Method and apparatus for additional reference signal monitoring

Abstract

Embodiments of the present disclosure relate to methods and devices. According to some embodiments of the present disclosure, a method may include: receiving, at a first base station, auxiliary information related to a user equipment (UE) group from a second base station; and determining whether to transmit a reference signal (RS) associated with a paging message for the UE based on the auxiliary information.

Description

Technical Field

[0001] Embodiments of the present application relate generally to wireless communication techniques, and more particularly to methods and apparatus for additional reference signal (RS) monitoring in wireless communication systems. Background Art

[0002] In narrowband Internet of Things (NB-IoT) technology, a wake-up signal (WUS) mechanism is introduced in Long Term Evolution (LTE) Release 15 (R15) to save power, where the WUS indicates whether there is a paging procedure in a predefined paging occasion (PO).

[0003] Specifically, when the WUS mechanism is disabled, the UE always monitors the paging messages on the PO. When the WUS mechanism is enabled, the UE monitors the following possible paging messages in the PO in response to the UE detecting the WUS, so that the physical downlink control channel (PDCCH) blind detection can be performed. On the other hand, when the WUS mechanism is enabled, the UE will not monitor the following paging messages in the PO in response to the UE not detecting any WUS.

[0004] In some other communication systems, such as the 3rd Generation Partnership Project (3GPP) 5G system, which may also be referred to as a New Radio (NR) system, an additional reference signal (RS) similar to the WUS may be introduced to save power. However, due to the differences between these systems (e.g., LTE system and NR system), a technique for applying an additional RS in, for example, an NR system is desired. Summary of the invention

[0005] One object of an embodiment of the present application is to provide a solution for applying RS associated with a paging message in a wireless communication system.

[0006] Some embodiments of the present disclosure provide a method. The method may include: receiving, at a first base station, assistance information related to a user equipment (UE) group from a second base station; and determining whether to transmit a reference signal (RS) associated with a paging message for the UE based on the assistance information.

[0007] Some embodiments of the present disclosure provide a method. The method may include: transmitting, at a second base station, assistance information related to a user equipment (UE) group to a first base station.

[0008] Some embodiments of the present disclosure provide a method. The method may include: receiving, at a second base station, from a first base station, an indication of completion of data transmission between a user equipment (UE) and the first base station, wherein the second base station is a last serving station for the UE.

[0009] Some embodiments of the present disclosure provide a method. The method may include: receiving a path switch request message indicating a cell associated with a base station, wherein the cell is a serving cell of a user equipment (UE); and in response to the receiving of the path switch request message, updating a cell list on which the UE monitors a reference signal (RS) associated with a paging message for the UE.

[0010] Some embodiments of the present disclosure provide a method. The method may include: receiving an indication of completion of data transmission between a user equipment (UE) and a first base station from a second base station, wherein the second base station is a last serving base station of the UE.

[0011] Some embodiments of the present disclosure provide a method. The method may include: at a user equipment (UE), monitoring a reference signal (RS) associated with a paging message for the UE based on a UE grouping configuration.

[0012] 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; at least one transmitting circuit; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuit, and the at least one transmitting circuit, wherein the at least one non-transitory computer-readable medium and the computer-executable instructions may be configured to utilize the at least one processor to cause the device to perform the method according to some embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and are therefore not to be considered limiting of its scope.

[0014] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present disclosure;

[0015] Figure 2A A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure;

[0016] Figure 2B A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure;

[0017] Figure 3A A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure;

[0018] Figure 3BA block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure;

[0019] Figure 4 A block diagram illustrating an exemplary WUS resource configuration according to some embodiments of the present disclosure;

[0020] Figure 5 Describe an exemplary procedure for wireless communication according to some embodiments of the present disclosure;

[0021] Figure 6 Describe an exemplary procedure for wireless communication according to some embodiments of the present disclosure;

[0022] Figure 7 Describe exemplary procedures for wireless communication according to some embodiments of the present disclosure; and

[0023] Figure 8 A block diagram illustrating an apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0024] The detailed description of the accompanying drawings is intended as a description of the currently preferred embodiments of the present application, and is not intended to represent the only form in which the present application can be practiced. It should be understood that the same or equivalent functions can be implemented by different embodiments, which are intended to be included in the spirit and scope of the present application.

[0025] Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. For ease of understanding, embodiments under specific network architectures and new service scenarios are provided, such as 3GPP 5G (NR), 3GPP LTE, etc. It is considered that with the development of network architectures and new service scenarios, all embodiments in the present disclosure are also applicable to similar technical problems; and in addition, the terms listed in the present disclosure may be changed, which should not affect the principles of the present disclosure.

[0026] Figure 1 A schematic diagram illustrating a wireless communication system 100 according to some embodiments of the present disclosure.

[0027] like Figure 1 , wireless communication system 100 may include one or more UEs (e.g., UE 110), one or more BSs (e.g., BS 120), and one or more radio access networks (RANs) (e.g., RAN 121). It is contemplated that wireless communication system 100 may include any number of UEs, BSs, networks, and / or network components.

[0028] UE 110 may be any type of device configured to operate and / or communicate in a wireless environment. For example, UE 110 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), a vehicle-mounted computer, a network device (e.g., a router, a switch, and a modem), or the like. According to some embodiments of the present disclosure, UE 110 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identification module, a personal computer, a selective call receiver, or any other device capable of sending and receiving communication signals on a wireless network. In some embodiments of the present disclosure, UE 110 may include a wearable device, such as a smart watch, a fitness bracelet, an optical head-mounted display, or the like.

[0029] In addition, UE 110 may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal or a device, or described using other terms used in the art. The UE may communicate with the BS via uplink or downlink communication signals. Those skilled in the art should understand that with the development and advancement of technology, the terms described in the present disclosure may change, but should not affect or limit the principles and spirit of the present disclosure.

[0030] 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. BS 120 may, for example, operate based on standard protocols such as Long Term Evolution (LTE), LTE-advanced (LTE-A), New Radio (NR), or other suitable protocols. In some embodiments of the present disclosure, BS 120 may be referred to as an access point, an access terminal, a base station, a base station unit, a macro cell, a node B, an evolved node B (eNB), a gNB, a home node B, a relay node, or a device, or described using other terms used in the art. Those skilled in the art should understand that with the development of the Third Generation Partnership Project (3GPP) and communication technology, the terms listed in the specification may change, which should not affect the principles of the present disclosure.

[0031] BS 120 may transmit downlink (DL) communication signals in the time, frequency, and / or spatial domains to serve a UE (e.g., UE 110). The DL communication signals may be carried by a wireless communication link. The wireless communication link may be any suitable carrier in a licensed or unlicensed radio spectrum. The wireless communication link facilitates communication between the UE and the BS.

[0032] BS 120 may be part of RAN 121, which may also include other BSs and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), and relay nodes. BS 120 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 In some cases, the geographic area of ​​a BS may be divided into sectors, each sector constituting a portion of the geographic area. The term "cell" may refer to a portion of a geographic area (e.g., a sector). A BS may be associated with one or more cells.

[0033] RAN 121 can communicate with the core network ( Figure 1 The RAN 121 may employ one of various radio access technologies (RATs), such as an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) radio technology or a NR radio technology. The core network (CN) may include multiple CN 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 Public Switched Telephone Network (PSTN) and / or other networks ( Figure 1 Gateway (not shown).

[0034] The wireless communication system 100 may be compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a network based on time division multiple access (TDMA), a network based on code division multiple access (CDMA), a network based on orthogonal frequency division multiple access (OFDMA), an LTE network, a network based on 3GPP, a 3GPP5G network, a satellite communication network, a high altitude platform network, and / or other communication networks.

[0035] In some embodiments of the present disclosure, the wireless communication system 100 is compatible with the 5G NR of the 3GPP protocol. For example, the BS 120 may transmit data using an OFDM modulation scheme on the DL, and the UE 110 may transmit data using a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) or cyclic prefix-OFDM (CP-OFDM) scheme on the UL. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocols, such as WiMAX and other protocols. The present application is not intended to be limited to any particular wireless communication system architecture or protocol implementation.

[0036] According to some embodiments of the present application, the WUS mechanism can be used to save power when monitoring paging messages in PO. For example, in response to accessing a wireless communication network, the UE can read wireless communication system information to identify the enabled or disabled state of the WUS mechanism. In response to the WUS mechanism being disabled, the UE can always monitor the possible paging messages in the PO calculated by the paging formula. Otherwise, in response to the WUS mechanism being enabled, the UE can detect the WUS before the PO in the time domain, and then monitor the paging messages in the PO based on the detected WUS.

[0037] The PO may be a PO in a discontinuous reception (DRX) mode / extended DRX (eDRX) mode, or may be a dedicated PO distributed in a DRX mode / eDRX mode. In an eDRX cycle in an eDRX mode, a paging transmission window (PTW) may include one or more POs. Multiple short DRXs (sDRXs) may exist in a PTW. In response to a PTW including multiple sDRXs, the number of POs may be offset based on the sDRX cycle. In addition, according to LTE R15, the relationship between WUS and PO may be 1 to N, and N may be 1, 2, or 4. That is, a WUS may be Figure 2A and 2B to a PO as shown in the example, or as Figure 3A and 3B It is mapped to multiple POs as shown in the figure.

[0038] Specifically, Figure 2A A block diagram illustrating mapping of WUSs to POs according to some embodiments of the present disclosure, wherein one WUS is mapped to one PO in eDRX mode.

[0039] like Figure 2A , in one eDRX cycle of the eDRX mode, there are three sDRXs in one PTW, and each WUS is applied to each PO in one sDRX of the PTW. It is well known to those skilled in the art that one PTW of the eDRX mode may include different numbers of sDRXs or POs. Therefore, the number of sDRXs or POs and the number of WUSs mapped to POs may be different from this embodiment of the present application.

[0040] Figure 2B A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure, wherein one WUS is mapped to one PO in DRX mode. Figure 2B As shown in FIG. 4 , in DRX mode, each WUS is applied to each PO in one DRX cycle.

[0041] Figure 3A A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure, wherein one WUS is mapped to multiple POs in eDRX mode.

[0042] like Figure 3A , in one eDRX cycle of the eDRX mode, there are three sDRXs in one PTW. Each sDRX includes one PO, and one WUS may be applied to two POs, i.e., PO1 and PO2 in one PTW of the eDRX mode. In some other embodiments of the present application, one WUS may be applied to all POs in one PTW. In addition, it is well known to those skilled in the art that one PTW of the eDRX mode may include different numbers of sDRXs or POs. Therefore, in different embodiments of the present application, the number of sDRXs or POs and the number of WUSs applied to POs may be different.

[0043] Figure 3B A block diagram illustrating mapping of WUS to PO according to some embodiments of the present disclosure, wherein one WUS may be mapped to multiple POs in DRX mode. Figure 3B As shown in the figure, in two DRX cycles (in Figure 3B In the embodiment of the present application, one WUS is applied to two POs in the DRX mode (denoted as "2DRX" in FIG). It is well known to those skilled in the art that in some other embodiments of the present application, one WUS can be applied to more than two DRX cycles in the DRX mode, for example, one WUS can be applied to three or more POs in the DRX mode.

[0044] LTE R15 specifies that UEs paged in the same PO will be associated with the same WUS. For example, ten UEs paged in the same PO will detect the same WUS. In the case where a specific UE among the ten UEs will be paged by the network (e.g., base station (BS)), the WUS of this specific UE will be sent from the network side to all ten UEs. That is, all ten UEs can receive this WUS of this specific UE. Therefore, although the paging information of the other nine UEs will not be received, the other nine UEs must monitor the paging messages due to the reception of the WUS. Obviously, in this case, at least for the above-mentioned other nine UEs, the purpose of saving power when monitoring the paging messages in the PO cannot be achieved.

[0045] In order to reduce the probability of false wake-up, a group wake-up signal (GWUS) is introduced in 5G New Radio Release 16 (R16) to support grouping of UEs in the WUS mechanism. Each UE group may correspond to a corresponding WUS sequence. Specifically, multiple UEs may be divided into different groups, and a specific WUS or WUS sequence is associated with a specific UE group, and indicates a PO associated with a specific UE group. The number of UE groups may be configured by the network (e.g., a BS or CN entity). For example, the number of UE groups may be broadcast in a system information block (SIB). In some embodiments of the present application, a specific WUS sequence may also be associated with one or more UE groups.

[0046] During the paging process, only UEs within a specific group can monitor the paging message in the PO based on the detected specific WUS, while other UEs not included in this specific group may not monitor the paging message in the PO based on the specific WUS. Therefore, during the paging process, the UE can save more power in the WUS mechanism of the GWUS scheme than when using the traditional R15 WUS scheme.

[0047] In addition, there may be several grouping rules, including but not limited to grouping rules based on UE-ID, grouping rules based on paging probability, or combinations thereof. Under the grouping rule based on UE-ID, the UE may determine its group index or group ID using a modulo operation, e.g., (group ID) = F(UE ID) mod(number of groups), where F(UE ID) represents a function associated with the UE ID.

[0048] Under the grouping rule based on paging probability, UEs with the same or similar paging probability may be grouped in the same UE group. For example, UEs with the same paging probability (e.g., 30%) or with paging probabilities within the same paging probability threshold range (e.g., 0% to 30%, 30% to 60%, or 60% to 100%) may be grouped in the same UE group and thus have the same group index.

[0049] In some embodiments of the present application, both the grouping rule based on UE-ID and the grouping rule based on paging probability can be applied. For example, the grouping based on paging probability information can include another grouping based on UE-ID. That is, the UE can first apply the grouping rule based on paging probability to determine the paging probability group, and then the UE in the paging probability group can continue to apply the grouping rule based on UE-ID to determine the UE group.

[0050] The UE may be configured with different DRX cycle types (e.g., long eDRX, short eDRX, and DRX). For the same PO, the UE may detect the corresponding WUS / GWUS through the DRX gap or the eDRX gap. The eDRX gap may include a short gap corresponding to short eDRX or a long gap corresponding to long eDRX, such as Figure 4 The BS can configure WUS / GWUS resources and WUS / GWUS to different DRX cycles, such as Figure 4 The paging probability threshold information may be common to all UEs with different DRX cycle types. The GWUS allocation for each paging probability threshold or UE-ID based group is gap specific.

[0051] Figure 4 A block diagram illustrating an exemplary WUS resource configuration according to some embodiments of the present application.

[0052] like Figure 4 , for each gap (i.e., long gap of long eDRX, short gap of short eDRX, and DRX gap of DRX), two WUS resources may be configured. WUS resource 2 is a WUS sequence group including WUS sequence 0 to WUS sequence m before WUS resource 1 in the time domain. WUS sequence 0 to WUS sequence m in WUS resource 2 may be code-multiplexed with each other. In some embodiments of the present application, there may be 16 WUS sequences code-multiplexed on the WUS resource. Each WUS sequence may be associated with at least one UE group.

[0053] WUS resource 1 includes R15 WUS and WUS sequence groups from WUS sequence 0 to WUS sequence n. In some embodiments of the present application, WUS sequence 0 to WUS sequence n in WUS resource 1 may be code multiplexed with each other and may be multiplexed with R15 WUS in the frequency domain. In some embodiments of the present application, R15 WUS and WUS sequence 0 to WUS sequence n in WUS resource 1 may be code multiplexed with each other. Each WUS sequence may be associated with at least one UE group.

[0054] In the following embodiments, the term "WUS" used may mean WUS or GWUS.

[0055] When configured in a cell, UEs (including but not limited to NB-IoT UEs, low complexity (BL) UEs with reduced bandwidth, and UEs in enhanced coverage) may use WUS to reduce power consumption associated with paging monitoring. In some embodiments of the present application, the UE may monitor the WUS in each cell. In some embodiments of the present application, in order to avoid waking up other UEs due to, for example, the network (e.g., MME) paging a specific UE across multiple cells, the use of WUS is limited to the last visited cell of the specific UE. The process may be implemented as follows.

[0056] For each WUS-capable UE, a BS supporting WUS may provide a list of recommended cells for paging in, for example, an S1 Application Protocol (S1-AP) UE Context Release Complete message or an S1-AP UE Context Suspend Request message to the CN (e.g., MME). When the CN (e.g., MME) receives a list of recommended cells for a particular UE, it may include the latest list of recommended cells for the particular UE in a paging message (e.g., an S1-AP paging message). The BS may receive the list of recommended cells in the paging message and may indicate the WUS only in the first cell of the list (e.g., the last visited cell of the particular UE). Otherwise, if the BS does not receive such a list, it may not indicate the WUS for the particular UE. The UE may monitor the WUS only in its last visited cell (i.e., the cell in which the UE was last released or suspended by the BS containing the cell).

[0057] In an NR system, from the network's perspective, the UE may be in one of the following states: RRC-IDLE state, RRC_CONNECTED state, and RRC_INACTIVE state at a given time. Thus, the UE may be in an idle mode corresponding to the RRC_IDLE state, an inactive mode corresponding to the RRC_INACTIVE state, or a connected mode corresponding to the RRC_CONNECTED state. The specific characteristics of the RRC-IDLE state, the RRC_CONNECTED state, and the RRC_INACTIVE state are defined in the 3GPP specifications.

[0058] In the RRC_IDLE state, there is no UE context for the idle UE in the RAN. In addition, the idle UE does not have a connection with the CN (e.g., AMF) via the BS. When the CN wants to exchange data or signaling with the idle UE, the CN may trigger a paging procedure (e.g., S1 paging) for the idle UE.

[0059] In the RRC_INACTIVE state, the inactive UE does not have an RRC connection with the RAN. However, RRC_INACTIVE is a state in which the UE remains in CM-CONNECTED and can move within an area configured by the RAN (e.g., NG RAN) without notifying the RAN. In other words, the transition from the RRC_CONNECTED state to the RRC_INACTIVE state is not notified to the CN. Therefore, even when the UE is in inactive mode, the CN can regard it as being in connected mode, that is, the signaling and user data connection associated with the UE between the CN and the RAN continues. When the last serving BS of the inactive UE (however, from the CN's perspective, this BS is the current serving BS of the UE) receives signaling or data of the inactive UE, it can trigger a paging procedure (e.g., RAN paging) for the inactive UE. Paging can be performed in a RAN-based Notification Area (RNA). The RNA can consist of one or more cells and can be configured to the UE when, for example, the UE is commanded to enter the inactive state. When the inactive UE moves out of the configured RNA, it may need to perform an RNA update procedure. RNA and RAN paging allow inactive UEs to move around in an area without notifying the network.

[0060] In order to improve power saving for idle UEs and inactive UEs, a reference signal (RS) associated with UE paging (also referred to as an "additional RS") may be introduced. The additional RS may be similar to the WUS signal in some aspects. The grouping rules may also be applied to the additional RS. The details of the description of the WUS in all the foregoing embodiments of the present disclosure apply to the additional RS. The WUS may be considered a type of additional RS.

[0061] However, the WUS mechanism does not take into account certain scenarios, such as the involvement of inactive UEs or data transmissions that may be initiated by idle or inactive UEs. For example, if a UE only monitors the WUS in its last visited cell, as mentioned above, then when the inactive UE has moved out of its last visited cell, the paging for this inactive UE may be extended to other cells. In this scenario, other UEs that share the same WUS with the inactive UE may be erroneously paged, which may result in false paging alerts to other UEs. This extension may be a serious situation when the inactive UE is paged in the entire tracking area (TA).

[0062] Embodiments of the present disclosure provide solutions for applying RS in wireless communication systems such as NR systems. More details about the embodiments of the present disclosure will be described in the following text in conjunction with the accompanying drawings.

[0063] For inactive UEs that can move around in a configured RNA, a technical solution is needed to maintain a balance between minimizing UE power and false paging alarms. Considering that an inactive UE can move around in an RNA for a long time or between several cells in an RNA, extending the cells of the additional RS that can indicate the inactive UE from the last used cell of the inactive UE to all or several cells in the same RNA can improve paging reachability in a short time. Although some false paging alarms can be generated in the RNA, it is not as serious as TA-level paging extension.

[0064] In some embodiments of the present disclosure, for an inactive UE, the application of an additional RS to the cell of the inactive UE may be extended to all cells in the same RNA as the last used cell of the inactive UE. In other words, all cells in the same RNA as the last used cell of the inactive UE may indicate an additional RS for the inactive UE. In some embodiments of the present disclosure, for an inactive UE, the application of an additional RS to the cell of the inactive UE may be extended to several specific cells in the same RNA as the last used cell of the inactive UE.

[0065] As mentioned above, an inactive UE may have a CN connection in a cell (e.g., cell A) associated with its last serving BS (also referred to as an "anchor BS"). However, in some scenarios, the inactive UE may perform data transmission via another cell (cell B). The data transmission may include at least one of uplink data transmission and downlink data transmission. For example, the inactive UE may initiate uplink data transmission via cell B, establish a RAN connection with cell B, enter connected mode, and then perform data transmission. Alternatively, the inactive UE may initiate uplink data transmission via cell B and remain in inactive mode during the data transmission procedure. An idle UE may act similarly.

[0066] After the data transmission is completed, the inactive or idle UE may receive a pause message or a release message from cell B, and then return to the inactive or idle mode. Alternatively, after the data transmission is completed, the inactive or idle UE may receive a pause message or a release message from cell B, and the UE remains in the inactive or idle mode during the data transmission procedure. In some embodiments of the present disclosure, the pause message or the release message is an RRC message. In some embodiments of the present disclosure, the data size in such data transmission may not be greater than the maximum transmission block (TB) size that can be applied in one transmission defined in the standard protocol. Small data transmission is one of such scenarios.

[0067] In the above scenario, the last serving BS will know that cell B, not cell A, is the last used cell of the inactive UE. In the case where the last serving BS of the inactive UE receives signaling or data of the inactive UE, the last serving BS may trigger a paging procedure for the inactive UE. However, the inactive UE may not be paged in cell A. Therefore, cell B may apply an additional RS to the inactive UE. To achieve this, the last serving BS may transmit auxiliary information to its neighboring BSs, which will be referred to below. Figure 5 Detailed explanation.

[0068] In some embodiments of the present disclosure, the term "last used cell" of a UE may refer to the cell in which the UE was last released or suspended by a BS including or associated with the cell.

[0069] In some embodiments of the present disclosure, the term "last used cell" of a UE may refer to a cell in which the UE was most recently released or suspended by a BS containing the cell or associated with the cell to be idle or inactive, and the ID of the cell can be transmitted to the CN (e.g., AMF or MME) to allow the CN to update the locally stored last used cell for the UE to the cell, and the CN can perform such an update.

[0070] For example, a release message or a suspend message may include an indication that the core network (CN) has successfully updated the last used cell of the UE. Therefore, the UE will know that the cell can be regarded as its last used cell. In some other instances, the release message or the suspend message may include an indication that the core network (CN) has not yet updated the last used cell of the UE, or an indication that the ID of the cell cannot be transmitted to the CN to update the cell to the last used cell. Therefore, the UE will know that the cell cannot be regarded as its last used cell. In some other instances, the last used cell of the UE is the last cell in which the UE has received a release message or a suspend message from a BS related to the CN. In yet other instances, the last used cell of the UE is the last cell in which the UE has received a release message or a suspend message from the BS, and the BS is able to obtain a confirmation that the CN has successfully updated the last used cell of the UE. In some embodiments of the present disclosure, in the above-mentioned procedures and other similar procedures, when the last used cell at the CN is not updated with the actual last used cell at the CN, the UE may regard the last used cell stored at the CN as its last used cell. The UE will detect an additional RS in the cell named as the last used cell at the CN.

[0071] For example, the BS may release or suspend the UE in a specific cell of the BS. However, due to, for example, a disconnection or congestion between the BS and the CN, the release or suspension of the UE may not be successfully notified to the CN. In this case, although the UE may receive a release or suspension message from the BS, the specific cell of the BS is not the last used cell of the UE. In another example, the BS may transmit a path switching request associated with the UE to the CN, and receive a path switching response indicating a successful path switching from the CN. After the BS transmits a release or suspension message to the UE to command it to enter an idle or inactive mode, the current serving cell of the UE becomes the last used cell of the UE. In some embodiments of the present disclosure, in the above-mentioned procedures and other similar procedures, when the last used cell at the CN is not updated with the actual last used cell, the UE may regard the last used cell stored at the CN as its last used cell. The UE will detect additional RSs in the cell named as the last used cell at the CN.

[0072] In other words, the UE may always consider the last used cell stored at the CN as its last used cell, which may be different from or the same as the actual last used cell of the UE, as explained above.

[0073] In some other embodiments of the present disclosure, the suspend message may be replaced by an RRC early data complete message used in a random access message 4 of a UE in an idle mode or an inactive mode. In the scenario, the present disclosure is still applicable to an LTE system or an NR system.

[0074] In some other embodiments of the present disclosure, in the above procedures and other similar procedures, when the last used cell at the CN is not updated with the actual last used cell, the UE may regard the actual last used cell (different from the last used cell stored at the CN) as its last used cell. The UE will detect an additional RS in the actual last used cell.

[0075] Figure 5 An exemplary procedure 500 for wireless communication according to some embodiments of the present disclosure is described. The details described in all the above embodiments of the present disclosure are applicable to Figure 5 The embodiments shown in .

[0076] exist Figure 5 BS 501A and BS 501B are in the same RNA. BS 501A and BS 501B can be used as Figure 1 For example, BS 501B and BS 501B may be eNBs or gNBs.

[0077] At the beginning, the UE may be connected to a specific cell of BS 501B. At a later time, the UE may be ordered by BS 501B to enter an inactive state and may be configured with an RNA. The inactive UE may move around in the RNA and may move out of the specific cell of BS 501B. BS 501B may be considered the last serving BS of the inactive UE, and the specific cell of BS 501B (e.g., cell S) may be considered the last used cell of the inactive UE.

[0078] At some time, BS 501B may receive signaling or data of an inactive UE and may trigger a RAN paging procedure for the inactive UE. For example, BS 501B may transmit an RS associated with a RAN paging message for the inactive UE in the last used cell of the inactive UE. However, the inactive UE may not be successfully paged because it has moved out of cell S. Therefore, paging for this inactive UE may be extended to other cells.

[0079] In some embodiments of the present disclosure, all cells in the same RNA as cell S may transmit RS associated with a RAN paging message for a UE.

[0080] For example, in operation 511, BS 501B may transmit a RAN paging message for the UE to its neighboring BS (eg, BS 501A), which includes cells within the same RNA as cell S. The RAN paging message may be transmitted over an Xn interface. The RAN paging message may include assistance information related to the UE grouping.

[0081] For example, the auxiliary information may include at least one of the following: paging probability information of the UE; and an indication of whether UE grouping for paging is enabled at the UE. The auxiliary information may include UE grouping information. The grouping information may be grouping rule information of the UE. When the indication indicates that UE grouping is enabled, the UE may execute a grouping rule based on UE-ID. When the indication indicates that UE grouping is disabled, the UE may not execute a grouping rule based on UE-ID or any grouping rule. When the auxiliary information includes paging probability information, the UE may execute a grouping rule based on paging probability; otherwise, the UE may not execute a grouping rule based on paging probability. In addition, the UE may execute a grouping rule based on paging probability and a grouping rule based on UE-ID together based on an additional RS configuration. For example, one or more additional RSs having the same paging probability information or sharing other grouping parameters may be associated with a UE group. Sharing grouping parameters means having the same grouping parameters. In this case, the UEs in the UE group may execute grouping based on UE-ID. In some instances, an additional RS may be associated with a UE group or multiple UE groups. When the assistance information includes both the paging probability information and the indication, the UE may perform both the grouping rule based on the paging probability and the grouping rule based on the UE-ID.

[0082] In operation 513, BS 501A may determine to transmit an RS associated with the received paging message for the UE based on the assistance information. For example, BS 501A may determine an RS dedicated to the UE based on the assistance information and transmit the RS in the corresponding cell. The neighboring BS may transmit the RAN paging message to its neighboring BSs so that all cells in the same RNA as the cell S may transmit the corresponding RS associated with the RAN paging message.

[0083] From the perspective of the UE, it can monitor the RS associated with the paging message in all cells within the same RNA as the cell S. The UE can monitor the RS based on the UE grouping configuration (e.g., resource configuration and UE grouping rules). For other cells within different RNAs from the cell S, the UE can monitor the paging message without the RS monitoring procedure. In other words, in these other cells, the UE can assume that the RS associated with the paging message will not be transmitted.

[0084] In some embodiments of the present disclosure, several specific cells in the same RNA as the cell S may transmit RS associated with a RAN paging message for a UE.

[0085] For example, the assistance information may further indicate a list of cells on which the UE monitors the RS. The cell list may contain several recently used cells of the UE, or several most frequently used cells of the UE. In these embodiments, in operation 513, BS 501A may determine whether its cell is listed in the cell list. When it is determined that at least one cell of BS 501A is listed in the cell list, BS 501A may transmit the RS associated with the paging message for the UE in at least one cell based on the assistance information. Otherwise, when it is determined that all cells of BS 501A are not listed in the cell list, BS 501A will not transmit the RS associated with the paging message for the UE.

[0086] From the perspective of the UE, the number of cells in the list may be predefined, for example, in a standard; or the number of cells in the list may be configured by the network (e.g., a BS or CN entity, such as an MME or AMF). Assuming that the number of cells is predefined or configured as N, the UE may record a cell list containing the N most recently used cells or the N most frequently used cells. In some instances, the number N may be equal to 1. The cells in the cell list may be in the same RNA as the cell S. When the UE is in inactive mode, it may monitor the RS associated with the paging message in each cell in the cell list. The UE may monitor the RS based on the UE grouping configuration (e.g., RS resource configuration and UE grouping rules). For other cells in a different RNA from the cell S, or other cells in the same RNA as the cell S but not listed in the above list, the UE may monitor the paging message without an RS monitoring procedure. In other words, in these other cells, the UE may assume that the RS associated with the paging message will not be transmitted.

[0087] In the above embodiment, since all or several specific cells in the same RAN as the last used cell can transmit the corresponding RS to the UE, false paging alarms can be generated in some or all of these cells. In order to reduce false paging alarms, a cell that is not the last used cell of the UE (e.g., a cell of BS 501A) can transmit the corresponding RS to the UE in an RS sequence (corresponding to an RS group) dedicated to mobile UEs. For example, the RS sequence in the RS resource can be indexed from 0 to m, and an RS sequence indexed as p (p is an integer in the range of 0 to m) can be assigned to the mobile UE. The cell of BS 501A can transmit the RS associated with the paging message to the mobile UE on the RS sequence p. In this way, the RS to the mobile UE will not cause a false paging alarm to the UE residing in the cell of BS 501A.

[0088] In some embodiments of the present disclosure, as mentioned above, after BS 501B puts the UE in an inactive state, the inactive UE may initiate data transmission with another BS (e.g., BS#C), which may send the UE back to the inactive mode after the data transmission is completed, or keep the UE in the inactive mode during the data transmission. In these embodiments, the cell S of BS501B may no longer be the last used cell of the UE. Instead, the cell of BS#C (e.g., cell C) that performs data transmission with the UE is the last used cell. Therefore, after BS 501B receives the signaling or data of the UE, in operation 511, BS 501B may transmit a RAN paging message for the UE to its neighboring BS (e.g., BS 501A), which includes a cell within the same RNA as the cell S. The RAN paging message may be transmitted on the Xn interface. The RAN paging message may include auxiliary information related to UE grouping. The auxiliary information may include at least one of the following: paging probability information of the UE; and an indication of whether UE grouping for paging is enabled at the UE. The auxiliary information may include UE grouping information. The grouping information may be grouping rule information of the UE. In some embodiments of the present disclosure, the auxiliary information may further indicate the cell C. In some embodiments of the present disclosure, the auxiliary information may further indicate the cell most frequently used by the UE.

[0089] In operation 513, BS 501A may determine whether it includes cell C based on the assistance information. When it is determined that BS 501A includes cell C, BS 501A may transmit RS associated with a paging message for the UE in cell C based on the assistance information. Otherwise, when it is determined that BS 501A does not include cell C, BS 501A will not transmit RS associated with a paging message for the UE. BS 501A may transmit the RAN paging message to its neighboring BSs until it reaches the BS corresponding to the last used cell of the UE.

[0090] From the perspective of the UE, it can monitor the RS associated with the paging message in the cell it last used. For other cells that are not the last used cell, the UE can monitor the paging message without the RS monitoring procedure. In other words, in these other cells, the UE can assume that the RS associated with the paging message will not be transmitted.

[0091] Those skilled in the art will appreciate that the order of operations in the exemplary process 500 may be changed, and some operations in the exemplary process 500 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0092] Figure 6 An exemplary procedure 600 for wireless communication according to some embodiments of the present disclosure is described. The details described in all the above embodiments of the present disclosure are applicable to Figure 6 The embodiments shown in .

[0093] refer to Figure 6 UE 602 can be used as Figure 1 UE 110 in the BS 601A and BS 601B can be used as Figure 1 BS 120 in the network. For example, BS 601A and BS 601B may be eNBs or gNBs.

[0094] At the beginning, UE 602 may communicate with a BS (e.g., BS 601B). When UE 602 moves out of BS 601B (i.e., the last serving BS), it may perform an RNA update procedure and may switch to a new base station (e.g., BS 601A). At this time, BS 601A is the serving BS of UE 602, and the cell of BS 601A where UE 602 is located (e.g., cell D) is the serving cell of UE 602. After the RNA update procedure is completed, BS 601A may set UE 602 to inactive, and cell D of BS 601A may become the last used cell of UE 602. In this case, the recommended cell list for paging should be updated at CN (e.g., AMF or MME). Otherwise, the cell regarded as the last used cell by UE 602 will be different from the cell recognized by CN as the last used cell of UE 602, and UE 602 may miss paging. The details will be explained below.

[0095] In operation 611, UE 602 may transmit an RRC connection restoration request to BS 601A. In some embodiments, the restoration request may include an identification of UE 602. The identification of UE 602 may be a restoration ID configured by the last serving base station (e.g., 601B) in the RRC release message. The restoration ID may include information about the last serving base station (e.g., BS 601B). In some embodiments, the restoration ID may include an inactive radio network temporary identifier (I-RNTI).

[0096] In operation 613, BS 601A may transmit a request for acquiring a UE context of UE 602 to a last serving base station (e.g., BS 601B) of UE 602. In some embodiments, the request for acquiring a UE context may include an identification of UE 602. In operation 615, BS 601B may transmit a retrieve UE context response message to BS 601A. The retrieve UE context response message may include assistance information related to a UE group of UE 602 and may be transmitted via an Xn interface.

[0097] For example, the auxiliary information may include at least one of the following: paging probability information of UE 602; and an indication of whether UE grouping for paging is enabled at UE 602. The auxiliary information may include UE grouping information. The grouping information may be grouping rule information of the UE. When the indication indicates that UE grouping is enabled, UE 602 may execute a grouping rule based on UE-ID. When the indication indicates that UE grouping is disabled, UE 602 may not execute a grouping rule based on UE-ID or any grouping rule. When the auxiliary information includes paging probability information, UE 602 may execute a grouping rule based on paging probability; otherwise, UE 602 may not execute a grouping rule based on paging probability. In addition, the UE may execute a grouping rule based on paging probability and a grouping rule based on UE-ID together based on an additional RS configuration. For example, one or more additional RSs having the same paging probability information or sharing other grouping parameters may be configured to belong to a UE group. Sharing grouping parameters means having the same grouping parameters. In this case, the UEs in the UE group may execute grouping based on UE-ID. When the assistance information includes both the paging probability information and the indication, the UE 602 may perform both the grouping rule based on the paging probability and the grouping rule based on the UE-ID.

[0098] In operation 617, BS 601A may determine to set UE 602 to inactive or idle. In operation 619, BS 601A may transmit a path switch request of UE 602 to CN 603 (e.g., AMF or MME). The path switch request may indicate a serving cell (e.g., cell D) of UE 602. In some examples, the path switch request may include user location information indicating cell D.

[0099] In response to the path switch request, CN 603 may update a list of cells (eg, a recommended cell list) on which UE 602 monitors the RS associated with the paging message of UE 602. For example, CN 603 may use cell D as the first cell indicated in the cell list.

[0100] In some embodiments of the present disclosure, in operation 621, CN 603 may transmit a path switch request response to BS 601A. In operation 623, BS 601A may transmit a release message or a suspend message to UE 602. The release message or the suspend message may indicate that at CN 603, the last used cell of UE 602 has been updated with the serving cell of UE (e.g., cell D). For example, CN 603 has updated the first cell in the list of recommended cells for paging UE 602 to cell D. In operation 625, BS 601A may transmit a UE context release message to BS 601B.

[0101] In some other embodiments of the present disclosure, the cell list may not be successfully updated at the CN 603. In this case, in operation 621, the CN 603 may transmit a path switch request failure message to the BS 601A. In operation 623, the BS 601A may transmit a release message or a suspend message to the UE 602. The release message or the suspend message may indicate that at the CN 603, the last used cell of the UE 602 has not been updated with the UE's serving cell (e.g., cell D).

[0102] From the perspective of UE 602, it can monitor the RS associated with the paging message in its last used cell (e.g., cell D). By updating the list of recommended cells for paging UE 602 at the CN, when the CN wants to page the UE, the CN can initiate a paging message (e.g., an S1 paging message) to the corresponding BS containing the last used cell of UE 602, and the BS can transmit the RS associated with the subsequent RAN paging message (corresponding to the S1 paging message) for the UE.

[0103] Those skilled in the art will appreciate that the order of operations in the exemplary process 600 may be changed, and some operations in the exemplary process 600 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0104] Figure 7 An exemplary procedure 700 for wireless communication according to some embodiments of the present disclosure is described. The details described in all the above embodiments of the present disclosure are applicable to Figure 7 The embodiments shown in .

[0105] refer to Figure 7 UE 702 can be used as Figure 1 UE 110 in the BS 701A and BS 701B can be used as Figure 1 BS 120 in the network. For example, BS 701A and BS 701B may be eNBs or gNBs.

[0106] At the beginning, UE 702 may communicate with BS 701B (e.g., in cell E) connected to CN 703 (e.g., AMF or MME). BS 701B may make UE 702 inactive or idle. BS 701B may be referred to as the last serving BS of UE 702. In operation 711, UE 702 may initiate data transmission with BS 701A (e.g., in cell F). The data transmission may include a small data transmission. In some examples, UE 702 may establish a RAN connection with BS 701A, enter a connected mode, and then perform a data transmission. After the data transmission is completed, UE 702 may receive a release or suspension message from BS 701A and may enter an idle or inactive mode. In some other examples, UE 702 may establish a RAN connection with BS 701A and then perform a data transmission in an inactive mode. After the data transmission is completed, UE 702 may receive a release or suspension message from BS 701A and may enter an idle or inactive mode. At this point, cell F, rather than cell E, is considered the last used cell of UE 702. UE 702 should monitor the RS associated with the paging message (if configured) and the paging message in cell F.

[0107] However, the CN (e.g., CN 703) may only recognize cell E as the last used cell of UE 702, and may not know BS 701A and the actual last used cell of UE 702, i.e., cell F. Therefore, the recommended cell list at the CN may not be updated. BS 701A may not transmit the RS associated with the paging message for UE 702 in cell F because cell F is not included in the recommended cell list received via the Xn interface. Therefore, UE 702 may miss the paging message because the associated RS is not detected. To solve this problem, the CN should be notified of the update of the last used cell of UE 702.

[0108] For example, refer to Figure 7 In operation 713, BS 701A may transmit an indication of completion of data transmission between UE 702 and BS 701A to BS 701B. The data transmission may include at least one of uplink data transmission or downlink data transmission.

[0109] The indication of data transfer completion may indicate at least one of the following:

[0110] (1) Indication of the end of data transmission;

[0111] (2) UE 702 has received a release message or a suspend message from BS 701A;

[0112] (3) UE 702 has successfully received a release message or a suspend message from BS 701A;

[0113] (4) BS 701A has transmitted a release message or a suspend message;

[0114] (5) BS 701A has successfully transmitted a release message or a suspend message;

[0115] (6) an indication of the end of a quality of service (QoS) flow via a data radio bearer (DRB) associated with the data transmission, wherein the DRB may be an uplink DRB or a downlink DRB;

[0116] (7) Service Data Adaptation Protocol (SDAP) end marker of the QoS flow via the corresponding DRB;

[0117] (8) The end marker of one or more DRBs;

[0118] (9) the end marker of one or more signalling radio bearers (SRBs); and

[0119] (10) The end marker of one or more SRBs and DRBs.

[0120] There are two schemes for notifying the CN 703 of the last used cell of the UE 702 (ie, Figure 7 Scheme A and Scheme B shown in ).

[0121] In scheme A, in operation 715, BS 701B may transmit an indication of completion of data transmission between UE 702 and BS 701A to CN 703. In operation 717, CN 703 may transmit a request to retrieve the context of UE 702 to BS 701B. In operation 719, BS 701B may transmit a response message in response to the request to retrieve the UE context. The response message may indicate the cell (e.g., cell F) in which UE 702 completed the data transmission. In response to receiving the response message, CN 703 may update a list of cells (e.g., a recommended cell list) on which UE 702 monitors the RS associated with the paging message for UE 702. For example, CN 703 may use cell F as the first cell indicated in the cell list.

[0122] In scheme B, in operation 721, BS 701B may transmit a UE context update message to CN 703 in response to an indication of data transmission completion. The UE context update message may indicate a cell (e.g., cell F) in which UE 702 completes data transmission. In response to receiving the UE context update message, CN 703 may update a list of cells (e.g., a recommended cell list) on which UE 702 monitors RS associated with a paging message for UE 702. For example, CN 703 may use cell F as the first cell indicated in the cell list.

[0123] In some examples, in response to receiving data or signaling for UE 702, BS 701A may transmit RS associated with a subsequent RAN paging message for UE 702 only in cell F. In some examples, CN 703 may transmit a paging message for UE 702 based on the updated cell list. For example, the paging message may include an ID of cell F, so that BS 701A transmits RS associated with the paging message for UE 702 only in cell F.

[0124] From the perspective of UE 702, it may monitor the RS associated with the paging message in its last used cell (e.g., cell F), and may monitor the paging message in a cell other than the last used cell without an RS monitoring procedure. In some embodiments of the present disclosure, UE 702 may monitor the RS in a cell in which UE 702 has performed a release procedure or a suspension procedure in response to the reception of a physical layer (PHY) acknowledgment (ACK) corresponding to data transmission. The reception of a PHY ACK corresponding to data transmission may be regarded as the UE having received a release message or a suspension message.

[0125] In some embodiments of the present disclosure, UE 702 may monitor RS in the last used cell of the UE. In some instances, the last used cell of the UE is the last cell in which the UE has received a release message or a suspension message, and the ID of the cell can be transmitted to the core network (CN) to update the cell to the last used cell.

[0126] In some instances, the last used cell of the UE is the last cell for which the UE has received a release message or a suspension message, which indicates that an ID of the cell can be transmitted to a core network (CN) to update the cell to the last used cell, or indicates that the last used cell of the UE has been updated with the serving cell of the UE at the core network entity. Updating the last used cell with the serving cell of the UE at the core network entity means updating the last used cell of the UE at the core network entity by the serving cell of the UE.

[0127] In some instances, the last used cell of the UE is not the last cell for which the UE has received a release message or a suspend message, indicating that the ID of the cell cannot be transmitted to the core network (CN) to update the cell as the last used cell, or indicating that the last used cell of the UE has not been updated with the serving cell of the UE at the core network entity. The last used cell of the UE is not updated with the serving cell of the UE at the core network entity means that the last used cell of the UE at the core network entity is not updated by the serving cell of the UE.

[0128] The release message or suspend message in the present disclosure may also be applied to LTE networks. For example, an idle mode UE in an LTE network may receive a release message or a suspend message from a BS (e.g., an eNB). An idle mode UE in an NR network may receive a release message or a suspend message from a BS (e.g., a gNB). An inactive mode UE in an NR network may receive a release message or a suspend message from its serving BS (e.g., a gNB).

[0129] Those skilled in the art should appreciate that the order of operations in the exemplary process 700 may be changed, and some operations in the exemplary process 700 may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0130] In the above text, a paging message may be a message with PDCCH enhanced paging, wherein UEs may be grouped in the paging message. There may be several ways to indicate UE grouping information, for example, by different paging radio network temporary identities (P-RNTIs) for different groups, by different control resource sets (CORESETs) / search spaces for paging DCIs for different groups, or by an indicator in the paging DCI that explicitly indicates group information. Therefore, a reference signal (RS) associated with a paging message may be for a UE or a group of UEs. In the present disclosure, a UE may be considered as a group of UEs or a UE in a group.

[0131] Figure 8 An example block diagram illustrating an apparatus 800 according to some embodiments of the present disclosure. In some embodiments of the present application, the apparatus 800 may be a BS as described in the above embodiments of the present application. In some embodiments of the present application, the apparatus 800 may be a CN entity (e.g., AMF or MME) as described in the above embodiments of the present application. In some embodiments of the present application, the apparatus 800 may be a UE as described in the above embodiments of the present application.

[0132] refer to Figure 8, the device 800 may include at least one non-transitory computer-readable medium 802, at least one receiving circuit 804, at least one transmitting circuit 806, and at least one processor 808. In some embodiments of the present application, the at least one receiving circuit 804 and the at least one transmitting circuit 806 may be integrated into at least one transceiver. At least one processor 808 may be coupled to at least one non-transitory computer-readable medium 802, at least one receiving circuit 804, and at least one transmitting circuit 806. In some embodiments of the present disclosure, the device 800 may further include an input device, a memory, and / or other components.

[0133] In some embodiments of the present disclosure, at least one non-transitory computer-readable medium 802 may store computer-executable instructions thereon to enable at least one processor 808 to implement the operations, steps, or methods described above with respect to the UE. For example, when the computer-executable instructions are executed, the at least one processor 808 interacts with at least one receiving circuit 804 and at least one transmitting circuit 806 to perform the operations, steps, or methods described above with respect to the UE. Figures 1 to 7 In some examples, at least one processor 808 may monitor the RS associated with the paging message based on the UE grouping configuration. At least one receiving circuit 804 may receive the RS based on the UE grouping configuration and may receive a subsequent paging message.

[0134] In some embodiments of the present disclosure, at least one non-transitory computer-readable medium 802 may store computer-executable instructions thereon to enable at least one processor 808 to implement the operations, steps, or methods related to the BS as described above. For example, when the computer-executable instructions are executed, the at least one processor 808 interacts with at least one receiving circuit 804 and at least one transmitting circuit 806 to perform the operations related to the BS. Figures 1 to 7 The steps of BS are depicted in FIG.

[0135] In some instances, at least one receiving circuit 804 may receive assistance information related to the UE group from the BS. At least one processor 808 may determine whether to transmit an RS associated with a paging message for the UE based on the assistance information. In some instances, at least one transmitting circuit 806 may transmit the assistance information related to the user equipment (UE) group to the BS. In some instances, at least one receiving circuit 804 may receive an indication of completion of data transmission between the UE and the base station.

[0136] In some embodiments of the present disclosure, at least one non-transitory computer-readable medium 802 may store computer-executable instructions thereon to enable at least one processor 808 to implement the operations, steps, or methods described above with respect to the CN entity. For example, when the computer-executable instructions are executed, the at least one processor 808 interacts with at least one receiving circuit 804 and at least one transmitting circuit 806 to perform operations with respect to the CN entity. Figures 1 to 7 The steps of BS described in .

[0137] In some instances, at least one receiving circuit 804 may receive a path switch request message. The path switch request message may indicate a cell associated with the base station, wherein the cell is a serving cell of the UE. In response to the path switch request message, at least one processor 808 may update a list of cells on which the UE monitors RS associated with a paging message for the UE. In some instances, at least one receiving circuit 804 may receive an indication of completion of data transmission between the UE and the base station from another base station, wherein the other base station is the last serving base station of the UE.

[0138] Those of ordinary skill in the art will appreciate that the 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 steps of the methods may reside as one or any combination or set of codes and / or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

[0139] Although the present disclosure has been described with specific embodiments of the present disclosure, it is apparent that many alternatives, modifications and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added or replaced in other embodiments. In addition, 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 as set forth herein are intended to be illustrative, not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0140] In this document, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device containing a list of elements not only contains those elements, but may contain other elements that are not explicitly listed or inherent to this process, method, article or device. Elements beginning with "one", "an" or the like do not exclude the presence of additional identical elements in the process, method, article or device containing the elements without more restrictions. In addition, the term "another" is defined as at least a second or more. The terms "having" and the like as used herein are defined as "comprising".

Claims

1. A method performed by a user equipment UE, comprising: monitoring a signal associated with a paging message for the UE based on the UE group configuration, so that the UE can monitor the paging message based on the signal; wherein the UE monitors the signal in the cell last used by the UE; The last used cell of the UE is not the last cell for which the UE has received a release message or a suspend message, the release message or the suspend message indicating that the last used cell of the UE has not been updated with the serving cell of the UE at the core network CN, and the last used cell of the UE is the last used cell of the UE stored at the CN.

2. The method according to claim 1, wherein when the UE is in an inactive mode, the UE monitors the signal in all cells within a same radio access network-based notification area RNA.

3. The method of claim 1, wherein when the UE is in an inactive mode, the UE monitors the signal in a number of cells within the same radio access network based notification area RNA as the last used cell of the UE.

4. A user equipment UE, comprising: Receiving circuit; Transmission circuit; and a processor, coupled to the receiving circuit and the transmitting circuit, configured to cause the UE to: monitoring a signal associated with a paging message for the UE based on the UE group configuration, so that the UE can monitor the paging message based on the signal; wherein the UE is configured to monitor the signal at a last used cell of the UE; The last used cell of the UE is not the last cell for which the UE has received a release message or a suspend message, the release message or the suspend message indicating that the last used cell of the UE has not been updated with the serving cell of the UE at the core network CN, and the last used cell of the UE is the last used cell of the UE stored at the CN.

5. The UE of claim 4, wherein when the UE is in an inactive mode, the UE monitors the signal in a number of cells within the same radio access network based notification area RNA as the last used cell of the UE.

6. The apparatus of claim 4, wherein when the UE is in an inactive mode, the UE monitors the signal in all cells within a same radio access network-based notification area (RNA).

7. A processor of a user equipment (UE) for wireless communication, the processor being configured to cause the UE to: monitoring a signal associated with a paging message for the UE based on the UE group configuration, so that the UE can monitor the paging message based on the signal; wherein the UE is configured to monitor the signal at a last used cell of the UE; The last used cell of the UE is not the last cell for which the UE has received a release message or a suspend message, the release message or the suspend message indicating that the last used cell of the UE has not been updated with the serving cell of the UE at the core network CN, and the last used cell of the UE is the last used cell of the UE stored at the CN.

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