WO2024250686A1

WO2024250686A1 - Handover failure prediction

Info

Publication number: WO2024250686A1
Application number: PCT/CN2024/072621
Authority: WO
Inventors: Lianhai WU; Congchi ZHANG; Ran YUE
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2024-01-16
Filing date: 2024-01-16
Publication date: 2024-12-12
Anticipated expiration: 2026-07-16

Abstract

Example embodiments of the present disclosure relate to a UE, a BS, methods, apparatuses, and computer readable medium for handover failure prediction. In the solution, the UE may report a capability of handover failure prediction. The UE may receive a configuration associated with one or more candidate cells and according the handover failure prediction may be performed. As such, predicted information may be obtained which may be provided to the BS for consideration for a handover decision

Description

HANDOVER FAILURE PREDICTION

TECHNICAL FIELD

The present disclosure relates to wireless communications, and more specifically to a user equipment (UE) , a base station (BS) , methods, apparatuses, and computer readable medium for handover (HO) failure prediction.

BACKGROUND

A wireless communications system may include one or multiple network communication devices, such as base stations, which may be otherwise known as an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. Each network communication devices, such as a base station may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communications system may support wireless communications 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) . Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G) ) .

For the failure in mobility, there may be radio link failure (RLF) , beam failure, and handover failure (HOF) happened, and current failure handling methods focus on fast recovery, and they are reactive and cannot eliminate the interruption or bad services caused by a failure event. Hence, the need for handover enhancement should be considered.

SUMMARY

The present disclosure relates to a UE, a BS, methods, apparatuses, processors, and computer readable medium for handover failure prediction. According to the proposed solution, the UE may have a capability of handover failure prediction and report it to the BS. The UE may receive a configuration associated with one or more candidate cells and according the handover failure prediction may be performed. As such, predicted information may be obtained which may be provided to the BS for consideration for a handover decision.

In some implementations, there is provided a UE. The UE comprises at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: transmit, to a base station, capability information indicating that the UE has a capability of handover failure prediction; receive, from the base station, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells; and perform the handover failure prediction based on the configuration.

In some implementations, there is provided a BS. The BS comprises at least one memory; and at least one processor coupled with the at least one memory and configured to cause the BS to: receive, from a UE, capability information indicating that the UE has a capability of handover failure prediction; and transmit, to the UE, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells.

In some implementations, there is provided a method performed by the UE. The method comprises: transmitting, to a base station, capability information indicating that the UE has a capability of handover failure prediction; receiving, from the base station, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells; and performing the handover failure prediction based on the configuration.

In some implementations, there is provided a method performed by the BS. The method comprises: receiving, from a UE, capability information indicating that the UE has a capability of handover failure prediction; and transmitting, to the UE, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells.

In some implementations, there is provided a processor for wireless communication. The processor comprises at least one controller coupled with at least one memory and configured to cause the processor to: transmit, to a base station, capability information indicating that the UE has a capability of handover failure prediction; receive, from the base station, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells; and perform the handover failure prediction based on the configuration.

In some implementations, there is provided a processor for wireless communication. The processor comprises at least one controller coupled with at least one memory and configured to cause the processor to: receive, from a UE, capability information indicating that the UE has a capability of handover failure prediction; and transmit, to the UE, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells.

In some implementations of the methods and the UE described herein, further comprising: in accordance with a determination that a channel quality of the serving cell is worse than the first threshold, triggering the performing of the handover failure prediction, wherein the configuration comprises a first threshold associated with the serving cell of the UE.

In some implementations of the methods and the UE described herein, further comprising: determining a channel quality of the serving cell; and in accordance with a determination that the channel quality of the serving cell is worse than the first threshold, providing, from an access stratum (AS) layer of the UE to an upper layer or an artificial intelligence (AI) entity of the UE, an indication for performing the handover failure prediction, wherein the configuration comprises a first threshold associated with the serving cell of the UE.

In some implementations of the methods and the UE described herein, further comprising: providing, by an AS layer of the UE to an upper layer or an AI entity of the UE, measurement results of the serving cell; and triggering, by the upper layer or the AI entity, the performing of the handover failure prediction based on the measurement results of the serving cell.

In some implementations of the methods and the UE described herein, further comprising: transmitting, to the base station, a report comprising third information associated with the handover failure prediction, and wherein the third information comprises one of: whether a handover failure to a candidate cell is to be occurred, whether a handover failure to a candidate cell is to be occurred within the time duration or before a time point, a possibility of the handover failure of the candidate cell within the time duration or before the time point, predicted measurement results associated with one or more candidate cells, an accuracy rate of the third information, or a selected candidate cell for a re-establishment procedure.

In some implementations of the methods and the UE described herein, further comprising: in accordance with a determination that a channel quality of the serving cell is worse than the second threshold, transmitting the report.

In some implementations of the methods and the UE described herein, further comprising: receiving, from a base station, a handover command to hand over to a target cell; and performing a handover to the target cell based on the handover command by stopping the handover failure prediction.

In some implementations of the methods and the UE described herein, further comprising: receiving, from a base station, a handover command to hand over to a target cell; continuing performing the handover failure prediction for the target cell; and in accordance with a determination that it is predicted a handover failure of the target cell is to be occurred, triggering a link recovery or a re-establishment procedure without performing a handover towards the target cell. The link recovery may be a fast master cell group (MCG) link recovery specified in third generation partnership project (3GPP) specification.

In some implementations of the methods and the BS described herein, further comprising: receiving, from the UE, a report comprising third information associated with the handover failure prediction, and wherein the third information comprises one of: whether a handover failure to a candidate cell is to be occurred, whether a handover failure to a candidate cell is to be occurred within the time duration or before a time point, a possibility of the handover failure of the candidate cell within the time duration or before the time point, predicted measurement results associated with one or more candidate cells, an accuracy rate of the third information, or a selected candidate cell for a re-establishment procedure.

In some implementations of the methods and the BS described herein, further comprising: transmitting, to the UE, a handover command indicating to the UE to hand over to a target cell.

In some implementations of the methods, the UE, the BS described herein, the capability information further indicates a maximum number of candidate cells of which the UE supports the handover failure prediction.

In some implementations of the methods, the UE, the BS described herein, the configuration comprises information of a time duration indicating to the UE to perform the handover failure prediction within the time duration.

In some implementations of the methods, the UE, the BS described herein, the configuration comprises first information associated with an input for the handover failure prediction, and wherein the first information comprises one of: a time length for a mobility timer, whether a dedicated random access channel resource is configured, or at least one handover related parameter.

In some implementations of the methods, the UE, the BS described herein, the configuration comprises second information to be predicted for the handover failure prediction, and wherein the second information comprises one of: whether a handover failure to a candidate cell is to be occurred, whether a handover failure to a candidate cell is to be occurred within the time duration, a possibility of the handover failure to the candidate cell within the time duration, or a selected candidate cell for a re-establishment procedure.

In some implementations of the methods, the UE, the BS described herein, the configuration comprises a first threshold associated with the serving cell of the UE, and wherein the first threshold is used for the UE to determine whether to trigger the handover failure prediction is met.

In some implementations of the methods, the UE, the BS described herein, the configuration comprises a second threshold associated with the serving cell of the UE, and wherein the second threshold is used for determining whether to trigger the report.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system in which some embodiments of the present disclosure can be implemented;

FIG. 2A illustrates an inter-gNB handover procedure in accordance with some example embodiments of the present disclosure;

FIG. 2B illustrates a schematic diagram of an example communication network in which some embodiments of the present disclosure can be implemented;

FIG. 3 illustrates a signalling chart illustrating a communication process in accordance with some example embodiments of the present disclosure;

FIG. 4 illustrates a signalling chart illustrating another communication process in accordance with some example embodiments of the present disclosure;

FIG. 5 illustrates an example of a device that is suitable for implementing embodiments of the present disclosure;

FIG. 6 illustrates an example of a processor that is suitable for implementing some embodiments of the present disclosure;

FIG. 7 illustrates a flowchart of an example method implemented at a UE in accordance with aspects of the present disclosure; and

FIG. 8 illustrates a flowchart of an example method implemented at a BS in accordance with aspects of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principles of the present disclosure will now be described with reference to some embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below. In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an example embodiment, ” “an embodiment, ” “some embodiments, ” and the like indicate that the embodiment (s) described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment (s) . Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” or the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could also be termed as a second element, and similarly, a second element could also be termed as a first element, without departing from the scope of embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms. In some examples, values, procedures, or apparatuses are referred to as “best, ” “lowest, ” “highest, ” “minimum, ” “maximum, ” or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments. As used herein, the singular forms “a, ” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises, ” “comprising, ” “has, ” “having, ” “includes” and/or “including, ” when used herein, specify the presence of stated features, elements, components and/or the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. For example, the term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” The use of an expression such as “A and/or B” can mean either “only A” or “only B” or “both A and B. ” Other definitions, explicit and implicit, may be included below.

FIG. 1 illustrates an example of a wireless communications system 100 in which some embodiments of the present disclosure can be implemented. The wireless communications system 100 may include one or more network entities 102 (also referred to as network equipment (NE) ) , one or more UEs 104, a core network (CN) 106, and a packet data network 108. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as a long term evolution (LTE) network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as a new radio (NR) network. In other implementations, the wireless communications 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) , IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G. Additionally, the wireless communications 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 network entities 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the network entities 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a radio access network (RAN) , a base transceiver station, an access point, a NodeB, an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. A network entity 102 and a UE 104 may communicate via a communication link 110, which may be a wireless or wired connection. For example, a network entity 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

A network entity 102 may provide a geographic coverage area 112 for which the network entity 102 may support services (e.g., voice, video, packet data, message, broadcast, etc. ) for one or more UEs 104 within the geographic coverage area 112. For example, a network entity 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, a network entity 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 112 may be associated with different network entities 102. Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a mobile device, a wireless device, a remote device, a remote unit, a handheld device, or a subscriber 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. In some implementations, a UE 104 may be stationary in the wireless communications system 100. In some other implementations, a UE 104 may be mobile in the wireless communications system 100.

The one or more UEs 104 may be devices in different forms or having different capabilities. Some examples of UEs 104 are illustrated in FIG. 1. A UE 104 may be capable of communicating with various types of devices, such as the network entities 102, other UEs 104, or network equipment (e.g., the CN 106, the packet data network 108, a relay device, an integrated access and backhaul (IAB) node, or another network equipment) , as shown in FIG. 1. Additionally, or alternatively, a UE 104 may support communication with other network entities 102 or UEs 104, which may act as relays in the wireless communications system 100.

A UE 104 may also be able to support wireless communication directly with other UEs 104 over a communication link 114. 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 (SL) . For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

A network entity 102 may support communications with the CN 106, or with another network entity 102, or both. For example, a network entity 102 may interface with the CN 106 through one or more backhaul links 116 (e.g., via an S1, N2, N3, or another network interface) . The network entities 102 may communicate with each other over the backhaul links 116 (e.g., via an X2, Xn, or another network interface) . In some implementations, the network entities 102 may communicate with each other directly (e.g., between the network entities 102) . In some other implementations, the network entities 102 may communicate with each other or indirectly (e.g., via the CN 106) . In some implementations, one or more network entities 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 a radio heads, smart radio heads, or transmission-reception points (TRPs) .

In some implementations, a network entity 102 may be configured in a disaggregated architecture, which may be configured to utilize a protocol stack physically or logically distributed among two or more network entities 102, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance) , or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN) ) . For example, a network entity 102 may include one or more of a central unit (CU) , a distributed unit (DU) , a radio unit (RU) , a RAN Intelligent Controller (RIC) (e.g., a Near-Real Time RIC (Near-RT RIC) , a Non-Real Time RIC (Non-RT RIC) ) , a Service Management and Orchestration (SMO) system, or any combination thereof.

An RU may also be referred to as a radio head, a smart radio head, a remote radio head (RRH) , a remote radio unit (RRU) , or a transmission reception point (TRP) . One or more components of the network entities 102 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities 102 may be located in distributed locations (e.g., separate physical locations) . In some implementations, one or more network entities 102 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU) , a virtual DU (VDU) , a virtual RU (VRU) ) .

Split of functionality between a CU, a DU, and an RU may be flexible and may support different functionalities depending upon which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combinations thereof) are performed at a CU, a DU, or an RU. For example, a functional split of a protocol stack may be employed between a CU and a DU such that the CU may support one or more layers of the protocol stack and the DU may support one or more different layers of the protocol stack. In some implementations, the CU may host upper protocol layer (e.g., a layer 3 (L3) , a layer 2 (L2) ) functionality and signaling (e.g., Radio Resource Control (RRC) , service data adaption protocol (SDAP) , Packet Data Convergence Protocol (PDCP) ) . The CU may be connected to one or more DUs or RUs, and the one or more DUs or RUs may host lower protocol layers, such as a layer 1 (L1) (e.g., physical (PHY) layer) or an L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU.

Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU and an RU such that the DU may support one or more layers of the protocol stack and the RU may support one or more different layers of the protocol stack. The DU may support one or multiple different cells (e.g., via one or more RUs) . In some implementations, a functional split between a CU and a DU, or between a DU and an RU may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU, a DU, or an RU, while other functions of the protocol layer are performed by a different one of the CU, the DU, or the RU) .

A CU may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU may be connected to one or more DUs via a midhaul communication link (e.g., F1, F1-C, F1-U) , and a DU may be connected to one or more RUs via a fronthaul communication link (e.g., open fronthaul (FH) interface) . In some implementations, a midhaul communication link or a fronthaul communication link may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 102 that are in communication via such communication links.

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 network entities 102 associated with the CN 106.

The CN 106 may communicate with the packet data network 108 over one or more backhaul links 116 (e.g., via an S1, N2, N3, or another network interface) . The packet data network 108 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via a network entity 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server 118 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 communications system 100, the network entities 102 and the UEs 104 may use resources of the wireless communications 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 communications) . In some implementations, the network entities 102 and the UEs 104 may support different resource structures. For example, the network entities 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the network entities 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 network entities 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures) . The network entities 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 communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix (CP) . 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 communications 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., 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 communications 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 communications 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 network entities 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the network entities 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data) . In some implementations, FR2 may be used by the network entities 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 handover decision optimization may include the following aspects: candidate/target cell prediction in L3-based mobility, or, candidate/target beam (s) and cell (s) prediction in LTM; HO parameter adjustment/tuning; Unintended events prediction, e.g., HO failure/RLF prediction, ping-pong and short-stay HO prediction.

Cell level mobility requires explicit RRC signalling to be triggered, i.e. handover. FIG. 2A illustrates an inter-gNB handover procedure 202. The procedure 202 involves an L3 handover for PCell change, and includes the following steps:

Step 1. The source gNB initiates handover and issues a HANDOVER REQUEST over the Xn interface.

Step 2. The target gNB performs admission control and provides the new RRC configuration as part of the HANDOVER REQUEST ACKNOWLEDGE.

Step 3. The source gNB provides the RRC configuration to the UE by forwarding the RRCReconfiguration message received in the HANDOVER REQUEST ACKNOWLEDGE. The RRCReconfiguration message includes at least cell ID and all information required to access the target cell so that the UE can access the target cell without reading system information. For some cases, the information required for contention-based and contention-free random access can be included in the RRCReconfiguration message. The access information to the target cell may include beam specific information, if any.

Step 4. The UE moves the RRC connection to the target gNB and replies with the RRCReconfigurationComplete.

During the procedure, a handover may be trigger by a handover request from the source gNB. However, in some cases, the information used by the source gNB to make a decision for handover may be not enough or not accurate, which may lead to a handover failure for example. Therefore, handover enhancement should be considered.

Embodiments of the present disclosure provide a solution of communication. In the solution, a UE may receive a configuration associated with one or more candidate cells and according the handover failure prediction may be performed. As such, predicted information may be obtained by the handover failure prediction and the information may be used for further consideration for a handover decision. Therefore, a following handover decision may be more accurate. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

FIG. 2B illustrates a schematic diagram of an example communication network 200 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 2B, the communication network 200 may include a BS 210 and a UE 220, which may communicate with each other. With reference to FIG. 1, the BS 210 may be one network entity 102, and the UE 220 may be one UE 104.

In some implementations, a model, such as an AI/ML model, may be deployed at the UE 220. In some examples, the UE 220 may determine prediction information by model inference. It is to be noted that the model at the UE 220 may be omitted in some cases, for example, the UE 220 may utilize some other manners to determine prediction information, and the present disclosure does not limit this aspect.

It is to be understood that the numbers of BSs or UEs shown in FIG. 2B are only for the purpose of illustration only. The communication network 200 may include any suitable numbers of devices. For example, the UE 220 may be configured with carrier aggregation (CA) or dual connectivity (DC) .

In the present disclosure, a handover failure prediction may be interchangeably used with one of the following: a HOF prediction, a prediction for a handover failure, a prediction of HOF for a candidate cell, etc.

FIG. 3 illustrates a signalling chart illustrating communication process 300 in accordance with some example embodiments of the present disclosure. The process 300 may involve a BS 210 and a UE 220. It would be appreciated that the process 300 may be applied to other communication scenarios, which will not be described in detail.

The BS 210 may be a serving gNB of the UE 220, for example, the UE 220 may access the serving gNB via MCG only or via DC, the present disclosure does not limit this aspect.

In the process 300, the UE 220 transmits capability information to the BS 210 at 310. In some implementations, the capability information may indicate whether the UE 220 supports a handover failure prediction, that is, the capability information may indicate whether the UE has a capability of handover failure prediction. In some examples, the capability information transmitted to the BS 210 may indicate that the UE 220 has a capability of handover failure prediction; while in some other examples, the capability information transmitted to the BS 210 may indicate that the UE 220 does not have a capability of handover failure prediction.

In case the UE 220 supports the handover failure prediction, the capability information may further indicate a maximum number of candidate cells that the UE 220 supports for the handover failure prediction. For example, the maximum number may be 1. For example, the maximum number may be a value larger than 1, such as 2, 3, or a larger value. In some embodiments, the maximum number of candidate cells for handover failure prediction may be predefined, e.g. in the 3GPP specification, in this case, the indication of the maximum number of candidate cells may be not included in the capability information.

Alternatively, the UE 220 may be configured with a measurement configuration, for example, the measurement configuration may be related to layer 1 (L1) measurement or layer 3 (L3) measurement. In some implementations, the UE 220 may perform the L1/L3 measurement based on the measurement configuration and transmit a measurement report to the BS 210.

In the process 300, the BS 210 transmits a configuration to the UE 220 at 320. In some implementations, the configuration may be associated with one or more candidate cells. In some implementations, the configuration may be used by the UE 220 to perform the handover failure prediction from a serving cell to one of the one or more candidate cells. In some examples, the number of the one or more candidate cells may be not larger than the maximum number discussed above.

In some example embodiments, the configuration at 320 may configure the UE 220 to perform the handover failure prediction towards the one or more candidate cells.

In some implementations, the configuration at 320 may indicate a time duration or a time window. In some examples, a start time of the time duration or the time window may be a time when the configuration is received by the UE 220. In some examples, the configuration at 320 may configure the UE 220 to perform the handover failure prediction within the time duration or the time window. For example, the configuration at 320 may indicate to (or request) the UE 220 to perform the handover failure prediction within the time duration or the time window upon receiving the configuration.

It should be noted that the time duration, the time window, may be used interchangeably in the present disclosure, which may represent a time period during which the prediction is made, the present disclosure does not limit this aspect.

In some implementations, the configuration at 320 may include a first threshold associated with the serving cell of the UE 220. That is, the BS 210 may configure the first threshold to the UE 220, which may be used by the UE 220 for determining whether to trigger the performing of the handover failure prediction, details of which may refer to step 330 discussed below.

In some implementations, the configuration at 320 may include first information associated with an input for the handover failure prediction. That is, the BS 210 may provide the first information to the UE 220 as input for the handover failure prediction.

In some embodiments, the first information may include a time length for a mobility timer, for example, the mobility timer may be T304. In some embodiments, the first information may include information about whether a dedicated random access channel (RACH) resource is configured, for example, the first information may indicate whether a dedicated RACH resource (e.g. preamble) will be configured or not. In some embodiments, the first information may include at least one handover related parameter, for example, a handover border related parameter (s) , such as a channel quality of the serving cell or a channel quality of a candidate cell, may be indicated by the first information.

In some implementations, the configuration at 320 may include second information to be predicted for the handover failure prediction. That is, the BS 210 may configure the content for prediction.

In some embodiments, the second information may include whether a handover failure to a candidate cell is to be occurred. That is, the second information may indicate to the UE 220 to predict whether the handover failure will occur if the UE 220 is handed over to the candidate cell.

In some embodiments, the second information may include whether a handover failure to a candidate cell is to be occurred within the time duration. That is, the second information may indicate to the UE 220 to predict whether the handover failure will occur within a time duration if the UE 220 is handed over to the candidate cell.

In some embodiments, the second information may include a possibility of the handover failure to the candidate cell within the time duration. That is, the second information may indicate to the UE 220 to predict a possibility of handover failure within a time duration if the UE 220 is handed over to the candidate cell. For example, the possibility may be a likelihood (%) .

In some embodiments, the second information may include a selected candidate cell for a re-establishment procedure. That is, the second information may indicate to the UE 220 to provide a suitable candidate cell for re-establishment.

In some embodiments, the second information may include L1/L3 measurement results or predicted measurement results of the serving cell. That is, the second information may indicate to the UE 220 to provide L1/L3 measurement results of the serving cell, or to provide predicted measurement results of the serving cell.

In some embodiments, the second information may include L1/L3 measurement results or predicted measurement results of a neighbor cell, which may be a candidate cell. That is, the second information may indicate to the UE 220 to provide L1/L3 measurement results of the neighbor cell, or to provide predicted measurement results of the neighbor cell.

It is to be understood that some examples of the second information included in the configuration are shown above for illustrative but not limited, some more information may be further included, or some information may be omitted, or some information may be combined or changed, the present disclosure does not limit.

In some implementations, the configuration at 320 may include a second threshold associated with the serving cell of the UE 220. Thus, the BS 210 may configure the second threshold to the UE 220, which may be used by the UE 220 for determining whether to transmit a report, details of which may refer to step 340 discussed below.

It should be noted that some information discussed above which is included in the configuration may be omitted in some cases, for example, the first threshold and/or the second threshold may be omitted.

In the process 300, the UE 220 performs the handover failure prediction at 330.

In some implementations, the UE 220 starts to perform the handover failure prediction upon receiving the configuration. In some examples, the UE 220 may determine prediction information, such as those indicated by the second information included in the configuration.

In some implementations, the configuration may include the first threshold associated with the serving cell of the UE 220. For example, the first threshold may be associated with L1 measurement results or L3 measurement results. In some embodiments, the UE 220 may perform a measurement to determine a channel quality of the serving cell.

In some example embodiments, if a condition related to the first threshold is met, the performing of the handover failure prediction may be triggered. In some example embodiments, if the condition related to the first threshold is not met, the performing of the handover failure prediction may be stopped.

In some examples, if the channel quality of the serving cell is worse than the first threshold, the UE 220 may determine to trigger the performing the handover failure prediction. In some other examples, if the channel quality of the serving cell is worse than the first threshold, an AS layer of the UE 220 may provide a notification to the upper layer or the AI entity of the UE 220, so that the upper layer or the AI entity of the UE 220 starts to perform the handover failure prediction upon a notification from the AS layer is obtained. In some other examples, if the channel quality of the serving cell is better than the first threshold, the handover failure prediction may not be performed, e.g. be stopped or ceased.

In some implementations, an AS layer of the UE 220 may determine measurement results, such as L1/L3 measurement results of the serving cell, by performing measurement. For example, the measurement results may relate to positioning information. In some example embodiments, the AS layer of the UE 220 may provide (or deliver) the measurement results to the upper layer or the AI entity of the UE 220, in addition, the upper layer or the AI entity of the UE 220 may determine to start performing handover failure prediction. In some examples, the upper layer or the AI entity of the UE 220 may determine to stop the handover failure prediction after a time duration.

In some implementations, the handover failure prediction may be performed by AI based processing, the present disclosure does not limit.

In some implementations, the UE 220 may determine prediction information (such as third information) by performing the handover failure prediction. For example, the UE 220 may determine whether a handover failure will occur (e.g. within the time duration) if the UE 220 is handed over from the serving cell to a candidate cell, and/or a possibility of the handover failure being occurred.

It is to be understood that although step 330 is illustrated in FIG. 3 in the present disclosure, in some other cases, the handover failure prediction may not be performed. In some examples, after receiving the configuration which indicates to the UE 220 to perform the handover failure prediction, the UE 220 may reject and does not perform the handover failure prediction, e.g. due to no capability of handover failure prediction, restricted capability, or overload.

In addition or alternatively, as shown in FIG. 3, the UE 220 may transmit a report to the BS 210 at 340.

In some implementations, the report may be transmitted upon a performance of the handover failure prediction at 330. In some implementations, the configuration may include a second threshold, in this case, the UE 220 may determine a channel quality of the serving cell, and if the channel quality of the serving cell is worse than the second threshold, the report may be triggered. That is, the report may be transmitted when the channel quality of the serving cell is worse than the second threshold, for example, the second threshold may be less than the first threshold.

In some implementations, the report may include third information associated with the prediction.

In some embodiments, the third information may include information about whether a handover failure to a candidate cell is to be occurred. In some examples, the third information may include an indication of “to be about handover failure” and corresponding candidate cell. That is, it is predicted that a handover failure will occur if the UE 220 handed over to the corresponding candidate cell. In some other examples, the third information may include an indication of “not to be about handover failure” and corresponding candidate cell. That is, it is predicted that a handover failure will not occur if the UE 220 handed over to the corresponding candidate cell.

In some embodiments, the third information may include information about whether a handover failure to a candidate cell is to be occurred within a time duration or before a time point, for example, the time point may be an absolute time (such as an end time point of the time duration) . In some examples, the configuration at 320 may indicate the time duration. In some other examples, there may be no indication of the time duration in the configuration at 320, and the time duration or the time point may be determined by the UE 220 by performing prediction, in this case, the third information may indicate the time duration or the time point. For example, it is predicted that a handover failure will occur if the UE 220 handed over to the candidate cell within the time duration or before the time point. In some instances, the third information may be used by the BS 210 as guidance for determining a time when provide a handover command, for example, the BS 210 may determine a specific time duration during which the handover command is provided. In some other examples, the third information may indicate that the handover failure will not occur if a handover to a corresponding candidate cell is performed within the time duration or before the time point.

In some embodiments, the third information may include predicted measurement results (i.e. measurement result prediction) for at least one candidate cell. In some examples, the third information may indicate a specific candidate cell with a best measurement results. For example, the best measurement results may include a best channel quality.

In some embodiments, the third information may include an accuracy rate of the third information, and/or a selected candidate cell for a re-establishment procedure.

In some example implementations, the report at 340 may be related with a first candidate cell, for example, the report may indicate that a handover failure will occur if handover to the first candidate cell is performed or a handover failure will occur if handover to the first candidate cell is performed within a time duration or before a time point. In some examples, the UE 220 may transmit a further report to the BS 210, e.g. after 340, for example the further report may be related with a second candidate cell. For example, the further report may indicate that a handover failure will occur if handover to the first candidate cell is performed or a handover failure will occur if handover to the first candidate cell is performed within a time duration or before a time point. In some embodiments, if the further report is different from the report at 340, then the further report is transmitted. In some embodiments, if the report related with the first candidate cell is still available, the further report may include predicted information related with the first candidate cell and predicted information related with the second candidate cell.

Alternatively, in the process 300, the BS 210 may perform at least one further operation based on the report at 350. In some implementations, the BS 210 may determine (or select or prepare) a candidate cell for the UE 220, e.g. for a handover of the UE 220. For example, the BS 210 may prepare the selected candidate cell that indicated in the report.

According to some embodiments with reference to FIG. 3, a configuration associated with one or more candidate cells may be transmitted to the UE 220, as such, the UE 220 may perform a handover failure prediction based on the configuration. In some cases, a report including predicted information may be provided to the BS 210. Therefore, a further operation performed by the BS 210 for a handover of the UE 220 may be more accurate, e.g. the operation may be made based on the report which indicate predicted information of the handover failure prediction. For example, the BS 210 may select a suitable candidate cell for handover and a failure possibility of a following handover may be lower.

FIG. 4 illustrates a signalling chart illustrating another communication process 400 in accordance with some example embodiments of the present disclosure. The process 400 may involve a BS 210 and a UE 220. It would be appreciated that the process 400 may be applied to other communication scenarios, which will not be described in detail.

In the process 400, the UE 220 transmits capability information to the BS 210 at 410, the BS 210 transmits a configuration associated with one or more candidate cells to the UE 220 at 420, and the UE 220 performs a handover failure prediction at 430. The steps 410-430 may refer to steps 310-330 described with reference to FIG. 3, respectively, and thus will not be repeated herein.

In the process 400, the BS 210 transmits a handover command to the UE 220 at 440. Optionally, the UE 220 may determine that an execution condition for conditional handover (CHO) is met at 445. In addition, the UE 220 determines whether to continue performing the handover failure prediction at 450.

In some implementations, the UE 220 may determine whether to perform a handover to a certain candidate cell (i.e. target cell) , e.g. based on the handover command from the BS 210. For example, the handover command may indicate to the UE 220 to hand over to the target cell.

In some implementations, the UE 220 may stop the handover failure prediction that is started at 430. In some implementations, the UE 220 may continue the handover failure prediction that is started at 430, for example, the continued handover failure prediction may be made for the target cell. In some examples, the handover failure prediction which is continuing performing may be limited to the target cell.

In some example embodiments, the handover failure prediction may be stopped upon receiving the handover command. In some examples, the UE 220 may switch (hand over, transfer) from the serving cell to the target cell based on the handover command. In some examples, the RRC layer of the UE 220 may provide an indication of the handover to an upper layer or an AI entity of the UE 220 related to AI prediction, where the indication may indicate an execution of the handover to the target cell.

In some other example embodiments, the handover failure prediction may be continued, e.g. limited to the target cell. In some examples, after receiving the handover command, the UE 220 may predict a handover failure to the target cell while performing a handover towards the target cell. For example, if it is predicted that the handover failure will not occur, then handover may be continued performed by the UE 220 until the target cell is a new serving cell of the UE 220. For another example, if it is predicted that the handover failure will occur, the UE 220 will not continue performing the handover procedure. For example, the UE 220 may stay in the current serving cell. For example, the UE 220 may trigger a link recovery (e.g. fast master cell group (MCG) link recovery) or a re-establishment procedure.

In some other implementations, the CHO is configured to the UE 220, and the UE 220 may start evaluation for the execution condition for CHO and also predict handover failure for corresponding candidate cell. That is, for a certain candidate cell, the UE 220 may determine whether an execution condition for CHO is met and whether it is predicted that the handover failure will happen if switches to the certain candidate cell.

In some example embodiments, if it is predicted that the handover failure will occur, the UE 220 will not execute a handover towards the certain candidate cell even if the execution condition for CHO is met.

In some example embodiments, if it is predicted that the handover failure will not occur and the execution condition for CHO is met, the UE 220 will perform a handover to the certain candidate cell, e.g. until the certain candidate cell is a new serving cell of the UE 220.

It is to be understood that whether the UE 220 can stop the ongoing handover due to a handover failure prediction may be configured by the BS 210, whether the UE 220 can perform or consider the handover failure prediction for CHO execution may be configured by the BS 210.

In some examples, if it is configured that the UE 220 can perform and consider the handover failure prediction for CHO execution, then the step 450 associated with an execution condition for CHO may be performed. Otherwise, the UE 220 may switch to the certain candidate cell if an execution condition associated with the certain candidate cell for CHO by stopping the handover failure prediction.

According to some embodiments with reference to FIG. 4, a predicted information of a handover failure prediction may be considered in a handover procedure associated with a handover command or an execution condition for CHO. As such, the handover may be not performed in case a handover failure is predicted to be happen. Therefore, the handover failure may be avoided, and a communication efficiency of the UE 220 may be guaranteed.

FIG. 5 illustrates an example of a device 500 that is suitable for implementing embodiments of the present disclosure. The device 500 may be an example of a UE or a BS as described herein. The device 500 may support wireless communication with a BS 210, a UE 220, or any combination thereof. The device 500 may include components for bi-directional communications including components for transmitting and receiving communications, such as a processor 502, a memory 504, a transceiver 506, and, optionally, an I/O controller 508. 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 502, the memory 504, the transceiver 506, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the processor 502, the memory 504, the transceiver 506, or various combinations or components thereof may support a method for performing one or more of the operations described herein.

In some implementations, the processor 502, the memory 504, the transceiver 506, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 502 and the memory 504 coupled with the processor 502 may be configured to perform one or more of the functions described herein (e.g., executing, by the processor 502, instructions stored in the memory 504) .

For example, the processor 502 may support wireless communication at the device 500 in accordance with examples as disclosed herein. The processor 502 may be configured to operable to support a means for operations discussed above.

The processor 502 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some implementations, the processor 502 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 502. The processor 502 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 504) to cause the device 500 to perform various functions of the present disclosure.

The memory 504 may include random access memory (RAM) and read-only memory (ROM) . The memory 504 may store computer-readable, computer-executable code including instructions that, when executed by the processor 502 cause the device 500 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. In some implementations, the code may not be directly executable by the processor 502 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 504 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The I/O controller 508 may manage input and output signals for the device 500. The I/O controller 508 may also manage peripherals not integrated into the device 500. In some implementations, the I/O controller 508 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 508 may utilize an operating system such as or another known operating system. In some implementations, the I/O controller 508 may be implemented as part of a processor, such as the processor 502. In some implementations, a user may interact with the device 500 via the I/O controller 508 or via hardware components controlled by the I/O controller 508.

In some implementations, the device 500 may include a single antenna 510. However, in some other implementations, the device 500 may have more than one antenna 510 (i.e., multiple antennas) , including multiple antenna panels or antenna arrays, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 506 may communicate bi-directionally, via the one or more antennas 510, wired, or wireless links as described herein. For example, the transceiver 506 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 506 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 510 for transmission, and to demodulate packets received from the one or more antennas 510. The transceiver 506 may include one or more transmit chains, one or more receive chains, or a combination thereof.

A transmit chain may be configured to generate and transmit signals (e.g., control information, data, packets) . The transmit chain 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 transmit chain 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 transmit chain may also include one or more antennas 510 for transmitting the amplified signal into the air or wireless medium.

A receive chain may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receive chain may include one or more antennas 510 for receive the signal over the air or wireless medium. The receive chain may include at least one amplifier (e.g., a low-noise amplifier (LNA) ) configured to amplify the received signal. The receive chain 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 receive chain may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

FIG. 6 illustrates an example of a processor 600 that is suitable for implementing some embodiments of the present disclosure. The processor 600 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 600 may include a controller 602 configured to perform various operations in accordance with examples as described herein. The processor 600 may optionally include at least one memory 604, such as L1/L2/L3 cache. Additionally, or alternatively, the processor 600 may optionally include one or more arithmetic-logic units (ALUs) 606. 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 600 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 600) 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 602 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 600 to cause the processor 600 to support various operations in accordance with examples as described herein. For example, the controller 602 may operate as a control unit of the processor 600, generating control signals that manage the operation of various components of the processor 600. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 602 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 604 and determine subsequent instruction (s) to be executed to cause the processor 600 to support various operations in accordance with examples as described herein. The controller 602 may be configured to track memory address of instructions associated with the memory 604. The controller 602 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 602 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 600 to cause the processor 600 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 602 may be configured to manage flow of data within the processor 600. The controller 602 may be configured to control transfer of data between registers, arithmetic logic units (ALUs) , and other functional units of the processor 600.

The memory 604 may include one or more caches (e.g., memory local to or included in the processor 600 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 604 may reside within or on a processor chipset (e.g., local to the processor 600) . In some other implementations, the memory 604 may reside external to the processor chipset (e.g., remote to the processor 600) .

The memory 604 may store computer-readable, computer-executable code including instructions that, when executed by the processor 600, cause the processor 600 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 602 and/or the processor 600 may be configured to execute computer-readable instructions stored in the memory 604 to cause the processor 600 to perform various functions. For example, the processor 600 and/or the controller 602 may be coupled with or to the memory 604, the processor 600, the controller 602, and the memory 604 may be configured to perform various functions described herein. In some examples, the processor 600 may include multiple processors and the memory 604 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 606 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 606 may reside within or on a processor chipset (e.g., the processor 600) . In some other implementations, the one or more ALUs 606 may reside external to the processor chipset (e.g., the processor 600) . One or more ALUs 606 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 606 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 606 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 606 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 606 to handle conditional operations, comparisons, and bitwise operations.

The processor 600 may support wireless communication in accordance with examples as disclosed herein. The processor 600 may be configured to or operable to support a means for operations described in some embodiments of the present disclosure.

FIG. 7 illustrates a flowchart of a method 700 performed by a UE in accordance with aspects of the present disclosure. The operations of the method 700 may be implemented by a device or its components as described herein. For example, the operations of the method 700 may be performed by the UE 220 in FIG. 2B. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

At 710, the method may include transmitting, to a base station, capability information indicating that the UE has a capability of handover failure prediction. The operations of 710 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 710 may be performed by the UE 220 as described with reference to FIG. 2B.

At 720, the method may include receiving, from the base station, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells. The operations of 720 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 720 may be performed by the UE 220 as described with reference to FIG. 2B.

At 730, the method may include performing the handover failure prediction based on the configuration. The operations of 730 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 730 may be performed by the UE 220 as described with reference to FIG. 2B.

FIG. 8 illustrates a flowchart of a method 800 performed by a BS in accordance with aspects of the present disclosure. The operations of the method 800 may be implemented by a device or its components as described herein. For example, the operations of the method 800 may be performed by the BS 210 in FIG. 2B. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

At 810, the method may include receiving, from a UE, capability information indicating that the UE has a capability of handover failure prediction. The operations of 810 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 810 may be performed by the BS 210 as described with reference to FIG. 2B.

At 820, the method may include transmitting, to the UE, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells. The operations of 820 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 820 may be performed by the BS 210 as described with reference to FIG. 2B.

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

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

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

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. By way of example, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

As used herein, including in the claims, 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.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

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:

transmit, to a base station, capability information indicating that the UE has a capability of handover failure prediction;

receive, from the base station, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells; and

perform the handover failure prediction based on the configuration.
The UE of claim 1, wherein the capability information further indicates a maximum number of candidate cells of which the UE supports the handover failure prediction.
The UE of claim 1, wherein the configuration comprises information of a time duration indicating to the UE to perform the handover failure prediction within the time duration.
The UE of claim 1, wherein the configuration comprises a first threshold associated with the serving cell of the UE, and wherein the at least one processor is further configured to cause the UE to:

in accordance with a determination that a channel quality of the serving cell is worse than the first threshold, trigger the performing of the handover failure prediction.
The UE of claim 1, wherein the configuration comprises a first threshold associated with the serving cell of the UE, and wherein the at least one processor is configured to cause the UE to:

determine a channel quality of the serving cell; and

in accordance with a determination that the channel quality of the serving cell is worse than the first threshold, provide, from an access stratum (AS) layer of the UE to an upper layer or an artificial intelligence (AI) entity of the UE, an indication for performing the handover failure prediction.
The UE of claim 1, wherein the at least one processor is configured to cause the UE to:

provide, by an AS layer of the UE to an upper layer or an AI entity of the UE, measurement results of the serving cell; and

trigger, by the upper layer or the AI entity, the performing of the handover failure prediction based on the measurement results of the serving cell.
The UE of claim 1, wherein the configuration comprises first information associated with an input for the handover failure prediction, and wherein the first information comprises one of:

a time length for a mobility timer,

whether a dedicated random access channel resource is configured, or

at least one handover related parameter.
The UE of claim 1, wherein the configuration comprises second information to be predicted for the handover failure prediction, and wherein the second information comprises one of:

whether a handover failure to a candidate cell is to be occurred,

whether a handover failure to a candidate cell is to be occurred within the time duration,

a possibility of the handover failure to the candidate cell within the time duration, or

a selected candidate cell for a re-establishment procedure.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to:

transmit, to the base station, a report comprising third information associated with the handover failure prediction, and wherein the third information comprises one of:

whether a handover failure to a candidate cell is to be occurred,

whether a handover failure to a candidate cell is to be occurred within the time duration or before a time point,

a possibility of the handover failure of the candidate cell within the time duration or before the time point,

predicted measurement results associated with one or more candidate cells,

an accuracy rate of the third information, or

a selected candidate cell for a re-establishment procedure.
The UE of claim 9, wherein the configuration comprises a second threshold associated with the serving cell of the UE, and wherein the at least one processor is configured to cause the UE to transmit the report by:

in accordance with a determination that a channel quality of the serving cell is worse than the second threshold, transmitting the report.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to:

receive, from a base station, a handover command to hand over to a target cell; and

perform a handover to the target cell based on the handover command by stopping the handover failure prediction.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to:

receive, from a base station, a handover command to hand over to a target cell;

continue performing the handover failure prediction for the target cell; and

in accordance with a determination that it is predicted a handover failure of the target cell is to be occurred, trigger a link recovery or a re-establishment procedure without performing a handover towards the target cell.
A base station comprising:

at least one memory; and

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

receive, from a user equipment (UE) , capability information indicating that the UE has a capability of handover failure prediction; and

transmit, to the UE, a configuration associated with one or more candidate cells, the configuration being used for the UE to perform the handover failure prediction from a serving cell to one of the one of more candidate cells.
The base station of claim 13, wherein the capability information further indicates a maximum number of candidate cells of which the UE supports the handover failure prediction.
The base station of claim 13, wherein the configuration comprises information of a time duration indicating to the UE to perform the handover failure prediction within the time duration.
The base station of claim 13, wherein the configuration comprises a first threshold associated with the serving cell of the UE, and wherein the first threshold is used for the UE to determine whether to trigger the handover failure prediction is met.
The base station of claim 13, wherein the configuration comprises first information associated with an input for the handover failure prediction, and wherein the first information comprises one of:

a time length for a mobility timer,

whether a dedicated random access channel resource is configured, or

at least one handover related parameter.
The base station of claim 13, wherein the configuration comprises second information to be predicted for the handover failure prediction, and wherein the second information comprises one of:

whether a handover failure to a candidate cell is to be occurred,

whether a handover failure to a candidate cell is to be occurred within the time duration,

a possibility of the handover failure to the candidate cell within the time duration, or

a selected candidate cell for a re-establishment procedure.
The base station of claim 13, wherein the at least one processor is further configured to cause the base station to:

receive, from the UE, a report comprising third information associated with the handover failure prediction, and wherein the third information comprises one of:

whether a handover failure to a candidate cell is to be occurred,

whether a handover failure to a candidate cell is to be occurred within the time duration or before a time point,

a possibility of the handover failure of the candidate cell within the time duration or before the time point,

predicted measurement results associated with one or more candidate cells,

an accuracy rate of the third information, or

a selected candidate cell for a re-establishment procedure.
The base station of claim 19, wherein the configuration comprises a second threshold associated with the serving cell of the UE, and wherein the second threshold is used for determining whether to trigger the report.