Method and device for mobility robustness optimization

Abstract

The invention relates to a method and apparatus for MRO in a communication system. According to some embodiments of the present disclosure, a UE may: receive a UE information request message; and transmitting a UE information response message in response to receiving the UE information request message. The UE information response message may include at least one of: a Radio Link Failure (RLF) report associated with a Multiple Universal Subscriber Identity Module (MUSIM) operation of the UE; or a successful handover report, wherein the handover may include handover of the UE from a first radio access technology (RAT) to a second RAT for voice fallback.

Description

Technical Field

[0001] The present disclosure relates generally to communication techniques, and more particularly to mobility robustness optimization (MRO) in communication systems. Background Art

[0002] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, broadcast, etc. Wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of wireless communication systems may include fourth generation (4G) systems (e.g., long term evolution (LTE) systems, advanced LTE (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems, which may also be referred to as new radio (NR) systems.

[0003] A wireless communication system may include at least one base station or network access node that supports communication for communication devices, which may otherwise be referred to as user equipment (UE).

[0004] There is a need to efficiently perform communications in a communication system. Summary of the invention

[0005] Some embodiments of the present disclosure provide a user equipment (UE). The UE may include: a transceiver; and a processor coupled to the transceiver, wherein the processor may be configured to: receive a UE information request message; and transmit a UE information response message in response to receiving the UE information request message, wherein the UE information response message may include at least one of the following: a radio link failure (RLF) report associated with a multiple universal user identity module (MUSIM) operation of the UE; or a successful handover report, wherein the handover may include the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

[0006] Some embodiments of the present disclosure provide a base station (BS). The BS may include: a transceiver; and a processor coupled to the transceiver. The processor may be configured to: transmit a UE information request message to a user equipment (UE); and receive a UE information response message from the UE in response to transmitting the UE information request message, wherein the UE information response message may include at least one of the following: a radio link failure (RLF) report associated with a multi-universal user identity module (MUSIM) operation of the UE; or a successful handover report, wherein the handover may include the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

[0007] Some embodiments of the present disclosure provide a method for wireless communication performed by a user equipment (UE). The method may include: receiving a UE information request message; and transmitting a UE information response message in response to receiving the UE information request message, wherein the UE information response message may include at least one of the following: a radio link failure (RLF) report associated with a multiple universal user identity module (MUSIM) operation of the UE; or a successful handover report, wherein the handover may include the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

[0008] In some embodiments of the present disclosure, the UE may include a first USIM, and the UE is in a connected state in a first radio access network (RAN) associated with the first USIM. The method may further include: when a timer for leaving without response is running, prohibiting initiation of a reestablishment process in response to detecting a RLF associated with the first RAN; when the timer for leaving without response is running, prohibiting storage of RLF information in response to detecting the RLF associated with the first RAN; when the timer for leaving without response is not running, storing the RLF information in response to detecting the RLF associated with the first RAN; or when the timer for leaving without response is running, storing the RLF information in response to detecting the RLF associated with the first RAN.

[0009] In some embodiments of the present disclosure, the RLF report associated with the MUSIM operation may include the RLF information or both the RLF information and an indication. The indication indicates that the timer for leaving without response was running when the RLF was detected.

[0010] In some embodiments of the present disclosure, the UE may include a first USIM, and the UE is in a connected state in a first radio access network (RAN) associated with the first USIM. The method may further include: transmitting a UE assistance information message to the first RAN to request to leave the connected state in the first RAN; and in response to the transmission of the UE assistance information message, starting a timer for leaving without response.

[0011] In some embodiments of the present disclosure, the method may further include at least one of the following: when the timer for leaving without response is running, prohibiting execution of a conditional handover (CHO) in response to satisfying a CHO execution condition; when the timer for leaving without response is running, stopping evaluation of the CHO execution condition; or when the timer for leaving without response is running, prohibiting execution of a handover (HO) command received from the first RAN.

[0012] In some embodiments of the present disclosure, the method may further include re-entering the connected state in the first RAN. After re-entering the connected state in the first RAN, receiving the UE information request message. The RLF report associated with the MUSIM operation may include at least one of the following: a first indication indicating that CHO is not performed or indicating that CHO is not performed when the timer for leaving without response is running; a second indication indicating that CHO evaluation is stopped when the timer for leaving without response is running; or a third indication indicating that a HO command is not performed or indicating that a HO command is received when the timer for leaving without response is running.

[0013] In some embodiments of the present disclosure, the method may further include: receiving a command for switching from the first RAT to the second RAT, wherein the command is for voice fallback; and successfully accessing a cell associated with the second RAT according to the command.

[0014] In some embodiments of the present disclosure, the method may further include storing information associated with the handover from the first RAT to the second RAT in response to satisfying a trigger condition for reporting a successful handover report. After successfully accessing the cell associated with the second RAT, the UE information request message is received. The successful handover report may include at least one of: a voice fallback indication; or information about the cell associated with the second RAT.

[0015] In some embodiments of the present disclosure, the information about the cell associated with the second RAT may include at least one of the following: a first indication indicating that a physical layer problem timer starts within a time period after the switch from the first RAT to the second RAT; or a second indication indicating that a timer associated with a measurement report trigger starts within a time period after the switch from the first RAT to the second RAT.

[0016] In some embodiments of the present disclosure, the method may further include prohibiting storage of information associated with the switching from the first RAT to the second RAT in response to satisfying a trigger condition for reporting a successful switching report.

[0017] Some embodiments of the present disclosure provide a method for wireless communication performed by a base station (BS). The method may include: transmitting a UE information request message to a user equipment (UE); and receiving a UE information response message from the UE in response to transmitting the UE information request message, wherein the UE information response message may include at least one of the following: a radio link failure (RLF) report associated with a multiple universal user identity module (MUSIM) operation of the UE; or a successful handover report, wherein the handover may include the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

[0018] In some embodiments of the present disclosure, the first BS is associated with a first radio access network (RAN). The RLF report associated with the MUSIM operation may include information of an RLF between a second BS associated with the first RAN and the UE, and an indication that a timer for a no-response leave is running at the UE when the RLF occurs.

[0019] In some embodiments of the present disclosure, the first BS is associated with a first radio access network (RAN). The RLF report associated with the MUSIM operation may include at least one of the following: a first indication indicating that a conditional handover (CHO) is not performed at the UE or that CHO is not performed at the UE when a timer for leaving without response is running at the UE; a second indication indicating that CHO evaluation is stopped at the UE when the timer for leaving without response is running at the UE; or a third indication indicating that a handover (HO) command is not performed at the UE or that a HO command is received at the UE when the timer for leaving without response is running at the UE, wherein the HO command is transmitted from a second BS associated with the first RAN.

[0020] In some embodiments of the present disclosure, the first BS is associated with the second RAT. The successful handover report may include at least one of the following: a voice fallback indication; or information related to a serving cell of the UE.

[0021] In some embodiments of the present disclosure, the information related to the serving cell of the UE may include at least one of the following: a first indication indicating that a physical layer problem timer starts within a time period after the UE successfully switches from the first RAT to the serving cell of the UE; or a second indication indicating that a timer associated with a measurement report trigger starts within a time period after the UE successfully switches from the first RAT to the serving cell of the UE.

[0022] Some embodiments of the present disclosure provide a device. According to some embodiments of the present disclosure, the device may include: at least one non-transitory computer-readable medium having computer-executable instructions stored thereon; at least one receiving circuit system; at least one transmitting circuit system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuit system, and the at least one transmitting circuit system, wherein the at least one non-transitory computer-readable medium and the computer-executable instructions may be configured to cause the device to perform the method according to some embodiments of the present disclosure with the at least one processor.

[0023] Embodiments of the present disclosure provide technical solutions that facilitate and improve implementation of various communication technologies such as 5G NR. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to describe the manner in which the advantages and features of the present disclosure can be obtained, the description of the present disclosure is presented by reference to specific embodiments thereof shown in the accompanying drawings. These drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered limiting of its scope.

[0025] Figure 1 A schematic diagram showing a wireless communication system according to some embodiments of the present disclosure;

[0026] Figure 2 A flow chart illustrating an exemplary UE assistance information process according to some embodiments of the present disclosure;

[0027] Figure 3 A flow chart illustrating an exemplary inter-radio access technology (RAT) handover process according to some embodiments of the present disclosure;

[0028] Figure 4 A flow chart illustrating an exemplary UE information process according to some embodiments of the present disclosure;

[0029] Figures 5 to 10 A flowchart illustrating an exemplary process of wireless communication according to some embodiments of the present disclosure; and

[0030] Fig.11 A block diagram of an exemplary device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0031] The detailed description of the 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 can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

[0032] Reference will now be made in detail to some embodiments of the present disclosure, examples of which are shown in the accompanying drawings. To facilitate understanding, embodiments may be provided under specific network architectures and new service cases (e.g., 3rd Generation Partnership Project (3GPP) 5G (NR), 3GPP Long Term Evolution (LTE) Release 8, etc.). It is considered that all embodiments in the present disclosure are also applicable to similar technical problems as network architectures and new service cases evolve; and in addition, the terms described in the present disclosure may vary, which should not affect the principles of the present disclosure.

[0033] Figure 1 A schematic diagram of a wireless communication system 100 is shown according to some embodiments of the present disclosure.

[0034] refer to Figure 1 , the wireless communication system 100 may include some UEs (e.g., UE 110a and UE 110b), some BSs 120 (e.g., BS120a, BS120b, and BS120c), some RANs (e.g., RAN 121a and RAN 121b), some core networks (e.g., CN 130a and CN 130b), and a public switched telephone network (e.g., PSTN 140). It is contemplated that the wireless communication system 100 may include any number of UEs, BSs, networks, and / or network components.

[0035] UE and BS may support communication based on, for example, 3G, long term evolution (LTE), advanced LTE (LTE-A), new radio (NR), or other suitable protocols. In some embodiments of the present disclosure, BS 120 may also be referred to as an access point, access terminal, base station, base unit, macro unit, node-B, evolved node B (eNB), gNB, ng-eNB, home node-B, relay node or device, or described using other terms used in the art. BS 120 may be any type of device configured to wirelessly interface with at least one UE (e.g., UE 110) to facilitate access to one or more communication networks (e.g., CN 130a and CN 130b).

[0036] BS 120 is typically part of a RAN that may include one or more controllers communicatively coupled to one or more corresponding BSs. In the context of the present disclosure, "configured by the RAN" may be interpreted as configured by a BS associated with the RAN, or vice versa. For example, referring to Figure 1 BS120a may be part of RAN 121a, which may further include other BSs and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. BS120b and BS120c may be part of RAN 121b, which may further include other BSs and / or network elements (not shown). Figure 1 Each of BS 120a, BS 120b, and BS 120c may be configured to transmit and / or receive wireless signals within a specific geographic area, which may be referred to as a cell ( Figure 1 not shown).

[0037] RAN 121a may communicate with CN 130a, and RAN 121b may communicate with CN 130b. RAN 121a and RAN 121b may employ the same or different radio access technologies (RATs). For example, RAN 121a may employ Evolved Universal Terrestrial Radio Access Network (E-UTRAN) radio technology, and RAN 121b may employ NR technology. For example, both RAN 121a and RAN 121b may employ NR technology. Each of CN 130a and CN 130b may include multiple core network components, such as a mobility management entity (MME) ( Figure 1 not shown) or Access and Mobility Management Function (AMF) ( Figure 1 The CN can be used by the UE to access the PTSN 140 and / or other networks ( Figure 1 Gateway (not shown).

[0038] UE 110 may be any type of device configured to operate and / or communicate in a communication system (e.g., a wireless environment). UE 110 may include, for example, but not limited to, a computing device, a wearable device, a portable device, a mobile device, an IoT device, a vehicle, etc. It should be understood by those skilled in the art that the terms described in the present disclosure may change with the development and advancement of technology, but should not affect or limit the principles and spirit of the present disclosure. UE 110 may communicate with BS 120 via an uplink (UL) communication signal. BS 102 may communicate with UE 110 via a downlink (DL) communication signal.

[0039] In some embodiments, UE 110 may include one or more subscriber identity modules (SIMs) that enable it to access one or more separate wireless communication networks. For example, UE 110b may include a single SIM ( Figure 1 1 (not shown) and may be configured to access RAN 121a via BS 120a using a single SIM. UE 110a may be configured to access RAN 121a via SIM#1 ( Figure 1 121a via BS 120a, or by means of SIM #2 (not shown) in UE 110a. Figure 1121b via BS 120b. Although UE 110a is shown as accessing RAN 121a and RAN 121b, in other examples (not shown), UE 110a may establish additional network connections using additional RATs.

[0040] Each of SIM#1 and SIM#2 may be associated with a wireless communication system. For example, any one of SIM#1 and SIM#2 may be represented by a SIM card corresponding to a GSM system, a universal subscriber identity module (USIM) card corresponding to a UMTS system, a removable user identity module (RUIM) card or a CDMA subscriber identity module (CSIM) card corresponding to a CDMA2000 communication system, a universal integrated circuit card (UICC) corresponding to a 5G (NR) communication system, a wireless network card corresponding to an IEEE 802.11x wireless local area network (WLAN), or other suitable modules that can identify a user.

[0041] The multi-SIM UE may be implemented as a multi-SIM single standby (MSSS) UE, a multi-SIM multi-standby (MSMS) UE, a multi-SIM multi-active (MSMA) UE, etc.

[0042] For example, a UE that includes multiple SIMs and is connected to two or more networks where two or more SIMs are active at a given time may be referred to as an MSMA UE. An example MSMA UE may be a Dual SIM Dual Active (DSDA) UE, which may include two SIMs. Both SIMs of a DSDA UE may remain active. For example, a UE that has multiple SIMs and is connected to two or more networks where one SIM is active at a given time may be referred to as an MSMS UE. An example of an MSMS UE may be a Dual SIM Dual Standby (DSDS) UE. A DSDS UE may include two SIMs and may use a single radio front end and baseband to register the communication device to a single (same) public land mobile network or to two different PLMNs with two SIMs, respectively.

[0043] In a multi-SIM UE, multiple SIMs may share a common set of radio frequency (RF) resources (eg, RF transceiver) of the UE. However, the embodiments described herein may also be applicable to multi-SIM UEs where each of the multiple SIMs is associated with a separate RF resource.

[0044] In some embodiments of the present disclosure, a multi-SIM UE in a connected state (e.g., an RRC_CONNECTED state specified in the 3GPP specification) in network A may be switched from network A to network B. For example, network A may be an NR system, and network B may be an E-UTRA system or an NR system. Figure 1, UE 110a may be in a connected state in RAN 121a and may be handed over from RAN 121a to RAN 121b to, for example, receive services in RAN 121b. Before handing over from network A to network B, the multi-SIM UE should notify network A that the UE will leave the connected state in network A, for example, switching to an inactive or idle state (e.g., RRC_INACTIVE state or RRC_IDLE state as specified in the 3GPP specification), or that the UE will remain in the connected state in network A. Such notification may be transmitted via a UE assistance information message, which will be described in detail below.

[0045] In some embodiments of the present disclosure, when a multi-SIM UE is configured to leave a connected state, the UE may signal a preference for leaving the connected state to network A through radio resource control (RRC) signaling or non-access stratum (NAS) signaling. After the UE transmits the preference for leaving the connected state through, for example, RRC signaling, if the UE does not receive an RRC release message from network A within a certain time period (if configured by network A), the UE may autonomously enter an idle state in network A. The certain time period may be configured by an RRC reconfiguration message (e.g., indicated by a MUSIM-LeaveWithoutResponseTimer information element (IE)).

[0046] In some embodiments of the present disclosure, a multi-SIM UE may signal to network A a preference to maintain a connection state in network A while temporarily switching to network B, which may be indicated by a scheduling gap preference. The gap preference may contain information for setting or releasing a gap.

[0047] Figure 2 A flowchart showing an exemplary UE assistance information process 200 according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 2 The embodiments shown in .

[0048] refer to Figure 2 UE 210 and BS 220 can be used as Figure 1 UE 110 and BS 120 are shown in FIG. 1 . In operation 211, UE 210 and BS 220 may interact to perform an RRC reconfiguration operation. For example, BS 220 may transmit an RRC reconfiguration message to UE 210. The RRC reconfiguration message may instruct UE 210 to report assistance information to BS 220. In some cases, UE 210 may transmit a UE assistance information message to BS 220 in operation 213.

[0049] For example, UE 210 may use the UE assistance information message to inform the network of the following information:

[0050] - its preference for minimum scheduling offset for scheduling across time slots to save power;

[0051] - its preference for RRC state;

[0052] - their preferences in being provided with reference time information;

[0053] - its Multi-SIM (e.g. Multi-USIM (MUSIM)) assistance information; or

[0054] - any combination thereof.

[0055] In some embodiments of the present disclosure, the UE may initiate a UE assistance information procedure (e.g., if the UE is configured to do so). For example, a UE capable of providing multi-SIM assistance information may initiate the above procedure (e.g., if the UE is configured to do so) in response to determining that it leaves a connected state or determines that it needs a gap, or in response to a change in gap information without leaving a connected state, for example.

[0056] Those skilled in the art will appreciate that the order of operations in exemplary process 200 may be changed, and some operations in exemplary process 200 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0057] In some embodiments of the present disclosure, a UE may configure a conditional handover (CHO) configuration via, for example, an RRC reconfiguration message. The CHO configuration may be associated with at least one execution condition of at least one candidate node. The candidate node of the CHO may be a relay node or a cell. Each of the at least one candidate node may be associated with one or more execution conditions. The execution condition may be generated by a source BS of the UE. The CHO configuration may include a configuration of a candidate node generated by a candidate BS (e.g., a BS of a candidate cell or a BS serving a candidate relay node).

[0058] In some embodiments of the present disclosure, the UE may start evaluating at least one execution condition in response to receiving a CHO configuration. In response to satisfying the execution condition of the candidate node, the UE may select the candidate node as the target node and may initiate a CHO process with the target node. The UE may stop evaluating the execution condition during CHO execution or initiation of the CHO process.

[0059] In some embodiments of the present disclosure, an inter-RAT handover may occur, which may refer to a handover from a RAT (source RAT, such as 5G or LTE) to another RAT (target RAT, such as LTE or 5G). An inter-RAT handover may be characterized by one or more of the following:

[0060] -The source RAT configures the target RAT measurements and reporting.

[0061] - The Source RAT decides to prepare for startup and provides the necessary information to the Target RAT in the format required by the Target RAT.

[0062] -Prepare radio resources in the target RAT before handover.

[0063] - The RRC reconfiguration message from the target RAT may be delivered to the source RAT via a transparent container and may be passed in a handover command to the UE to be handed over by the source RAT.

[0064] The purpose of inter-RAT handover may include moving a UE in a connected state (e.g., RRC_CONNECTED state specified in 3GPP specifications) to a cell using another RAT. When such a procedure moves a UE from 5G to another RAT (e.g., E-UTRA or UTRA-FDD), the procedure may be referred to as a mobility procedure from NR.

[0065] In some embodiments of the present disclosure, a network (e.g., a BS) may initiate an inter-RAT handover procedure (e.g., from an NR mobility procedure) to a UE in a connected state in response to, for example, a measurement report message (e.g., a MeasurementReport as specified in a 3GPP specification) or a failure information message (e.g., a MCGFailureInformation message as specified in a 3GPP specification). For example, the network may transmit a handover command (e.g., a MobilityFromNRCommand as specified in a 3GPP specification) to the UE, which may include radio resources that have been allocated to the UE in the target cell. For example, the handover command may include an RRC reconfiguration message from the target RAT. In some embodiments of the present disclosure, a voice fallback indication may be included in the handover command, and thus, in the event of a handover failure, the UE may attempt to select, for example, an E-UTRA cell.

[0066] Figure 3 A flowchart showing an exemplary inter-RAT handover process 300 according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 3 The embodiments shown in .

[0067] refer to Figure 3 , UE 310 and BS 320 can be used as Figure 1 UE 110 and BS 120 are shown in FIG. UE 310 may access BS 320 and may transmit measurement reports to BS 320.

[0068] In operation 311, BS 320 may transmit a handover command (e.g., an RRC reconfiguration message including a reconfiguration with synchronization) to UE 310. The handover command may indicate an inter-RAT handover of UE 310 from a RAT (e.g., 5G) to another RAT (e.g., LTE), which may be associated with a target cell ( Figure 3 In response to receiving the handover command, UE 310 may initiate a random access procedure with the target cell.

[0069] Those skilled in the art will appreciate that the order of operations in exemplary process 300 may be changed, and some operations in exemplary process 300 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0070] In some embodiments of the present disclosure, a UE information procedure may occur. The procedure may be used by the network to request the UE to report information. The network may initiate this procedure only after a successful security activation.

[0071] Figure 4 A flowchart showing an exemplary UE information process 400 according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 4 The embodiments shown in .

[0072] refer to Figure 4 UE 410 and BS 420 can be used as Figure 1 UE 110 and BS 120 are shown in FIG. 4. In operation 411, BS 420 may transmit a UE information request message to UE 410. In operation 413, UE 410 may transmit a UE information response message in response to the UE information request message.

[0073] In some embodiments, the UE information response message may include a radio link failure (RLF) report. For example, the UE information request message may indicate that the UE should report information about RLF. The UE information response message may include RLF information or handover failure information.

[0074] Those skilled in the art will appreciate that the order of operations in exemplary process 400 may be changed, and some operations in exemplary process 400 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0075] Providing RLF reports to the network can facilitate mobility robustness optimization (MRO) in a communication network (e.g., an NR network). In some embodiments, the MRO function in the communication network can be further enhanced to provide more robust mobility by reporting failure events observed during successful handovers. To achieve this goal, the UE may be configured to compile a report associated with a successful handover, which includes, for example, a set of measurements collected during the handover phase, the set of measurements including, for example, measurements at the time of handover triggering, measurements at the end of handover execution, or measurements after handover execution. In some embodiments, the UE may be configured with one or more trigger conditions to compile a successful handover report, and the report will only be triggered when the conditions are met. This limits UE reporting to relevant situations, such as potential problems detected by radio link monitoring (RLM), or beam failure detection (BFD) detected in response to a successful handover event.

[0076] The availability of the 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 (e.g., a next generation radio access network NG-RAN node). The target BS may extract the information of the successful handover report via the UE information procedure as described above. For example, refer to Figure 4 The UE Information Request message may indicate that the UE should report information about the successful handover. The UE Information Response message may include a successful handover report. In some embodiments, the target BS may forward the successful handover report to the source BS (e.g., NR-RAN node) to indicate the failures experienced during the successful handover event.

[0077] In response to receiving the successful handover report, the receiving node (e.g., the target BS or the source BS) can analyze whether its mobility configuration needs to be adjusted. Such adjustments may result in changes to the mobility configuration, such as changes to the RLM configuration or changes to the mobility threshold between the source and the target. In some embodiments, the target BS in the executed handover may further optimize the dedicated random access channel (RACH) beam resources based on the beam measurements reported in response to the successful handover.

[0078] Embodiments of the present disclosure propose technical solutions for facilitating MRO in communication networks. For example, an enhanced MRO is provided in the case of multiple SIMs. For example, the impact of multiple SIM-related timers on RLF reports is considered. For example, in the case of inter-system (e.g., inter-RAT) switching for voice fallback, an enhanced MRO is provided. It may be beneficial to distinguish between normal switching and voice fallback switching, because there is a high probability that voice fallback switching may have a relatively long random access, and it may be inappropriate to use samples of voice fallback switching to optimize normal switching. More details about embodiments of the present disclosure will be described in the following text in combination with the accompanying drawings.

[0079] Figure 5 A flowchart showing an exemplary process 500 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 5 The embodiments shown in .

[0080] refer to Figure 5 UE 510 and BS 520 can be used as Figure 1 UE 110 and BS 120 shown in . UE 510 may include USIM # 5A and USIM # 5B. UE 510 may access a network (denoted as "network # 5A") via BS 520, and may be in a connected state in network # 5A. UE 510 may be in an idle or inactive state in another network (denoted as "network # 5B"). Network # 5A and network # 5B may be associated with USIM # 5A and USIM # 5B, respectively. For example, UE 510 may access network # 5A via USIM # 5A, and access network # 5B via USIM # 5B.

[0081] In operation 511, UE 510 may receive a configuration message (eg, an RRC reconfiguration message) from BS 520 (or network #5A). In some embodiments of the present disclosure, the configuration message may instruct the UE to report assistance information, such as MUSIM-related assistance information. The assistance information described above may be applied here.

[0082] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to “not leaving the connected state for MUSIM purposes.” For example, the configuration message may include a MUSIM-GapAssistanceConfig information element (IE).

[0083] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to "leaving a connected state for MUSIM purposes." For example, the configuration message may include a musim-LeaveAssistanceConfig IE.

[0084] In some embodiments, a timer for leaving without response (e.g., T346g specified in the 3GPP specification) may be configured. UE 510 may start the timer in response to the transmission of the UE Assistance Information message indicating that UE 510 will leave the connected state in network #5A. When the timer expires, UE 510 may autonomously leave the connected state and enter the idle state in network #5A for the purpose of MUSIM operation. For example, the musim-LeaveAssistanceConfig IE may include a musim-LeaveWithoutResponseTimer IE that indicates a timer (e.g., a value of the timer).

[0085] In some embodiments of the present disclosure, the configuration message may indicate the CHO configuration of the UE 510. In some embodiments of the present disclosure, the configuration message may not indicate the CHO configuration of the UE 510.

[0086] In operation 513, UE 510 may detect RLF associated with network #5A (e.g., RLF on a link between UE 510 and BS 520). In some embodiments, RLF may be detected when a timer for leaving without response is not running. In this case, UE 510 may store relevant RLF information. For example, the RLF information may be stored in a variable for RLF reporting (e.g., VarRLF-Report as specified in the 3GPP specification).

[0087] In response to the RLF, UE 510 may perform a reestablishment process. During the reestablishment process, UE 510 may select a cell. The selected cell is associated with network #5A. UE 510 may report RLF information to the selected cell. For example, UE 510 may report RLF information to the selected cell via, for example, a UE information process. The UE information process as described above may be applied here. For example, UE 510 may receive a UE information request message from network #5A (e.g., a selected cell), and may transmit a UE information response message in response to receiving the UE information request message. The UE information response message may include RLF information (e.g., an RLF report).

[0088] In some other embodiments, RLF may be detected when a timer for leaving without response is running. For example, UE 510 may transmit a UE assistance information message to BS 520 to indicate that UE 510 has determined that it is in network #5A ( Figure 5 UE 510 may leave the connected state in response to the transmission of the UE assistance information message. UE 510 may start a timer for leaving without response in response to the transmission of the UE assistance information message. When the timer for leaving without response is running, RLF may be detected. In this case, UE 510 may not store RLF information. In addition, UE 510 may not initiate a reestablishment procedure in response to the RLF.

[0089] Those skilled in the art will appreciate that the order of operations in exemplary process 500 may be changed, and some operations in exemplary process 500 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0090] Figure 6 A flowchart showing an exemplary process 600 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure are applicable to Figure 6 The embodiments shown in .

[0091] refer to Figure 6 UE 610 and BS 620 can be used as Figure 1 UE 110 and BS 120 shown in . UE 610 may include USIM # 6A and USIM # 6B. UE 610 may access a network (denoted as "network # 6A") via BS 620, and may be in a connected state in network # 6A. UE 610 may be in an idle or inactive state in another network (denoted as "network # 6B"). Network # 6A and network # 6B may be associated with USIM # 6A and USIM # 6B, respectively. For example, UE 610 may access network # 6A via USIM # 6A, and access network # 6B via USIM # 6B.

[0092] In operation 611, UE 610 may receive a configuration message (eg, an RRC reconfiguration message) from BS 620 (or network #6A). In some embodiments of the present disclosure, the configuration message may instruct the UE to report assistance information, such as MUSIM-related assistance information. The assistance information described above may be applied here.

[0093] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to “not leaving the connected state for MUSIM purposes.” For example, the configuration message may include a MUSIM-GapAssistanceConfig information element (IE).

[0094] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to "leaving a connected state for MUSIM purposes." For example, the configuration message may include a musim-LeaveAssistanceConfig IE.

[0095] In some embodiments, a timer for leaving without response (e.g., T346g specified in the 3GPP specification) may be configured. UE 610 may start the timer in response to the transmission of the UE Assistance Information message indicating that UE 610 will leave the connected state in network #6A. When the timer expires, UE 610 may autonomously leave the connected state and enter the idle state in network #6A for the purpose of MUSIM operation. For example, the musim-LeaveAssistanceConfig IE may include a musim-LeaveWithoutResponseTimer IE that indicates a timer (e.g., a value of the timer).

[0096] In some embodiments of the present disclosure, the configuration message may indicate the CHO configuration of the UE 610. In some embodiments of the present disclosure, the configuration message may not indicate the CHO configuration of the UE 610.

[0097] In some embodiments of the present disclosure, UE 610 may determine to leave the connected state (e.g., as a preferred state to the idle state) in network #6A. For example, when UE 610 receives a paging message from network #6B, wants to transmit a busy indication to network #6B, or wants to receive system information from network #6B, UE 610 may make such a determination for the purpose of MUSIM operation.

[0098] In operation 613, UE 610 may transmit a UE assistance information message to BS 620. The UE assistance information message may indicate an idle state or an inactive state as a preferred state (e.g., UE 610 has determined to leave the connected state in network #6A). In response to the transmission of the UE assistance information message, UE 610 may start a timer for leaving without response.

[0099] In operation 615, UE 610 may detect RLF associated with network #6A (e.g., RLF on a link between UE 610 and BS 620). RLF may be detected while a timer for leaving without response is running. In this case, although UE 610 is required to detect RLF, UE 610 may not be required to initiate a reestablishment process in response to detection of RLF. In other words, while the timer for leaving without response is running, UE 610 may refrain from initiating a reestablishment process in response to detecting RLF associated with network #6A. While the timer for leaving without response is running, UE 610 may store RLF information in response to detecting RLF. For example, the RLF information may be stored in a variable for RLF reporting (e.g., VarRLF-Report as specified in the 3GPP specification).

[0100] In response to the expiration of the timer for No Response Leave, UE 610 may autonomously leave the Connected state and enter the Idle state in network #6A.

[0101] In some embodiments, UE 610 may (re)enter a connected state in network #6A. For example, UE 610 may access BS 620 or another BS associated with network #6A. Figure 6UE 610 may report RLF information to network #6A via, for example, a UE information procedure. The UE information procedure as described above may be applied here. For example, UE 610 may receive a UE information request message from network #6A, and may transmit a UE information response message in response to the received UE information request message. The UE information response message may include stored RLF information (e.g., RLF report). In some embodiments, an indication that a timer for leaving without response is running or a timer for leaving without response is running when RLF is detected may also be added to the RLF report. In some other embodiments, such an indication may be stored with the RLF information.

[0102] Those skilled in the art will appreciate that the order of operations in exemplary process 600 may be changed, and some operations in exemplary process 600 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0103] Figure 7 A flowchart showing an exemplary process 700 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 7 The embodiments shown in .

[0104] refer to Figure 7 , UE 710 and BS 720 can be used as Figure 1 UE 110 and BS 120 shown in . UE 710 may include USIM#7A and USIM#7B. UE 710 may access a network (denoted as "network #7A") via BS 720, and may be in a connected state in network #7A. UE 710 may be in an idle or inactive state in another network (denoted as "network #7B"). Network #7A and network #7B may be associated with USIM#7A and USIM#7B, respectively. For example, UE 710 may access network #7A via USIM#7A, and access network #7B via USIM#7B.

[0105] In operation 711, UE 710 may receive a configuration message (eg, an RRC reconfiguration message) from BS 720 (or network #7A). In some embodiments of the present disclosure, the configuration message may instruct the UE to report assistance information, such as MUSIM-related assistance information. The assistance information described above may be applied here.

[0106] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to “not leaving the connected state for MUSIM purposes.” For example, the configuration message may include a MUSIM-GapAssistanceConfig information element (IE).

[0107] For example, in some embodiments, the configuration message may instruct the UE to report assistance information related to "leaving a connected state for MUSIM purposes." For example, the configuration message may include a musim-LeaveAssistanceConfig IE.

[0108] In some embodiments, a timer for leaving without response (e.g., T347g specified in the 3GPP specification) may be configured. UE 710 may start the timer in response to the transmission of the UE Assistance Information message indicating that UE 710 will leave the connected state in network #7A. When the timer expires, UE 710 may autonomously leave the connected state and enter the idle state in network #7A for the purpose of MUSIM operation. For example, the musim-LeaveAssistanceConfig IE may include a musim-LeaveWithoutResponseTimer IE, which indicates the timer (e.g., the value of the timer).

[0109] In some embodiments of the present disclosure, the configuration message may indicate the CHO configuration of the UE 710. In some embodiments of the present disclosure, the configuration message may not indicate the CHO configuration of the UE 710.

[0110] In some embodiments of the present disclosure, UE 710 may determine to leave the connected state in network #7A. For example, when UE 710 receives a paging message from network #7B, wants to transmit a busy indication to network #7B, or wants to receive system information from network #7B, UE 710 may make such a determination for the purpose of MUSIM operation.

[0111] In operation 713, UE 710 may transmit a UE assistance information message to BS 720. The UE assistance information message may indicate an idle state or an inactive state as a preferred state (e.g., UE 710 has determined to leave the connected state in network #7A). In response to the transmission of the UE assistance information message, UE 710 may start a timer for leaving without response.

[0112] In some embodiments of the present disclosure, UE 710 may be configured with a CHO configuration by network #7A (e.g., BS 720). In operation 715, when the timer for leaving without response is running, UE 710 may determine that the CHO execution condition is met. In this case, UE 710 may not perform CHO. In other words, when the timer for leaving without response is running, UE 710 may prohibit performing CHO in response to satisfying the CHO execution condition. As will be described later, in operation 717, a corresponding indication may be reported to network #7A to indicate this situation.

[0113] In some embodiments of the present disclosure, when the timer for leaving without response is running, UE 710 may stop evaluating the CHO execution condition. For example, when configuring the CHO configuration, UE 710 may stop evaluating the configured CHO execution condition in response to starting the timer for leaving without response running. As will be described later, in operation 717, a corresponding indication may be reported to network #7A to indicate this situation.

[0114] In some embodiments of the present disclosure, when the timer for leaving without response is running, UE 710 may receive a handover (HO) command. In this case, UE 710 may not execute the HO command. As will be described later, in operation 717, a corresponding indication may be reported to network #7A to indicate this situation.

[0115] In some embodiments of the present disclosure, in operation 715, UE 710 may detect RLF associated with network #7A (e.g., RLF on a link between UE 710 and BS 720). In some embodiments, RLF may be detected while a timer for leaving without response is running. In this case, although UE 710 is required to detect RLF, UE 710 may not be required to initiate a reestablishment process in response to RLF. In other words, UE 710 may refrain from initiating a reestablishment process in response to detecting RLF associated with network #7A while a timer for leaving without response is running.

[0116] In some embodiments of the present disclosure, as described above, when the timer for leaving without response is running, the UE 710 may store RLF information in response to detecting RLF. For example, the RLF information may be stored in a variable for RLF reporting (e.g., VarRLF-Report as specified in the 3GPP specification). In some other embodiments of the present disclosure, as described above, when the timer for leaving without response is running, the UE 710 may not store RLF information in response to detecting RLF.

[0117] In response to the expiration of the timer for No Response Leave, UE 710 may autonomously leave the Connected state and enter the Idle state in network #7A.

[0118] In some embodiments of the present disclosure, UE 710 may (re)enter a connected state in network #7A. For example, UE 710 may access BS 720 or another BS associated with network #7A. Figure 7 For simplicity, Figure 7 Assume that UE 710 accesses BS 720 .

[0119] In some embodiments, as described above, UE 710 may report RLF information to network #7A via, for example, a UE information procedure after (re)entering a connected state in network #7A. For example, in operation 717, UE 710 may transmit a UE information response message to network #7A.

[0120] In some embodiments, the UE Information Response message may include RLF information (eg, RLF Report) or both RLF information and an indication that a timer for No Response Leave was running when RLF was detected.

[0121] In some embodiments, the UE information response message may include an indication indicating that CHO is not to be performed. In other words, the indication may indicate that CHO is not to be performed when the timer for leaving without response is running.

[0122] In some embodiments, the UE Information Response message may include an indication to stop the CHO evaluation when the timer for No Response Leave is running.

[0123] In some embodiments, the UE information response message may include an indication indicating that the HO command is not to be performed. In other words, the indication may indicate that the HO command is not to be performed when the timer for leaving without response is running.

[0124] Those skilled in the art will appreciate that the order of operations in exemplary process 700 may be changed, and some operations in exemplary process 700 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0125] Figure 8 A flowchart showing an exemplary process 800 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure apply to Figure 8 The embodiments shown in .

[0126] refer to Figure 8 UE 810 can be used as Figure 1 UE 110 shown in FIG. 1 , and BS 820a and BS 820b may be used as Figure 1 BS 120 is shown in FIG. UE 810 may access BS 820a. UE 810 may have UL data for voice.

[0127] In some embodiments, BS 820a may be associated with a RAT such as NR, and BS 820b may be associated with another RAT such as E-UTRA. BS 820a may decide to handover UE 810 to a target cell (e.g., BS 820b) for voice traffic. In operation 811, UE 810 may receive a handover command (e.g., MobilityFromNRCommand specified in the 3GPP specification) from BS 820a.

[0128] In some embodiments, in response to receiving the handover command, UE 810 may stop a timer associated with a measurement report trigger (eg, T312 specified in 3GPP specifications) if the timer associated with the measurement report trigger is running.

[0129] In some embodiments, the switching command may include a voice fallback instruction, that is, the switching command is used for voice fallback.

[0130] In some embodiments, the handover command may include a trigger condition for reporting a successful handover report. In some embodiments, when the trigger condition is met, the UE 810 may report a successful handover report. For example, the trigger condition may include one or more of the following:

[0131] - a threshold value of the ratio (e.g., percentage) between the elapsed time of a timer for path switching (e.g., T304 as specified in the 3GPP specification) and the configured value of the timer for path switching;

[0132] - a threshold value of the ratio (eg, percentage) between the elapsed time of a physical layer problem timer (eg, T310 as specified in 3GPP specifications) and the configured value of the physical layer problem timer; and

[0133] - A threshold value of the ratio (eg, percentage) between an elapsed timer of a timer associated with a measurement report trigger (eg, T312 specified in 3GPP specifications) and a configured value of the timer associated with the measurement report trigger.

[0134] In operation 813, in response to receiving the handover command, UE 810 may start a timer for path switching (e.g., T304 as specified in the 3GPP specification). In operation 815, UE 810 may access BS 820b (e.g., E-UTRA cell) according to the handover command. In some embodiments, UE 810 may successfully access BS 820b and then stop the timer for path switching.

[0135] In some embodiments of the present disclosure, during the handover process, UE 810 may store information associated with the handover in response to satisfying a trigger condition for reporting a successful handover report. As will be described later, UE 810 may transmit the stored successful handover report to the network.

[0136] In some other embodiments of the present disclosure, if the handover is triggered for the purpose of voice fallback, it is not expected that the UE 810 reports a successful handover report. For example, the UE 810 may prohibit storing information associated with the handover in response to satisfying the triggering condition for reporting a successful handover report.

[0137] In operation 817, UE 810 may transmit an RRC reconfiguration complete message to BS 820b. The message may indicate that information associated with a successful handover report is available. In some embodiments, the message may indicate which trigger condition(s) have been met.

[0138] In some embodiments of the present disclosure, a UE information procedure may be performed to obtain a successful handover report.

[0139] For example, in operation 819, in response to the RRC reconfiguration complete message, the BS 820b may transmit a UE information request message to the UE 810. The UE information request message may request the UE 810 to report a successful handover report.

[0140] In operation 821, UE 810 may transmit a UE information response message in response to receiving the UE information request message. The UE information response message may include a successful handover report. The successful handover report may include at least one of the following: a voice fallback indication or information related to the target cell. For example, the information related to the target cell may include at least one of the following: an indication indicating that a physical layer problem timer (e.g., T310 as specified in the 3GPP specification) starts within a time period after the handover; or an indication indicating that a timer associated with a measurement report trigger (e.g., T312 specified in the 3GPP specification) starts within a time period after the handover.

[0141] The above information can help the source BS, the target BS, or both to optimize the system. For example, by distinguishing between normal handover and voice fallback handover, the network can optimize normal handover without using information associated with voice fallback handover.

[0142] In operation 823, BS 820b may forward the successful handover report to source BS 820a via, for example, an Xn message. The Xn message may include a failure indication message or another Xn message (e.g., a message specific to the transmission of a successful handover report). In some instances, the successful handover report (or information response message) from UE 810 may be transmitted to BS 820a as a container. In some instances, the Xn message may include an indication of a "successful handover report".

[0143] Those skilled in the art will appreciate that the order of operations in exemplary process 800 may be changed, and some operations in exemplary process 800 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0144] Fig. 9 A flowchart showing an exemplary process 900 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure are applicable to Fig. 9 In some examples, the process may be performed by a UE.

[0145] refer to Fig. 9 In operation 911, the UE may receive a UE information request message. In operation 913, the UE may transmit a UE information response message in response to receiving the UE information request message. In some embodiments, the UE information response message may include at least one of the following: a RLF report associated with MUSIM operation of the UE; or a successful handover report, wherein the handover may include the UE switching from a first RAT to a second RAT for voice fallback.

[0146] For example, in some embodiments of the present disclosure, the UE information response message may include information about Figures 5 to 7 For example, the UE may include a first USIM and a second USIM, and the UE is in a connected state in a first RAN associated with the first USIM.

[0147] In some embodiments of the present disclosure, the UE may perform one or more of the following: refrain from initiating a reestablishment procedure in response to detecting a RLF associated with the first RAN when a timer for leaving without response is running; refrain from storing RLF information in response to detecting a RLF associated with the first RAN when a timer for leaving without response is running; store RLF information in response to detecting a RLF associated with the first RAN when the timer for leaving without response is not running; or store RLF information in response to detecting a RLF associated with the first RAN when a timer for leaving without response is running. In some embodiments, an RLF report associated with MUSIM operation may include RLF information or both RLF information and an indication, wherein the indication indicates that the timer for leaving without response was running when the RLF was detected.

[0148] In some embodiments of the present disclosure, the UE may transmit a UE assistance information message to the first RAN to request to leave the connected state in the first RAN; and in response to the transmission of the UE assistance information message, start a timer for leaving without response. In some embodiments, the UE may perform at least one of the following: prohibiting execution of CHO in response to satisfying a CHO execution condition when the timer for leaving without response is running; stopping evaluating the CHO execution condition when the timer for leaving without response is running; or prohibiting execution of a HO command received from the first RAN when the timer for leaving without response is running.

[0149] In some embodiments, the UE may re-enter a connected state in the first RAN. After re-entering the connected state in the first RAN, a UE information request message may be received. The RLF report associated with the MUSIM operation may include at least one of the following: a first indication indicating that CHO was not performed or indicating that CHO was not performed when a timer for leaving without response was running; a second indication indicating that CHO evaluation was stopped when a timer for leaving without response was running; or a third indication indicating that a HO command was not performed or indicating that a HO command was received when a timer for leaving without response was running.

[0150] For example, in some embodiments of the present disclosure, the UE information response message may include information about Figure 8 Successful handover report as described.

[0151] In some embodiments of the present disclosure, the UE may receive a command for switching from a first RAT to a second RAT, wherein the command is for voice fallback. The UE may successfully access a cell associated with the second RAT according to the command.

[0152] In some embodiments, the UE may store information associated with switching from the first RAT to the second RAT in response to satisfying a trigger condition for reporting a successful switching report. A UE information request message may be received after successfully accessing a cell associated with the second RAT. The successful switching report may include at least one of: a voice fallback indication; or information about a cell associated with the second RAT. In some embodiments, the information about the cell associated with the second RAT may include at least one of: a first indication indicating that a physical layer problem timer starts within a time period after switching from the first RAT to the second RAT; or a second indication indicating that a timer associated with a measurement report trigger starts within a time period after switching from the first RAT to the second RAT.

[0153] In some embodiments, the UE may refrain from storing information associated with a handover from a first RAT to a second RAT in response to satisfying a trigger condition for reporting a successful handover report.

[0154] Those skilled in the art will appreciate that the order of operations in exemplary process 900 may be changed, and some operations in exemplary process 900 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0155] Fig.10 A flowchart showing an exemplary process 1000 of wireless communication according to some embodiments of the present disclosure. The details described in all the above embodiments of the present disclosure are applicable to Fig.10 In some examples, the process may be performed by a BS.

[0156] refer to Fig.10 In operation 1011, the BS may transmit a UE information request message to the UE. In operation 1013, the BS may receive a UE information response message in response to the UE information request message. In some embodiments, the UE information response message may include at least one of the following: a RLF report associated with the MUSIM operation of the UE; or a successful handover report, wherein the handover may include the UE switching from the first RAT to the second RAT for voice fallback.

[0157] For example, in some embodiments of the present disclosure, the UE information response message may include information about Figures 5 to 7 RLF report as described.

[0158] In some embodiments, the first BS may be associated with the first RAN.The RLF report associated with MUSIM operation may include information of RLF between the second BS associated with the first RAN and the UE, and an indication that a timer for No Response Leave was running at the UE when the RLF occurred.

[0159] In some embodiments, the first BS may be associated with the first RAN. The RLF report associated with the MUSIM operation may include at least one of the following: a first indication indicating that CHO is not performed at the UE or that CHO is not performed at the UE when a timer for leaving without response is running at the UE; a second indication indicating that CHO evaluation is stopped at the UE when a timer for leaving without response is running at the UE; or a third indication indicating that a HO command is not performed at the UE or that a HO command is received at the UE when a timer for leaving without response is running at the UE, wherein the HO command is transmitted from a second BS associated with the first RAN.

[0160] For example, in some embodiments of the present disclosure, the UE information response message may include information about Figure 8 Successful handover report as described.

[0161] In some embodiments, the first BS may be associated with the second RAT.The successful handover report may include at least one of: a voice fallback indication; or information related to a serving cell of the UE.

[0162] The information related to the UE's serving cell may include at least one of the following: a first indication indicating that the physical layer problem timer starts within a time period after the UE successfully switches from the first RAT to the UE's serving cell; or a second indication indicating that the timer associated with the measurement report trigger starts within a time period after the UE successfully switches from the first RAT to the UE's serving cell.

[0163] Those skilled in the art will appreciate that the order of operations in exemplary process 1000 may be changed, and some operations in exemplary process 1000 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0164] Fig.11 1 is a block diagram of an exemplary device 1100 according to some embodiments of the present disclosure. Fig.11 , the apparatus 1100 may include at least one processor 1106 and at least one transceiver 1102 coupled to the processor 1106. The apparatus 1100 may be a UE or a BS.

[0165] Although elements such as at least one transceiver 1102 and a processor 1106 are described in singular form in this figure, plural forms are contemplated unless explicitly stated to be limited to the singular form. In some embodiments of the present application, the transceiver 1102 may be divided into two devices, such as a receiving circuit system and a transmitting circuit system. In some embodiments of the present application, the device 1100 may further include an input device, a memory and / or other components. In some embodiments of the present application, the device 1100 may be a UE including at least one SIM (e.g., a USIM). At least one SIM may be coupled to the processor 1106.

[0166] According to some embodiments of the present application, the device 1100 may be a UE. The transceiver 1102 and the processor 1106 may interact with each other to execute the above, for example, Figures 1 to 10 The operations of the UE are described in .

[0167] According to some embodiments of the present application, the device 1100 may be a BS. The transceiver 1102 and the processor 1106 may interact with each other to execute the above, for example, Figures 1 to 10 The operation of BS is described in .

[0168] In some embodiments of the present application, the device 1100 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 store thereon computer-executable instructions for causing the processor 1106 to implement the method described above with respect to the UE. For example, when the computer-executable instructions are executed, the processor 1106 interacts with the transceiver 1102 to perform Figures 1 to 10 The operations of the UE are described in .

[0169] In some embodiments of the present application, the device 1100 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 store thereon computer-executable instructions for causing the processor 1106 to implement the method for the BS described above. For example, when the computer-executable instructions are executed, the processor 1106 interacts with the transceiver 1102 to perform Figures 1 to 10 The operation of BS is described in .

[0170] It should be understood by those of ordinary skill in the art that the operations or steps of the methods described in conjunction 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. The 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. In addition, 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 that can be incorporated into a computer program product.

[0171] Although the present disclosure has been described with reference to specific embodiments of the present disclosure, it is apparent that many substitutions, modifications, and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added, or substituted in other embodiments. Moreover, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, a person of ordinary skill in the field of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0172] In this document, the term "includes / including" or any other changes thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment containing the element list not only includes those elements but also may include other elements that are not explicitly listed or inherent to such process, method, article or equipment. The element starting with "a / an" or the like (without more constraints) does not exclude the existence of additional identical elements in the process, method, article or equipment containing the element. Moreover, the term "another" is defined as at least one second or more. As used herein, the term "having" and the like are defined as "including". For example, the expression of "A and / or B" or "at least one of A and B" may include any and all combinations of words listed together with the expression. For example, the expression "A and / or B" or "at least one of A and B" may include A, B or both A and B. The words of "first", "second" or the like are only used to clearly illustrate the embodiments of the present application, and are not used to limit the essence of the present application.

Claims

1. A user equipment UE, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: Receiving a UE information request message; and In response to receiving the UE information request message, a UE information response message is transmitted, wherein the UE information response message includes at least one of the following: a Radio Link Failure (RLF) report associated with a Multiple Universal Subscriber Identity Module (MUSIM) operation of the UE; or A successful handover report, wherein the handover comprises the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

2. The UE according to claim 1, wherein the UE further comprises a first USIM and a second USIM, and the UE is in a connected state in a first radio access network RAN ​​associated with the first USIM; and wherein the processor is coupled to the first USIM and the second USIM and is configured to perform at least one of the following: refraining from initiating a reestablishment procedure in response to detecting a RLF associated with the first RAN while a timer for leaving without response is running; refraining from storing RLF information in response to detecting the RLF associated with the first RAN while the timer for leaving without response is running; storing the RLF information in response to detecting the RLF associated with the first RAN when the timer for leaving without response is not running; or The RLF information is stored in response to detecting the RLF associated with the first RAN while the timer for leaving without response is running.

3. The UE of claim 2, wherein the RLF report associated with the MUSIM operation includes the RLF information or both the RLF information and an indication, wherein the indication indicates that the timer for leaving without response was running when the RLF was detected.

4. The UE according to claim 1, wherein the UE further comprises a first USIM and a second USIM, and the UE is in a connected state in a first radio access network RAN ​​associated with the first USIM; and wherein the processor is coupled to the first USIM and the second USIM and is configured to: transmitting a UE assistance information message to the first RAN to request to leave the connected state in the first RAN; and A timer for leaving without response is started in response to the transmission of the UE assistance information message.

5. The UE of claim 4, wherein the processor is further configured to perform at least one of the following: prohibiting execution of CHO in response to satisfying a conditional switching CHO execution condition when the timer for leaving without response is running; When the timer for leaving without response is running, stop evaluating the CHO execution condition; or When the timer for leaving without response is running, executing a handover HO command received from the first RAN is prohibited.

6. The UE of claim 5, wherein the processor is further configured to re-enter the connected state in the first RAN, and receive the UE information request message after re-entering the connected state in the first RAN; and The RLF report associated with the MUSIM operation includes at least one of the following: a first indication indicating that CHO is not performed or indicating that CHO is not performed when the timer for leaving without response is running; a second indication indicating to stop CHO evaluation when the timer for leaving without response is running; or A third indication indicates that the HO command is not executed or indicates that the HO command is received when the timer for leaving without response is running.

7. The UE of claim 1, wherein the processor is configured to: receiving a command for switching from the first RAT to the second RAT, wherein the command is for voice fallback; and A cell associated with the second RAT is successfully accessed according to the command.

8. The UE of claim 7, wherein the processor is further configured to, in response to satisfying a trigger condition for reporting a successful handover report, store information associated with the handover from the first RAT to the second RAT; wherein after successfully accessing the cell associated with the second RAT, receiving the UE information request message; and The successful handover report includes at least one of the following: Voice fallback indication; or Information about the cell associated with the second RAT.

9. The UE of claim 8, wherein the information about the cell associated with the second RAT comprises at least one of: a first indication indicating that a physical layer problem timer starts within a time period after the switching from the first RAT to the second RAT; or A second indication indicating that a timer associated with a measurement report trigger starts within a time period after the switching from the first RAT to the second RAT.

10. The UE of claim 7, wherein the processor is further configured to refrain from storing information associated with the switching from the first RAT to the second RAT in response to satisfying a trigger condition for reporting a successful switching report.

11. A first base station BS, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: Transmitting a UE information request message to a user equipment UE; and In response to transmitting the UE information request message, receiving a UE information response message from the UE, wherein the UE information response message includes at least one of the following: a Radio Link Failure (RLF) report associated with a Multiple Universal Subscriber Identity Module (MUSIM) operation of the UE; or A successful handover report, wherein the handover comprises the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

12. The first BS according to claim 11, wherein the first BS is associated with a first radio access network RAN, and The RLF report associated with the MUSIM operation includes information of an RLF between a second BS associated with the first RAN and the UE, and an indication that a timer for leaving without response is running at the UE when the RLF occurs.

13. The first BS of claim 11, wherein the first BS is associated with a first radio access network RAN, and the RLF report associated with the MUSIM operation comprises at least one of: a first indication indicating that a conditional handover (CHO) is not performed at the UE or indicating that a CHO is not performed at the UE when a timer for leaving without response is running at the UE; a second indication indicating to stop CHO evaluation at the UE when the timer for leaving without response is running at the UE; or a third indication indicating that a handover HO command is not performed at the UE or indicating that a HO command is received at the UE when the timer for leaving without response is running at the UE, wherein the HO command is transmitted from a second BS associated with the first RAN.

14. The first BS of claim 11, wherein the first BS is associated with the second RAT, and the successful handover report comprises at least one of: Voice fallback indication; or Information related to the serving cell of the UE.

15. A method performed by a user equipment UE, comprising: Receiving a UE information request message; and In response to receiving the UE information request message, a UE information response message is transmitted, wherein the UE information response message includes at least one of the following: a Radio Link Failure (RLF) report associated with a Multiple Universal Subscriber Identity Module (MUSIM) operation of the UE; or A successful handover report, wherein the handover comprises the UE switching from a first radio access technology (RAT) to a second RAT for voice fallback.

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