WO2024082736A1

WO2024082736A1 - Method and apparatus for mobility robustness optimization

Info

Publication number: WO2024082736A1
Application number: PCT/CN2023/108413
Authority: WO
Inventors: Lianhai WU; Le Yan; Mingzeng Dai
Original assignee: Lenovo (Beijing) Limited
Priority date: 2023-07-20
Filing date: 2023-07-20
Publication date: 2024-04-25

Abstract

Embodiments of the present disclosure relate to method and apparatus for mobility robustness optimization in a network. According to some embodiments of the disclosure, a UE may: receive, an RRC configuration from a first BS via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and report measurement results associated with the at least one candidate relay node to the first BS. According to some embodiments of the disclosure, the UE may receive an RRC configuration for path switch related to a relay UE. To assist the network optimization, the UE may report information related to a successful path switch or a failed path switch to the network.

Description

METHOD AND APPARATUS FOR MOBILITY ROBUSTNESS OPTIMIZATION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to wireless communication technology, and more particularly to mobility robustness optimization (MRO) in a network.

BACKGROUND

A wireless communication system may include one or multiple network communication devices, such as base stations, which may support wireless communication for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communication system may support wireless communication with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like) . Additionally, the wireless communication system may support wireless communication across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) (which is also known as new radio (NR) ) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G) ) .

In a wireless communication system, a user equipment (UE) may communicate with another UE via a data path supported by an operator's network, e.g., a cellular or a Wi-Fi network infrastructure. The data path supported by the operator's network may include a base station (BS) and multiple gateways.

Some wireless communication systems may support sidelink communications, in which devices (e.g., UEs) that are relatively close to each other may communicate with one another directly via a sidelink, rather than being linked through the BS. A relaying function based on a sidelink may be supported in a communication network. For example, a UE supporting sidelink communication may function as a relay node to extend the coverage of a BS. An out-of-coverage or in-coverage UE may communicate with a BS via a relay node (e.g., a relay UE) . In the context of the present disclosure, a UE, which functions as a relay between another UE and a BS, may be referred to as a UE-to-network (U2N) relay.

There is a need for efficiently performing communication in a communication system supporting a U2N relay.

SUMMARY

An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a, ” “at least one, ” “one or more, ” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” or “one or both of” ) indicates an inclusive list such that, 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, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ” Further, as used herein, including in the claims, a “set” may include one or more elements.

Some embodiments of the present disclosure provide a UE. The UE may include at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive a radio resource control (RRC) configuration from a first BS via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and report measurement results associated with the at least one candidate relay node to the first BS.

Some embodiments of the present disclosure provide a first BS. The first BS may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the first BS to: transmit an RRC configuration to a UE via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; receive measurement results associated with the at least one candidate relay node from the UE; and receive assistant information from another BS, wherein the assistant information is reported by the UE.

In some embodiments of the present disclosure, the at least one processor is further configured to cause the first BS to transmit a path switch command to the UE to switch the UE to a fourth BS. The another BS is a second BS serving the UE by performing a successful reestablishment procedure in response to a failure to perform the path switch, or the another BS is a third BS serving the UE by performing a connection establishment procedure after a failed reestablishment procedure in response to the failure to perform the path switch.

In some embodiments of the present disclosure, the assistant information indicates one or more of the following: measurement results of a link between the UE and the first relay node in response to the path switch failure; measurement results associated with the at least one candidate relay node in response to the path switch failure; an ID of the first relay node; an ID of a second relay node through which the UE attempts to perform a reestablishment procedure before accessing the third BS; an ID of a third relay node through which the UE accesses the third BS; an ID of a fourth relay node in the case that the path switch command indicating the UE to switch to the fourth BS via the fourth relay node; a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure; a cause for the assistant information reporting, which indicates an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path; a ninth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure; and a tenth indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires.

In some embodiments of the present disclosure, the at least one processor is further configured to cause the first BS to: transmit, to the UE, a condition to trigger a report of assistant information associated with a path switch success; and transmit, to the UE, a path switch command to the UE to switch the UE to a fourth BS. The first BS receives the assistant information from the fourth BS in response to a successful path switch to the fourth BS and the condition being met.

In some embodiments of the present disclosure, the assistant information indicates one or more of the following: an ID of the first relay node; the measurement results of the link between the UE and the first relay node; an ID of a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node; the measurement results of a link between the UE and the fourth relay node; and a cause for the assistant information reporting.

In some embodiments of the present disclosure, the cause indicates that a percentage threshold associated with a timer for path switch to an indirect path is reached.

In some embodiments of the present disclosure, the condition comprises a percentage threshold associated with a timer for path switch to an indirect path.

Some embodiments of the present disclosure provide a fourth BS. The fourth BS may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the fourth BS to: receive a path switch request to switch a user equipment (UE) from a first BS to the fourth BS; transmit a response based on the path switch request, wherein the response includes a configuration for the path switch; and in response to a successful path switch, receive assistant information associated with the successful path switch from the UE.

Some embodiments of the present disclosure provide a processor. The processor may include at least one controller coupled with at least one memory and configured to cause the processor to: receive an RRC configuration from a first BS via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and report measurement results associated with the at least one candidate relay node to the first BS.

Some embodiments of the present disclosure provide a method for wireless communication. The method may include: receiving an RRC configuration from a first BS via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and reporting measurement results associated with the at least one candidate relay node to the first BS.

Some embodiments of the present disclosure provide a method for wireless communication. The method may include: transmit, to a BS, an indication indicating an availability of assistant information associated with a radio link failure (RLF) , a path switch failure or a path switch success, wherein the assistant information is related to an indirect path; receive, from the BS, a request message for requesting the assistant information; and transmit, to the BS, a response message comprising the assistant information.

Some embodiments of the present disclosure provide a method for wireless communication. The method may include: receive, from a UE, an indication indicating an availability of assistant information associated with a radio link failure (RLF) , a path switch failure or a path switch success, wherein the assistant information is related to an indirect path; transmit, to the UE, a request message for requesting the assistant information; and receive, from the UE, a response message comprising the assistant information; and transmit the received assistant information to a BS.

Some embodiments of the present disclosure provide a method for wireless communication. The method may include: serving a UE; and receiving, from a BS, assistant information associated with an RLF, a path switch failure or a path switch success at the UE, wherein the assistant information is related to an indirect path.

Some embodiments of the present disclosure provide an apparatus. According to some embodiments of the present disclosure, the apparatus may include: at least one non-transitory computer-readable medium having stored thereon computer-executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer- readable medium, the at least one receiving circuitry and the at least one transmitting circuitry, wherein the at least one non-transitory computer-readable medium and the computer executable instructions may be configured to, with the at least one processor, cause the apparatus to perform a method according to some embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered limiting of its scope.

FIG. 1 illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present disclosure;

FIG. 2 illustrates a flowchart of a method for obtaining UE information in accordance with some embodiments of the present disclosure;

FIGs. 3-5 illustrate flowcharts of methods for wireless communication in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates a flowchart of a method for wireless communication performed by a UE in accordance with some embodiments of the present disclosure;

FIGs. 7 and 8 illustrate flowcharts of methods for wireless communication performed by a network equipment (NE) in accordance with some embodiments of the present disclosure;

FIG. 9 illustrates a block diagram of an exemplary apparatus in accordance with some embodiments of the present disclosure;

FIG. 10 illustrates an example of a UE in accordance with some embodiments of the present disclosure;

FIG. 11 illustrates an example of a processor in accordance with some embodiments of the present disclosure; and

FIG. 12 illustrates an example of an NE in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under a specific network architecture (s) and new service scenarios, such as the 3rd generation partnership project (3GPP) 5G NR or 6G, 3GPP LTE, and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principles of the present disclosure.

In a communication system, a UE may store certain information and report it to a communication network to facilitate mobility robustness optimization (MRO) in the communication network. However, such information only includes information associated with a direct path (e.g., the UE directly accessing a cell or BS via a Uu interface) . When a UE is allowed to access a serving cell via an indirect path, for example, via a relay node (e.g., a L2 relay UE) , it is desired to optimize the communication network based on information associated with the direct path.

The present disclosure provides solutions to solve the above issues. For example, information associated with an indirect path may be provided to the communication network so as to optimize the network. Such information can enhance the MRO in a communication network.

FIG. 1 illustrates a schematic diagram of wireless communication system 100 in accordance with some embodiments of the present disclosure.

The wireless communication system 100 may include one or more NEs 102 (e.g., one or more BSs) , one or more UEs 104, and a core network (CN) 106. The wireless communication system 100 may support various radio access technologies. In some implementations, the wireless communication system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communication system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultra-wideband (5G-UWB) network. In other implementations, the wireless communication system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , and IEEE 802.20. The wireless communication system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communication system 100 may support technologies, such as time division multiple access (TDMA) , frequency division multiple access (FDMA) , or code division multiple access (CDMA) , etc.

The one or more NEs 102 may be dispersed throughout a geographic region to form the wireless communication system 100. One or more of the NEs 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN) , a NodeB, an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc. ) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN) . In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with a different NE 102.

The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communication system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link 114 may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

An NE 102 may support communication with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with another NE 102 or the CN 106 through one or more backhaul links (e.g., S1, N2, N3, or network interface) . In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other or indirectly (e.g., via the CN 106. In some implementations, one or more NEs 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC) . An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as radio heads, smart radio heads, or transmission-reception points (TRPs) .

The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC) , or a 5G core (5GC) , which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management functions (AMF) ) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc. ) for the one or more UEs 104 served by the one or more NEs 102 associated with the CN 106.

The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an S1, N2, N3, or another network interface) . The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session) . The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106) .

In the wireless communication system 100, the NEs 102 and the UEs 104 may use resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers) ) to perform various operations (e.g., wireless communication) . In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures) . The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

One or more numerologies may be supported in the wireless communication system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., μ=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., μ=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., μ=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames) . Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communication system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., orthogonal frequency-division multiplexing (OFDM) symbols) . In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing) , a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., μ=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

In the wireless communication system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communication system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz –7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4 (52.6 GHz –114.25 GHz) , FR4a or FR4-1 (52.6 GHz –71 GHz) , and FR5 (114.25 GHz –300 GHz) . In some implementations, the NEs 102 and the UEs 104 may perform wireless communication over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communication traffic (e.g., control information, data) . In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies) . For example, FR1 may be associated with a first numerology (e.g., μ =0) , which includes 15 kHz subcarrier spacing; a second numerology (e.g., μ =1) , which includes 30 kHz subcarrier spacing; and a third numerology (e.g., μ=2) , which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies) . For example, FR2 may be associated with a third numerology (e.g., μ=2) , which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., μ=3) , which includes 120 kHz subcarrier spacing.

A UE 104 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to some embodiments of the present disclosure, a UE 104 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments of the present disclosure, a UE 104 includes wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, a UE 104 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art. A UE 104 may communicate with an NE 102 (e.g., a BS) via uplink (UL) communication signals. An NE 102 may communicate with a UE 104 via downlink (DL) communication signals.

In some embodiments of the present disclosure, an NE 102 and a UE 104 may communicate over licensed spectrums, whereas in some other embodiments, an NE 102 and a UE 104 may communicate over unlicensed spectrums. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

MRO aims at detecting and enabling correction of various problems in a communication system or network. For example, such problems may include, but are not limited to, the following:

- Connection failure due to intra-system or inter-system mobility;

- Inter-system unnecessary handover (HO) (e.g., too early inter-system HO from NR to evolved universal terrestrial radio access network (E-UTRAN) with no radio link failure) ;

- Inter-system HO ping-pong;

- PSCell change failure.

The MRO function can provide a means to distinguish the above problems from NR coverage related problems and other problems, not related to mobility. In some embodiments, the MRO function can be enhanced to provide more robust mobility by reporting failure events observed during a successful handover. For example, for the detection of sub-optimal successful handovers, MRO additionally enables the observability of a successful HO due to intra-NR mobility.

FIG. 2 illustrates a flow chart of method 200 for obtaining UE information in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 2.

Referring to FIG. 2, UE 204 and BS 202 may function as UE 104 and NE 102 shown in FIG. 1, respectively. At 211, BS 202 may transmit a UE information request message to UE 204. At 213, UE 204 may transmit a UE information response message in response to the UE information request message.

In some embodiments of the present disclosure, method 200 may be used by a network (e.g., an NE or a BS) to request a UE to report information for facilitating the MRO in the network. For example, as will be described in the following text, the network may request a UE to report an RLF report or a successful handover report to facilitate the MRO in the network. The network may initiate method 200 only after a successful security activation.

In some embodiments of the present disclosure, a UE may make an RLF report available to the network for the analysis of connection failures and facilitating the MRO in the network.

For example, a UE may store the latest RLF report, including, for example, both the LTE and NR RLF report, until the RLF report is fetched by the network or for a certain time (e.g., 48 hours) after the connection failure (e.g., RLF) is detected. In some embodiments, the UE may only indicate the availability of the RLF report and only provide the RLF report to the network in the case that the current registered public land mobile network (RPLMN) is a public land mobile network (PLMN) that was present in the UE's equivalent PLMN (EPLMN) list or was the RPLMN at the time the connection failure (e.g., RLF) was detected.

In some embodiments, when an RLF happens in an evolved universal terrestrial radio access (E-UTRA) cell, the UE may make an LTE RLF report available to a next-generation radio access network (NG-RAN) node and eNB (s) . In some embodiments, when an RLF happens in an NR cell, the UE may make an NR RLF report available to a gNB (s) . In some embodiments, in the case that an LTE RLF report is reported to a NG-RAN node, and the last serving node is an E-UTRAN node, the NG-RAN node may transfer the report to the E-UTRAN node by, for example, triggering an uplink RAN configuration transfer procedure over NG and the E-UTRAN node can take the report into account.

In some embodiments of the present disclosure, a UE may report failure events observed during a successful handover (or path switch) to the network to facilitate the MRO in the network.

For example, a UE may be configured to compile a report associated with a successful handover comprising, for example, a set of measurements collected during the handover phase including, for example, a measurement at the handover trigger, a measurement at the end of the handover execution, or a measurement after the handover execution. In some embodiments, the UE may be configured with one or more triggering conditions to compile the successful handover report, and the report would only be triggered in response to a condition (s) being met. This can limit UE reporting to relevant cases, such as underlying issues detected by radio link monitoring (RLM) , or beam failure detection (BFD) detected in response to a successful handover event.

In some embodiments, the availability of a successful handover report may be indicated by a handover complete message (e.g., an RRC reconfiguration complete message) transmitted from the UE to the target BS of the handover (e.g., a NG-RAN node) . The target BS may fetch information of a successful handover report via the UE information procedure as described with respect to FIG. 2. In some embodiments, the target BS may forward the successful handover report to the source BS of the handover (e.g., a NR-RAN node) to indicate a failure (s) experienced during the successful handover.

In response to the reception of the successful handover report, the receiving node (e.g., the target BS or the source BS) is able to analyze whether its mobility configuration needs adjustment. Such adjustment may result in changes of mobility configurations, such as changes of RLM configurations or changes of mobility thresholds between the source and the target. In some embodiments, the target BS, in the performed handover, may further optimize the dedicated random access channel (RACH) -beam resources based on the beam measurements reported in response to the successful handover (s) .

Embodiments of the present disclosure propose technical solutions for facilitating the MRO in a communication network. For example, a UE may access a serving cell via an indirect path, for example, via a relay node (e.g., an L2 relay UE) . There is an end-to-end RRC connection between the UE and the BS. It would be advantageous to provide information associated with the indirect path for MRO. More details on the embodiments of the present disclosure will be illustrated in the following text in combination with the appended drawings.

FIG. 3 illustrates a flow chart of exemplary method 300 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 3. For example, UE 304 and BSs 302A and 302B may function as UE 104 and NE 102 shown in FIG. 1, respectively.

Referring to FIG. 3, at 311, UE 304 may access BS 302A and may be in a connected state. In some embodiments, UE 304 may access BS 302A via a direct path. That is, UE 304 directly connects to BS 302A without any relay node. In some other embodiments, UE 304 may access BS 302A via an indirect path. That is, UE 304 connects to BS 302A via a relay node (denoted as relay node #A1) .

UE 304 may receive an RRC configuration from BS 302A via the direct path or the indirect path (i.e., via relay node #A1) . The RRC configuration may include a measurement configuration (s) related to at least one candidate relay node. UE 304 may report measurement results associated with the at least one candidate relay node to BS 302A.

An RLF may occur on the link between UE 304 and BS 302A. For example, at 313, UE 304 may detect an RLF on the link (e.g., PC5 link) between UE 304 and relay node #A1. For example, UE 304 may receive a notification message or a release message from relay node #A1. Relay node #A1 may transmit the notification message or the release message due to a handover of relay node #A1 or an RLF on the link between BS 302A and relay node #A1. For example, UE 304 may detect an RLF on the direct link with BS 302A.

In some embodiments, UE 304 may store some information in response to the RLF. For example, in response to detecting an RLF on the link between UE 304 and relay node #A1 or the reception of the notification message or the release message from relay node #A1, UE 304 may store one or more of the following: measurement results of the link between the UE and UE 304 and relay node #A1; and measurement results (e.g., last measurement results) associated with the at least one candidate relay node. The stored information may be reported to the network at a later phase. For example, the measurement results of the link between the UE and UE 304 and relay node #A1 may be carried in an information element (IE) (e.g., "measResultLastServRelay" ) and transmitted to the network.

UE 304 may initiate a reestablishment procedure. For example, UE 304 may transmit an RRC reestablishment request message to a selected cell via a direct path or an indirect path.

In some embodiments, the reestablishment procedure may be successfully performed. For example, at 315, UE 304 may successfully access a cell (e.g., a cell of BS 302B) via a direct path or an indirect path. UE 304 may transmit an indication indicating the availability of assistant information to BS 302B (e.g., the serving cell or serving BS) at 317. The assistant information may be associated with an RLF that occurred on the link between UE 304 and the source BS (i.e., BS 302A) .

BS 302B may obtain the assistant information via a UE information procedure. For example, at 319, BS 302B may transmit, to UE 304, a request message (e.g., a UE information request message) for requesting the assistant information. At 321, UE 304 may transmit a response message (e.g., a UE information response message) to BS 302B. The response message may include the assistant information. For example, the assistant information may include certain measurement results stored at UE 304 and other information.

In some embodiments, the assistant information may include one or more of the following: (1a) measurement results of the link between UE 304 and relay node #A1 in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (2a) measurement results (e.g., last measurement results) associated with the at least one candidate relay node in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (3a) an ID of relay node #A1 in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (4a) a cause for the assistant information reporting, which may include one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message; and (5a) an indication indicating a type of an executed path switch before a failure is detected at UE 304, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

In information (5a) , the failure detected at UE 304 may refer to, for example, an RLF on the direct link between UE 304 and BS 302A, an RLF on the link between UE 304 and relay node #A1, or an RLF on the link between BS 302A and relay node #A1.

In some embodiments, in the case that UE 304 accesses BS 302A via a direct link at 311, the assistant information may not include information (1a) to (3a) . In some embodiments, in the case of an RLF on the link between UE 304 and relay node #A1, information (4a) may indicate the cause for the assistant information reporting being a sidelink RLF. In some embodiments, in the case of an RLF on the link between BS 302A and relay node #A1, information (4a) may indicate the cause for the assistant information reporting being a reception of a notification message or a reception of a release message depending on whether relay node #A1 transmits a notification message or a release message to inform UE 304 of such RLF.

In some embodiments, the assistant information may include an ID of the cell (e.g., primary cell (PCell) ID) of BS 302A which UE 304 accesses. The information can indicate the cell in which the RLF is detected.

In some embodiments, the reestablishment procedure may fail.

For example, UE 304 may attempt reestablishment with a cell or a relay node (denoted as relay node #A2) which accesses a cell. For example, UE 304 may start a timer (e.g., timer T311 as specified in 3GPP specifications) in response to transmitting a reestablishment request for the reestablishment procedure. The reestablishment procedure to the cell or relay node (e.g., relay node #A2) may fail. UE 304 may perform cell selection. In some examples, UE 304 may fail to select any suitable relay node when the timer expires. In some examples, UE 304 may fail to select any suitable relay node or suitable cell when the timer expires.

In response to the failed reestablishment, UE 304 may enter into an idle state, and may perform a connection establishment procedure. For example, at 315, UE 304 may successfully access a cell (e.g., a cell of BS 302B) via a direct path or an indirect path. For example, UE 304 may directly access BS 302B without any relay node. Alternatively, UE 304 may access BS 302B via a relay node (denoted as relay node #A3) . UE 304 may transmit an indication indicating the availability of assistant information to BS 302B (e.g., the serving cell or serving BS) at 317. The assistant information may be associated with an RLF that occurred on the link between UE 304 and the source BS (i.e., BS 302A) .

In some embodiments, the assistant information may include one or more of the following: (1b) measurement results of the link between UE 304 and relay node #A1 in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (2b) measurement results (e.g., last measurement results) associated with the at least one candidate relay node in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (3b) an ID of relay node #A1 in response to one of: detecting an RLF on the link between UE 304 and relay node #A1, receiving a notification message from relay node #A1, and receiving a release message from relay node #A1; (4b) an ID of a relay node (e.g., relay node #A2) through which UE 304 attempts to perform the reestablishment procedure before accessing BS 302B; (5b) an ID of a relay node (e.g., relay node #A3) through which UE 304 accesses BS 302B; (6b) a cause for the assistant information reporting, which may include one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message; (7b) an indication indicating that no suitable relay node was found when a timer expires, wherein the timer (e.g., timer T311) starts in response to transmitting a reestablishment request for the reestablishment procedure; (8b) an indication indicating that neither a suitable relay node nor a suitable cell was found when the timer expires; and (9b) an indication indicating a type of an executed path switch before a failure is detected at UE 304, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

In information (9b) , the failure detected at UE 304 may refer to, for example, an RLF on the direct link between UE 304 and BS 302A, an RLF on the link between UE 304 and relay node #A1, or an RLF on the link between BS 302A and relay node #A1.

In some embodiments, in the case that UE 304 accesses BS 302A via a direct link at 311, the assistant information may not include information (1b) to (3b) . In some embodiments, in the case that UE 304 does not attempt to perform the reestablishment procedure with any relay node, the assistant information may not include information (4b) . In some embodiments, in the case that UE 304 accesses BS 302B via a direct link, the assistant information may not include information (5b) . In some embodiments, in the case of an RLF on the link between UE 304 and relay node #A1, information (6b) may indicate the cause for the assistant information reporting being a sidelink RLF. In some embodiments, in the case of an RLF on the link between BS 302A and relay node #A1, information (6b) may indicate the cause for the assistant information reporting being a reception of a notification message or a reception of a release message depending on whether relay node #A1 transmits a notification message or a release message to inform UE 304 of such RLF.

In some embodiments, the assistant information may include one or more of the following: (1b') an ID of the cell (e.g., PCell ID) of BS 302A which UE 304 accesses; (2b') an ID of the cell of BS 302B which UE 304 accesses; and (3b') an indication indicating that no suitable cell was found when a timer expires, wherein the timer (e.g., timer T311) starts in response to transmitting a reestablishment request for the reestablishment procedure.

Information (1b') can indicate the cell in which the RLF is detected. Information (2b') can indicate the cell in which UE 304 comes back to the connected state after a connection failure and after a reestablishment failure.

At 323, in response to receiving the assistant information from UE 304, BS 302B may transmit the received assistant information to BS 302A via, for example, an Xn message. The Xn message may be a failure indication message or any other Xn message. In some examples, the assistant information received from UE 304 may be transmitted as a container. In some examples, the Xn message may include an "establishment failure" indication. In some embodiments, the assistant information may indicate the cell ID (e.g., a PCell ID) in which the RLF is detected. BS 302B can identify BS 302A based on this information.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 300 may be changed and some of the operations in exemplary method 300 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 4 illustrates a flow chart of exemplary method 400 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 4. For example, UE 404 and BSs 402A and 402B may function as UE 104 and NE 102 shown in FIG. 1, respectively.

Referring to FIG. 4, at 411, UE 404 may access BS 402A and may be in a connected state. In some embodiments, UE 404 may access BS 402A via a direct path. That is, UE 404 directly connects to BS 402A without any relay node. In some other embodiments, UE 404 may access BS 402A via an indirect path. That is, UE 404 connects to BS 402A via a relay node (denoted as relay node #B1) .

UE 404 may receive an RRC configuration from BS 402A via the direct path or the indirect path (i.e., via relay node #B1) . The RRC configuration may include a measurement configuration (s) related to at least one candidate relay node. UE 404 may report measurement results associated with the at least one candidate relay node to BS 402A.

At 412, UE 404 may receive, from BS 402A, a path switch command to switch UE 404 to another BS (denoted as BS #D) . The path switch to BS #D may be a switch to a direct path or an indirect path. That is, the path switch command may instruct UE 404 to directly connect to BS #D or indirectly connect to BS #D via a relay node (denoted as relay node #B4) .

In some embodiments, the path switch may be an inter-BS indirect-to-direct path switch. That is, UE 404 accesses the source cell (e.g., BS 402A) via a relay node (e.g., relay node #B1) , receives a path switch command towards a target cell (e.g., BS #D) , performs the path switch towards the target cell (e.g., BS #D) , and starts a timer for path switch to a direct path (e.g., timer T304 as specified in 3GPP specifications) .

In some embodiments, the path switch may be an inter-BS direct-to-indirect path switch. That is, UE 404 accesses the source cell (e.g., BS 402A) via a Uu interface, receives a path switch command towards a target relay (e.g., relay node #B4) which accesses a target cell (e.g., BS #D) , performs the path switch towards the target relay, and starts a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) .

In some embodiments, the path switch may be an inter-BS indirect-to-indirect path switch. That is, UE 404 accesses the source cell (e.g., BS 402A) via a relay node (e.g., relay node #B1) , receives a path switch command towards a target relay (e.g., relay node #B4) which accesses a target cell (e.g., BS #D) , performs the path switch towards the target relay, and starts a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) .

At 413, the path switch to BS #D may fail. The cause for the path switch failure may include, for example, the expiry of the timer for path switch to a direct path, the expiry of the timer for path switch to an indirect path, reception of a notification message from the target relay node (e.g., relay node #B4) , or reception of a release message (e.g., PC5 release message) from the target relay node (e.g., relay node #B4) .

In some embodiments, UE 404 may store some information in response to the path switch failure. For example, in response to the path switch failure, UE 404 may store one or more of the following: measurement results of the link between the UE and UE 404 and relay node #B1; and measurement results (e.g., last measurement results) associated with the at least one candidate relay node. The stored information may be reported to the network at a later phase. For example, the measurement results of the link between the UE and UE 404 and relay node #B1 may be carried in an IE and transmitted to the network.

In response to the path switch failure, UE 404 may initiate a reestablishment procedure. For example, UE 404 may transmit an RRC reestablishment request message to a selected cell via a direct path or an indirect path.

In some embodiments, the reestablishment procedure may be successfully performed. For example, UE 404 may successfully access a cell (e.g., a cell of BS 402B) via a direct path or an indirect path at 415. UE 404 may transmit an indication indicating the availability of assistant information to BS 402B (e.g., the serving cell or serving BS) at 417. The assistant information may be associated with the path switch failure.

BS 402B may obtain the assistant information via a UE information procedure. For example, at 419, BS 402B may transmit, to UE 404, a request message (e.g., a UE information request message) for requesting the assistant information. At 421, UE 404 may transmit a response message (e.g., a UE information response message) to BS 402B. The response message may include the assistant information. For example, the assistant information may include certain measurement results stored at UE 404 and other information.

In some embodiments, the assistant information may include one or more of the following: (1c) measurement results of the link between UE 404 and relay node #B1 in response to the path switch failure; (2c) measurement results (e.g., last measurement results) associated with the at least one candidate relay node in response to the path switch failure; (3c) an ID of relay node #B1 in response to the path switch failure; (4c) an ID of a relay node (e.g., relay node #B4) in the case that the path switch command at 412 indicates UE 404 to switch to a BS (e.g., BS #D) via the relay node (e.g., relay node #B4) ; (5c) a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure; (6c) a cause for the assistant information reporting, which may indicate one of the following: an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path; and (7c) an indication indicating a type of an executed path switch before the path switch failure, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

In some embodiments, in the case that UE 404 accesses BS 402A via a direct link at 411, the assistant information may not include information (1c) to (3c) . In some embodiments, in the case that the target path of the failed path switch is a direct path (e.g., the path switch command at 412 indicating UE 404 to switch to BS #D without a relay node) , the assistant information may not include information (4c) .

In some embodiments, the assistant information may include one or more of the following: (1c') an ID of the cell (e.g., PCell ID) of BS 402A which UE 304 accesses; and (2c') an ID of the target cell (e.g., PCell ID) of the failed path switch (e.g., cell of BS #D) . Information (1c') can indicate the source cell of the failed path switch. Information (2c') can indicate the target cell of the failed path switch.

In some embodiments, the reestablishment procedure may fail.

For example, UE 404 may attempt reestablishment with a cell or a relay node (denoted as relay node #B2) which accesses a cell. For example, UE 404 may start a timer (e.g., timer T311 as specified in 4GPP specifications) in response to transmitting a reestablishment request for the reestablishment procedure. The reestablishment procedure to the cell or relay node (e.g., relay node #B2) may fail. UE 404 may perform cell selection. In some examples, UE 404 may fail to select any suitable relay node when the timer expires. In some examples, UE 404 may fail to select any suitable relay node or suitable cell when the timer expires.

In response to the failed reestablishment, UE 404 may enter into an idle state, and may perform a connection establishment procedure. For example, UE 404 may successfully access a cell (e.g., a cell of BS 402B) via a direct path or an indirect path. For example, UE 404 may directly access BS 402B without any relay node. Alternatively, UE 404 may access BS 402B via a relay node (denoted as relay node #B3) . UE 404 may transmit an indication indicating the availability of assistant information to BS 402B (e.g., the serving cell or serving BS) at 417. The assistant information may be associated with the failed path switch of UE 404 from the source BS (e.g., BS 402A) to a target BS (e.g., BS #D) .

In some embodiments, the assistant information may include one or more of the following: (1d) measurement results of the link between UE 404 and relay node #B1 in response to the path switch failure; (2d) measurement results (e.g., last measurement results) associated with the at least one candidate relay node in response to the path switch failure; (3d) an ID of relay node #B1 in response to the path switch failure; (4d) an ID of a relay node (e.g., relay node #B4) in the case that the path switch command indicates UE 404 to switch to a BS (e.g., BS #D) via the relay node (e.g., relay node #B4) ; (5d) an ID of a relay node (e.g., relay node #B2) through which UE 404 attempts to perform the reestablishment procedure before accessing BS 402B; (6d) an ID of a relay node (e.g., relay node #B3) through which the UE accesses BS 402B; (7d) a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure; (8d) a cause for the assistant information reporting, which may indicate one of the following: an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path; (9d) an indication indicating that no suitable relay node was found when a timer expires, wherein the timer (e.g., timer T311) starts in response to transmitting a reestablishment request for the reestablishment procedure; (10d) an indication indicating that neither a suitable relay node nor a suitable cell was found when the timer expires; and (11d) an indication indicating a type of an executed path switch before the path switch failure, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

In some embodiments, in the case that UE 404 accesses BS 402A via a direct link at 411, the assistant information may not include information (1d) to (3d) . In some embodiments, in the case that the target path of the failed path switch is a direct path (e.g., the path switch command at 412 indicating UE 404 to switch to BS #D without a relay node) , the assistant information may not include information (4d) .

In some embodiments, in the case that UE 404 does not attempt to perform the reestablishment procedure with any relay node, the assistant information may not include information (5d) . In some embodiments, in the case that UE 404 accesses BS 402B via a direct link, the assistant information may not include information (6d) . In some embodiments, in the case of the path switch being failed due to the expiry of the timer for path switch to an indirect path, information (8d) may indicate the cause for the assistant information reporting being an expiry of a timer for path switch to an indirect path. In some embodiments, in the case of the path switch being failed due to the expiry of the timer for path switch to a direct path, information (8d) may indicate the cause for the assistant information reporting being an expiry of a timer for path switch to a direct path.

In some embodiments, the assistant information may include one or more of the following: (1d') an ID of the cell (e.g., PCell ID) of BS 402A which UE 304 accesses; (2d') an ID of the target cell (e.g., PCell ID) of the failed path switch (e.g., cell of BS #D) ; (3d') an ID of the cell of BS 402B which UE 404 accesses; and (4d') an indication indicating that no suitable cell was found when a timer expires, wherein the timer (e.g., timer T311) starts in response to transmitting a reestablishment request for the reestablishment procedure.

Information (1d') can indicate the source cell of the failed path switch. Information (2d') can indicate the target cell of the failed path switch. Information (3d') can indicate the cell in which UE 404 comes back to the connected state after a connection failure and after a reestablishment failure.

At 423, in response to receiving the assistant information from UE 404, BS 402B may transmit the received assistant information to BS 402A via, for example, an Xn message. The Xn message may be a failure indication message or any other Xn message. In some examples, the assistant information received from UE 404 may be transmitted as a container. In some examples, the Xn message may include an "establishment failure" indication. In some embodiments, the assistant information may indicate the source cell ID (e.g., a PCell ID) of the failed path switch. BS 402B can identify BS 402A based on this information.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 400 may be changed and some of the operations in exemplary method 400 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 5 illustrates a flow chart of exemplary method 500 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 5. For example, UE 504 and BSs 502A and 502B may function as UE 104 and NE 102 shown in FIG. 1, respectively.

Referring to FIG. 5, at 511, UE 504 may access BS 502A and may be in a connected state. In some embodiments, UE 504 may access BS 502A via a direct path. That is, UE 504 directly connects to BS 502A without any relay node. In some other embodiments, UE 504 may access BS 502A via an indirect path. That is, UE 504 connects to BS 502A via a relay node (denoted as relay node #C1) .

UE 504 may receive an RRC configuration from BS 502A via the direct path or the indirect path (i.e., via relay node #C1) . The RRC configuration may include a measurement configuration (s) related to at least one candidate relay node. UE 504 may report measurement results associated with the at least one candidate relay node to BS 502A.

In some embodiments, UE 504 may receive, from BS 502A, a condition to trigger a report of assistant information associated with a path switch success. UE 504 may prepare assistant information associated with the path switch success to the target BS of the successful path switch in the case that the condition is met.

In some examples, the condition may include a percentage threshold associated with a timer for path switch to a direct path (e.g., timer T304 as specified in 3GPP specifications) . UE 504 may start the timer for path switch to a direct path in response to receiving a path switch command. UE 504 may determine whether the condition is met or not based on an elapsed time of the timer and the percentage threshold. For example, if the elapsed time of the timer (e.g., timer T304) is greater than or equal to the percentage threshold × (length of the timer) , UE 504 may determine the condition being met and may report the assistant information. The reported assistant information can be used to optimize the near-failure path switch.

In some examples, the condition may include a percentage threshold associated with a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) . UE 504 may start the timer for path switch to an indirect path in response to receiving a path switch command. UE 504 may determine whether the condition is met or not based on an elapsed time of the timer and the percentage threshold. For example, if the elapsed time of the timer (e.g., timer T420) is greater than or equal to the percentage threshold × (length of the timer) , UE 504 may determine the condition being met and may report the assistant information. The reported assistant information can be used to optimize the near-failure path switch.

In some examples, the condition may include a percentage threshold associated with a link failure timer (e.g., timer T310 or T312 as specified in 3GPP specifications) . UE 504 may determine whether the condition is met or not based on an elapsed time of the timer and the percentage threshold. For example, if the elapsed time of the timer (e.g., timer T310 or T312) is greater than or equal to the percentage threshold × (length of the timer) , UE 504 may determine the condition being met and may report the assistant information. The reported assistant information can be used to optimize the near-failure path switch.

At 512, UE 504 may receive, from BS 502A, a path switch command to switch UE 504 to BS 502D. The path switch to BS 502D may be a switch to a direct path or an indirect path. That is, the path switch command may instruct UE 504 to directly connect to BS 502D or indirectly connect to BS 502D via a relay node (denoted as relay node #C4) .

In some embodiments, the path switch may be an inter-BS indirect-to-direct path switch. That is, UE 504 accesses the source cell (e.g., BS 502A) via a relay node (e.g., relay node #C1) , receives a path switch command towards a target cell (e.g., BS 502D) , performs the path switch towards the target cell (e.g., BS 502D) , and starts a timer for path switch to a direct path (e.g., timer T304 as specified in 3GPP specifications) .

In some embodiments, the path switch may be an inter-BS direct-to-indirect path switch. That is, UE 504 accesses the source cell (e.g., BS 502A) via a Uu interface, receives a path switch command towards a target relay (e.g., relay node #C4) which accesses a target cell (e.g., BS 502D) , performs the path switch towards the target relay, and starts a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) .

In some embodiments, the path switch may be an inter-BS indirect-to-indirect path switch. That is, UE 504 accesses the source cell (e.g., BS 502A) via a relay node (e.g., relay node #C1) , receives a path switch command towards a target relay (e.g., relay node #C4) which accesses a target cell (e.g., BS 502D) , performs the path switch towards the target relay, and starts a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) .

At 513, the path switch to BS 502D may succeed. In some embodiments, UE 504 may store some information in response to the successful path switch from BS 502A to BS 502D and the condition being met. For example, UE 504 may store one or more of the following: measurement results (e.g., last measurement) of the link (e.g., source PC5 link) between UE 504 and relay node #C1 (i.e., in the case that UE 504 accesses BS 502A via an indirect link such as via relay node #C1) ; and measurement results (e.g., last measurement) of the link (e.g., target PC5 link) between UE 504 and relay node #C4 (i.e., in the case that UE 504 accesses BS 502D via an indirect link such as via relay node #C4) .

In response to UE 504 successfully accessing BS 502D via the path switch, UE 504 may transmit an indication indicating the availability of assistant information to BS 502D (e.g., the target serving cell or serving BS) at 517. The assistant information may be associated with the path switch success. In some embodiments, the indication may be included in an RRC message such as an RRC reconfiguration complete message.

BS 502D may obtain the assistant information via a UE information procedure. For example, at 519, BS 502D may transmit, to UE 504, a request message (e.g., a UE information request message) for requesting the assistant information. At 521, UE 504 may transmit a response message (e.g., a UE information response message) to BS 502D. The response message may include the assistant information. For example, the assistant information may include certain measurement results stored at UE 504 and other information.

In some embodiments, the assistant information may include one or more of the following: (1e) an ID of relay node #C1; (2e) measurement results (e.g., last measurement results) of the link between UE 504 and relay node #C1; (3e) an ID of relay node #C4) ; (4e) measurement results (e.g., last measurement results) of the link between UE 504 and relay node #C4; and (5e) a cause for the assistant information reporting.

In some embodiments, in the case that UE 504 accesses BS 502A via a direct link at 511, the assistant information may not include information (1e) and (2e) . In some embodiments, in the case that UE 504 accesses BS 502D via a direct link, the assistant information may not include information (3e) and (4e) . In some embodiments, information (5e) may indicate that the cause for the assistant information reporting is due to a certain trigger condition being met. For example, information (5e) may indicate that a percentage threshold associated with a timer for path switch to an indirect path (e.g., timer T420 as specified in 3GPP specifications) is reached. For example, UE 504 may set "t420-cause" in "shr-Cause" to "true. " An example of "shr-Cause" IE is shown below.

At 523, in response to receiving the assistant information from UE 504, BS 502D may transmit the received assistant information to BS 502A via, for example, an Xn message. The Xn message may be a failure indication message or any other Xn message. In some examples, the assistant information received from UE 504 may be transmitted as a container. In some examples, the Xn message may include a "successful handover report (SHR) " indication.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 500 may be changed and some of the operations in exemplary method 500 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 6 illustrates a flowchart of method 600 for wireless communication in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 6. In some examples, method 600 may be performed by a UE, for example, UE 104 as described with reference to FIG. 1. In some embodiments, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions or operations.

At 611, the UE may receive an RRC configuration from a first BS via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node. At 613, the UE may report measurement results associated with the at least one candidate relay node to the first BS.

In some embodiments of the present disclosure, the UE may detect an RLF on a link between the UE and the first relay node or receive a notification message or a release message from the first relay node. In response to the detected RLF or the reception of the notification message or the release message, the UE may store one or more of the following: measurement results of the link between the UE and the first relay node; and measurement results associated with the at least one candidate relay node.

In some embodiments of the present disclosure, the UE may perform a reestablishment procedure; access a second BS in response to a success of the reestablishment procedure; and access a third BS via a connection establishment procedure in response to a failure of the reestablishment procedure.

In some embodiments of the present disclosure, the UE may report assistant information to the second BS or the third BS. The assistant information may indicate or include one or more of the following: measurement results of a link between the UE and the first relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node; measurement results associated with the at least one candidate relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node; an ID of the first relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node; an ID of a second relay node through which the UE attempts to perform the reestablishment procedure before accessing the third BS; an ID of a third relay node through which the UE accesses the third BS; a cause for the assistant information reporting, which may include one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message; a first indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure; a second indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires; and a third indication indicating a type of an executed path switch before a failure is detected at the UE, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

In some embodiments of the present disclosure, the UE may receive, from the first BS, a path switch command to switch the UE to a fourth BS. In response to a failure to perform the path switch, the UE may store one or more of the following information: measurement results of a link between the UE and the first relay node; and measurement results associated with the at least one candidate relay node.

In some embodiments of the present disclosure, the UE may perform a reestablishment procedure in response to the failure to perform the path switch; access a second BS in response to a success of the reestablishment procedure; and access a third BS via a connection establishment procedure in response to a failure of the reestablishment procedure.

In some embodiments of the present disclosure, the UE may report assistant information to the second BS or the third BS. The assistant information may indicate or include one or more of the following: measurement results of a link between the UE and the first relay node in response to the path switch failure; measurement results associated with the at least one candidate relay node in response to the path switch failure; an ID of the first relay node; an ID of a second relay node through which the UE attempts to perform the reestablishment procedure before accessing the third BS; an ID of a third relay node through which the UE accesses the third BS; an ID of a fourth relay node in the case that the path switch command indicating the UE to switch to the fourth BS via the fourth relay node; a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure; a cause for the assistant information reporting, which indicates an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path; a fourth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure; and a fifth indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires.

In some embodiments of the present disclosure, the UE may receive, from the first BS, a condition to trigger a report of assistant information associated with a path switch success. The UE may receive, from the first BS, a path switch command. In response to a successful path switch from the first BS to a fourth BS and the condition being met, the UE may store one or more of the following information: measurement results of a link between the UE and the first relay node; and measurement results of a link between the UE and a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node.

In some embodiments of the present disclosure, the UE may report the assistant information to the fourth BS. The assistant information may indicate or include one or more of the following: an ID of the first relay node; the measurement results of the link between the UE and the first relay node; an ID of the fourth relay node; the measurement results of a link between the UE and the fourth relay node; and a cause for the assistant information reporting.

In some embodiments of the present disclosure, the cause may indicate that a percentage threshold associated with a timer for path switch to an indirect path is reached.

In some embodiments of the present disclosure, the condition may include a percentage threshold associated with a timer for path switch to an indirect path.

In some embodiments of the present disclosure, the UE may start the timer for path switch to an indirect path in response to receiving the path switch command; and determine whether the condition is met or not based on an elapsed time of the timer for path switch to an indirect path and the percentage threshold.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 600 may be changed and some of the operations in exemplary method 600 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 7 illustrates a flowchart of method 700 for wireless communication in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 7. In some examples, method 700 may be performed by a BS or an NE (for example, NE 102 as described with reference to FIG. 1) . In some embodiments, the BS or the NE may execute a set of instructions to control the functional elements of the BS or the NE to perform the described functions or operations.

At 711, a first BS may transmit an RRC configuration to a UE via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node. At 713, the first BS may receive measurement results associated with the at least one candidate relay node from the UE. At 715, the first BS may receive assistant information from another BS, wherein the assistant information is reported by the UE.

The assistant information as described above may apply here.

For example, in some embodiments of the present disclosure, the another BS may be a second BS serving the UE by performing a successful reestablishment procedure in response to an RLF between the first BS and the UE. In some embodiments of the present disclosure, the another BS may be a third BS serving the UE by performing a connection establishment procedure after a failed reestablishment procedure in response to the RLF between the first BS and the UE.

The assistant information may indicate one or more of the following: measurement results of a link between the UE and the first relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node; measurement results associated with the at least one candidate relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node; an ID of the first relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node; an ID of a second relay node through which the UE attempts to perform a reestablishment procedure before accessing the third BS; an ID of a third relay node through which the UE accesses the third BS; a cause for the assistant information reporting, which may include one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message; a sixth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for initiating the reestablishment procedure; a seventh indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires; and an eighth indication indicating a type of an executed path switch before the failure is detected at the UE, wherein the type of the executed path switch may include an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.

For example, in some embodiments of the present disclosure, the first BS may transmit a path switch command to the UE to switch the UE to a fourth BS. In some embodiments, the another BS may be a second BS serving the UE by performing a successful reestablishment procedure in response to a failure to perform the path switch. In some embodiments, the another BS may be a third BS serving the UE by performing a connection establishment procedure after a failed reestablishment procedure in response to the failure to perform the path switch.

The assistant information may indicate one or more of the following: measurement results of a link between the UE and the first relay node in response to the path switch failure; measurement results associated with the at least one candidate relay node in response to the path switch failure; an ID of the first relay node; an ID of a second relay node through which the UE attempts to perform a reestablishment procedure before accessing the third BS; an ID of a third relay node through which the UE accesses the third BS; an ID of a fourth relay node in the case that the path switch command indicating the UE to switch to the fourth BS via the fourth relay node; a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure; a cause for the assistant information reporting, which indicates an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path; a ninth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure; and a tenth indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires.

For example, in some embodiments of the present disclosure, the first BS may transmit, to the UE, a condition to trigger a report of assistant information associated with a path switch success; and transmit, to the UE, a path switch command to the UE to switch the UE to a fourth BS. The first BS may receive the assistant information from the fourth BS in response to a successful path switch to the fourth BS and the condition being met.

The assistant information may indicate one or more of the following: an ID of the first relay node; the measurement results of the link between the UE and the first relay node; an ID of a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node; the measurement results of a link between the UE and the fourth relay node; and a cause for the assistant information reporting.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 700 may be changed and some of the operations in exemplary method 700 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 8 illustrates a flowchart of method 800 for wireless communication in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 8. In some examples, method 800 may be performed by a BS or an NE (for example, NE 108 as described with reference to FIG. 1) . In some embodiments, the BS or the NE may execute a set of instructions to control the functional elements of the BS or the NE to perform the described functions or operations.

At 811, a fourth BS may receive a path switch request to switch a UE from a first BS to the fourth BS. At 813, the fourth BS may transmit a response based on the path switch request, wherein the response may include a configuration for the path switch. In response to a successful path switch, the fourth BS may receive assistant information associated with the successful path switch from the UE at 815.

In some embodiments of the present disclosure, the assistant information may indicate one or more of the following: an ID of a first relay node in the case that the UE accesses the first BS via the first relay node; measurement results of a link between the UE and the first relay node; an ID of a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node; measurement results of a link between the UE and the fourth relay node; and a cause for the assistant information reporting.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 800 may be changed and some of the operations in exemplary method 800 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 9 illustrates a block diagram of exemplary apparatus 900 according to some embodiments of the present disclosure. As shown in FIG. 9, the apparatus 900 may include at least one processor 906 and at least one transceiver 902 coupled to the processor 906. The apparatus 900 may be a UE or an NE (e.g., a BS) .

Although in this figure, elements such as the at least one transceiver 902 and processor 906 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the transceiver 902 may be divided into two devices, such as a receiving circuitry and a transmitting circuitry. In some embodiments of the present disclosure, the apparatus 900 may further include an input device, a memory, and/or other components.

In some embodiments of the present disclosure, the apparatus 900 may be a UE. The transceiver 902 and the processor 906 may interact with each other so as to perform the operations with respect to the UE described in FIGs. 1-8. In some embodiments of the present disclosure, the apparatus 900 may be an NE (e.g., a BS) . The transceiver 902 and the processor 906 may interact with each other so as to perform the operations with respect to the BS or NE described in FIGs. 1-8.

In some embodiments of the present disclosure, the apparatus 900 may further include at least one non-transitory computer-readable medium.

For example, in some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 906 to implement the method with respect to the UE as described above. For example, the computer-executable instructions, when executed, cause the processor 906 interacting with transceiver 902 to perform the operations with respect to the UE described in FIGs. 1-8.

In some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 906 to implement the method with respect to the BS or NE as described above. For example, the computer-executable instructions, when executed, cause the processor 906 interacting with transceiver 902 to perform the operations with respect to the BS or NE described in FIGs. 1-8.

FIG. 10 illustrates an example of a UE 1000 in accordance with aspects of the present disclosure. The UE 1000 may include a processor 1002, a memory 1004, a controller 1006, and a transceiver 1008. The processor 1002, the memory 1004, the controller 1006, or the transceiver 1008, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 1002, the memory 1004, the controller 1006, or the transceiver 1008, or various combinations or components thereof may be implemented in hardware (e.g., circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 1002 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 1002 may be configured to operate the memory 1004. In some other implementations, the memory 1004 may be integrated into the processor 1002. The processor 1002 may be configured to execute computer-readable instructions stored in the memory 1004 to cause the UE 1000 to perform various functions of the present disclosure.

The memory 1004 may include volatile or non-volatile memory. The memory 1004 may store computer-readable, computer-executable code including instructions when executed by the processor 1002 cause the UE 1000 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 1004 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 1002 and the memory 1004 coupled with the processor 1002 may be configured to cause the UE 1000 to perform one or more of the functions described herein (e.g., executing, by the processor 1002, instructions stored in the memory 1004) . For example, the processor 1002 may support wireless communication at the UE 1000 in accordance with examples as disclosed herein. For example, the UE 1000 may be configured to support means for performing the operations as described with respect to FIG. 6.

For example, the UE 1000 may be configured to support a means for receiving an RRC configuration from a first BS (e.g. an NE) via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node; and a means for reporting measurement results associated with the at least one candidate relay node to the first BS.

The controller 1006 may manage input and output signals for the UE 1000. The controller 1006 may also manage peripherals not integrated into the UE 1000. In some implementations, the controller 1006 may utilize an operating system such as or other operating systems. In some implementations, the controller 1006 may be implemented as part of the processor 1002.

In some implementations, the UE 1000 may include at least one transceiver 1008. In some other implementations, the UE 1000 may have more than one transceiver 1008. The transceiver 1008 may represent a wireless transceiver. The transceiver 1008 may include one or more receiver chains 1010, one or more transmitter chains 1012, or a combination thereof.

A receiver chain 1010 may be configured to receive signals (e.g., control information, data, or packets) over a wireless medium. For example, the receiver chain 1010 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 1010 may include at least one amplifier (e.g., a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 1010 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1010 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 1012 may be configured to generate and transmit signals (e.g., control information, data, or packets) . The transmitter chain 1012 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 1012 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1012 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

It should be appreciated by persons skilled in the art that the components in exemplary UE 1000 may be changed, for example, some of the components in exemplary UE 1000 may be omitted or modified or a new component (s) may be added to exemplary UE 1000, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the UE 1000 may not include the controller 1006.

FIG. 11 illustrates an example of a processor 1100 in accordance with aspects of the present disclosure. The processor 1100 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 1100 may include a controller 1102 configured to perform various operations in accordance with examples as described herein. The processor 1100 may optionally include at least one memory 1104, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 1100 may optionally include one or more arithmetic-logic units (ALUs) 1106. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses) .

The processor 1100 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 1100) or other memory (e.g., random access memory (RAM) , read-only memory (ROM) , dynamic RAM (DRAM) , synchronous dynamic RAM (SDRAM) , static RAM (SRAM) , ferroelectric RAM (FeRAM) , magnetic RAM (MRAM) , resistive RAM (RRAM) , flash memory, phase change memory (PCM) , and others) .

The controller 1102 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 1100 to cause the processor 1100 to support various operations in accordance with examples as described herein. For example, the controller 1102 may operate as a control unit of the processor 1100, generating control signals that manage the operation of various components of the processor 1100. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 1102 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 1104 and determine a subsequent instruction (s) to be executed to cause the processor 1100 to support various operations in accordance with examples as described herein. The controller 1102 may be configured to track memory address of instructions associated with the memory 1104. The controller 1102 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 1102 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 1100 to cause the processor 1100 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 1102 may be configured to manage flow of data within the processor 1100. The controller 1102 may be configured to control transfer of data between registers, ALUs, and other functional units of the processor 1100.

The memory 1104 may include one or more caches (e.g., memory local to or included in the processor 1100 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 1104 may reside within or on a processor chipset (e.g., local to the processor 1100) . In some other implementations, the memory 1104 may reside external to the processor chipset (e.g., remote to the processor 1100) .

The memory 1104 may store computer-readable, computer-executable code including instructions that, when executed by the processor 1100, cause the processor 1100 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 1102 and/or the processor 1100 may be configured to execute computer-readable instructions stored in the memory 1104 to cause the processor 1100 to perform various functions. For example, the processor 1100 and/or the controller 1102 may be coupled with or to the memory 1104, the processor 1100, the controller 1102, and the memory 1104 may be configured to perform various functions described herein. In some examples, the processor 1100 may include multiple processors and the memory 1104 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

The one or more ALUs 1106 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 1106 may reside within or on a processor chipset (e.g., the processor 1100) . In some other implementations, the one or more ALUs 1106 may reside external to the processor chipset (e.g., the processor 1100) . One or more ALUs 1106 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 1106 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 1106 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 1106 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 1106 to handle conditional operations, comparisons, and bitwise operations.

The processor 1100 may support wireless communication in accordance with examples as disclosed herein.

For example, the processor 1100 may be configured to support means for performing the operations as described with respect to FIG. 6. For example, the processor 1100 may be configured to or operable to support a means for receiving an RRC configuration from a first BS (e.g. an NE) via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node; and a means for reporting measurement results associated with the at least one candidate relay node to the first BS.

For example, the processor 1100 may be configured to support means for performing the operations as described with respect to FIG. 7. For example, the processor 1100 may be configured to support a means for transmitting an RRC configuration to a UE via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node; a means for receiving measurement results associated with the at least one candidate relay node from the UE; and a means for receiving assistant information from a BS (or an NE) , wherein the assistant information is reported by the UE.

For example, the processor 1100 may be configured to support means for performing the operations as described with respect to FIG. 8. For example, the processor 1100 may be configured to support a means for receiving a path switch request to switch a UE from a BS (or an NE) to the processor 1100; a means for transmitting a response based on the path switch request, wherein the response includes a configuration for the path switch; and a means for receiving, in response to a successful path switch, assistant information associated with the successful path switch from the UE.

It should be appreciated by persons skilled in the art that the components in exemplary processor 1100 may be changed, for example, some of the components in exemplary processor 1100 may be omitted or modified or a new component (s) may be added to exemplary processor 1100, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the processor 1100 may not include the ALUs 1106.

FIG. 12 illustrates an example of an NE 1200 in accordance with aspects of the present disclosure. The NE 1200 may include a processor 1202, a memory 1204, a controller 1206, and a transceiver 1208. The processor 1202, the memory 1204, the controller 1206, or the transceiver 1208, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 1202, the memory 1204, the controller 1206, or the transceiver 1208, or various combinations or components thereof may be implemented in hardware (e.g., circuitry) . The hardware may include a processor, a DSP, an ASIC, or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 1202 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 1202 may be configured to operate the memory 1204. In some other implementations, the memory 1204 may be integrated into the processor 1202. The processor 1202 may be configured to execute computer-readable instructions stored in the memory 1204 to cause the NE 1200 to perform various functions of the present disclosure.

The memory 1204 may include volatile or non-volatile memory. The memory 1204 may store computer-readable, computer-executable code including instructions when executed by the processor 1202 cause the NE 1200 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 1204 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 1202 and the memory 1204 coupled with the processor 1202 may be configured to cause the NE 1200 to perform one or more of the functions described herein (e.g., executing, by the processor 1202, instructions stored in the memory 1204) . For example, the processor 1202 may support wireless communication at the NE 1200 in accordance with examples as disclosed herein.

For example, the NE 1200 may be configured to support means for performing the operations as described with respect to FIG. 7. For example, the NE 1200 may be configured to support a means for transmitting an RRC configuration to a UE via a direct path or a first relay node, wherein the RRC configuration may include a measurement configuration related to at least one candidate relay node; a means for receiving measurement results associated with the at least one candidate relay node from the UE; and a means for receiving assistant information from a BS (or another NE) , wherein the assistant information is reported by the UE.

For example, the NE 1200 may be configured to support means for performing the operations as described with respect to FIG. 8. For example, the NE 1200 may be configured to support a means for receiving a path switch request to switch a UE from a BS (or another NE) to the NE 1200; a means for transmitting a response based on the path switch request, wherein the response includes a configuration for the path switch; and a means for receiving, in response to a successful path switch, assistant information associated with the successful path switch from the UE.

The controller 1206 may manage input and output signals for the NE 1200. The controller 1206 may also manage peripherals not integrated into the NE 1200. In some implementations, the controller 1206 may utilize an operating system such as or other operating systems. In some implementations, the controller 1206 may be implemented as part of the processor 1202.

In some implementations, the NE 1200 may include at least one transceiver 1208. In some other implementations, the NE 1200 may have more than one transceiver 1208. The transceiver 1208 may represent a wireless transceiver. The transceiver 1208 may include one or more receiver chains 1210, one or more transmitter chains 1212, or a combination thereof.

A receiver chain 1210 may be configured to receive signals (e.g., control information, data, or packets) over a wireless medium. For example, the receiver chain 1210 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 1210 may include at least one amplifier (e.g., an LNA) configured to amplify the received signal. The receiver chain 1210 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1210 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 1212 may be configured to generate and transmit signals (e.g., control information, data, or packets) . The transmitter chain 1212 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as AM, FM, or digital modulation schemes like PSK or QAM. The transmitter chain 1212 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1212 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

It should be appreciated by persons skilled in the art that the components in exemplary NE 1200 may be changed, for example, some of the components in exemplary NE 1200 may be omitted or modified or a new component (s) may be added to exemplary NE 1200, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the NE 1200 may not include the controller 1206.

Those having ordinary skill in the art would understand that the operations or steps of the methods described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations or steps of the methods may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. The disclosure is not limited to the examples and designs described herein but is to be accorded with the broadest scope consistent with the principles and novel features disclosed herein. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Also, all of the elements of each figure are not necessary for the operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

In this document, this document, the terms “handover” and “path switch” may be used interchangeably. The terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" or the like, as used herein, is defined as "including. " Expressions such as "A and/or B" or "at least one of A and B" may include any and all combinations of words enumerated along with the expression. For instance, the expression "A and/or B" or "at least one of A and B" may include A, B, or both A and B. The wording "the first, " "the second" or the like is only used to clearly illustrate the embodiments of the present disclosure, but is not used to limit the substance of the present disclosure.

Claims

A user equipment (UE) , comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the UE to:

receive a radio resource control (RRC) configuration from a first base station (BS) via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and

report measurement results associated with the at least one candidate relay node to the first BS.
The UE of Claim 1, wherein the at least one processor is further configured to cause the UE to:

detect a radio link failure (RLF) on a link between the UE and the first relay node or receive a notification message or a release message from the first relay node;

in response to the detected RLF or the reception of the notification message or the release message, store one or more of the following:

measurement results of the link between the UE and the first relay node; and

measurement results associated with the at least one candidate relay node.
The UE of claim 2, wherein the at least one processor is further configured to cause the UE to:

perform a reestablishment procedure;

access a second BS in response to a success of the reestablishment procedure; and

access a third BS via a connection establishment procedure in response to a failure of the reestablishment procedure.
The UE of Claim 3, wherein the at least one processor is further configured to cause the UE to report assistant information to the second BS or the third BS, wherein the assistant information indicates one or more of the following:

measurement results of a link between the UE and the first relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node;

measurement results associated with the at least one candidate relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node;

an ID of the first relay node in response to one of: detecting the RLF on the link between the UE and the first relay node, receiving a notification message from the first relay node, and receiving a release message from the first relay node;

an ID of a second relay node through which the UE attempts to perform the reestablishment procedure before accessing the third BS;

an ID of a third relay node through which the UE accesses the third BS;

a cause for the assistant information reporting, which comprises one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message;

a first indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure;

a second indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires; and

a third indication indicating a type of an executed path switch before a failure is detected at the UE, wherein the type of the executed path switch comprises an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.
The UE of Claim 1, wherein the at least one processor is further configured to cause the UE to:

receive, from the first BS, a path switch command to switch the UE to a fourth BS; and

in response to a failure to perform the path switch, store one or more of the following information:

measurement results of a link between the UE and the first relay node; and

measurement results associated with the at least one candidate relay node.
The UE of claim 5, wherein the at least one processor is further configured to cause the UE to:

perform a reestablishment procedure in response to the failure to perform the path switch;

access a second BS in response to a success of the reestablishment procedure; and

access a third BS via a connection establishment procedure in response to a failure of the reestablishment procedure.
The UE of Claim 6, wherein the at least one processor is further configured to cause the UE to report assistant information to the second BS or the third BS, and wherein the assistant information indicates one or more of the following:

measurement results of a link between the UE and the first relay node in response to the path switch failure;

measurement results associated with the at least one candidate relay node in response to the path switch failure;

an ID of the first relay node;

an ID of a second relay node through which the UE attempts to perform the reestablishment procedure before accessing the third BS;

an ID of a third relay node through which the UE accesses the third BS;

an ID of a fourth relay node in the case that the path switch command indicating the UE to switch to the fourth BS via the fourth relay node;

a failure type indicating that the path switch failure is an indirect-to-direct path switch failure, a direct-to-indirect path switch failure, or an indirect-to-indirect path switch failure;

a cause for the assistant information reporting, which indicates an expiry of a timer for path switch to an indirect path or an expiry of a timer for path switch to a direct path;

a fourth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for the reestablishment procedure; and

a fifth indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires.
The UE of Claim 1, wherein the at least one processor is further configured to cause the UE to:

receive, from the first BS, a condition to trigger a report of assistant information associated with a path switch success;

receive, from the first BS, a path switch command; and

in response to a successful path switch from the first BS to a fourth BS and the condition being met, store one or more of the following information:

measurement results of a link between the UE and the first relay node; and

measurement results of a link between the UE and a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node.
The UE of Claim 8, wherein the at least one processor is further configured to cause the UE to report the assistant information to the fourth BS, and wherein the assistant information indicates one or more of the following:

an ID of the first relay node;

the measurement results of the link between the UE and the first relay node;

an ID of the fourth relay node;

the measurement results of a link between the UE and the fourth relay node; and

a cause for the assistant information reporting.
The UE of Claim 9, wherein the cause indicates that a percentage threshold associated with a timer for path switch to an indirect path is reached.
The UE of any of Claim 8-10, wherein the condition comprises a percentage threshold associated with a timer for path switch to an indirect path.
The UE of Claim 11, wherein the at least one processor is further configured to cause the UE to:

start the timer for path switch to an indirect path in response to receiving the path switch command; and

determine whether the condition is met or not based on an elapsed time of the timer for path switch to an indirect path and the percentage threshold.
A first base station (BS) , comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the first BS to:

transmit a radio resource control (RRC) configuration to a user equipment (UE) via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node;

receive measurement results associated with the at least one candidate relay node from the UE; and

receive assistant information from another BS, wherein the assistant information is reported by the UE.
The first BS of Claim 13, wherein the another BS is a second BS serving the UE by performing a successful reestablishment procedure in response to a radio link failure (RLF) between the first BS and the UE, or the another BS is a third BS serving the UE by performing a connection establishment procedure after a failed reestablishment procedure in response to the RLF between the first BS and the UE.
The first BS of Claim 14, wherein the assistant information indicates one or more of the following:

measurement results of a link between the UE and the first relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node;

measurement results associated with the at least one candidate relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node;

an ID of the first relay node in response to one of: the UE detecting the RLF on the link between the UE and the first relay node, the UE receiving a notification message from the first relay node, and the UE receiving a release message from the first relay node;

an ID of a second relay node through which the UE attempts to perform a reestablishment procedure before accessing the third BS;

an ID of a third relay node through which the UE accesses the third BS;

a cause for the assistant information reporting, which comprises one of the following: a sidelink RLF, a relay reselection, a reception of a notification message, or a reception of a release message;

a sixth indication indicating that no suitable relay node was found when a first timer expires, wherein the first timer starts in response to transmitting a reestablishment request for initiating the reestablishment procedure;

a seventh indication indicating that neither a suitable relay node nor a suitable cell was found when the first timer expires; and

an eighth indication indicating a type of an executed path switch before the failure is detected at the UE, wherein the type of the executed path switch comprises an indirect-to-direct path switch, a direct-to-indirect path switch, or an indirect-to-indirect path switch.
The first BS of Claim 13, wherein the at least one processor is further configured to cause the first BS to transmit a path switch command to the UE to switch the UE to a fourth BS; and

wherein the another BS is a second BS serving the UE by performing a successful reestablishment procedure in response to a failure to perform the path switch, or the another BS is a third BS serving the UE by performing a connection establishment procedure after a failed reestablishment procedure in response to the failure to perform the path switch.
A fourth base station (BS) , comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the fourth BS to:

receive a path switch request to switch a user equipment (UE) from a first BS to the fourth BS;

transmit a response based on the path switch request, wherein the response includes a configuration for the path switch; and

in response to a successful path switch, receive assistant information associated with the successful path switch from the UE.
The fourth BS of Claim 17, wherein the assistant information indicates one or more of the following:

an ID of a first relay node in the case that the UE accesses the first BS via the first relay node;

measurement results of a link between the UE and the first relay node;

an ID of a fourth relay node in the case that the UE accesses the fourth BS via the fourth relay node;

measurement results of a link between the UE and the fourth relay node; and

a cause for the assistant information reporting.
The fourth BS of Claim 18, wherein the cause indicates that a percentage threshold associated with a timer for path switch to an indirect path is reached.
A processor, comprising:

at least one controller coupled with at least one memory and configured to cause the processor to:

receive a radio resource control (RRC) configuration from a first base station (BS) via a direct path or a first relay node, wherein the RRC configuration comprises a measurement configuration related to at least one candidate relay node; and

report measurement results associated with the at least one candidate relay node to the first BS.