0119] In some examples, the communications manager 820 can be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 810, the transmitter 815, or both. For example, the communications manager 820 can receive information from the receiver 810, transmit information to the transmitter 815, or be integrated in combination with the receiver 810, the transmitter 815, or both to obtain information, output information, or perform various other operations as described herein.

[0120] The communications manager 820 can support wireless communication at a first wireless device in accordance with examples as disclosed herein. For example, the communications manager 820 can enable, be configured to, or be operable to support means for transmitting or receiving a link establishment message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one wireless device of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection. The communications manager 820 can enable, be configured to, or be operable to support means for transmitting or receiving a link release message to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection via the second wireless link and based on establishing the first wireless link. The communications manager 820 can enable, be configured to, or be operable to support means for relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0121] By including or configuring the communications manager 820 in accordance with examples as described herein, the device 805 (e.g., at least one processor of the control receiver 810, the transmitter 815, the communications manager 820, or a combination thereof, or otherwise coupled to them) can support techniques for enhanced multi-hop relay connection mobility management, which can improve multi-hop relay connection communications by dynamically updating a path of a multi-hop relay connection.

[0122] Figure 9 A block diagram 900 of a device 905 that supports mobility handling for multi-hop relay connections is shown, in accordance with one or more aspects of the present disclosure. The device 905 can be an example of aspects of a device 805 or a UE 115 as described herein. The device 905 can include a receiver 910, a transmitter 915, and a communications manager 920. The device 905, or one or more components of the device 905 (e.g., the receiver 910, the transmitter 915, and the communications manager 920), can include at least one processor. The at least one processor of the device 905 can be coupled with at least one memory to support the described techniques. Each of these components can be in communication with one another (e.g., via one or more buses).

[0123] The receiver 910 can provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to mobility handling for multi-hop relay connections). Information can be passed on to other components of the device 905. The receiver 910 can utilize a single antenna or a set of multiple antennas.

[0124] The transmitter 915 can provide a means for transmitting signals generated by other components of the device 905. For example, the transmitter 915 can transmit information associated with various information channels (e.g., control channels, data channels, information channels related to mobility handling for multi-hop relay connections), such as packets, user data, control information, or any combination thereof. In some examples, the transmitter 915 can be collocated with the receiver 910 in a transceiver module. The transmitter 915 can utilize a single antenna or a set of multiple antennas.

[0125] The device 905, or various components thereof, can be an example of means for performing various aspects of mobility handling for multi-hop relay connections as described herein. For example, the communications manager 920 can include a link establishment component 925, a link release component 930, a message relay component 935, or any combination thereof. The communications manager 920 can be an example of aspects of the communications manager 820 as described herein. In some examples, the communications manager 920, or various components thereof, can be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or in conjunction with the receiver 910, the transmitter 915, or both. For example, the communications manager 920 can receive information from the receiver 910, transmit information to the transmitter 915, or be integrated in combination with the receiver 910, the transmitter 915, or both, to obtain information, output information, or perform various other operations as described herein.

[0126] The communications manager 920 can support wireless communications at a first wireless device in accordance with examples as disclosed herein. The link establishment component 925 can enable, be configured as, or be operable to support means for transmitting or receiving a link establishment message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection. The link release component 930 can enable, be configured as, or be operable to support means for transmitting or receiving a link release message via the second wireless link and based on establishing the first wireless link to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection. The message relay component 935 can enable, be configured as, or be operable to support means for relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0127] Figure 10A block diagram 1000 illustrating the communication manager 1020 that supports mobility handling for multi-hop relay connections in accordance with one or more aspects of the present disclosure is shown. The communication manager 1020 can be an example of aspects of a communication manager 820, a communication manager 920, or both, as described herein. The communication manager 1020, or various components thereof, can be an example of means for performing various aspects of mobility handling for multi-hop relay connections as described herein. For example, the communication manager 1020 can include a link establishment component 1025, a link release component 1030, a message relay component 1035, a device discovery component 1040, a trigger sending component 1045, a control information receiving component 1050, a control information sending component 1055, or any combination thereof. Each of these components, or the components or sub-components thereof (e.g., one or more processors, one or more memories), can communicate, directly or indirectly, with one another (e.g., via one or more buses).

[0128] The communication manager 1020 can support wireless communication at a first wireless device in accordance with examples as disclosed herein. The link establishment component 1025 can enable, be configured as, or be operable to support means for transmitting or receiving a link establishment message based on a trigger to perform a relay reselection procedure and a selection of a second wireless device as part of the relay reselection procedure to establish a first wireless link between the first wireless device and the second wireless device, where the first wireless device is one wireless device of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection. The link release component 1030 can enable, be configured as, or be operable to support means for transmitting or receiving a link release message via the second wireless link and based on establishing the first wireless link to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection. The message relay component 1035 can enable, be configured as, or be operable to support means for relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0129] In some examples, the device discovery component 1040 can enable, be configured as, or be operable to support means for discovering at least the second wireless device based on the trigger, where transmitting or receiving the link establishment message is based on discovering at least the second wireless device.

[0130] In some examples, the trigger is based on a quality of the second wireless link, a radio link failure associated with at least one wireless link of the multi-hop wireless connection, a number of the group of multiple wireless devices, or any combination thereof.

[0131] In some examples, the link establishment message is transmitted based on a trigger corresponding to an expiration of a timer.

[0132] In some examples, the trigger transmitting component 1045 can be, be configured as, or be operable with a means for transmitting, to the source wireless device, an indication of the trigger to perform the relay reselection procedure.

[0133] In some examples, the control information receiving component 1050 can be, be configured as, or be operable with a means for receiving, from the third wireless device, an indication that a third wireless link between the third wireless device and a fourth wireless device has experienced radio link failure, where the link establishment message is transmitted based on the indication.

[0134] In some examples, the control information transmitting component 1055 can be, be configured as, or be operable with a means for transmitting, to the source wireless device, the indication via a fourth wireless link between the first wireless device and the source wireless device. In some examples, the link releasing component 1030 can be, be configured as, or be operable with a means for receiving, from the source wireless device, a second link release message for terminating the fourth wireless link via the fourth wireless link and based on transmitting the indication. In some examples, the link establishing component 1025 can be, be configured as, or be operable with a means for receiving, from the source wireless device, a second link establishment message for reestablishing the fourth wireless link.

[0135] In some examples, the control information receiving component 1050 can be, be configured as, or be operable with a means for transmitting or receiving an indication that a third wireless link between the fourth wireless device and a destination wireless device has been terminated and a fourth wireless link between a fifth wireless device and the destination wireless device has been established. In some examples, the control information transmitting component 1055 can be, be configured as, or be operable with a means for transmitting, to the source wireless device, the indication via the multi-hop wireless connection.

[0136] In some examples, the destination wireless device is a second UE; or the destination wireless device is a network entity.

[0137] Figure 11A diagram illustrating a system 1100 including a device 1105 that supports mobility handling for multi-hop relay connections in accordance with one or more aspects of the present disclosure is shown. The device 1105 can be an example of or include the components of a device 805, a device 905, or a UE 115 as described herein. The device 1105 can communicate with one or more network entities 105, one or more UEs 115, or any combination thereof (e.g., wirelessly). The device 1105 can include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communications manager 1120, an input / output (I / O) controller 1110, a transceiver 1115, an antenna 1125, at least one memory 1130, code 1135, and at least one processor 1140. These components can be in electronic communication or otherwise

[0138] The I / O controller 1110 can manage input and output signals for the device 1105. The I / O controller 1110 can also manage peripherals not integrated into the device 1105. In some cases, the I / O controller 1110 can represent a physical connection or port to an external peripheral. In some cases, the I / O controller 1110 can utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, ® ® ® ® ® ® ® UNIX®, LINUX®, or another known operating system. Additionally or alternatively, the I / O controller 1110 can represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I / O controller 1110 can be implemented as part of one or more processors, such as the at least one processor 1140. In some cases, a user can interact with the device 1105 via the I / O controller 1110 or via hardware components controlled by the I / O controller 1110.

[0139] ​​​​​​In some cases, the device 1105 can include a single antenna 1125. However, in some other cases the device 1105 can have more than one antenna 1125, which can be capable of concurrently sending or receiving multiple wireless transmissions. The transceiver 1115 can communicate bi-directionally, via one or more antennas 1125, wired, or wireless links as described herein. For example, the transceiver 1115 can represent a wireless transceiver and can communicate bi-directionally with another wireless transceiver. The transceiver 1115 can also include a modem to modulate the packets and to demodulate packets received from one or more antennas 1125. The transceiver 1115, or the transceiver 1115 and one or more antennas 1125, can be an example of a transmitter 815, a transmitter 915, a receiver 810, a receiver 910, or any combination thereof, or components thereof, as described herein.

[0140] The at least one memory 1130 can include random access memory (RAM) and read-only memory (ROM). The at least one memory 1130 can store computer-readable, computer-executable code 1135 including instructions that, when executed by the at least one processor 1140, cause the device 1105 to perform various functions described herein. The code 1135 can be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 1135 can not be directly executable by the at least one processor 1140 but can cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the at least one memory 1130 can include, among other things, a basic I / O system (BIOS), which can control basic hardware or software operation such as the interaction with peripheral components or devices.

[0141] The at least one processor 1140 can include an intelligent hardware device, (e.g., a general- purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the at least one processor 1140 can be configured to operate a memory array using a memory controller. In some other cases, a memory controller can be integrated into the at least one processor 1140. The at least one processor 1140 can be configured to execute computer-readable instructions stored in a memory (e.g., the at least one memory 1130) to cause the device 1105 to perform various functions (e.g., functions or tasks supporting mobility handling for multi-hop relay connections). For example, the device 1105 or a component of the device 1105 can include the at least one processor 1140 and the at least one memory 1130 coupled with or to the at least one processor 1140, the at least one processor 1140 and the at least one memory 1130 configured to perform various functions described herein. In some examples, the at least one processor 1140 can include a plurality of processors, and the at least one memory 1130 can include a plurality of memories. One or more processors in the plurality of processors can be coupled with one or more memories in the plurality of memories, which can be individually or collectively configured to perform various functions herein.

[0142] The communications manager 1120 can support wireless communication at a first wireless device in accordance with examples as disclosed herein. For example, the communications manager 1120 can be, be configured to, or be operable to support means for transmitting or receiving a link establishment message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one wireless device of a group of multiple wireless devices for relaying communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection. The communications manager 1120 can be, be configured to, or be operable to support means for transmitting or receiving a link release message to terminate a second wireless link between the first wireless device and a third wireless device of the multi-hop wireless connection via the second wireless link and based on establishing the first wireless link. The communications manager 1120 can be, be configured to, or be operable to support means for relaying one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection using the first wireless link.

[0143] By including or configuring the communication manager 1120 in accordance with examples as described herein, the device 1105 can support techniques for enhanced multi-hop relay connection mobility management, which can improve multi-hop relay connection communications by dynamically updating a path of a multi-hop relay connection.

[0144] In some examples, the communication manager 1120 can be configured to use, or otherwise be associated with, the transceiver 1115, the one or more antennas 1125, or any combination thereof, to perform various operations (e.g., receiving, monitoring, transmitting). Although the communication manager 1120 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1120 can be supported by, or performed by, the at least one processor 1140, the at least one memory 1130, the code 1135, or any combination thereof. For example, the code 1135 can include instructions executable by the at least one processor 1140 to cause the device 1105 to perform various aspects of mobility handling for multi-hop relay connections as described herein, or the at least one processor 1140 and the at least one memory 1130 can be otherwise configured to, individually or collectively, perform or support performance of such operations.

[0145] Figure 12 A flow diagram illustrating a method 1200 that supports mobility handling for multi-hop relay connections in accordance with aspects of the present disclosure is shown. The operations of method 1200 can be implemented by a UE or its components as described herein. For example, the operations of method 1200 can be performed by a UE 115 as described with reference to Figure 1 to Figure 11 In some examples, a UE can execute a set of instructions to control its functional elements to perform the described functions. Additionally or alternatively, the UE can perform aspects of the described functions using special-purpose hardware.

[0146] At 1205, the method can include transmitting or receiving a link establishment message to establish a first wireless link between the first wireless device and a second wireless device based on a trigger to perform a relay reselection procedure and a selection of the second wireless device as part of the relay reselection procedure, where the first wireless device is one of a group of multiple wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection. The operations of block 1205 can be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1205 can be performed by a link establishment component 1025 as described with reference to Figure 10

[0147] ​At 1210, the method can include transmitting or receiving, via the second wireless link and based on establishing the first wireless link, a link release message to terminate a second wireless link of the multi-hop wireless connection between the first wireless device and a third wireless device. The operations of block 1210 can be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1210 can be performed by a link release component 1030 as described with reference to Figure 10

[0148] At 1215, the method can include relaying, using the first wireless link, one or more messages between a source wireless device and a destination wireless device via the multi-hop wireless connection. The operations of block 1215 can be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1215 can be performed by a message relay component 1035 as described with reference to Figure 10

[0149] An overview of aspects of the disclosure is provided below.

[0150] Aspect 1 : A method for wireless communication at a first wireless device, comprising: transmitting or receiving, based at least in part on a trigger to perform a relay reselection procedure and a selection of a second wireless device as part of the relay reselection procedure, a link establishment message to establish a first wireless link between the first wireless device and the second wireless device, wherein the first wireless device is one of a plurality of wireless devices to relay communications via a multi-hop wireless connection established between a source wireless device and a destination wireless device, the first wireless link to replace a second wireless link of the multi-hop wireless connection; transmitting or receiving, via the second wireless link and based at least in part on establishing the first wireless link, a link release message to terminate the second wireless link of the multi-hop wireless connection between the first wireless device and a third wireless device; and relaying, using the first wireless link, one or more messages between the source wireless device and the destination wireless device via the multi-hop wireless connection.

[0151] Aspect 2: The method of aspect 1, further comprising discovering at least the second wireless device based at least in part on the trigger, wherein transmitting or receiving the link establishment message is based at least in part on discovering at least the second wireless device.

[0152] Aspect 3: The method of any one of aspects 1 -2, wherein the trigger is based at least in part on a quality of the second wireless link, a radio link failure associated with at least one wireless link of the multi-hop wireless connection, a number of the plurality of wireless devices, or any combination thereof.

[0153] ​​Aspect 4: The method of any one of aspects 1 through 3, wherein the link establishment message is transmitted based at least in part on the trigger corresponding to an expiration of a timer.

[0154] Aspect 5: The method of any one of aspects 1 through 4, further comprising transmitting, to the source wireless device, an indication of the trigger to perform the relay reselection procedure.

[0155] Aspect 6: The method of any one of aspects 1 through 5, further comprising receiving, from the third wireless device, an indication that a third wireless link between the third wireless device and a fourth wireless device has experienced a radio link failure, wherein the link establishment message is transmitted based at least in part on the indication.

[0156] Aspect 7: The method of aspect 6, further comprising transmitting, to the source wireless device via a fourth wireless link between the first wireless device and the source wireless device, the indication; receiving, via the fourth wireless link and based at least in part on transmitting the indication, a second link release message to terminate the fourth wireless link; and receiving, from the source wireless device, a second link establishment message to reestablish the fourth wireless link.

[0157] Aspect 8: The method of any one of aspects 1 through 7, further comprising transmitting or receiving an indication that a third wireless link between a fourth wireless device and the destination wireless device has been terminated and a fourth wireless link between a fifth wireless device and the destination wireless device has been established; and transmitting, to the source wireless device via the multi-hop wireless connection, the indication.

[0158] Aspect 9: The method of any one of aspects 1 through 8, wherein the source wireless device is a first UE, and wherein the destination wireless device is a second UE; or the destination wireless device is a network entity.

[0159] Aspect 10: A first wireless device for wireless communication, comprising: one or more memories storing processor-executable code; and one or more processors coupled with the one or more memories and capable of individually or collectively executing the code to cause the first wireless device to perform the method of any of aspects 1 through 9.

[0160] Aspect 11: A first wireless device for wireless communication, comprising at least one means for performing the method of any of aspects 1 through 9.

[0161] Aspect 12: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of any of aspects 1 through 9.

[0162] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps can be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods can be combined.

[0163] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system can be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology can be used in much of the description, aspects of the described technology can be applicable to any wireless communication system, including other cellular systems and non-cellular wireless systems.

[0164] Information and signals described herein can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the description can be represented by voltages, currents, electromagnetic waves, magnetic fields, or particles, optical fields, or particles, or any combination thereof.

[0165] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). The various functions and operations described herein as being able to be performed by the processor can alternatively be performed by the processor in combination with one or more other processors.

[0166] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions can be stored or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

[0167] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium can be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Any of the functions or operations described herein can be performed by a plurality of memories capable of executing the described functions or operations either individually or collectively.

[0168] As used herein, including in the claims, “or” as used in a list of items (for example, the

[0169] As used herein, including in the claims, the article “a” is used as an open- ended Therefore, the terms “a,” “at least one,” “one or more,” and “at least one of’ can be

[0170] The term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, looking up (such as via a table, a database, or another data structure), ascertaining and the like. Also, “determining” can include receiving (such as receiving information), accessing (such as accessing data in a memory), and the like. Also, “determining” can include resolving, selecting, choosing, establishing, and other such similar

[0171] In the drawings, like reference numerals can be used to denote similar components throughout the several views. Additionally, various components of the same type can be distinguished from each other by a second label appended to the reference numeral, e.g., "100a" and "100b" can represent the same type of component but serving different functions. If only the first reference numeral is used in the specification, the description can be applied to any one of the similar components having the same first reference numeral, unless otherwise indicated.

[0172] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that can be implemented or that are within the scope of the claims. The term "example" is used herein to mean "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0173] The description herein is presented to enable any person skilled in the art to practice the present disclosure. Various modifications to the disclosure can be made by persons skilled in the art, and the disclosure can be applied to other situations other than the one specifically described herein, without departing from the scope of the present disclosure. Accordingly, the disclosure is not intended to be limited to the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A first wireless device for wireless communication, the first wireless device comprising: One or more memories, wherein the one or more memories store processor-executable code; and One or more processors, said one or more processors coupled to said one or more memories and capable of operating individually or jointly to execute said code to enable the first wireless device: The link establishment message is sent or received at least in part based on the triggering of the relay reselection process and the selection of a second wireless device as part of the relay reselection process to establish a first wireless link between the first wireless device and the second wireless device, wherein the first wireless device is one of a plurality of wireless devices used to relay communication via a multi-hop wireless connection established between a source wireless device and a destination wireless device, and the first wireless link is used to replace the second wireless link of the multi-hop wireless connection. The second wireless link between the first wireless device and the third wireless device is used to terminate the multi-hop wireless connection by sending or receiving a link release message via the second wireless link and at least in part based on the establishment of the first wireless link; as well as One or more messages are relayed between the source wireless device and the destination wireless device using the first wireless link via the multi-hop wireless connection.

2. The first wireless device of claim 1, wherein the one or more processors are individually or jointly further operable to execute the code to cause the first wireless device to: The discovery of at least the second wireless device is based at least in part on the trigger, wherein sending or receiving the link establishment message is based at least in part on the discovery of at least the second wireless device.

3. The first wireless device of claim 1, wherein the triggering is based at least in part on the quality of the second wireless link, a radio link failure associated with at least one wireless link of the multi-hop wireless connection, the number of the plurality of wireless devices, or any combination thereof.

4. The first wireless device of claim 1, wherein the link establishment message is sent at least in part based on the trigger corresponding to the expiration of a timer.

5. The first wireless device of claim 1, wherein the one or more processors are individually or jointly further operable to execute the code to cause the first wireless device to: Send an instruction to the source wireless device to trigger the relay reselection process.

6. The first wireless device of claim 1, wherein the one or more processors are individually or jointly further operable to execute the code to cause the first wireless device to: The third wireless device receives an indication that a radio link failure has occurred between the third wireless device and the fourth wireless device, wherein the link establishment message is sent at least in part based on the indication.

7. The first wireless device of claim 6, wherein the one or more processors are individually or jointly further operable to execute the code to cause the first wireless device to: The instruction is sent to the source wireless device via a fourth wireless link between the first wireless device and the source wireless device. Receive a second link release message for terminating the fourth wireless link via the fourth wireless link and at least in part based on sending the instruction; as well as Receive a second link establishment message from the source wireless device for reconstructing the fourth wireless link.

8. The first wireless device of claim 1, wherein the one or more processors are individually or jointly further operable to execute the code to cause the first wireless device to: Sending or receiving an indication that the third wireless link between the fourth wireless device and the destination wireless device has been terminated and that the fourth wireless link between the fifth wireless device and the destination wireless device has been established; and The instruction is sent to the source wireless device via the multi-hop wireless connection.

9. The first wireless device of claim 1, wherein the first wireless device is a first user equipment (UE), and wherein: The destination wireless device is a second UE; or The destination wireless device is a network entity.

10. A method for wireless communication by a first wireless device, the method comprising: The link establishment message is sent or received at least in part based on the triggering of the relay reselection process and the selection of a second wireless device as part of the relay reselection process to establish a first wireless link between the first wireless device and the second wireless device, wherein the first wireless device is one of a plurality of wireless devices used to relay communication via a multi-hop wireless connection established between a source wireless device and a destination wireless device, and the first wireless link is used to replace the second wireless link of the multi-hop wireless connection. The second wireless link between the first wireless device and the third wireless device is used to terminate the multi-hop wireless connection by sending or receiving a link release message via the second wireless link and at least in part based on the establishment of the first wireless link; as well as One or more messages are relayed between the source wireless device and the destination wireless device using the first wireless link via the multi-hop wireless connection.

11. The method according to claim 10, further comprising: The discovery of at least the second wireless device is based at least in part on the trigger, wherein sending or receiving the link establishment message is based at least in part on the discovery of at least the second wireless device.

12. The method of claim 10, wherein the triggering is based at least in part on the quality of the second wireless link, a radio link failure associated with at least one wireless link of the multi-hop wireless connection, the number of the plurality of wireless devices, or any combination thereof.

13. The method of claim 10, wherein the link establishment message is sent at least in part based on the trigger corresponding to the expiration of a timer.

14. The method according to claim 10, further comprising: Send an instruction to the source wireless device to trigger the relay reselection process.

15. The method according to claim 10, further comprising: The third wireless device receives an indication that a radio link failure has occurred between the third wireless device and the fourth wireless device, wherein the link establishment message is sent at least in part based on the indication.

16. The method according to claim 15, further comprising: The instruction is sent to the source wireless device via a fourth wireless link between the first wireless device and the source wireless device. Receive a second link release message for terminating the fourth wireless link via the fourth wireless link and at least in part based on sending the instruction; as well as Receive a second link establishment message from the source wireless device for reconstructing the fourth wireless link.

17. The method of claim 10, further comprising: Send or receive an indication that the third wireless link between the fourth wireless device and the destination wireless device has been terminated and that the fourth wireless link between the fifth wireless device and the destination wireless device has been established; as well as The instruction is sent to the source wireless device via the multi-hop wireless connection.

18. The method of claim 10, wherein the source radio device is a first user equipment (UE), and wherein: The destination wireless device is a second UE; or The destination wireless device is a network entity.

19. A non-transitory computer-readable medium storing code for wireless communication at a first wireless device, the code comprising instructions executable by one or more processors to: The link establishment message is sent or received at least in part based on the triggering of the relay reselection process and the selection of a second wireless device as part of the relay reselection process to establish a first wireless link between the first wireless device and the second wireless device, wherein the first wireless device is one of a plurality of wireless devices used to relay communication via a multi-hop wireless connection established between a source wireless device and a destination wireless device, and the first wireless link is used to replace the second wireless link of the multi-hop wireless connection. The second wireless link between the first wireless device and the third wireless device is used to terminate the multi-hop wireless connection by sending or receiving a link release message via the second wireless link and at least in part based on the establishment of the first wireless link; as well as One or more messages are relayed between the source wireless device and the destination wireless device using the first wireless link via the multi-hop wireless connection.

20. The non-transitory computer-readable medium of claim 19, wherein the instructions are further executable by the one or more processors to: The discovery of at least the second wireless device is based at least in part on the trigger, wherein sending or receiving the link establishment message is based at least in part on the discovery of at least the second wireless device.

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