Forward Handover Procedure for L2 Relay Mobility

Abstract

Methods, systems, and devices for wireless communications are described. A base station may identify a relay pairing between a user equipment (UE) and a relay UE. The base station may further identify a configuration of the relay UE based on a handover decision related to the relay pairing. The base station may indicate to the UE the configuration of the relay UE, an identifier of the relay UE, and that the UE switches to a sidelink communication link with the relay UE. The UE may then establish a sidelink communication link with the relay UE and indicate to the relay UE that the sidelink communication link is for a handover related to the relay pairing between the UE and the relay UE. Based on receiving an indication that the sidelink communication link is for a handover related to the relay pairing, the relay UE may perform a connection setup procedure with the base station.

Description

[Technical field]

[0001] The following relates to wireless communications, including forward handover procedures for Layer 2 (L2) relay mobility. [Background technology]

[0002]

[0002] Wireless communication systems have been widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasts, and the like. These systems may be capable of supporting communication with multiple users by sharing 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), LTE Advanced (LTE-A), or LTE-A Pro systems, and fifth generation (5G) systems, sometimes referred to as New Radio (NR) systems. These systems may employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, sometimes known as user equipment (UE).

[0003]

[0003] Some wireless communication networks may support relay or sidelink communications to extend coverage and improve reliability between devices in the network. However, conventional techniques for establishing and maintaining sidelinks may be flawed. Summary of the Invention

[0004]

[0004] The described techniques relate to improved methods, systems, devices, and apparatuses that support handover procedures (e.g., forward handover procedures) for Layer 2 (L2) relay mobility. Generally, the described techniques provide a user equipment (UE) (e.g., a remote UE) that communicates with a base station via a relay UE. The base station may identify a handover decision to switch the remote UE from direct communication with the base station to communication with the base station via the relay UE. In some cases, the base station may select a relay UE from a set of candidate relay UEs to enable the remote UE to communicate with the base station via the relay UE. The base station may further identify a configuration of the relay UE based on the handover decision related to a relay pairing. The base station may indicate to the remote UE the configuration of the relay UE, an identifier of the relay UE, and that the remote UE switches to a sidelink communications link with the relay UE. The remote UE may then establish a sidelink communication link with the relay UE and indicate to the relay UE that the sidelink communication link is for a handover associated with the relay pairing. Based on receiving an indication that the sidelink communication link is for a handover associated with the relay pairing, the relay UE may perform a connection setup procedure or a connection resumption procedure with the base station. In some cases, performing a connection setup or connection resumption procedure may trigger the relay UE to establish or resume a connection with the base station. Thus, the relay UE may transition from an idle or inactive state to a connected state that may enable a relay link between the remote UE and the base station via the relay UE.

[0005] A method for wireless communication in a base station is described, which may include identifying a relay pairing between a UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, identifying a configuration of the relay UE based on a handover decision associated with the relay pairing, and sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE.

[0006] An apparatus for wireless communication in a base station is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify a relay pairing between a UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, identify a configuration of the relay UE based on a handover decision associated with the relay pairing, and send a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE.

[0007] Another apparatus for wireless communication in a base station is described, which may include means for identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, means for identifying a configuration of the relay UE based on a handover decision related to the relay pairing, and means for transmitting a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE.

[0008] A non-transitory computer-readable medium storing code for wireless communication in a base station is described. The code may include instructions executable by a processor to identify a relay pairing between a UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, identify a configuration of the relay UE based on a handover decision associated with the relay pairing, and send a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE.

[0009]

[0009] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for receiving a setup request message from the relay UE based on a sidelink communication link between the UE and the relay UE, establishing a first signaling radio bearer for the relay UE based on receiving the setup request message, and sending a connection setup complete message to the relay UE including an indication of the first signaling radio bearer.

[0010]

[0010] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based on a configuration of the relay UE, and sending a reconfiguration complete message to the relay UE including an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof.

[0011]

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for receiving a connection re-establishment request message from the UE via the relay UE based on a relay pairing between the UE and the relay UE, identifying context information related to the relay UE, and sending a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, where sending the connection re-establishment message may be based on identifying context information related to the relay UE.

[0012]

[0012] In some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification, the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof may be established after receiving a connection re-establishment request message from the UE.

[0013]

[0013] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, identifying context information related to the relay UE may include sending a request for context information related to the relay UE to an anchor base station associated with the relay UE, where the request for the context information may be based on receiving a connection re-establishment request message from the UE, and receiving the context information related to the relay UE from the anchor base station based on the request for the context information.

[0014]

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for receiving a measurement report from the UE, where the measurement report includes an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, where relay pairing may be based on the measurement report.

[0015]

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for generating a handover command for the UE based on the handover decision.

[0016]

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based on the relay pairing, and releasing an access link with the UE based on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the message includes a radio resource control (RRC) reconfiguration message.

[0018] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the connection state of the relay UE includes an idle state or an inactive state.

[0019] A method for wireless communication in a relay UE is described. The method may include receiving, from the UE, a message for establishing a sidelink communication link with the UE, where the message includes an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE, sending a connection setup request message to a base station based on establishing the sidelink communication link with the UE, and receiving, in response to the connection setup request message, from the base station, a connection setup complete message including an indication of a first signaling radio bearer associated with the relay link for the relay pairing.

[0020] An apparatus for wireless communication in a relay UE is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a message for establishing a sidelink communication link with the UE, where the message includes an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE, send a connection setup request message to a base station based on establishing the sidelink communication link with the UE, and receive a connection setup complete message from the base station in response to the connection setup request message, the connection setup complete message including an indication of a first signaling radio bearer associated with the relay link for the relay pairing.

[0021] Another apparatus for wireless communication in a relay UE is described. The apparatus may include means for receiving, from the UE, a message for establishing a sidelink communication link with the UE, where the message includes an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE, means for sending a connection setup request message to a base station based on establishing the sidelink communication link with the UE, and means for receiving, in response to the connection setup request message, from the base station, a connection setup complete message including an indication of a first signaling radio bearer associated with the relay link for the relay pairing.

[0022] A non-transitory computer-readable medium storing code for wireless communication in a relay UE is described. The code may include instructions executable by a processor to: receive a message for establishing a sidelink communication link with the UE, where the message includes an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; send a connection setup request message to a base station based on establishing the sidelink communication link with the UE; and receive a connection setup complete message from the base station in response to the connection setup request message, the connection setup complete message including an indication of a first signaling radio bearer associated with the relay link for the relay pairing.

[0023]

[0023] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for sending a reconfiguration request message to the base station based on receiving the connection setup complete message, and receiving a reconfiguration complete message from the base station that includes an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof.

[0024]

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for relaying a connection re-establishment request message from the UE to a base station based on a relay pairing between the UE and a relay UE, and relaying a connection re-establishment message from the base station to the UE in response to the connection re-establishment request message.

[0025]

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the connection re-establishment request message and the connection re-establishment message may be relayed before receiving a reconfiguration complete message from the base station.

[0026]

[0026] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the connection state of the relay UE includes an idle state or an inactive state.

[0027] A method for wireless communication in a UE is described, which may include receiving, from a base station, a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE, sending, to the relay UE, a second message for establishing a sidelink communication link with the relay UE, where the second message includes an indication that the sidelink communication link is for a handover related to the relay pairing, and receiving, from the relay UE, a third message in response to the second message, configuring the sidelink communication link with the relay UE.

[0028] An apparatus for wireless communication in a UE is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE; send a second message to the relay UE to establish a sidelink communication link with the relay UE, where the second message includes an indication that the sidelink communication link is for a handover related to the relay pairing; and receive a third message from the relay UE in response to the second message, configuring the sidelink communication link with the relay UE.

[0029] Another apparatus for wireless communication in a UE is described. The apparatus may include means for receiving, from a base station, a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communication link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE, means for sending, to the relay UE, a second message for establishing a sidelink communication link with the relay UE, where the second message includes an indication that the sidelink communication link is for a handover related to the relay pairing, and means for receiving, from the relay UE, a third message configuring the sidelink communication link with the relay UE in response to the second message.

[0030] A non-transitory computer-readable medium storing code for wireless communications in a UE is described. The code may include instructions executable by a processor to receive, from a base station, a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE; send, to the relay UE, a second message for establishing a sidelink communications link with the relay UE, where the second message includes an indication that the sidelink communications link is for a handover associated with the relay pairing; and receive, from the relay UE, a third message in response to the second message, configuring the sidelink communications link with the relay UE.

[0031]

[0031] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for sending a measurement report to a base station, where the measurement report includes an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and where relay pairing may be based on the measurement report.

[0032]

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for sending a connection re-establishment request message to a base station via the relay UE based on a relay pairing between the UE and the relay UE, and receiving a connection re-establishment message from the base station via the relay UE in response to the connection re-establishment request message.

[0033]

[0033] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for releasing an access link between the UE and a source base station based on receiving a connection re-establishment message via the relay UE, where the source base station may be different from the base station.

[0034]

[0034] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for releasing an access link between the UE and a source base station based on receiving the first message, where the source base station may be different from the base station. [Brief description of the drawings]

[0035] [Figure 1] FIG. 1 illustrates an example of a wireless communication system supporting a forward handover procedure for Layer 2 (L2) relay mobility in accordance with an aspect of the present disclosure. [Diagram 2]

[0036] FIG. 2 illustrates an example of a wireless communication system supporting a forward handover procedure for L2 relay mobility, according to an aspect of the present disclosure. [Diagram 3]

[0037] 1 illustrates an example process flow in a system supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 4]1 illustrates an example process flow in a system supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Diagram 5]

[0038] 1 is a block diagram of a device supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 6] 1 is a block diagram of a device supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 7]

[0039] 1 illustrates a block diagram of a communications manager supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 8]

[0040] FIG. 1 illustrates a diagram of a system including a device that supports a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 9]

[0041] 1 is a block diagram of a device supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 10] 1 is a block diagram of a device supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 11]

[0042] 1 illustrates a block diagram of a communications manager supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 12]

[0043] FIG. 1 illustrates a diagram of a system including a device that supports a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 13]

[0044] 1 is a flow chart illustrating a method for supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 14] 1 is a flow chart illustrating a method for supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 15]1 is a flow chart illustrating a method for supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 16] 1 is a flow chart illustrating a method for supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. [Figure 17] 1 is a flow chart illustrating a method for supporting a forward handover procedure for L2 relay mobility, according to an aspect of the disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036]

[0045] In some wireless communication networks, user equipment (UE) may utilize device-to-device (D2D) communication (sometimes referred to as sidelink communication), where a first UE may transmit data to a second UE in the network via a direct link or a sidelink. In some cases, sidelink communication may enable one or more remote UEs (e.g., UEs that are outside the coverage of the wireless network) to communicate with the network through a relay UE (e.g., UEs that are within the coverage of the wireless network). In some cases, relay communication may efficiently redirect traffic to and from remote UEs near the network, thus extending the coverage of the wireless network.

[0037]

[0046] To establish a relay connection between the UE and the relay UE, the base station may identify a relay pairing between the UE and the relay UE (e.g., from a set of relay UE candidates). For example, the UE may transmit one or more measurement reports to the base station. In some aspects, the remote UE may be mobile and may provide a measurement report to the base station based on the mobility of the UE (e.g., including measurements of one or more potential relay UEs while the UE is mobile). In some cases, the base station may identify a decision to handover the UE from direct communication with the base station to communication with the base station via a relay UE (e.g., based on the measurement report). Further, based on the measurement report, the base station may identify a relay pairing and a configuration of the relay UE associated with the relay pairing. The base station may then transmit a message to the UE indicating the configuration of the relay UE and an indication that the UE will switch to a sidelink communication link with the relay UE.

[0038]

[0047] In some examples, however, the relay UE may be in an inactive or idle connected state. In these examples, the relay UE may not be in a connected state and therefore may not be able to relay communications between the remote UE and the base station. Here, the relay UE may be triggered to become in a connected state (e.g., by performing a connection setup or connection resumption procedure with the base station) after establishing a sidelink communication link with the relay UE. For example, during a sidelink communication link setup procedure between the remote UE and the relay UE, the remote UE may indicate that the sidelink communication link is for a handover related to a relay pairing between the remote UE and the relay UE.

[0039]

[0048] Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are then described in the context of a process flow. Aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow charts relating to a forward handover procedure for Layer 2 (L2) relay mobility.

[0040]

[0049] FIG. 1 illustrates an example of a wireless communication system 100 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, a LTE Advanced (LTE-A) network, a LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof. The wireless communication system 100 may support triggering of a connection establishment or connection resumption procedure through a remote UE establishing a sidelink with a relay UE in an idle or inactive state.

[0041]

[0050] The base stations 105 may be distributed throughout a geographic area to form a wireless communication system 100 and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support communication of signals according to one or more radio access technologies.

[0042]

[0051] The UEs 115 may be distributed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be fixed, or mobile, or both at different times. The UEs 115 may be devices of different forms or with different capabilities. Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in FIG. 1.

[0043]

[0052] The base stations 105 may communicate with the core network 130, with each other, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface). The base stations 105 may communicate with each other over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130), or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

[0044]

[0053] One or more of the base stations 105 described herein may include or be referred to by one skilled in the art as a base transceiver station, radio base station, access point, radio transceiver, Node B, eNode B (eNB), Next Generation Node B or Giga Node B (any of which may be referred to as a gNB), Home Node B, Home eNode B, or other suitable terminology.

[0045]

[0054] The UE 115 may include or 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 a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. The UE 115 may also include or 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, the UE 115 may 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 Communication (MTC) device, among other examples, which may be implemented in various objects, such as an appliance, or a vehicle, a meter, among other examples.

[0046]

[0055] The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, which may act as relays at times, as shown in FIG. 1, as well as base stations 105 and network equipment, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples.

[0047]

[0056] The UE 115 and the base station 105 may wirelessly communicate with each other via one or more communication links 125 on one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier used for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP)) operated 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 may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates the operation of the carriers, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0048]

[0057] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition or control signaling that coordinates operation for other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be arranged according to a channel raster for discovery by the UE 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be made by the UE 115 over the carrier, or a carrier may be operated in a non-standalone mode where a connection is established using a different carrier (e.g., of the same or different radio access technology).

[0049]

[0058] The communication links 125 shown in the wireless communication system 100 may include uplink transmissions from the UE 115 to the base station 105 or downlink transmissions from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode).

[0050]

[0059] A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one of several determined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 Megahertz (MHz)) for a carrier of a particular radio access technology. The devices (e.g., the base station 105, the UE 115, or both) of the wireless communication system 100 may have a hardware configuration that supports communication on a particular carrier bandwidth or may be configurable to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a sub-band, BWP) or all of the carrier bandwidth.

[0051]

[0060] A signal waveform transmitted on a carrier may be composed of multiple subcarriers (e.g., using a multicarrier modulation (MCM) technique 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 may include one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements the UE 115 receives and the higher the order of the modulation scheme, the higher the data rate for the UE 115 may be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communication with the UE 115.

[0052]

[0061] One or more numerologies may be supported for a carrier, where the numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time, and communication for the UE 115 may be limited to one or more active BWPs.

[0053]

[0062] The time interval for the base station 105 or the UE 115 may be, for example, T s =1 / (Δf max N f ) seconds, where Δf max may represent the maximum subcarrier spacing supported, and N fmay represent the maximum discrete Fourier transform (DFT) size supported. The communication resource time intervals may be organized according to radio frames, each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0054]

[0063] Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into several slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on the subcarrier spacing. Each slot may include several symbol periods (e.g., depending on the length of a cyclic prefix prepended to each symbol period). In some wireless communications systems 100, a slot may be further divided into multiple minislots containing one or more symbols. Excluding the cyclic prefix, each symbol period may include one or more (e.g., N f A symbol period may include a sampling period of at least one symbol (symbol period). The duration of a symbol period may depend on the subcarrier spacing or the frequency operating band.

[0055]

[0064] A subframe, slot, minislot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may 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) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0056]

[0065] The physical channels may be multiplexed on the carriers according to various techniques. The physical control channels and the physical data channels may be multiplexed on the downlink carriers using, for example, one or more of a time division multiplexing (TDM), a frequency division multiplexing (FDM), or a hybrid TDM-FDM technique. A control region (e.g., a control resource set (CORESET)) for the physical control channel may be defined by a number of symbol periods and may span the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., a CORESET) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search the control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates at one or more aggregation levels configured in a cascaded manner. The aggregation levels for the control channel candidates may refer to a number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for sending control information to multiple UEs 115 and a UE-specific search space set for sending control information to a particular UE 115.

[0057]

[0066] Each base station 105 may provide communication coverage via one or more cells, e.g., macro cells, small cells, hot spots, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with the base station 105 (e.g., on a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) to distinguish neighboring cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 in which the logical communication entity operates. Such a cell may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or an exterior space between or overlapping with the geographic coverage area 110, among other examples.

[0058]

[0067] A macro cell generally covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs 115 subscribing to the service of a network provider supporting the macro cell. A small cell may be associated with a lower power base station 105 compared to a macro cell, and the small cell may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to UEs 115 subscribing to the service of a network provider, or may provide restricted access to UEs 115 having an association with a small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with a user at home or in the office). A base station 105 may support one or more cells and may also support communication on one or more cells using one or more component carriers.

[0059]

[0068] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, Narrowband IoT (NB-IoT), enhanced Mobile Broadband (eMBB)) that may provide access to different types of devices.

[0060]

[0069] In some examples, the base stations 105 are mobile and may therefore provide communication coverage to moving geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include heterogeneous networks in which different types of base stations 105 provide coverage to various geographic coverage areas 110, e.g., using the same or different radio access technologies.

[0061]

[0070] The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing and transmissions from different base stations 105 may not be aligned in time, in some examples. The techniques described herein may be used for either synchronous or asynchronous operation.

[0062]

[0071] Some UEs 115, such as MTC devices or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from devices that incorporate sensors or meters to measure or capture information and relay such information to a central server or application program that utilizes the information or presents the information to a human interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0063]

[0072] Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception, rather than transmission and reception simultaneously). In some examples, half-duplex communication may be implemented at a reduced peak rate. Other power saving techniques for the UE 115 include entering a power saving deep sleep mode when not engaged in active communication, operating on a limited bandwidth (e.g., pursuant to narrowband communication), or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of the carrier, or outside of the carrier.

[0064]

[0073] The wireless communication system 100 may be configured to support ultra-reliable or low latency communications, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low latency communications (URLLC) or mission-critical communications. The UE 115 may be designed to support ultra-reliable, low latency, or critical functions (e.g., mission-critical functions). Ultra-reliable communications may include private or group communications and may be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions may include service prioritization, and the mission-critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low latency, mission-critical, and ultra-reliable low latency may be used interchangeably herein.

[0065]

[0074] In some examples, the UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105 or may not be able to receive transmissions from the base station 105 in some cases. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication occurs between UEs 115 without the involvement of the base station 105.

[0066]

[0075] In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UE 115). In some examples, the vehicles may communicate using vehicle-to-anything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination thereof. The vehicles may signal information regarding traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some examples, the vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or a network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communication, or both.

[0067]

[0076] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) that routes packets or interconnection to external networks. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management, for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be forwarded through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entities may be connected to IP services 150 for one or more network operators. The IP services 150 may include access to the Internet, an intranet(s), an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0068]

[0077] Some of the network devices, such as the base station 105, may include subcomponents, such as an access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with the UE 115 through one or more other access network transmitting entities 145, which may be referred to as a radio head, a smart radio head, or a transmit / receive point (TRP). Each access network transmitting entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or integrated into a single network device (e.g., the base station 105).

[0069]

[0078] The wireless communication system 100 may operate using one or more frequency bands, for example, within a range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the 300 MHz to 3 GHz region is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately 1 decimeter to 1 meter in length. Although UHF waves may be blocked or redirected by buildings and environmental features, the waves may penetrate structures sufficiently for a macrocell to serve UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0070]

[0079] The wireless communication system 100 may also operate in the Super High Frequency (SHF) region, using a frequency band from 3 GHz to 30 GHz, also known as the centimeter band, or the Extremely High Frequency (EHF) region of the spectrum, also known as the millimeter band (e.g., from 30 GHz to 300 GHz). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of the respective devices may be smaller and more closely spaced than the UHF antennas. In some examples, this may facilitate the use of antenna arrays within the devices. However, propagation of EHF transmissions may experience greater atmospheric attenuation and shorter distances than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the designated use of bands across these frequency regions may vary by country or regulatory body.

[0071]

[0080] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices such as the base station 105 and the UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation in an unlicensed band may be based on a carrier aggregation configuration with a component carrier operating in a licensed band (e.g., LAA). Operation in an unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0072]

[0081] The base station 105 or UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located in one or more antenna arrays or antenna panels that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located in an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with the base station 105 may be located in various geographic locations. The base station 105 may have an antenna array with several rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panels may support radio frequency beamforming for signals transmitted through the antenna ports.

[0073]

[0082] A base station 105 or a UE 115 may use MIMO communications to exploit multipath signal propagation and increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may be transmitted by a transmitting device via, for example, different antennas or different combinations of antennas. Similarly, the multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits related to the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports used for channel measurements and reporting. MIMO techniques include single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0074]

[0083] Beamforming, sometimes also referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used in a transmitting or receiving device (e.g., base station 105, UE 115) to shape or steer an antenna beam (e.g., transmit beam, receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated through antenna elements of an antenna array such that some signals propagating in a particular orientation relative to the antenna array experience constructive interference and others experience destructive interference. Adjustment of signals communicated through antenna elements may include a transmitting or receiving device applying an amplitude offset, a phase offset, or both to signals conveyed through an antenna element associated with the device. The adjustment associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., relative to the antenna array of the transmitting or receiving device, or to some other orientation).

[0075]

[0084] The base station 105 or the UE 115 may use beam sweeping techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform a beamforming operation for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by the base station 105 in different directions. For example, the base station 105 may transmit signals according to different beamforming weight sets associated with different transmission directions. The transmissions in different beam directions may be used to identify beam directions (e.g., by a transmitting device such as the base station 105 or by a receiving device such as the UE 115) for subsequent transmission or reception by the base station 105.

[0076]

[0085] Some signals, such as data signals associated with a particular receiving device, may be transmitted by the base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as the UE 115). In some examples, the beam direction associated with the transmission along the single beam direction may be determined based on signals transmitted in one or more beam directions. For example, the UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and report to the base station 105 an indication of the signal received by the UE 115 with the best signal quality or an otherwise acceptable signal quality.

[0077]

[0086] In some examples, transmission by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a composite beam for transmission (e.g., from the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or amplicoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques have been described with respect to signals transmitted in one or more directions by the base station 105, the UE 115 may employ similar techniques for transmitting a signal multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., to transmit data to a receiving device).

[0078]

[0087] A receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directional listening) when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, the receiving device may attempt multiple receive directions by receiving via different antenna subarrays, by processing the received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of the antenna array, or by processing the received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of the antenna array, any of which may be referred to as "listening" according to different receive configurations or receive directions. In some examples, the receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0079]

[0088] The wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communication at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate on logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection, error correction, or both techniques to support retransmissions at the MAC layer to improve link efficiency. In the control plane, a Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between the UE 115 and the base station 105 or core network 130, which supports radio bearers for user plane data. In the physical layer, the transport channels may be mapped to physical channels.

[0080]

[0089] The UE 115 and the base station 105 may support retransmission of data to increase the likelihood that the data is successfully received. Hybrid Automatic Repeat Request (HARQ) feedback is one technique for increasing the likelihood that the data is accurately received on the communication link 125. HARQ may include a combination of error detection (e.g., using a Cyclic Redundancy Check (CRC)), forward error correction (FEC), and retransmission (e.g., Automatic Repeat Request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a particular slot for data received in a previous symbol in that slot. In other cases, the device may provide HARQ feedback in a subsequent slot or according to some other time interval.

[0081]

[0090] In some cases, the UE 115 may be transitioned from a serving base station 105 (known as a source base station) to another base station 105 (known as a target base station). For example, the UE 115 may move into the coverage area of ​​the target base station 105, or the target base station 105 may be able to better serve the UE 115 or relieve excessive load on the source base station 105. The transition may be referred to as a "handover." Prior to the handover, the source base station 105 may configure the UE 115 with a procedure to measure the signal quality of neighboring base stations 105. The UE 115 may then respond with a measurement report. The source base station 105 may use the measurement report to make a handover decision. The decision may also be based on radio resource management (RRM) factors such as network loading and interference mitigation. Once the handover decision is made, the source base station 105 may send a handover request message to the target base station 105, which may include context information to prepare the target base station 105 to serve the UE 115. The target base station 105 may make admission control decisions, for example, to ensure that it meets the quality of service (QoS) specifications of the UE 115. The target base station 105 may then configure resources for the receiving UE 115 and send a handover request acknowledgement message to the source base station 105, which may include RRC information that is passed to the UE 115. The source base station 105 may then instruct the UE 115 to perform the handover and pass a status transfer message to the target base station using Packet Data Convergence Protocol (PDCP) bearer status information. The UE 115 may attach to the target base station via a random access procedure.

[0082]

[0091] The UE 115 may operate according to various states or modes for communicating with the network. As an example, the UE 115 may operate in an RRC idle state (e.g., RRC_IDLE), an RRC inactive state (e.g., RRC_INACTIVE), and / or an RRC connected state (e.g., RRC_CONNECTED). The UE 115 may transition between various states or modes, for example, based on communication traffic for the UE 115. In the RRC idle state (sometimes referred to as an idle mode), the UE 115 may not be registered with a particular cell and thus may lack an access stratum (AS) context, and thus the UE 115 may not have an active RRC connection established with the network (e.g., via the base station 105). In the idle mode, the UE 115 may wake up periodically to monitor the channel for paging or other signaling, and the mobility of the UE 115 may be managed by the UE 115 when performing measurements of one or more cells. In the RRC connected state (sometimes referred to as connected mode), the UE 115 may have an established RRC connection (e.g., with the 5GC) in which the UE 115 may store AS context. Here, the UE 115 may belong to a known cell and may be identified using a Cell Radio Network Temporary Identifier (C-RNTI) assigned to the UE 115. During the connected mode, the UE 115 may monitor messages sent by the network, which may include monitoring various channels (e.g., paging channels or control channels, etc.).

[0083]

[0092] The RRC inactive state may be used to reduce signaling overhead and may provide an intermediate mode or state (e.g., between idle and connected) that may also be used to reduce latency when transitioning to another state (e.g., connected state). The UE 115 may wake up periodically during the inactive state to monitor for paging messages from the network, where the UE 115 may possibly perform a random access procedure to transition to a connected mode and communicate with the network.

[0084]

[0093] In the wireless communication system 100, the UEs 115 may utilize D2D communication (e.g., communication over a sidelink communication link), sometimes referred to as sidelink communication, where a first UE 115 may transmit data to a second UE 115 in the network via a direct link or a sidelink. In some cases, the sidelink communication may enable one or more remote UEs 115 (e.g., UEs 115 that are outside the coverage of a wireless network) to communicate with the network via a relay UE 115 (e.g., UEs 115 that are within the coverage of the wireless network). In some cases, the relay communication may efficiently redirect traffic to and from a remote UE 115 near the network, thus extending the coverage of the wireless network.

[0085]

[0094] To establish a relay connection between the UE 115 and the relay UE 115, the base station 105 may identify a relay pairing between the UE 115 and the relay UE 115 (e.g., from a set of relay UE candidates). For example, the UE 115 may transmit one or more measurement reports to the base station 105. In some aspects, the remote UE 115 may be mobile and may provide a measurement report to the base station based on the mobility of the UE 115 (e.g., including measurements of one or more potential relay UEs 115 while the UE 115 is mobile). In some cases, the base station 105 may decide (e.g., based on the measurement report) to handover the UE 115 from direct communication with the base station 105 to communication with the base station 105 via the relay UE 115. Further, based on the measurement report, the base station 105 may identify a relay pairing and a configuration of the relay UE 115 associated with the relay pairing. The base station 105 may then send a message to the UE 115 indicating the configuration of the relay UE 115 and an indication that the UE 115 will switch to a sidelink communication link with the relay UE 115.

[0086]

[0095] In some examples, however, the relay UE 115 may be in an inactive or idle connected state. In these cases, the relay UE 115 may not be in a connected state and therefore may not be able to relay communications between the remote UE 115 and the base station 105. Here, the relay UE 115 may be triggered to become in a connected state (e.g., by performing a connection setup or connection resumption procedure with the base station 105) after establishing a sidelink communication link with the relay UE 115. For example, during a sidelink communication link setup procedure between the remote UE 115 and the relay UE 115, the remote UE 115 may indicate that the sidelink communication link is for a handover related to a relay pairing between the remote UE 115 and the relay UE 115. Based on receiving an indication that the sidelink communication link is for a handover related to the relay pairing, the relay UE 115 may then perform a connection setup or connection resumption procedure with the base station 105 to become in a connected state.

[0087]

[0096] 2 illustrates an example of a wireless communication system 200 supporting a forward handover procedure for L2 relay mobility according to aspects of the disclosure. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100. For example, the wireless communication system 200 may include base station 105-a and UEs 115-a, 115-b, and 115-c, which may be examples of the base station 105 and UE 115 described with reference to FIG. 1. The base station 105-a may serve several cells or geographic coverage areas (e.g., geographic coverage area 110-a).

[0088]

[0097] In the wireless communication system 200, the UEs 115 may utilize D2D communication, where a first UE 115-a may transmit data to a second UE 115-b within a network coverage area 110-a via a direct link or a sidelink. In some cases, the sidelink communication may enable a remote UE 115 (e.g., a UE 115-a that is outside the coverage of a wireless network) to communicate with the network via a relay UE 115 (e.g., a UE 115-b or 115-c that is within the coverage of the wireless network). In some cases, the relay communication may efficiently redirect traffic to and from a remote UE 115 near the network, extending the coverage of the wireless network.

[0089]

[0098] In some examples, the relay selection may be performed according to L2 routing. During the L2 relay procedure, the relay UE 115-b may relay data below the PDCP layer. The user plane protocol stack 205 associated with the L2 relay includes a protocol data unit (PDU) connected to the PDCP layer, which is connected to the sidelink RLC layer. The PDU provided by the RLC layer is directed to a device to network (D2N) MAC entity, or a D2D MAC entity. The D2D MAC may provide a connection to the base station 105-a via a Uu interface, and the D2D MAC connects to the relay UE 115-b via a sidelink 225 (e.g., PC5). In some examples, the relay UE 115-b may forward the PC5 bearer and the Uu bearer using an adaptation layer function. In the user plane protocol stack 205, traffic may terminate at the core network, which may prevent direct communication between the remote UEs 115-a (e.g., the data radio bearers of the remote UE 115-a may be controlled by the network). Furthermore, in the user plane protocol stack 205, the network may be aware of the relay configuration between the remote UE 115-a and several relay UE candidates 115-b and 115-c and may select a sidelink relay pairing (e.g., a pairing between the remote UE 115-a and the relay UE 115-b) based on the link strength or quality of the relay link. Such relay selection by the network may increase the quality and reliability of the relay communications and may further extend the coverage of the wireless communication system.

[0090]

[0099] In the control plane protocol stack 210, the remote UE 115-a may include both a PC5 C-plane and an NR Uu C-plane. In some cases, the PC5 C-plane may be for setting up a unicast link before communicating with the base station 105-a via the relay UE 115-b. In some examples, the remote UE 115-a may support an NR Uu access stratum (AS) connection and a non-access stratum (NAS) connection (e.g., above the PC5 RLC layer). In addition, the NG-RAN may control the sidelink 225 (e.g., a PC5 link) via the NR RRC. In some examples, an adaptation layer may support multiplexing traffic associated with multiple UEs 115 on the relay UE 115-b Uu interface.

[0091]

[0100] In some cases, the UE 115-a may communicate directly with the base station 105-a before communicating with the base station 105-a via the relay UE 115-b. For example, the UE 115-a may conduct uplink and downlink communications directly with the base station 105-a. When the UE 115-a is communicating directly with the base station 105-a, the UE 115-a may transmit a measurement report to the base station 105-a. Additionally or alternatively, the UE 115-a may be mobile and may transmit a measurement report to the base station 105-a, where the measurement report may provide information regarding nearby candidate UEs 115 that may be selected for relay pairing (e.g., based on the mobility of the UE 115-a). The measurement report may indicate one or more parameters associated with each of the candidate relay UEs 115-b and 115-c. For example, the measurement report may indicate the connection state of the relay UEs 115-b and 115-c, an identifier for each relay UE 115-b and 115-c, and an indication of the context information of the relay UEs 115-b and 115-c.

[0092]

[0101] Based on receiving the measurement report from the UE 115-a, the base station 105-a may determine to perform a handover with the UE 115-a to switch from direct communication with the UE 115-a to communication with the UE 115-a via the relay UE 115-b. For example, the base station 105-a may identify a relay pairing between the UE 115-a and the relay UE 115-b. In some cases, the base station 105-a may decide to perform the handover based on determining that the signal quality of the communication between the UE 115-a and the base station 105-a may be improved by performing the handover. Furthermore, based on the measurement report, the base station 105-a may identify a relay pairing and a configuration of the relay UE 115-b associated with the relay pairing. The base station 105-a may then send a message to the UE 115-a indicating the configuration of the relay UE 115-b and an indication that the UE 115-a will switch to a sidelink communication link with the relay UE 115-b.

[0093]

[0102] In some examples, however, the relay UE 115-b may be in an inactive or idle connected state (e.g., RRC_INACTIVE or RRC_IDLE). When the relay UE 115-b is in an inactive or idle state, the relay UE 115-b may not be able to relay communication between the UE 115-a and the base station 105-a. For the relay UE 115-b to transition to a connected state, the relay UE 115-b may perform an RRC setup procedure (e.g., to transition from an idle state to a connected state) or an RRC resumption procedure (e.g., to transition from an inactive state to a connected state) with the base station 105-a.

[0094]

[0103] The relay UE 115-b may be triggered to perform an RRC setup procedure or an RRC restart procedure with the base station 105-a based on the sidelink setup procedure with the UE 115-a. For example, based on receiving a message from the base station 105-a indicating a configuration of the relay UE 115-b and an indication that the UE 115-a switches to a sidelink communication link with the relay UE 115-b, the UE 115-a may determine to perform a sidelink setup procedure with the relay UE 115-b. During the sidelink setup procedure between the UE 115 and the UE 115-b, the UE 115-a may send a message to establish a sidelink communication link with the UE 115-b, where the message includes an indication that the sidelink communication link is for a handover related to the relay pairing. Based on receiving an indication that the sidelink communication link is for a handover procedure, the relay UE 115-b may perform a connection setup procedure (e.g., an RRC setup procedure, an RRC restart procedure) with the base station 105-a. Thus, the relay UE 115-b may transition to a connected state, allowing the relay UE 115-b to relay communications between the UE 115-a and the base station 105-a.

[0095]

[0104] In some cases, a handover switching from direct communication with the UE 115 to communication with the UE 115 via a relay UE 115-b may further include a handover from the source base station 105-a to a different base station 105 (e.g., the target base station 105). For example, the handover between the source and target base stations 105 may be based on the mobility of the UE 115-a, or based on the relay UE 115-b selected for relay pairing, or some other reason. However, in some other cases, the source and target base stations 105 may be the same base station 105-a.

[0096]

[0105] FIG. 3 illustrates an example of a process flow 300 in a system supporting a forward handover procedure for L2 relay mobility according to an embodiment of the disclosure. The process flow 300 includes UEs 115-d and 115-e and base stations 105-b and 105-c, which may be examples of corresponding devices described with reference to FIGS. 1-2. In some cases, the source base station 105-b and the target base station 105-c may be the same base station 105. The following alternatives may be implemented, in which some steps are performed in a different order than described or not performed at all. In some cases, the steps may include additional features not mentioned below, or further steps may be added.

[0097]

[0106] The process flow 300 illustrates an example of a forward handover procedure (e.g., initiated by the remote UE 115-d) for switching the remote UE 115-d from direct communication with the base station 105b to communication with the base station 105c via the relay UE 115e when the relay UE 115-e is in an idle state (e.g., RRC_IDLE).

[0098]

[0107] At 310, the remote UE 115-d may communicate directly with the base station 105b (e.g., the source base station 105b). For example, the remote UE 115-d may transmit uplink data to the base station 105-b, and the base station 105-b may transmit downlink data to the remote UE 115-d.

[0099]

[0108] At 315, the remote UE 115-d may send a measurement report (e.g., a mobility trigger) to the base station 105-b. The measurement report may include an indication of the connection state of the relay UE 115-e (e.g., an RRC state of the relay UE 115-e), an identifier of the relay UE 115-e, a cell identifier of the relay UE 115-e, or any combination thereof. In some cases, the identifier of the relay UE 115-e may include a serving temporary mobile subscriber identity (S-TMSI), such as a 5G-S-TMSI or a hashed version of the 5G-S-TMSI.

[0100]

[0109] At 320, the source base station 105-b and the target base station 105-c may make a handover decision. For example, the base stations 105-b and 105-c may decide to handover the remote UE 115-d from direct communication with the source base station 105-b to communication with the target base station 105-c via the relay UE 115-e. In some cases, the source base station 105-b and the target base station 105-c may be the same. Here, the handover decision may involve switching the remote UE 115-d from direct communication with the base station 105 to communication with the base station 105 via the relay UE 115-e (e.g., handover from Uu to PC5). In either case, when the source base station 105-b makes the handover decision, the base station 105-b may identify a relay pairing between the remote UE 115-d and the relay UE 115-e. Additionally, the source base station 105-b may identify the configuration of the relay UE 115-e based on a handover decision associated with the relay pairing between the remote UE 115-d and the relay UE 115-e.

[0101]

[0110] At 325, the remote UE 115-d and the source base station 105-b may perform an RRC reconfiguration procedure. For example, the source base station 105-b may send a message indicating the configuration of the relay UE 115-e, an identifier of the relay UE 115-e, and an indication that the remote UE 115-d switches to a sidelink communication link (e.g., a PC5 link) with the relay UE 115-e. In some cases, the remote UE 115-d may release an access link (e.g., a Uu connection) with the source base station 105-b after performing the RRC reconfiguration procedure at 325.

[0102]

[0111] At 330, the remote UE 115-d and the relay UE 115-e may establish (e.g., set up and configure) a sidelink channel (e.g., a PC5 channel) based on the remote UE 115-d receiving a message from the source base station 105-b as part of the RRC reconfiguration procedure. In some examples, the remote UE 115-d may initiate the sidelink channel setup by sending a message to the relay UE 115-e to establish a sidelink communications link with the relay UE 115-e, where the message includes an indication that the sidelink communications link is for a handover associated with the relay pairing.

[0103]

[0112] At 335, the relay UE 115-e and the target base station 105-c may perform an RRC setup procedure. In some cases, the relay UE 115-e may determine to perform an RRC setup procedure with the target base station 105-c in response to receiving (e.g., from the remote UE 115-d at 330) an indication that the sidelink communication link is for a handover associated with the relay pairing. During the RRC setup procedure, the relay UE 115-e may send an RRC setup request message to the target base station 105-c. The target base station 105-c may establish a first signaling radio bearer (e.g., SRB0) for the relay UE 115-e based on receiving the RRC setup request message. The target base station 105-c may then send an RRC connection setup complete message to the relay UE 115-e, including an indication of the first signaling radio bearer.

[0104]

[0113] At 340, the relay UE 115-e and the target base station 105-c may perform an RRC reconfiguration procedure. For example, the relay UE 115-e may send an RRC reconfiguration request message to the target base station 105-c based on receiving the RRC connection setup complete message (e.g., at 335). The target base station 105-c may then establish a second signaling radio bearer (e.g., SRB1) for the relay link, or a data radio bearer (e.g., DRB) for the relay link, or both, based on the configuration of the relay UE's configuration 115-e and receiving the RRC reconfiguration request message. The target base station 105-c may then send an RRC reconfiguration complete message to the relay UE 115-e, where the RRC reconfiguration complete message includes the second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or both.

[0105]

[0114] At 345 and 350, the remote UE 115-d may send an RRC connection re-establishment request to the target base station 105-c. For example, at 345, the remote UE 115-d may send the RRC connection re-establishment request to the relay UE 115-e, which may relay (e.g., forward) the RRC connection re-establishment request to the target base station 105-c, at 350. In some examples, the remote UE 115-d may send the RRC re-establishment request to the relay UE 115-e before the relay UE 115-e and the target base station 105-c perform RRC setup and RRC reconfiguration procedures (e.g., at 335 and 340). Here, the relay UE 115-e and the target base station 105-c may perform RRC setup and RRC reconfiguration procedures after the relay UE 115-e receives an RRC connection re-establishment request from the remote UE 115-d at 345 (e.g., and before the relay UE 115-e relays the RRC connection re-establishment request to the target base station 105-c).

[0106]

[0115] At 355, the target base station 105-c may identify context information associated with the relay UE 115-e based on receiving the RRC connection re-establishment request from the remote UE 115-d via the relay UE 115-e.

[0107]

[0116] At 360 and 365, the target base station 105-c may send an RRC connection re-establishment message to the remote UE 115-d via the relay UE 115-e based on identifying context information related to the relay UE 115-e. For example, at 360, the target base station 105-c may send an RRC connection re-establishment message to the relay UE 115-e, and at 365, the relay UE 115-e may relay (e.g., forward) the RRC connection re-establishment message to the remote UE 115-d. In some cases, the remote UE 115-d may release an access link (e.g., Uu connection) with the source base station 105-b after receiving the RRC connection re-establishment message from the target base station 105-c at 365.

[0108]

[0117] At 370, the target base station 105-c may maintain an identifier (e.g., an L2 identifier) ​​for the relay UE 115-e and the remote UE 115-d (e.g., based on receiving an RRC reconfiguration complete message from the remote UE 115-d via the relay UE 115-e).

[0109]

[0118] At 375, the remote UE 115-d may optionally communicate with the target base station 105-c via the relay UE 115-e. For example, the remote UE 115-d may transmit uplink data to the target base station 105-c via the relay UE 115-e. Additionally, the base station 105-c may transmit downlink data to the remote UE 115-d via the relay UE 115-e.

[0110]

[0119] FIG. 4 illustrates an example of a process flow 400 in a system supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The process flow 400 includes UEs 115-f and 115-g and base stations 105-d and 105-e, which may be examples of corresponding devices described with reference to FIGS. 1-2. The process flow 400 may further include an anchor base station 405 associated with the relay UE 115-g. In some cases, the source base station 105-d and the target base station 105-e may be the same base station 105. Additionally or alternatively, the target base station 105-e and the anchor base station 405 may be the same base station 105. The following alternatives may be implemented in which some steps are performed in a different order than described or not performed at all. In some cases, the steps may include additional features not mentioned below or further steps may be added.

[0111]

[0120] Process flow 400 may illustrate an example of a forward handover procedure (e.g., initiated by the remote UE 115-f) for switching the remote UE 115-f from direct communication with the base station 105-d to communication with the base station 105-e via the relay UE 115-g when the UE 115-g is in an inactive state (e.g., RRC_INACTIVE).

[0112]

[0121] At 410, the remote UE 115-f may communicate directly with the base station 105-d (e.g., the source base station 105-d). For example, the remote UE 115-f may transmit uplink data to the base station 105-d, and the base station 105-d may transmit downlink data to the remote UE 115-f.

[0113]

[0122] At 415, the remote UE 115-f may send a measurement report (e.g., a mobility trigger) to the base station 105-d. The measurement report may include an indication of the connection state of the relay UE 115-g (e.g., an RRC state of the relay UE 115-g), an identifier of the relay UE 115-g, a cell identifier of the relay UE 115-g, or any combination thereof. In some cases, the identifier of the relay UE 115-g may include a Radio Network Temporary Identifier (RNTI), such as an inactive RNTI (I-RNTI) or a hashed version of the I-RNTI.

[0114]

[0123] At 420, the source base station 105-d and the target base station 105-e may make a handover decision. For example, the base stations 105-d and 105-e may decide to handover the remote UE 115-f from direct communication with the source base station 105-d to communication with the target base station 105-e via the relay UE 115-g. In some cases, the source base station 105-d and the target base station 105-e may be the same. Here, the handover decision may involve switching the remote UE 115-f from direct communication with the base station 105 to communication with the base station 105 via the relay UE 115-g (e.g., handover from Uu to PC5). In either case, when the source base station 105-d makes the handover decision, the base station 105-d may identify a relay pairing between the remote UE 115-f and the relay UE 115-g. Additionally, the source base station 105-d may identify the configuration of the relay UE 115-g based on a handover decision associated with the relay pairing between the remote UE 115-f and the relay UE 115-g.

[0115]

[0124] At 425, the remote UE 115-f and the source base station 105-d may perform an RRC reconfiguration procedure. For example, the source base station 105-d may send a message indicating the configuration of the relay UE 115-g, an identifier of the relay UE 115-g, and an indication that the remote UE 115-f switches to a sidelink communication link (e.g., a PC5 link) with the relay UE 115-g. In some cases, the remote UE 115-f may release an access link (e.g., a Uu connection) with the source base station 105-d after performing the RRC reconfiguration procedure at 425.

[0116]

[0125] At 430, the remote UE 115-f and the relay UE 115-g may establish (e.g., set up and configure) a sidelink channel (e.g., a PC5 channel) based on the remote UE 115-f receiving a message from the source base station 105-d as part of the RRC reconfiguration procedure. In some examples, the remote UE 115-f may initiate the sidelink channel setup by sending a message to the relay UE 115-g to establish a sidelink communications link with the relay UE 115-g, where the message includes an indication that the sidelink communications link is for a handover associated with the relay pairing.

[0117]

[0126] At 435, the relay UE 115-g and the target base station 105-e may perform an RRC restart procedure (e.g., resume a previously established RRC connection). In some cases, the relay UE 115-g may determine to perform an RRC restart procedure with the target base station 105-e in response to receiving (e.g., from the remote UE 115-f at 430) an indication that the sidelink communication link is for a handover associated with the relay pairing. During the RRC restart procedure, the relay UE 115-g may send an RRC Resume Request message to the target base station 105-e. The target base station 105-e may establish a first signaling radio bearer (e.g., SRB0) for the relay UE 115-g based on receiving the RRC Resume Request message. The target base station 105-e may then send an RRC Resume Complete message to the relay UE 115-g including an indication of the first signaling radio bearer.

[0118]

[0127] At 440, the relay UE 115-g and the target base station 105-e may perform an RRC reconfiguration procedure. For example, the relay UE 115-g may send an RRC reconfiguration request message to the target base station 105-e based on receiving the RRC restart complete message (e.g., at 435). The target base station 105-e may then establish a second signaling radio bearer (e.g., SRB1) for the relay link, or a data radio bearer (e.g., DRB) for the relay link, or both, based on the configuration of the relay UE 115-g and receiving the RRC reconfiguration request message. The target base station 105-e may then send an RRC reconfiguration complete message to the relay UE 115-g, where the RRC reconfiguration complete message includes the second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or both.

[0119]

[0128] At 445 and 450, the remote UE 115-f may send an RRC connection re-establishment request to the target base station 105-e. For example, at 445, the remote UE 115-f may send the RRC connection re-establishment request to the relay UE 115-g, which may relay (e.g., forward) the RRC connection re-establishment request to the target base station 105-e, at 450. In some examples, the remote UE 115-f may send the RRC re-establishment request to the relay UE 115-g before the relay UE 115-g and the target base station 105-e perform RRC setup and RRC reconfiguration procedures (e.g., at 435 and 440). Here, the relay UE 115-g and the target base station 105-e may perform RRC setup and RRC reconfiguration procedures after the relay UE 115-g receives the RRC connection re-establishment request from the remote UE 115-f at 445 (e.g., and before the relay UE 115-g relays the RRC connection re-establishment request to the target base station 105-e).

[0120]

[0129] At 455, the target base station 105-e may identify context information associated with the relay UE 115-g based on receiving the RRC connection re-establishment request from the remote UE 115-f via the relay UE 115-g. If the target base station 105-e is not the anchor base station 405 of the relay UE 115-g, the target base station 105-e receiving the RRC re-establishment request from the relay UE 115-g may trigger the target base station to obtain context information associated with the relay UE 115-g from the anchor base station 405 of the relay UE 115-g. If the target base station 105-e is the same as the anchor base station 405 of the relay UE 115-g, the target base station 105-e may identify context information associated with the relay UE 115-g.

[0121]

[0130] At 460 and 465, the target base station 105-e may send an RRC connection re-establishment message to the remote UE 115-f via the relay UE 115-g based on identifying the context information associated with the relay UE 115-g. For example, at 460, the target base station 105-e may send an RRC connection re-establishment message to the relay UE 115-g, and at 465, the relay UE 115-g may relay (e.g., forward) the RRC connection re-establishment message to the remote UE 115-f.

[0122]

[0131] At 470, the target base station 105-e may maintain an identifier (e.g., an L2 identifier) ​​for the relay UE 115-g and the remote UE 115-f (e.g., based on receiving an RRC reconfiguration complete message from the remote UE 115-f via the relay UE 115-g). In some cases, the remote UE 115-f may release an access link (e.g., a Uu connection) with the source base station 105-d after the base station 105-e maintains the identifiers.

[0123]

[0132] At 475, the remote UE 115-f may optionally communicate with the target base station 105-e via the relay UE 115-g. For example, the remote UE 115-f may transmit uplink data to the target base station 105-e via the relay UE 115-g. Additionally, the base station 105-e may transmit downlink data to the remote UE 115-f via the relay UE 115-g.

[0124]

[0133] 5 illustrates a block diagram 500 of a device 505 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 505 may be an example of an aspect of a base station 105 described herein. The device 505 may include a receiver 510, a transmitter 515, and a communications manager 520. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0125]

[0134] The receiver 510 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). The information may be passed to other components of the device 505. The receiver 510 may utilize a single antenna or a set of multiple antennas.

[0126]

[0135] The transmitter 515 may provide a means for transmitting signals generated by other components of the device 505. For example, the transmitter 515 may transmit information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). In some examples, the transmitter 515 may be co-located with the receiver 510 in a transceiver module. The transmitter 515 may utilize a single antenna or a set of multiple antennas.

[0127]

[0136] The communications manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be examples of means for implementing various aspects of the forward handover procedure for L2 relay mobility described herein. For example, the communications manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may support a method for implementing one or more of the functions described herein.

[0128]

[0137] In some examples, the communications manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be implemented in hardware (e.g., communications management circuitry). The hardware may include a processor, a DSP, an ASIC, a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing functions described in this disclosure. In some examples, the processor and a memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

[0129]

[0138] Additionally or alternatively, in some examples, the communications manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communications management software or firmware). When implemented in code executed by a processor, the functionality of the communications manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be performed by a general purpose processor (e.g., configured as or otherwise supporting a means for performing the functions described in this disclosure), a DSP, a CPU, an ASIC, an FPGA, or any combination of these or other programmable logic devices.

[0130]

[0139] In some examples, the communications manager 520 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise cooperating with the receiver 510, the transmitter 515, or both. For example, the communications manager 520 may receive information from the receiver 510, transmit information to the transmitter 515, or be combined and integrated with the receiver 510, the transmitter 515, or both to receive information, transmit information, or perform various other operations described herein.

[0131]

[0140] The communications manager 520 may support wireless communications in a base station according to examples disclosed herein. For example, the communications manager 520 may be configured as or otherwise support a means for identifying a relay pairing between a UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, the communications manager 520 may be configured as or otherwise support a means for identifying a configuration of the relay UE based on a handover decision related to the relay pairing. The communications manager 520 may be configured as or otherwise support a means for transmitting a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE.

[0132]

[0141] By including or configuring the communications manager 520 according to examples described herein, the device 505 (e.g., a processor controlling or otherwise coupled to the receiver 510, the transmitter 515, the communications manager 520, or a combination thereof) may support techniques for determining context information related to a relay UE while maintaining continuity of service (e.g., to a remote UE).

[0133]

[0142] 6 illustrates a block diagram 600 of a device 605 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 605 may be an example of an aspect of a device 505 or a base station 105 described herein. The device 605 may include a receiver 610, a transmitter 615, and a communications manager 620. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0134]

[0143] The receiver 610 may provide a means for receiving information such as packets, user data, control information, or any combination thereof, associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). The information may be passed to other components of the device 605. The receiver 610 may utilize a single antenna or a set of multiple antennas.

[0135]

[0144] The transmitter 615 may provide a means for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). In some examples, the transmitter 615 may be co-located with the receiver 610 in a transceiver module. The transmitter 615 may utilize a single antenna or a set of multiple antennas.

[0136]

[0145] The device 605 or various components thereof may be an example of a means for implementing various aspects of a forward handover procedure for L2 relay mobility described herein. For example, the communications manager 620 may include a relay manager 625, a handover manager 630, a sidelink manager 635, or any combination thereof. The communications manager 620 may be an example of an aspect of a communications manager 520 described herein. In some examples, the communications manager 620, or various components thereof, may be configured to use or otherwise cooperate with the receiver 610, the transmitter 615, or both to implement various operations (e.g., receive, monitor, transmit). For example, the communications manager 620 may receive information from the receiver 610, transmit information to the transmitter 615, or be combined and integrated with the receiver 610, the transmitter 615, or both to receive information, transmit information, or implement various other operations described herein.

[0137]

[0146] The communications manager 620 may support wireless communications in the base station according to examples disclosed herein. The relay manager 625 may be configured as, or may otherwise support, a means for identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates. The handover manager 630 may be configured as, or may otherwise support, a means for identifying a configuration of the relay UE based on a handover decision related to the relay pairing. The sidelink manager 635 may be configured as, or may otherwise support, a means for transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE.

[0138]

[0147] FIG. 7 illustrates a block diagram 700 of a communications manager 720 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The communications manager 720 may be an example of an aspect of the communications manager 520, the communications manager 620, or both described herein. The communications manager 720, or various components thereof, may be an example of a means for implementing various aspects of the forward handover procedure for L2 relay mobility described herein. For example, the communications manager 720 may include a relay manager 725, a handover manager 730, a side link manager 735, a connection manager 740, a bearer manager 745, a measurement manager 750, a context manager 755, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0139]

[0148] The communications manager 720 may support wireless communications in the base station according to examples disclosed herein. The relay manager 725 may be configured as, or may otherwise support, a means for identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates. The handover manager 730 may be configured as, or may otherwise support, a means for identifying a configuration of the relay UE based on a handover decision related to the relay pairing. The sidelink manager 735 may be configured as, or may otherwise support, a means for transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE.

[0140]

[0149] In some examples, the connection manager 740 may be configured as, or may otherwise support, a means for receiving a setup request message from a relay UE based on a sidelink communication link between the UE and the relay UE. In some examples, the bearer manager 745 may be configured as, or may otherwise support, a means for establishing a first signaling radio bearer for the relay UE based on receiving the setup request message. In some examples, the connection manager 740 may be configured as, or may otherwise support, a means for transmitting a connection setup complete message to the relay UE including an indication of the first signaling radio bearer.

[0141]

[0150] In some examples, the bearer manager 745 may be configured as or otherwise support a means for establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based on the configuration of the relay UE. In some examples, the connection manager 740 may be configured as or otherwise support a means for transmitting a reconfiguration complete message to the relay UE that includes an indication of the second signaling radio bearer, or a data radio bearer, or any combination thereof.

[0142]

[0151] In some examples, the connection manager 740 may be configured as, or may otherwise support, a means for receiving a connection re-establishment request message from the UE, via the relay UE, based on a relay pairing between the UE and the relay UE. In some examples, the context manager 755 may be configured as, or may otherwise support, a means for identifying context information related to the relay UE. In some examples, the connection manager 740 may be configured as, or may otherwise support, a means for transmitting a connection re-establishment message to the UE, via the relay UE, in response to the connection re-establishment request message, where transmitting the connection re-establishment message is based on identifying context information related to the relay UE. In some examples, the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof, is established after receiving a connection re-establishment request message from the UE.

[0143]

[0152] In some examples, to support identifying context information related to the relay UE, the context manager 755 may be configured or otherwise support a means for sending a request for context information related to the relay UE to an anchor base station associated with the relay UE, where the request for the context information is based on receiving a connection re-establishment request message from the UE. In some examples, to support identifying context information related to the relay UE, the context manager 755 may be configured or otherwise support a means for receiving context information related to the relay UE from an anchor base station based on the request for the context information.

[0144]

[0153] In some examples, the measurement manager 750 may be configured with or otherwise support a means for receiving measurement reports from the UE, where the measurement reports include an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and where the relay pairing is based on the measurement reports.

[0145]

[0154] In some examples, the handover manager 730 may be configured as or otherwise support a means for generating a handover command for the UE based on a handover decision.

[0146]

[0155] In some examples, the relay manager 725 may be configured or otherwise support a means for storing an L2 identifier of the UE and an L2 identifier of the relay UE based on the relay pairing. In some examples, the connection manager 740 may be configured or otherwise support a means for releasing an access link with the UE based on storing an L2 identifier of the UE and an L2 identifier of the relay UE.

[0147]

[0156] In some examples, the message includes an RRC reconfiguration message. In some examples, the connection state of the relay UE includes an idle state or an inactive state.

[0148]

[0157] FIG. 8 illustrates a diagram of a system 800 including a device 805 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 805 may be an example of or include components of the device 505, device 605, or base station 105 described herein. The device 805 may wirelessly communicate with one or more base stations 105, UEs 115, or any combination thereof. The device 805 may include components for two-way voice and data communication, including components for transmitting and receiving communications, such as a communications manager 820, a network communications manager 810, a transceiver 815, an antenna 825, a memory 830, code 835, a processor 840, and an inter-station communications manager 845. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 850).

[0149]

[0158] The network communications manager 810 may manage communications with the core network 130 (e.g., via one or more wired backhaul links). For example, the network communications manager 810 may manage the transfer of data communications for client devices, such as one or more UEs 115.

[0150]

[0159] In some cases, the device 805 may include a single antenna 825. However, in some other cases, the device 805 may have two or more antennas 825 that may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The transceiver 815 may communicate bidirectionally via one or more antennas 825, wired links, or wireless links as described herein. For example, the transceiver 815 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 815 may also include a modem for modulating packets and providing the modulated packets to the one or more antennas 825 for transmission, and for demodulating packets received from the antenna 825. The transceiver 815, or the transceiver 815 and the one or more antennas 825, may be an example of the transmitter 515, the transmitter 615, the receiver 510, the receiver 610, or any combination or components thereof described herein.

[0151]

[0160] The memory 830 may include random access memory (RAM) and read only memory (ROM). The memory 830 may store computer readable computer executable code 835 including instructions that, when executed by the processor 840, cause the device 805 to perform various functions described herein. The code 835 may be stored in a non-transitory computer readable medium, such as a system memory or another type of memory. In some cases, the code 835 may not be directly executable by the processor 840, but may (e.g., when compiled and executed) cause the computer to perform functions described herein. In some cases, the memory 830 may include a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices, among others.

[0152]

[0161] The processor 840 may 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 processor 840 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be incorporated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting a forward handover procedure for L2 relay mobility). For example, the device 805, or a component of the device 805, may include a processor 840 and a memory 830 coupled to the processor 840, where the processor 840 and the memory 830 are configured to perform various functions described herein.

[0153]

[0162] The inter-station communications manager 845 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with the UE 115 in cooperation with the other base stations 105. For example, the inter-station communications manager 845 may coordinate scheduling for transmissions to the UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-station communications manager 845 may provide an X2 interface within the LTE / LTE-A wireless communications network technology to communicate between the base stations 105.

[0154]

[0163] The communications manager 820 may support wireless communications in a base station according to examples disclosed herein. For example, the communications manager 820 may be configured as, or otherwise support, a means for identifying a relay pairing between a UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates. The communications manager 820 may be configured as, or otherwise support, a means for identifying a configuration of the relay UE based on a handover decision related to the relay pairing. The communications manager 820 may be configured as, or otherwise support, a means for transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE.

[0155]

[0164] By including or configuring a communications manager 820 according to examples described herein, the device 805 may support techniques for improving coordination between devices by improving continuity of service between a base station and a remote UE.

[0156]

[0165] In some examples, the communications manager 820 may be configured to perform various operations (e.g., receive, monitor, transmit) using or in other cooperation with the transceiver 815, the one or more antennas 825, or any combination thereof. Although the communications manager 820 is illustrated as a separate component, in some examples, one or more functions described with reference to the communications manager 820 may be supported or performed by the processor 840, the memory 830, the code 835, or any combination thereof. For example, the code 835 may include instructions executable by the processor 840 to cause the device 805 to perform various aspects of the forward handover procedure for L2 relay mobility described herein, or the processor 840 and the memory 830 may be configured to perform or support such operations in other manners.

[0157]

[0166] 9 illustrates a block diagram 900 of a device 905 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 905 may be an example of an aspect of a UE 115 described herein. The device 905 may include a receiver 910, a transmitter 915, and a communications manager 920. The device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0158]

[0167] The receiver 910 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). The information may be passed to other components of the device 905. The receiver 910 may utilize a single antenna or a set of multiple antennas.

[0159]

[0168] The transmitter 915 may provide a means for transmitting signals generated by other components of the device 905. For example, the transmitter 915 may transmit information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). In some examples, the transmitter 915 may be co-located with the receiver 910 in a transceiver module. The transmitter 915 may utilize a single antenna or a set of multiple antennas.

[0160]

[0169] The communications manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be examples of means for implementing various aspects of the forward handover procedure for L2 relay mobility described herein. For example, the communications manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may support a method for implementing one or more of the functions described herein.

[0161]

[0170] In some examples, the communications manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be implemented in hardware (e.g., communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing functions described in this disclosure. In some examples, the processor and a memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

[0162]

[0171] Additionally or alternatively, in some examples, the communications manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communications management software or firmware). When implemented in code executed by a processor, the functionality of the communications manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be performed by a general-purpose processor (e.g., configured as or otherwise supporting a means for performing the functions described in this disclosure), a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices.

[0163]

[0172] In some examples, the communications manager 920 may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the receiver 910, the transmitter 915, or both. For example, the communications manager 920 may receive information from the receiver 910, transmit information to the transmitter 915, or be combined and integrated with the receiver 910, the transmitter 915, or both to receive information, transmit information, or perform various other operations described herein.

[0164]

[0173] The communications manager 920 may support wireless communications at the relay UE in accordance with examples disclosed herein. For example, the communications manager 920 may be configured as, or may otherwise support, a means for receiving, from the UE, a message for establishing a sidelink communications link with the UE, where the message includes an indication that the sidelink communications link is for a handover associated with a relay pairing between the UE and the relay UE. The communications manager 920 may be configured as, or may otherwise support, a means for sending, to the base station, a connection setup request message based on establishing the sidelink communications link with the UE. The communications manager 920 may be configured as, or may otherwise support, a means for receiving, from the base station in response to the connection setup request message, a connection setup complete message including an indication of a first signaling radio bearer associated with a relay link for the relay pairing.

[0165]

[0174] Additionally or alternatively, the communications manager 920 may support wireless communications at the UE according to examples disclosed herein. For example, the communications manager 920 may be configured as or otherwise support a means for receiving from a base station a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE. The communications manager 920 may be configured as or otherwise support a means for sending to the relay UE a second message for establishing a sidelink communications link with the relay UE, where the second message includes an indication that the sidelink communications link is for a handover related to the relay pairing. The communications manager 920 may be configured as or otherwise support a means for receiving from the relay UE a third message configuring a sidelink communications link with the relay UE in response to the second message.

[0166]

[0175] By including or configuring a communications manager 920 according to examples described herein, the device 905 (e.g., a processor controlling or otherwise coupled to the receiver 910, the transmitter 915, the communications manager 920, or a combination thereof) may support techniques for maintaining continuity of service while performing a reverse handover procedure.

[0167]

[0176] 10 illustrates a block diagram 1000 of a device 1005 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 1005 may be an example of an aspect of a device 905 or a UE 115 described herein. The device 1005 may include a receiver 1010, a transmitter 1015, and a communications manager 1020. The device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0168]

[0177] The receiver 1010 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). The information may be passed to other components of the device 1005. The receiver 1010 may utilize a single antenna or a set of multiple antennas.

[0169]

[0178] The transmitter 1015 may provide a means for transmitting signals generated by other components of the device 1005. For example, the transmitter 1015 may transmit information such as packets, user data, control information, or any combination thereof associated with various traffic channels (e.g., control channels, data channels, traffic channels related to forward handover procedures for L2 relay mobility). In some examples, the transmitter 1015 may be co-located with the receiver 1010 in a transceiver module. The transmitter 1015 may utilize a single antenna or a set of multiple antennas.

[0170]

[0179] The device 1005 or various components thereof may be an example of a means for implementing various aspects of a forward handover procedure for L2 relay mobility described herein. For example, the communications manager 1020 may include a sidelink component 1025, a connection setup component 1030, a relay component 1035, or any combination thereof. The communications manager 1020 may be an example of an aspect of a communications manager 920 described herein. In some examples, the communications manager 1020 or various components thereof may be configured to perform various operations (e.g., receive, monitor, transmit) using or in other ways cooperate with the receiver 1010, the transmitter 1015, or both. For example, the communications manager 1020 may receive information from the receiver 1010, transmit information to the transmitter 1015, or be combined and integrated with the receiver 1010, the transmitter 1015, or both to receive information, transmit information, or perform various other operations described herein.

[0171]

[0180] The communications manager 1020 may support wireless communications in the relay UE according to examples disclosed herein. The sidelink component 1025 may be configured as, or may otherwise support, a means for receiving, from the UE, a message for establishing a sidelink communications link with the UE, where the message includes an indication that the sidelink communications link is for a handover associated with a relay pairing between the UE and the relay UE. The connection setup component 1030 may be configured as, or may otherwise support, a means for sending, to the base station, a connection setup request message based on establishing the sidelink communications link with the UE. The connection setup component 1030 may be configured as, or may otherwise support, a means for receiving, from the base station in response to the connection setup request message, a connection setup complete message including an indication of a first signaling radio bearer associated with a relay link for the relay pairing.

[0172]

[0181] Additionally or alternatively, the communications manager 1020 may support wireless communications in the UE according to examples disclosed herein. The relay component 1035 may be configured as, or may otherwise support, a means for receiving, from the base station, a first message indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE. The sidelink component 1025 may be configured as, or may otherwise support, a means for sending, to the relay UE, a second message for establishing a sidelink communications link with the relay UE, where the second message includes an indication that the sidelink communications link is for a handover related to the relay pairing. The sidelink component 1025 may be configured as, or may otherwise support, a means for receiving, from the relay UE, a third message for configuring a sidelink communications link with the relay UE in response to the second message.

[0173]

[0182] FIG. 11 illustrates a block diagram 1100 of a communications manager 1120 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The communications manager 1120 may be an example of an aspect of the communications manager 920, the communications manager 1020, or both described herein. The communications manager 1120 or various components thereof may be an example of a means for implementing various aspects of the forward handover procedure for L2 relay mobility described herein. For example, the communications manager 1120 may include a sidelink component 1125, a connection setup component 1130, a relay component 1135, a connection reconfiguration component 1140, a measurement reporting component 1145, a connection reestablishment component 1150, an access link component 1155, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0174]

[0183] The communications manager 1120 may support wireless communications in the relay UE according to examples disclosed herein. The sidelink component 1125 may be configured as, or may otherwise support, a means for receiving, from the UE, a message for establishing a sidelink communications link with the UE, where the message includes an indication that the sidelink communications link is for a handover associated with a relay pairing between the UE and the relay UE. The connection setup component 1130 may be configured as, or may otherwise support, a means for sending, to the base station, a connection setup request message based on establishing the sidelink communications link with the UE. In some examples, the connection setup component 1130 may be configured as, or may otherwise support, a means for receiving, from the base station in response to the connection setup request message, a connection setup complete message including an indication of a first signaling radio bearer associated with a relay link for the relay pairing.

[0175]

[0184] In some examples, the connection reconfiguration component 1140 may be configured as, or may otherwise support, a means for transmitting a reconfiguration request message to the base station based on receiving a connection setup complete message. In some examples, the connection reconfiguration component 1140 may be configured as, or may otherwise support, a means for receiving, from the base station, a reconfiguration complete message that includes an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof.

[0176]

[0185] In some examples, the connection re-establishment component 1150 may be configured or otherwise support a means for relaying a connection re-establishment request message from the UE to a base station based on a relay pairing between the UE and the relay UE. In some examples, the connection re-establishment component 1150 may be configured or otherwise support a means for relaying a connection re-establishment message from the base station to the UE in response to the connection re-establishment request message.

[0177]

[0186] In some examples, the connection re-establishment request message and the connection re-establishment message are relayed before receiving a reconfiguration complete message from the base station.

[0178]

[0187] In some examples, the connection state of the relay UE includes an idle state or an inactive state.

[0179]

[0188] Additionally or alternatively, the communications manager 1120 may support wireless communications at the UE according to examples disclosed herein. The relay component 1135 may be configured as, or may otherwise support, a means for receiving, from the base station, a first message indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE. In some examples, the sidelink component 1125 may be configured as, or may otherwise support, a means for sending, to the relay UE, a second message for establishing a sidelink communications link with the relay UE, where the second message includes an indication that the sidelink communications link is for a handover related to the relay pairing. In some examples, the sidelink component 1125 may be configured as, or may otherwise support, a means for receiving, from the relay UE, a third message in response to the second message, for configuring a sidelink communications link with the relay UE.

[0180]

[0189] In some examples, the measurement reporting component 1145 may be configured as or otherwise support a means for transmitting a measurement report to the base station, where the measurement report includes an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, where the relay pairing is based on the measurement report.

[0181]

[0190] In some examples, the connection re-establishment component 1150 may be configured as, or may otherwise support, a means for transmitting a connection re-establishment request message to a base station via a relay UE based on a relay pairing between the UE and the relay UE. In some examples, the connection re-establishment component 1150 may be configured as, or may otherwise support, a means for receiving a connection re-establishment message from a base station via a relay UE in response to the connection re-establishment request message.

[0182]

[0191] In some examples, the access link component 1155 may be configured as or otherwise support a means for releasing an access link between the UE and the source base station based on receiving a connection re-establishment message via the relay UE, where the source base station is different from the base station.

[0183]

[0192] In some examples, the access link component 1155 may be configured as or otherwise support a means for releasing an access link between the UE and the source base station based on receiving the first message, where the source base station is different from the base station.

[0184]

[0193] FIG. 12 illustrates a diagram of a system 1200 including a device 1205 supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The device 1205 may be an example of or include components of a device 905, a device 1005, or a UE 115 described herein. The device 1205 may wirelessly communicate with one or more base stations 105, UEs 115, or any combination thereof. The device 1205 may include components for two-way voice and data communication, including components for transmitting and receiving communications, such as a communications manager 1220, an input / output (I / O) controller 1210, a transceiver 1215, an antenna 1225, a memory 1230, code 1235, and a processor 1240. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 1245).

[0185]

[0194] The I / O controller 1210 may manage input and output signals for the device 1205. The I / O controller 1210 may also manage peripherals that are not built into the device 1205. In some cases, the I / O controller 1210 may represent a physical connection or port to an external peripheral. In some cases, the I / O controller 1210 may utilize an operating system, such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. Additionally or alternatively, the I / O controller 1210 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, the I / O controller 1210 may be implemented as part of a processor, such as the processor 1240. In some cases, a user may interact with the device 1205 through the I / O controller 1210 or through hardware components controlled by the I / O controller 1210.

[0186]

[0195] In some cases, the device 1205 may include a single antenna 1225. However, in some other cases, the device 1205 may have two or more antennas 1225 that may be capable of simultaneously transmitting or receiving multiple wireless transmissions. The transceiver 1215 may communicate bidirectionally via one or more antennas 1225, wired links, or wireless links as described herein. For example, the transceiver 1215 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1215 may also include a modem for modulating packets and providing the modulated packets to the antenna 1225 for transmission, and for demodulating packets received from the antenna 1225. The transceiver 1215, or the transceiver 1215 and one or more antennas 1225, may be an example of the transmitter 915, the transmitter 1015, the receiver 910, the receiver 1010, or any combination or components thereof described herein.

[0187]

[0196] The memory 1230 may include RAM and ROM. The memory 1230 may store computer-readable computer-executable code 1235 including instructions that, when executed by the processor 1240, cause the device 1205 to perform various functions described herein. The code 1235 may be stored in a non-transitory computer-readable medium, such as a system memory or another type of memory. In some cases, the code 1235 may not be directly executable by the processor 1240, but may (e.g., when compiled and executed) cause the computer to perform functions described herein. In some cases, the memory 1230 may include a basic I / O system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0188]

[0197] The processor 1240 may 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 processor 1240 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be incorporated into the processor 1240. The processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting a forward handover procedure for L2 relay mobility). For example, the device 1205, or a component of the device 1205, may include the processor 1240 and the memory 1230 coupled to the processor 1240, where the processor 1240 and the memory 1230 are configured to perform various functions described herein.

[0189]

[0198] The communications manager 1220 may support wireless communications at the relay UE according to examples disclosed herein. For example, the communications manager 1220 may be configured as, or may otherwise support, a means for receiving, from the UE, a message for establishing a sidelink communications link with the UE, where the message includes an indication that the sidelink communications link is for a handover associated with a relay pairing between the UE and the relay UE. The communications manager 1220 may be configured as, or may otherwise support, a means for sending, to the base station, a connection setup request message based on establishing the sidelink communications link with the UE. The communications manager 1220 may be configured as, or may otherwise support, a means for receiving, from the base station in response to the connection setup request message, a connection setup complete message including an indication of a first signaling radio bearer associated with a relay link for the relay pairing.

[0190]

[0199] Additionally or alternatively, the communications manager 1220 may support wireless communications at the UE according to examples disclosed herein. For example, the communications manager 1220 may be configured as or otherwise support a means for receiving from a base station a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switches to a sidelink communications link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE. The communications manager 1220 may be configured as or otherwise support a means for sending to the relay UE a second message for establishing a sidelink communications link with the relay UE, where the second message includes an indication that the sidelink communications link is for a handover related to the relay pairing. The communications manager 1220 may be configured as or otherwise support a means for receiving from the relay UE a third message configuring a sidelink communications link with the relay UE in response to the second message.

[0191]

[0200] By including or configuring a communications manager 1220 according to examples described herein, the device 1205 may support techniques for improving coordination between devices.

[0192]

[0201] In some examples, the communications manager 1220 may be configured to perform various operations (e.g., receive, monitor, transmit) using or in other cooperation with the transceiver 1215, the one or more antennas 1225, or any combination thereof. Although the communications manager 1220 is illustrated as a separate component, in some examples, one or more functions described with reference to the communications manager 1220 may be supported or performed by the processor 1240, the memory 1230, the code 1235, or any combination thereof. For example, the code 1235 may include instructions executable by the processor 1240 to cause the device 1205 to perform various aspects of a forward handover procedure for L2 relay mobility described herein, or the processor 1240 and the memory 1230 may be configured to perform or support such operations in other manners.

[0193]

[0202] FIG. 13 illustrates a flow chart illustrating a method 1300 of supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The operations of the method 1300 may be implemented by a base station or components thereof described herein. For example, the operations of the method 1300 may be performed by the base station 105 described with reference to FIGS. 1-8. In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may perform aspects of the described functions using dedicated hardware.

[0194]

[0203] At 1305, the method may include identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates. The operations of 1305 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1305 may be performed by a relay manager 725 described with reference to FIG.

[0195]

[0204] At 1310, the method may include identifying a configuration of the relay UE based on the handover decision related to the relay pairing. The operations of 1310 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1310 may be performed by the handover manager 730 described with reference to FIG.

[0196]

[0205] At 1315, the method may include transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE will switch to a sidelink communication link with the relay UE. The operations of 1315 may be performed according to examples disclosed herein. In some examples, aspects of the operations of 1315 may be performed by the sidelink manager 735 described with reference to FIG. 7.

[0197]

[0206] FIG. 14 illustrates a flow chart illustrating a method 1400 of supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The operations of the method 1400 may be performed by a base station or components thereof described herein. For example, the operations of the method 1400 may be performed by the base station 105 described with reference to FIGS. 1-8. In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0198]

[0207] At 1405, the method may include identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates. The operations of 1405 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1405 may be performed by a relay manager 725 described with reference to FIG.

[0199]

[0208] At 1410, the method may include identifying a configuration of the relay UE based on a handover decision related to the relay pairing. The operations of 1410 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1410 may be performed by the handover manager 730 described with reference to FIG.

[0200]

[0209] At 1415, the method may include transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE will switch to a sidelink communications link with the relay UE. The operations of 1415 may be performed according to examples disclosed herein. In some examples, aspects of the operations of 1415 may be performed by the sidelink manager 735 described with reference to FIG. 7.

[0201]

[0210] At 1420, the method may include receiving a setup request message from the relay UE based on a sidelink communication link between the UE and the relay UE. The operations of 1420 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1420 may be performed by the connection manager 740 described with reference to FIG.

[0202]

[0211] At 1425, the method may include establishing a first signaling radio bearer for the relay UE based on receiving the setup request message. The operations of 1425 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1425 may be performed by the bearer manager 745 described with reference to FIG.

[0203]

[0212] At 1430, the method may include transmitting a connection setup complete message to the relay UE including an indication of the first signaling radio bearer. The operations of 1430 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1430 may be performed by a connection manager 740 described with reference to FIG.

[0204]

[0213] FIG. 15 illustrates a flow chart illustrating a method 1500 of supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The operations of the method 1500 may be implemented by a base station or components thereof described herein. For example, the operations of the method 1500 may be performed by the base station 105 described with reference to FIGS. 1-8. In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0205]

[0214] At 1505, the method may include receiving a measurement report from the UE, where the measurement report includes an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof. The operations of 1505 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1505 may be performed by a measurement manager 750 described with reference to FIG.

[0206]

[0215] At 1510, the method may include identifying a relay pairing between the UE and a relay UE based on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates, where the relay pairing is based on the measurement report. The operations of 1510 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1510 may be performed by the relay manager 725 described with reference to FIG.

[0207]

[0216] At 1515, the method may include identifying a configuration of the relay UE based on the handover decision related to the relay pairing. The operations of 1515 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1515 may be performed by the handover manager 730 described with reference to FIG.

[0208]

[0217] At 1520, the method may include transmitting a message to the UE indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE will switch to a sidelink communication link with the relay UE. The operations of 1520 may be performed according to examples disclosed herein. In some examples, aspects of the operations of 1520 may be performed by the sidelink manager 735 described with reference to FIG. 7.

[0209]

[0218] FIG. 16 illustrates a flow chart illustrating a method 1600 of supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The operations of the method 1600 may be implemented by a UE or components thereof described herein. For example, the operations of the method 1600 may be performed by the UE 115 described with reference to FIGS. 1-4 and 9-12. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may perform aspects of the described functions using dedicated hardware.

[0210]

[0219] At 1605, the method may include receiving, from the UE, a message for establishing a sidelink communication link with the UE, where the message includes an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE. The operations of 1605 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1605 may be performed by the sidelink component 1125 described with reference to FIG. 11.

[0211]

[0220] At 1610, the method may include transmitting a connection setup request message to the base station based on establishing a sidelink communication link with the UE, where operations of 1610 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1610 may be performed by the connection setup component 1130 described with reference to FIG.

[0212]

[0221] At 1615, the method may include receiving a connection setup complete message from the base station in response to the connection setup request message, the connection setup complete message including an indication of a first signaling radio bearer associated with a relay link for relay pairing. The operations of 1615 may be performed according to examples disclosed herein. In some examples, aspects of the operations of 1615 may be performed by the connection setup component 1130 described with reference to FIG.

[0213]

[0222] FIG. 17 illustrates a flow chart illustrating a method 1700 of supporting a forward handover procedure for L2 relay mobility according to an aspect of the disclosure. The operations of the method 1700 may be implemented by a UE or components thereof as described herein. For example, the operations of the method 1700 may be performed by the UE 115 described with reference to FIGS. 1-4 and 9-12. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may perform aspects of the described functionality using dedicated hardware.

[0214]

[0223] At 1705, the method may include receiving a first message from the base station indicating a configuration of the relay UE, an identifier of the relay UE, and an indication that the UE switch to a sidelink communication link with the relay UE, where the first message is based on a relay pairing between the UE and the relay UE. The operations of 1705 may be performed according to examples disclosed herein. In some examples, aspects of the operations of 1705 may be performed by the relay component 1135 described with reference to FIG. 11.

[0215]

[0224] At 1710, the method may include transmitting a second message to the relay UE for establishing a sidelink communication link with the relay UE, where the second message includes an indication that the sidelink communication link is for a handover associated with the relay pairing. The operations of 1710 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1710 may be performed by the sidelink component 1125 described with reference to FIG. 11.

[0216]

[0225] At 1715, the method may include receiving, from the relay UE, a third message in response to the second message, configuring a sidelink communications link with the relay UE. The operations of 1715 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operations of 1715 may be performed by the sidelink component 1125 described with reference to FIG. 11.

[0217]

[0226] The following provides a summary of aspects of the disclosure.

[0218]

[0227] Aspect 1: A method for wireless communications in a base station, comprising: identifying a relay pairing between a UE and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more relay UE candidates; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; and transmitting a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE will switch to a sidelink communications link with the relay UE.

[0219]

[0228] Aspect 2: The method of aspect 1, further comprising: receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; and transmitting a connection setup complete message to the relay UE comprising an indication of the first signaling radio bearer.

[0220]

[0229] Aspect 3: The method of aspect 2, further comprising: establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based at least in part on a configuration of the relay UE; and transmitting a reconfiguration complete message to the relay UE comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof.

[0221]

[0230] Aspect 4: The method of aspect 3, further comprising: receiving a connection re-establishment request message from the UE via the relay UE based at least in part on a relay pairing between the UE and the relay UE; identifying context information related to the relay UE; and transmitting a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein transmitting the connection re-establishment message is based at least in part on identifying the context information related to the relay UE.

[0222]

[0231] Aspect 5: The method of aspect 4, wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving a connection re-establishment request message from the UE.

[0223]

[0232] Aspect 6: The method of aspect 4 or 5, wherein identifying context information related to the relay UE comprises sending a request for context information related to the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving a connection re-establishment request message from the UE, and receiving the context information related to the relay UE from the anchor base station based at least in part on the request for the context information.

[0224]

[0233] Aspect 7: The method of any of aspects 1 to 6, further comprising receiving a measurement report from the UE, wherein the measurement report comprises an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and wherein the relay pairing is based at least in part on the measurement report.

[0225]

[0234] Aspect 8: The method of any of aspects 1-7, further comprising generating a handover command for the UE based at least in part on the handover decision.

[0226]

[0235] Aspect 9: The method of any of aspects 1 to 8, further comprising: storing an L2 identifier of the UE and an L2 identifier of the relay UE based at least in part on the relay pairing; and releasing an access link with the UE based at least in part on the storing the L2 identifier of the UE and the L2 identifier of the relay UE.

[0227]

[0236] Aspect 10: The method of any of aspects 1 to 9, wherein the message comprises an RRC reconfiguration message.

[0228]

[0237] Aspect 11: The method of any of aspects 1 to 10, wherein a connection state of the relay UE comprises an idle state or an inactive state.

[0229]

[0238] Aspect 12: A method for wireless communication in a relay UE, the method comprising: receiving, from the UE, a message for establishing a sidelink communication link with the UE, where the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE, where the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with the relay link for the relay pairing.

[0230]

[0239] Aspect 13: The method of aspect 12, further comprising: sending a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; and receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof.

[0231]

[0240] Aspect 14: The method of aspect 13, further comprising: relaying a connection re-establishment request message from the UE to a base station based at least in part on a relay pairing between the UE and the relay UE; and relaying a connection re-establishment message from the base station to the UE in response to the connection re-establishment request message.

[0232]

[0241] Aspect 15: The method of aspect 14, wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving a reconfiguration complete message from the base station.

[0233]

[0242] Aspect 16: The method of any of aspects 12 to 15, wherein a connection state of the relay UE comprises an idle state or an inactive state.

[0234]

[0243] Aspect 17: A method for wireless communication in a UE, comprising: receiving from a base station a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switch to a sidelink communications link with the relay UE, where the first message indicates a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE switch to a sidelink communications link with the relay UE; ... sending to the relay UE a second message for establishing a sidelink communications link with the relay UE based at least in part on a relay pairing between the UE and the relay UE; and receiving from the relay UE a third message configuring a sidelink communications link with the relay UE in response to the second message, where the second message comprises an indication that the sidelink communications link is for a handover associated with the relay pairing.

[0235]

[0244] Aspect 18: The method of aspect 17, further comprising transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, an identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and wherein the relay pairing is based at least in part on the measurement report.

[0236]

[0245] Aspect 19: The method of any of aspects 17 or 18, further comprising: sending a connection re-establishment request message to a base station, via the relay UE, based at least in part on a relay pairing between the UE and the relay UE; and receiving a connection re-establishment message from the base station, via the relay UE, in response to the connection re-establishment request message.

[0237]

[0246] Aspect 20: The method of aspect 19, further comprising releasing an access link between the UE and a source base station based at least in part on receiving a connection re-establishment message via the relay UE, wherein the source base station is different from the base station.

[0238]

[0247] Aspect 21: The method of any of aspects 17 to 20, further comprising releasing an access link between the UE and a source base station based at least in part on receiving the first message, wherein the source base station is different from the base station.

[0239]

[0248] Aspect 22: An apparatus for wireless communication in a base station, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory, the instructions being executable by the processor to cause the apparatus to perform a method as recited in any of aspects 1 to 11.

[0240]

[0249] Aspect 23: An apparatus for wireless communication in a base station, comprising at least one means for performing the method according to any one of aspects 1 to 11.

[0241]

[0250] Aspect 24: A non-transitory computer-readable medium storing code for wireless communication in a base station, the code comprising instructions executable by a processor to perform a method as described in any of aspects 1 to 11.

[0242]

[0251] Aspect 25: An apparatus for wireless communication in a relay UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory, the instructions being executable by the processor to cause the apparatus to perform a method as described in any of aspects 12 to 16.

[0243]

[0252] Aspect 26: An apparatus for wireless communication in a relay UE, comprising at least one means for performing the method described in any of aspects 12 to 16.

[0244]

[0253] Aspect 27: A non-transitory computer-readable medium storing code for wireless communication in a relay UE, the code comprising instructions executable by a processor to perform a method as described in any of aspects 12 to 16.

[0245]

[0254] Aspect 28: An apparatus for wireless communication in a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory, the instructions being executable by the processor to cause the apparatus to perform a method as described in any of aspects 17 to 21.

[0246]

[0255] Aspect 29: An apparatus for wireless communication in a UE, comprising at least one means for performing the method described in any of aspects 17 to 21.

[0247]

[0256] Aspect 30: A non-transitory computer-readable medium storing code for wireless communication in a UE, the code comprising instructions executable by a processor to perform a method as described in any of aspects 17 to 21.

[0248]

[0257] It should be noted that the methods described herein represent possible implementations, and that the acts and steps may be rearranged or possibly modified, and that other implementations are possible. Furthermore, aspects from two or more of the methods may be combined.

[0249]

[0258] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described as examples, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may be applicable to other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0250]

[0259] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0251]

[0260] The various example blocks and components described in connection with the disclosure herein may be implemented or performed using 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. A general purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0252]

[0261] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of the disclosure and the appended claims. For example, depending on the nature of the software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located in various locations, including being distributed such that parts of the functions are implemented in different physical locations.

[0253]

[0262] 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. Non-transitory storage media may 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 may 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 coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer readable media. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer readable media.

[0254]

[0263] As used herein, including within the claims, "or" used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such as, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, the phrase "based on" as used herein is not to be construed as a reference to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, the phrase "based on" as used herein is to be construed in the same manner as the phrase "based at least in part on."

[0255]

[0264] In the accompanying figures, similar components or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes the similar components. If only a first reference label is used herein, the description is applicable to any of the similar components having the same first reference label, regardless of the second reference label, or any other subsequent reference label.

[0256]

[0265] The description set forth herein with respect to the accompanying drawings describes exemplary configurations and does not necessarily represent all examples that may be implemented or fall within the scope of the claims. The term "exemplary" as used herein means "serving as an example, instance, or illustration" and does not mean "preferred" or "advantageous over other examples." The detailed description includes specific details for the purposes of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0257]

[0266] The description herein is provided to enable any person skilled in the art to make or use the disclosure. Various modifications of the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The invention as described in the claims of the original application is set forth below. [C1] 1. A method for wireless communication in a base station, comprising: identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE shall switch to a sidelink communication link with the relay UE; A method comprising: [C2] receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; and sending a connection setup complete message to the relay UE, the connection setup complete message comprising an indication of the first signaling radio bearer; The method of claim C1, further comprising: [C3] establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based at least in part on the configuration of the relay UE; sending a reconfiguration complete message to the relay UE comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof; The method of C2, further comprising: [C4] receiving a connection re-establishment request message from the UE, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; identifying context information associated with the relay UE; sending a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein sending the connection re-establishment message is based at least in part on identifying the context information associated with the relay UE. The method of C3, further comprising: [C5] The method of claim 4, wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving the connection re-establishment request message from the UE. [C6] Identifying the context information associated with the relay UE includes: sending a request for the context information associated with the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving the connection re-establishment request message from the UE. receiving, from the anchor base station, the context information regarding the relay UE based at least in part on the request for the context information; The method of claim C4, comprising: [C7] receiving the measurement report from the UE, where the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The method according to C1. [C8] generating a handover command for the UE based at least in part on the handover decision; The method of C1, further comprising: [C9] storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based at least in part on the relay pairing; releasing an access link with the UE based at least in part on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE; The method of C1, further comprising: [C10] The method of C1, wherein the message comprises a radio resource control reconfiguration message. [C11] The method of C1, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C12] A method for wireless communication in a relay user equipment (UE), comprising: receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; A method comprising: [C13] transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; The method of C12, further comprising: [C14] relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; The method of C13, further comprising: [C15] The method of C14, wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving the reconfiguration complete message from the base station. [C16] The method of C12, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C17] 1. A method for wireless communication in a user equipment (UE), comprising: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. receiving, from the relay UE, a third message in response to the second message, the third message configuring the sidelink communication link with the relay UE; A method comprising: [C18] and transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The method according to C17. [C19] sending a connection re-establishment request message to the base station, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; receiving a connection re-establishment message from the base station via the relay UE in response to the connection re-establishment request message; The method of C17, further comprising: [C20] and releasing an access link between the UE and a source base station based at least in part on receiving the connection re-establishment message via the relay UE, wherein the source base station is different from the base station. The method according to C19. [C21] and releasing an access link between the UE and a source base station based at least in part on receiving the first message, where the source base station is different from the base station. The method according to C17. [C22] An apparatus for wireless communication in a base station, comprising: means for identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; means for identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; means for transmitting a message to the relay UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE will switch to a sidelink communication link with the relay UE; An apparatus comprising: [C23] means for receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; means for establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; means for transmitting a connection setup complete message to the relay UE, the connection setup complete message comprising an indication of the first signaling radio bearer; The apparatus of C22, further comprising: [C24] means for establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based at least in part on the configuration of the relay UE; and means for transmitting a reconfiguration complete message to the relay UE comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof; The apparatus of C23, further comprising: [C25] means for receiving a connection re-establishment request message from the UE, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; means for identifying context information associated with the relay UE; means for transmitting a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein transmitting the connection re-establishment message is based at least in part on identifying the context information associated with the relay UE. The apparatus of C24, further comprising: [C26] The apparatus of C25, wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving the connection re-establishment request message from the UE. [C27] The means for identifying the context information associated with the relay UE further comprises: means for transmitting a request for the context information associated with the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving the connection re-establishment request message from the UE. means for receiving, from the anchor base station, the context information regarding the relay UE based at least in part on the request for the context information; The apparatus of C25, comprising: [C28] and means for receiving the measurement report from the UE, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The apparatus described in C22. [C29] means for generating a handover command for the UE based at least in part on the handover decision; The apparatus of C22, further comprising: [C30] means for storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based at least in part on the relay pairing; means for releasing an access link with the UE based at least in part on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE; The apparatus of C22, further comprising: [C31] The apparatus of C22, wherein the message comprises a radio resource control reconfiguration message. [C32] The apparatus of C22, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C33] An apparatus for wireless communication in a relay user equipment (UE), comprising: means for receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE. means for transmitting a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; means for receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; An apparatus comprising: [C34] means for transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; means for receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; The apparatus of C33, further comprising: [C35] means for relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; means for relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; The apparatus of C34, further comprising: [C36] The apparatus of C35, wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving the reconfiguration complete message from the base station. [C37] The apparatus of C33, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C38] An apparatus for device wireless communication in a user equipment (UE), comprising: means for receiving from a base station a first message indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; means for transmitting a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. means for receiving, from the relay UE, a third message in response to the second message, the third message configuring the sidelink communication link with the relay UE; An apparatus comprising: [C39] means for transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The apparatus described in C38. [C40] means for transmitting, via the relay UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; means for receiving a connection re-establishment message from the base station via the relay UE in response to the connection re-establishment request message; The apparatus of C38, further comprising: [C41] and means for releasing an access link between the UE and a source base station based at least in part on receiving the connection re-establishment message via the relay UE, wherein the source base station is different from the base station. The apparatus described in C40. [C42] and means for releasing an access link between the UE and a source base station based at least in part on receiving the first message, where the source base station is different from the base station. The apparatus described in C38. [C43] An apparatus for wireless communication in a base station, comprising: A processor; a memory coupled to the processor; and instructions stored in the memory, the instructions causing the device to: identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE shall switch to a sidelink communication link with the relay UE; The apparatus is executable by the processor to cause [C44] The instructions cause the device to: receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; and sending a connection setup complete message to the relay UE, the connection setup complete message comprising an indication of the first signaling radio bearer; The apparatus of C43, further executable by the processor to cause [C45] The instructions cause the device to: establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based at least in part on the configuration of the relay UE; sending a reconfiguration complete message to the relay UE comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof; The apparatus of C44, further executable by the processor to cause [C46] The instructions cause the device to: receiving a connection re-establishment request message from the UE, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; identifying context information associated with the relay UE; sending a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein sending the connection re-establishment message is based at least in part on identifying the context information associated with the relay UE. The apparatus of C45, further executable by the processor to cause [C47] The apparatus of C46, ​​wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving the connection re-establishment request message from the UE. [C48] The instructions to identify the context information associated with the relay UE include instructions to the apparatus: sending a request for the context information associated with the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving the connection re-establishment request message from the UE. receiving, from the anchor base station, the context information regarding the relay UE based at least in part on the request for the context information; The apparatus of C46, ​​wherein the apparatus is executable by the processor to cause [C49] The instructions cause the device to: and receiving the measurement report from the UE, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The apparatus described in C43. [C50] The instructions cause the device to: generating a handover command for the UE based at least in part on the handover decision; The apparatus of C43, further executable by the processor to cause [C51] The instructions cause the device to: storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based at least in part on the relay pairing; releasing an access link with the UE based at least in part on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE; The apparatus of C43, further executable by the processor to cause [C52] The apparatus of C43, wherein the message comprises a radio resource control reconfiguration message. [C53] The apparatus of C43, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C54] An apparatus for wireless communication in a relay user equipment (UE), comprising: A processor; a memory coupled to the processor; and instructions stored in the memory, the instructions causing the device to: receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; The apparatus is executable by the processor to cause [C55] The instructions cause the device to: transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; The apparatus of C54, further executable by the processor to cause [C56] The instructions cause the device to: relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; The apparatus of C55, further executable by the processor to cause [C57] The apparatus of C56, wherein the connection re-establishment request message and the connection re-establishment message are relayed prior to receiving the reconfiguration complete message from the base station. [C58] The apparatus of C54, wherein a connection state of the relay UE comprises an idle state or an inactive state. [C59] An apparatus for wireless communication in a user equipment (UE), comprising: A processor; a memory coupled to the processor; and instructions stored in the memory, the instructions causing the device to: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. receiving, from the relay UE, a third message in response to the second message, the third message configuring the sidelink communication link with the relay UE; The apparatus is executable by the processor to cause [C60] The instructions cause the device to: and transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The apparatus described in C59. [C61] The instructions cause the device to: sending a connection re-establishment request message to the base station, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; receiving a connection re-establishment message from the base station via the relay UE in response to the connection re-establishment request message; The apparatus of C59, further executable by the processor to cause [C62] The instructions cause the device to: and further operable by the processor to cause, based at least in part on receiving the connection re-establishment message via the relay UE, releasing an access link between the UE and a source base station, wherein the source base station is different from the base station. The apparatus described in C61. [C63] The instructions cause the device to: and further operable by the processor to cause, based at least in part on receiving the first message, to release an access link between the UE and a source base station, where the source base station is different from the base station. The apparatus described in C59. [C64] 1. A non-transitory computer readable medium storing code for wireless communication in a base station, the code comprising: identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE shall switch to a sidelink communication link with the relay UE; A non-transitory computer-readable medium comprising instructions executable by a processor to perform the steps of: [C65] 1. A non-transitory computer-readable medium storing code for wireless communication in a relay user equipment (UE), the code comprising: receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; A non-transitory computer-readable medium comprising instructions executable by a processor to perform the steps of: [C66] 1. A non-transitory computer-readable medium storing code for wireless communication in a user equipment (UE), the code comprising: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. receiving, from the relay UE, a third message in response to the second message, the third message configuring the sidelink communication link with the relay UE; A non-transitory computer-readable medium comprising instructions executable by a processor to perform the steps of: [C67] 1. A method for wireless communication in a base station, comprising: identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE shall switch to a sidelink communication link with the relay UE; A method comprising: [C68] receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; and sending a connection setup complete message to the relay UE, the connection setup complete message comprising an indication of the first signaling radio bearer; The method of C67, further comprising: [C69] establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof, based at least in part on the configuration of the relay UE; sending a reconfiguration complete message to the relay UE, the reconfiguration complete message comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof; The method of C68, further comprising: [C70] receiving a connection re-establishment request message from the UE, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; identifying context information associated with the relay UE; sending a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein sending the connection re-establishment message is based at least in part on identifying the context information associated with the relay UE. The method of C69, further comprising: [C71] The method of C70, wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving the connection re-establishment request message from the UE. [C72] Identifying the context information associated with the relay UE includes: sending a request for the context information associated with the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving the connection re-establishment request message from the UE. receiving, from the anchor base station, the context information regarding the relay UE based at least in part on the request for the context information; The method of C70 or 71, comprising: [C73] receiving the measurement report from the UE, where the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The method according to any one of C67 to 72. [C74] generating a handover command for the UE based at least in part on the handover decision; The method of any one of C67 to 73, further comprising: [C75] storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based at least in part on the relay pairing; releasing an access link with the UE based at least in part on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE; The method of any one of C67 to 74, further comprising: [C76] The method of any one of C67 to 75, wherein the message comprises a radio resource control reconfiguration message. [C77] The method of any one of C67 to 76, wherein the connection state of the relay UE comprises an idle state or an inactive state. [C78] A method for wireless communication in a relay user equipment (UE), comprising: means for receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE. sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; A method comprising: [C79] transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; The method of C78, ​​further comprising: [C80] relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; The method of C79, further comprising: [C81] The method of C80, wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving the reconfiguration complete message from the base station. [C82] The method of any one of C78 to 81, wherein the connection state of the relay UE comprises an idle state or an inactive state. [C83] 1. A method for wireless communication in a user equipment (UE), comprising: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. receiving, from the relay UE, a third message in response to the second message, the third message configuring the sidelink communication link with the relay UE; A method comprising: [C84] and transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The method described in C83. [C85] sending a connection re-establishment request message to the base station, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; receiving a connection re-establishment message from the base station via the relay UE in response to the connection re-establishment request message; The method of C83 or 84, further comprising: [C86] and releasing an access link between the UE and a source base station based at least in part on receiving the connection re-establishment message via the relay UE, wherein the source base station is different from the base station. The method described in C85. [C87] and releasing an access link between the UE and a source base station based at least in part on receiving the first message, where the source base station is different from the base station. A method according to any one of C83 to 86.

Claims

1. 1. A method for wireless communication in a base station, comprising: identifying a relay pairing between a user equipment (UE) and a relay UE based at least in part on a measurement report from the UE, where the relay UE is from a set of one or more candidate relay UEs; identifying a configuration of the relay UE based at least in part on a handover decision associated with the relay pairing; sending a message to the UE indicating the configuration of the relay UE, an identifier of the relay UE, and an indication that the UE shall switch to a sidelink communication link with the relay UE; receiving a setup request message from the relay UE based at least in part on a sidelink communication link between the UE and the relay UE; establishing a first signaling radio bearer for the relay UE based at least in part on receiving the setup request message; and sending a connection setup complete message to the relay UE, the connection setup complete message comprising an indication of the first signaling radio bearer; A method comprising:

2. establishing a second signaling radio bearer, or a data radio bearer, or any combination thereof based at least in part on the configuration of the relay UE; and sending a reconfiguration complete message to the relay UE comprising an indication of the second signaling radio bearer, or the data radio bearer, or any combination thereof; The method of claim 1 further comprising:

3. receiving a connection re-establishment request message from the UE, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; identifying context information associated with the relay UE; sending a connection re-establishment message to the UE via the relay UE in response to the connection re-establishment request message, wherein sending the connection re-establishment message is based at least in part on identifying the context information associated with the relay UE. The method of claim 2 , further comprising:

4. 4. The method of claim 3, wherein the first signaling radio bearer, the second signaling radio bearer, the data radio bearer, or any combination thereof is established after receiving the connection re-establishment request message from the UE.

5. Identifying the context information associated with the relay UE comprises: sending a request for the context information associated with the relay UE to an anchor base station associated with the relay UE, wherein the request for the context information is based at least in part on receiving the connection re-establishment request message from the UE. receiving, from the anchor base station, the context information regarding the relay UE based at least in part on the request for the context information; The method of claim 3 comprising:

6. receiving the measurement report from the UE, where the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report. The method of claim 1.

7. generating a handover command for the UE based at least in part on the handover decision; The method of claim 1 further comprising:

8. storing a Layer 2 identifier of the UE and a Layer 2 identifier of the relay UE based at least in part on the relay pairing; releasing an access link with the UE based at least in part on storing the Layer 2 identifier of the UE and the Layer 2 identifier of the relay UE; The method of claim 1 further comprising:

9. The method of claim 1 , wherein the message comprises a radio resource control reconfiguration message.

10. The method of claim 1 , wherein a connection state of the relay UE comprises an idle state or an inactive state.

11. A method for wireless communication in a relay user equipment (UE), comprising: receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; A method comprising:

12. transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; The method of claim 11 further comprising:

13. relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; The method of claim 12 further comprising:

14. The method of claim 13 , wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving the reconfiguration complete message from the base station.

15. The method of claim 11 , wherein a connection state of the relay UE comprises an idle state or an inactive state.

16. 1. A method for wireless communication in a user equipment (UE), comprising: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. sending a connection re-establishment request message to the base station, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; receiving, from the relay UE, a connection re-establishment message transmitted from the base station to the relay UE in response to the connection re-establishment request message; A method comprising:

17. and transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report.

17. The method of claim 16.

18. and releasing an access link between the UE and a source base station based at least in part on receiving the connection re-establishment message via the relay UE, wherein the source base station is different from the base station.

17. The method of claim 16.

19. and releasing an access link between the UE and a source base station based at least in part on receiving the first message, wherein the source base station is different from the base station.

17. The method of claim 16.

20. An apparatus for wireless communication in a relay user equipment (UE), comprising: A processor; a memory coupled to the processor; and instructions stored in the memory, the instructions causing the device to: receiving, from a UE, a message for establishing a sidelink communication link with the UE, wherein the message comprises an indication that the sidelink communication link is for a handover associated with a relay pairing between the UE and the relay UE; sending a connection setup request message to a base station based at least in part on establishing the sidelink communication link with the UE; and receiving, in response to the connection setup request message, from the base station, a connection setup complete message comprising an indication of a first signaling radio bearer associated with a relay link for the relay pairing; The apparatus is executable by the processor to cause

21. The instructions cause the device to: transmitting a reconfiguration request message to the base station based at least in part on receiving the connection setup complete message; receiving a reconfiguration complete message from the base station comprising an indication of a second signaling radio bearer for the relay link, or a data radio bearer for the relay link, or any combination thereof; 21. The apparatus of claim 20, further executable by the processor to:

22. The instructions cause the device to: relaying, from the UE, a connection re-establishment request message to the base station based at least in part on the relay pairing between the UE and the relay UE; relaying, from the base station, a connection re-establishment message to the UE in response to the connection re-establishment request message; 22. The apparatus of claim 21, further executable by the processor to:

23. The apparatus of claim 22 , wherein the connection re-establishment request message and the connection re-establishment message are relayed before receiving the reconfiguration complete message from the base station.

24. The apparatus of claim 20 , wherein a connection state of the relay UE comprises an idle state or an inactive state.

25. An apparatus for wireless communication in a user equipment (UE), comprising: A processor; a memory coupled to the processor; and instructions stored in the memory, the instructions causing the device to: receiving a first message from a base station indicating a configuration of a relay UE, an identifier of the relay UE, and an indication that the UE should switch to a sidelink communication link with the relay UE, wherein the first message is based at least in part on a relay pairing between the UE and the relay UE; sending a second message to the relay UE for establishing a sidelink communication link with the relay UE, wherein the second message comprises an indication that the sidelink communication link is for a handover associated with the relay pairing. after establishing the sidelink communication link with the relay UE, sending a connection re-establishment request message to the base station, via the relay UE, based at least in part on the relay pairing between the UE and the relay UE; and receiving, from the relay UE, a connection re-establishment message transmitted from the base station to the relay UE in response to the connection re-establishment request message; The apparatus is executable by the processor to cause

26. The instructions cause the device to: and transmitting a measurement report to the base station, wherein the measurement report comprises an indication of a connection state of the relay UE, the identifier of the relay UE, a cell identifier of the relay UE, or any combination thereof, and the relay pairing is based at least in part on the measurement report.

26. The apparatus of claim 25.

27. The instructions cause the device to: and further operable by the processor to cause, based at least in part on receiving the connection re-establishment message via the relay UE, releasing an access link between the UE and a source base station, where the source base station is different from the base station.

26. The apparatus of claim 25.

28. The instructions cause the device to: and further operable by the processor to cause, based at least in part on receiving the first message, to release an access link between the UE and a source base station, where the source base station is different from the base station.

26. The apparatus of claim 25.

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