Serving cell as additional candidate for mobility management

Abstract

Techniques described herein include solutions for some aspects of configuration and signaling of candidate cells or groups of cells. After completion of the cell change, a user equipment (UE) does not release but maintains candidate configurations of remaining candidate cells for a subsequent cell change procedure. In addition, a candidate configuration of a source cell or group of cells may be added as an additional candidate configuration for a subsequent cell change procedure such that the source cell may be reused if the UE moves back to the corresponding coverage area.

Description

Technical Field

[0001] The present disclosure relates to wireless communication networks, including techniques for using serving nodes as candidate nodes for mobility management (such as L2 mobility or secondary node handover). Other aspects and techniques are also described. Background Art

[0002] Wireless communication networks provide an integrated communication platform and telecommunications services to wireless user equipment. Example telecommunications services include telephony, data (e.g., voice, audio, and / or video data), messaging, Internet access, and / or other services. Wireless communication networks have wireless access nodes that exchange wireless signals with wireless user equipment using wireless network protocols (such as those described in various telecommunications standards promulgated by the 3rd Generation Partnership Project (3GPP)). Example wireless communication networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal Frequency Division Multiple Access (OFDMA) networks, Long Term Evolution (LTE), and 5th Generation New Radio (5G NR). Wireless communication networks use techniques such as OFDM, Multiple-Input Multiple-Output (MIMO), advanced channel decoding, massive MIMO, beamforming, and / or other features to facilitate mobile broadband services. Brief Description of the Drawings

[0003] The present disclosure will be readily understood and implemented through the detailed description and the drawings. The same reference numerals may designate the same features and structural elements. The drawings and the corresponding description are provided as non-limiting examples of aspects, embodiments, etc. of the present disclosure, and the reference to "one" or "a" aspect, embodiment, etc. may not necessarily refer to the same aspect, embodiment, etc., and may mean at least one, one or more, etc.

[0004] Figure 1 is a schematic diagram illustrating a cell change procedure in a wireless network system for using a source node as a candidate for a subsequent cell change of a User Equipment (UE) according to some aspects of the present disclosure.

[0005] Figure 2 is a schematic diagram illustrating a signaling example of a cell change procedure for L2 mobility for applying the candidate configuration techniques described herein according to some aspects of the present disclosure.

[0006] Figure 3 is a schematic diagram respectively illustrating a signaling example of a cell change procedure for SN handover for applying the candidate configuration techniques described herein according to some aspects of the present disclosure.

[0007] Figure 4 is a configuration example for including serving cell candidates for subsequent cell change using an implicit indication in configuration information according to some aspects of the present disclosure.

[0008] Figure 5 is an example of assigning a fixed candidate configuration ID to a serving cell candidate according to some aspects of the present disclosure.

[0009] Figure 6 Provides an example of assigning a dedicated candidate configuration ID to a serving cell candidate according to some aspects of the present disclosure.

[0010] Figures 7A to 7B Illustrates an example of the configuration of a serving cell and a candidate list for L2 mobility according to some aspects of the present disclosure.

[0011] Figure 8 Illustrates another example of the configuration of a serving cell and a candidate list for SN handover according to some aspects of the present disclosure.

[0012] Figure 9 Illustrates another configuration example of using an implicit indication in configuration information to include serving cell candidates for subsequent cell changes according to some aspects of the present disclosure.

[0013] Figure 10 Illustrates a configuration example of using an explicit candidate configuration of a serving cell candidate according to some aspects of the present disclosure.

[0014] Figures 11 to 12 Illustrates a configuration example of using a mixture of implicit and explicit candidate configurations of a serving cell candidate according to some aspects of the present disclosure.

[0015] Figure 13 Is a schematic diagram illustrating signaling for communicating UE capabilities information including serving cell candidates between a base station and a UE according to some aspects of the present disclosure.

[0016] Figure 14 Is a block diagram illustrating a device that can be used to perform gapless UE measurements according to some aspects of the present disclosure.

[0017] Figure 15 Is a block diagram illustrating a baseband circuit that can be used to perform gapless UE measurements according to some aspects of the present disclosure.

[0018] Figure 16 Is a process flow of a cell change procedure for a UE to use a serving node as a candidate for subsequent cell changes according to some aspects of the present disclosure.

[0019] Figure 17 Is a process flow of a cell change procedure for a base station (BS) to configure a serving node as a candidate for subsequent cell changes according to some aspects of the present disclosure. Detailed Description

[0020] The present disclosure is described with reference to the accompanying drawings. Like reference numerals throughout are used to indicate like elements. The accompanying drawings are provided solely for illustrating the present disclosure. Several aspects of the present disclosure are described below with reference to example applications for illustration. Numerous specific details, relationships, and methods are set forth to provide an understanding of the present disclosure. The present disclosure is not limited by the order of the actions or events illustrated, as some actions may occur in a different order and / or concurrently with other actions or events. In addition, not all of the actions or events illustrated are necessary for implementing the method according to the selected aspect of the present disclosure.

[0021] A wireless communication network includes mobile devices capable of communicating with base stations, which further connect these mobile devices to a core network or other network devices. The base stations include cells to support coverage of various geographical areas. The evolution of wireless communication requires continuously enhanced robust mobility performance with low latency and high reliability. Mobility management in a mobile network provides service continuity to mobile devices. When a mobile device moves from the coverage area of one cell (referred to as a source cell) to another cell (referred to as a target cell), a cell change is sought to avoid link degradation or even termination. In some aspects, the cell change can be, for example, a handover from the source cell to the target cell, or a handover from the source node to the target node, including at least a handover of the primary cell (PCell). As another example, for the dual connectivity (DC) case, the cell change can also be a master node (MN) handover or a secondary node (SN) handover.

[0022] Cell change has traditionally been based on layer 3 (L3) measurements and radio resource control (RRC) signaling. In Release 18 of 3GPP, layer 1 (L1) / layer 2 (L2)-based cell change without RRC reconfiguration was introduced to reduce the latency, overhead, and interruption time associated with RRC signaling for L3-based mobility management. During operation, L1 / L2 measurements are performed and reported. If the L1 / L2 measurements meet the mobility change conditions, corresponding cell change actions can be executed to switch from the serving cell to the target cell, or from the serving cell group to the target cell group. The target cell or the target cell group is selected from a list of candidate cells or cell groups configured by the network. Since the list of candidate cells or cell groups is not reconfigured for each L1 / L2-based cell change, a mechanism for maintaining and / or updating the list of candidate cells or cell groups needs to be studied.

[0023] Accordingly, some aspects of the present disclosure relate to the configuration and signaling of candidate cells or cell groups. After a cell change is completed, the user equipment (UE) does not release but maintains the candidate configurations of the remaining candidate cells for subsequent cell change procedures. Additionally, the candidate configuration of the source cell or cell group may be added as an additional candidate configuration for subsequent cell change procedures, such that if the UE moves back to the corresponding coverage area, the source cell can be reused.

[0024] In some aspects, the serving configuration of the source cell or cell group is considered a candidate configuration. For example, the serving configuration of the source cell or cell group may always be assumed to be a candidate configuration, or may only be assumed to be a candidate configuration if the UE is configured as such based on an implicit indicator from the network. In some other aspects, the source cell or cell group is explicitly configured by the network as a candidate. In one example, the explicit configuration may identify the complete cell or cell group configuration as the candidate configuration. In another example, the explicit configuration may include a differential configuration that references the serving configuration of the source cell or cell group, and the candidate configuration may be derived from the differential configuration and the serving configuration. Other aspects and details of the present disclosure are further described below with respect to the figures.

[0025] Figure 1 An overview of the cell change procedure of the network system 100 according to various aspects is provided. The network system 100 includes a UE 101 and a radio access network (RAN) 110. The UE 101 may be configured to connect to the RAN 110, e.g., communicatively coupled. The RAN 110 may include one or more base stations (BS or access nodes), such as Figure 1 the BSs 111-1, 111-2, 111-C1, 111-C2 shown in

[0026] As an example scenario for illustrative purposes, the UE 101 is initially connected to the source BS 111-1, as shown in action 124. The UE 101 receives configuration information that includes the configuration of the serving cell group and candidate cells for mobility management, as shown in action 122. For the DC case, the configuration information may be sent by the source BS 111-1 or another BS such as the MN. The configuration information may be sent via RRC signaling and then used by multiple subsequent cell change procedures without involving additional RRC reconfigurations. Thus, the configuration information is used not only for the first cell change but also for subsequent cell changes such as L2 mobility changes or SN handovers. As illustrated in more detail below, in some aspects, the serving configuration of the serving cell may be used as a candidate configuration for subsequent cell changes. In some alternative aspects, the serving configuration of the serving cell may be used as a reference for the candidate configuration, and a differential configuration is applied to the serving cell configuration in order to derive the candidate configuration.

[0027] When the UE 101 moves away from the geographical coverage area of the source BS 111-1, for example, from the first position P1 to the second position P2 which is farther away from the source BS 111-1, the UE 101 experiences link degradation due to its distance from the source BS 111-1. The second position P2 may be better covered by one or more other BSs which can be referred to as candidate BSs. After performing measurements on the candidate BSs, a decision may be made to perform a first cell change to move the UE connection from the source BS 111-1 to the target BS 111-2, as shown in action 126. The target BS 111-2 is selected from the list of candidate BSs configured for the UE 101 using the configuration information provided at action 122.

[0028] As shown in action 127, after the first cell change at action 126, instead of releasing the configuration information of the remaining candidate BSs and receiving new candidate cell configurations, the UE 101 maintains the configuration information of the remaining candidate BSs and performs L1 / L2 measurements and control / activation for subsequent cell changes, so as to reduce the latency, overhead, and interruption time associated with RRC signaling for L3-based mobility management. In addition, the source BS 111-1 may be added as an additional candidate to the configuration information for subsequent cell changes, such that if the conditions are met, the source BS 111-1 can be the new target cell for this subsequent cell change. In some aspects, the additional candidate configuration may use the same serving cell configuration of the source BS 111-1. In some other aspects, the additional candidate configuration may be based on the serving cell configuration of the source BS 111-1 as a reference and apply configuration changes to derive the candidate configuration of the source BS 111-1. The derived candidate configuration cannot be accessed by the previous serving cell and thus can provide improved security.

[0029] When the UE 101 moves away from the geographical coverage area of the target BS 111-2, for example, from the second position P2 to the third position P3, the third position P3 may be better covered by one or more other candidate BSs. As mentioned above, one or more other candidate BSs may include the previous serving cell as an additional candidate, for example, the previous source BS 111-1. After performing measurements on the candidate BSs, a decision may be made to perform a subsequent cell change to a new target BS which is selected from the candidate BSs configured for the UE 101 (such as candidate BS 111-C1 or the previous source BS 111-1).

[0030] As used herein, terms such as "UE" or "mobile device" may describe equipment that can include any wireless computing device, such as consumer electronic devices, cellular phones, smart phones, feature phones, tablet computers, wearable computing devices, personal digital assistants (PDAs), pagers, wireless handheld devices, desktop computers, laptop computers, in-vehicle infotainment (IVI), in-vehicle entertainment (ICE) devices, instrument clusters (IC), head-up display (HUD) devices, on-board diagnostic (OBD) devices, in-vehicle mobile equipment (DME), mobile data terminals (MDT), electronic engine management systems (EEMS), electronic / engine control units (ECU), electronic / engine control modules (ECM), embedded systems, microcontrollers, control modules, engine management systems (EMS), networked or "smart" home appliances, machine type communication (MTC) devices, machine-to-machine (M2M) and / or Internet of Things (IoT) devices, etc. Relative to an access node or BS of the RAN, a UE can be "mobile" or "wireless". A UE can be referred to as a processor and / or other parts of a device or equipment that is a fixed device of a removable carrier and is not necessarily mobile or without communication wires itself.

[0031] As used herein, terms such as "BS", "access node", "access point", or "base station" may describe equipment that provides radio baseband functionality for data and / or voice connectivity between the RAN 110 and one or more users. The RAN 110 can operate in an NR or 5G system, an LTE or 4G system, and / or other traditional or advanced wireless systems. The access nodes in the RAN 110 can be inter-radio access technology (RAT), and can alternatively be referred to as BS, gNodeB, gNB, eNB, eNodeB, eNB, RAN node, RSU, transmit receive point (TRxP) or TRP, etc., and can include terrestrial stations (e.g., land access points) or satellite stations that provide coverage within various geographical areas (e.g., cells). According to various aspects, a BS can be implemented as one or more physical devices such as macrocell base stations and / or low-power (LP) base stations for providing femtocells, picocells, or other similar cells with a smaller coverage area, a smaller user capacity, or a higher bandwidth compared to macrocells.

[0032] Figures 2 to 3FIG. is a schematic diagram illustrating signaling examples of L2 mobility and SN handover for cell change procedures that apply the candidate configuration techniques described herein. In some aspects, a subsequent cell change can be, for example, an L2-based cell handover from a source primary cell (PCell) to a target PCell. In other aspects, the cell change can be a handover between a master node (MN) and a master cell group (MCG) and / or a change or addition between a secondary node (SN) and a secondary cell group (SCG). In some aspects, the candidate configuration can include a conditional trigger configuration such that a conditional handover (CHO), a conditional PSCell change (CPC), or a conditional PSCell addition (CPA) can be triggered or executed when the corresponding condition is met.

[0033] As Figure 2 shown in the example of, sequential L1 / L2 cell changes between candidates can be supported without RRC reconfiguration. As shown in action 124, UE 101 communicates data with source BS111-1. As shown in action 122, UE 101 receives configuration information from the network, the configuration information including configurations of serving cell groups and candidate cells for cell change. In some aspects, the configuration information can be sent by source BS111-1. In some alternative aspects, the configuration information can be received from another previous BS and maintained by UE101. In some aspects, the configuration information is conveyed via an RRC reconfiguration message or a cell group configuration message. The configuration information can be conveyed via RRC signaling and used by multiple subsequent cell change procedures without involving additional RRC-based reconfigurations. Thus, for example, the configuration information is used not only for the first cell change but also for subsequent L2 cell handovers.

[0034] As shown in action 126, after performing measurements on the candidate cell, if the handover condition is met, a decision can be made to perform a first cell change to target BS111-2. As described in connection with action 122, target BS111-2 is selected from the list of candidate BSs provided to UE 101 in the configuration information.

[0035] As shown in action 127, after the first cell change at action 126, UE 101 maintains configuration information including the candidate configuration of the remaining candidate BSs for subsequent cell changes instead of releasing the configurations of the remaining candidate BSs and receiving new candidate cell configurations. In addition, the configuration of source BS111-1 is added as an additional candidate configuration for subsequent cell changes. In some aspects, the additional candidate configuration can use the same serving cell configuration of source BS111-1. In some other aspects, the additional candidate configuration can be a differential candidate configuration that is based on the serving cell configuration of source BS111-1 as a reference configuration. The differential candidate configuration can indicate the configuration changes used to derive the candidate configuration of source BS111-1.

[0036] As shown in operation 210, UE 101 continues to perform L1 / L2 measurements on the reference signals received from the candidate cells for subsequent cell changes. The candidate cells are configured by the configuration information at operation 122 and include the candidate configurations of the source BS111-1 as additional candidates. The measurements can be periodic or in response to a control signal received from the target BS111-2, as shown in operation 208. For example, the control signal can be sent via MAC-CE.

[0037] As shown in operations 211 and 213, if the subsequent cell change conditions are met, UE 101 or the target BS111-2 can request or indicate a subsequent cell change. As shown in operation 212, the cell change request from UE 101 can be sent together with the reported measurement results or separately. The target BS111-2 can determine the cell change in response to the cell change request and / or measurement report received from UE 101. If the source BS111-1 meets the subsequent cell change conditions, the previous source BS111-1 can be selected as the new target BS.

[0038] As shown in operation 128, the subsequent cell change can be performed by switching the connection of UE 101 from the previous target BS111-2 to the new target BS, which can be the previous source BS111-1 or a different candidate BS111-C1 or 111-C2, as Figure 1 shown. After sending the instruction for the subsequent cell change, the subsequent cell change can be initiated by the previous target BS111-2. Alternatively, after receiving the instruction confirmation sent by UE 101, the subsequent cell change can be initiated by the target BS111-2.

[0039] As Figure 3 shown in the example of, subsequent SCG changes between candidates can be supported without RRC reconfiguration. At operation 124, UE 101 communicates with the source SN 113-1. The source SN 113-1 can be added or changed while UE 101 is anchored to the MN 112. The MN 112 and the source SN 113-1 are connected via a network interface.

[0040] As shown in operation 122, the candidate configurations of the candidate list for SN switching can be sent by the master node (MN) 112 and received by UE 101. The candidate configurations can be included in the configuration information, which is conveyed via RRC signaling and used by multiple subsequent cell change procedures without involving additional RRC reconfiguration. Thus, the configuration information is used not only for the first cell change but also for subsequent cell changes. In addition, in some aspects, conditional mobility operations such as conditional PSCell addition (CPA) or conditional PSCell change (CPC) can be supported.

[0041] The configuration information received at operation 122 may include configurations of serving cell groups and candidate cells for cell change, such as for SN handover, CPA, or CPC. The configuration information may be sent by the MN 112. In some aspects, the configuration information is conveyed via RRC signaling and used by multiple subsequent cell change procedures without involving additional RRC reconfiguration.

[0042] At operation 126, the UE 101 performs a first cell change to switch to the target SN 113-2. In some aspects, optionally, before performing the first cell change, the UE 101 receives a CPA / CPC command with a trigger condition for the first cell change and does not apply the command until the trigger condition is met, as shown in operation 312. When the trigger condition for the target SN 113-2 is met, at operation 126, the UE 101 performs a cell change to the target SN 113-2.

[0043] At operation 127, in some embodiments, after completing the first cell change to the target SN 113-2, the UE 101 maintains and does not release the candidate configurations in the configuration information, and thus the UE 101 may perform subsequent cell changes without prior CPC / CPA reconfiguration and re-initialization from the network. Thereby, the latency and signaling overhead of cell change (e.g., SCG change) are reduced. In addition, the candidate configuration of the source SN 113-1 is added as an additional candidate configuration for subsequent cell changes. In some aspects, the additional candidate configuration may use the same serving cell configuration of the source SN 113-1. In some other aspects, the additional candidate configuration may be based on the serving cell configuration of the source SN 113-1 as a reference configuration and apply a differential configuration to derive the candidate configuration of the source SN 113-1.

[0044] At operation 128, in some aspects, a subsequent cell change is performed to switch from the target SN 113-2 to a new target SN (not shown in the figure). As illustrated in the figure, in some aspects, optionally, the UE 101 receives a CPA / CPC command with a trigger condition and does not apply the command until the trigger condition is met, as shown in operation 314. When the trigger condition for the new target SN (not shown in the figure) is met, at operation 126, the UE 101 performs a subsequent cell change to switch from the target SN 113-2 to the new target SN.

[0045] The UE can maintain the candidate cell configuration for cell change operations to eliminate the need for L3 reconfiguration, thereby improving efficiency and reducing latency. In one aspect, the UE is pre-configured to always include the serving cell as an additional candidate for subsequent cell change. The serving cell configuration can be used as the candidate configuration for the serving cell as an additional candidate. In other aspects, an implicit indication of using the serving cell as an additional candidate, an explicit candidate configuration for the serving cell as an additional candidate, or a mixture of indication and configuration can be included in the configuration information to indicate or derive the candidate configuration for the serving cell as an additional candidate. Although most examples are given using L2 mobility or SN handover configuration for illustrative purposes, it should be understood that other applicable mobility operations such as CHO, CPC, or CPA are also applicable to the present disclosure.

[0046] Figures 4 to 9 An example of a configuration using an implicit indication in the configuration information to include the current serving cell (e.g., source BS111-1 or source SN 113-1 as described in association with Figures 1 to 3 as an additional candidate for subsequent cell change is illustrated. If the serving cell candidate indicator is presented in the configuration information, the serving cell configuration can be used as the candidate configuration for the serving cell as an additional candidate.

[0047] In Figure 4 examples of parameters related to including the serving cell as an additional cell change candidate are provided. In some aspects, the configuration information for the serving cell as an additional cell change candidate is included in the RRC reconfiguration message. The RRC reconfiguration message includes mobility configuration information elements (IEs), such as for L2 mobility or SN handover. Although L2 mobility configuration is provided in Figure 4 for illustrative purposes, it should be understood that the configurations of other applicable mobility operations can be applied separately but similarly.

[0048] As shown in the first box 402, the L2 mobility configuration IE (e.g., L2mobilityconfiguration) may optionally include candidate addition / modification parameters (e.g., L2MobilityCanididatesToAddModList) and / or candidate removal parameters (e.g., L2MobilityCanididatesToRemoveList). The candidate addition / modification parameter lists the L2 mobility candidate cells to be added or modified. The candidate removal parameter lists the L2 mobility candidate cells to be removed. In some aspects of conditional procedures such as CHO, CPC, or CPA, a conditional parameter attemptCondReconfig is also included. If the conditional parameter is present (e.g., indicated as "true"), a conditional reconfiguration should be triggered. In some other aspects, other parameters such as a trigger configuration ID may be included in the mobility configuration.

[0049] As shown in the second box 404, in some aspects, the L2 mobility configuration IE includes an indicator (e.g., ServingCellAsCandidate) that indicates a candidate configuration for configuring the serving cell as an additional candidate. If the indicator ServingCellAsCandidate is present (e.g., indicated as "true"), the UE treats the current serving node as a candidate. If the indicator ServingCellAsCandidate is not present (e.g., does not exist or is indicated as "false"), the UE does not treat the current serving node as a candidate.

[0050] In some additional aspects also shown in the second box 404, the L2 mobility configuration IE may include a fixed configuration identifier (ID) associated with the serving cell as an additional candidate (e.g., ServingCellCandidateConfigID). The fixed configuration ID is not used by other candidate configurations. The ID pool and ID association remain the same through different mobility handovers. The network may use an RRC reconfiguration message to change the ID.

[0051] Figure 5 Examples of assigning a dedicated candidate configuration ID to a serving cell candidate according to various aspects are provided. Figure 5 In Figure 1 Taking the network system 100 shown as an example. The upper figure shows the assignment of the candidate configuration ID after the first cell change as shown in action 126, while the lower figure shows the assignment of the candidate configuration ID after the second cell change as shown in action 128.

[0052] As with Figure 1As described in connection therewith, when the UE 101 moves away from the source BS 111-1, a decision may be made to perform a first cell change to the target BS 111-2, as shown in action 126. The target BS 111-2 is selected from a list of candidate BSs configured for the UE 101. As an example, the list of candidate BSs includes BSs 111-C1, 111-C2, and 111-2, which are configured as candidate 1, candidate 2, and candidate 3, respectively.

[0053] After the first cell change at action 126, candidate 3 may be removed from the candidate list because the target BS 111-2 is connected to the UE 101. Then, the UE 101 maintains the configurations of the remaining candidate BSs, candidate 1 (111-C1) and candidate 2 (111-C2), instead of releasing the configurations of the remaining candidate BSs, candidate 1 (111-C1) and candidate 2 (111-C2), and receiving all new candidate cell configurations, so as to reduce the latency, overhead, and interruption time associated with RRC signaling for L3-based mobility management. In addition, the source BS 111-1 is added as an additional candidate for subsequent cell changes. A fixed configuration ID (e.g., candidate 4) is assigned to the candidate configuration of the source BS 111-1 as an additional candidate, so that candidate 4 (the candidate configuration of the source BS 111-1) can be considered through subsequent cell changes.

[0054] For example, when the UE 101 moves away from the new source BS 111-2, a decision may be made to perform a second cell change to the new target BS 111-C1. As described above, the new target BS 111-C1 is selected from the candidate list of candidate 1, candidate 2, and candidate 4. Then, for subsequent cell changes, since the new target BS 111-C1 is connected to the UE 101, candidate 1 may be removed from the candidate list. The UE 101 maintains candidate 2 and candidate 4, and adds the candidate configuration of the new source BS 111-2, and assigns a fixed configuration ID (e.g., candidate 5) to the candidate configuration for the new source BS 111-2. Thus, through different mobility handovers, the candidate configuration ID pool and ID association remain the same.

[0055] Figure 6 Examples of assigning dedicated candidate configuration IDs to current serving cell candidates according to various aspects are provided. The current serving cell candidate configuration ID may be set to a dedicated candidate configuration ID (e.g., 0), and this dedicated candidate configuration ID is not used by other candidate configurations. When there is a handover, the candidate configuration IDs are exchanged between the previous target cell and the previous source cell. More specifically, the candidate ID used by the previous target cell will be acquired by the previous source BS, and the previous target cell will now use the dedicated candidate configuration ID as the candidate configuration ID. More specific examples are provided in Figure 6 to illustrate the ID exchange. Figure 6 InFigure 1 Taking the network system 100 shown as an example. The upper figure shows the assignment of candidate configuration IDs after the first cell change as shown in action 126, while the lower figure shows the assignment of candidate configuration IDs after the second cell change as shown in action 128.

[0056] As described in association with Figure 1 When the UE 101 moves away from the source BS111-1, a decision to perform the first cell change to the target BS111-2 can be made. The target BS111-2 is selected from the list of candidate BSs configured for the UE 101. As an example, the list of candidate BSs includes BS111-C1, 111-C2, and 111-2, which are configured as candidate 1, candidate 2, and candidate 3 respectively.

[0057] After the first cell change at action 126, candidate 3 can be removed from the candidate list because the target BS111-2 is connected to the UE 101. Then, the UE 101 maintains the configurations of the remaining candidate BSs, candidate 1 (111-C1) and candidate 2 (111-C2), instead of releasing the configurations of the remaining candidate BSs, candidate 1 (111-C1) and candidate 2 (111-C2), and receiving all new candidate cell configurations, so as to reduce the latency, overhead, and interruption time associated with RRC signaling for L3-based mobility management. Additionally, the source BS111-1 is added as an additional candidate for the second cell change. A dedicated configuration ID (e.g., candidate 0) is assigned to the candidate configuration of the source BS111-1 as an additional candidate, so that the candidate configuration of the source BS111-1 can be considered through subsequent cell changes.

[0058] For example, when the UE 101 moves away from the new source BS111-2, a decision to perform the second cell change to the new target BS111-C1 can be made. As described above, the new target BS111-C1 is selected from the candidate list of candidate 1, candidate 2, and candidate 0. Then, for subsequent cell changes, since the new target BS111-C1 is connected to the UE 101, candidate 1 can be removed from the candidate list. Additionally, the candidate configuration ID candidate 3 used by the previous target BS111-2 is used to identify the previous source BS111-1. The previous target BS111-2 (i.e., the new source BS) now uses the dedicated candidate configuration ID "candidate 0" as the candidate configuration ID of the serving cell. Assigning a dedicated candidate configuration ID to the current serving cell may be less efficient because the candidate configuration ID pool and ID association change through different mobility handovers.

[0059] Figures 7A to 7BIllustrates examples of the serving configuration of a serving cell and the candidate configuration of a candidate list for L2 mobility. For example, the configurations of the serving cell and the candidate list may have IE RRCReconfiguration or IE CellGroupConfig.

[0060] As Figure 7A shown, the serving configuration of the serving cell may include an MCG configuration of the serving cell (e.g., an MCG-D configuration with a serving PCell). The configuration of the candidate list may be included in the candidate list addition / modification parameters (e.g., L2MobilityCanididatesToAddModList) described in association with Figure 4 The configuration of the candidate list may include various MCG configurations associated with candidate configuration IDs. For example, as shown in block 702A, candidate configuration 1 may include a first MCG configuration (an MCG-D configuration with candidate PCell-1); candidate configuration 2 may include a second MCG configuration (an MCG-D configuration with candidate PCell-2); and candidate configuration 3 may include a third MCG configuration (an MCG-D configuration with candidate PCell-3). In some other aspects, other parameters such as a trigger configuration ID, etc. may be included in the mobility configuration. In some aspects of conditional procedures such as CHO, one or more conditional parameters (conditional trigger configuration 1, conditional trigger configuration 2) may also be included and associated with the candidate configuration ID. If the conditional parameters are present, conditional reconfiguration should be triggered.

[0061] As Figure 7B shown, the configuration of the serving cell may include an MCG configuration (e.g., an MCG-D configuration) and an SCG configuration with L2 mobility (e.g., an SCG-E configuration). The candidate configurations of the candidate list may include various SCG configurations associated with candidate configuration IDs. For example, as shown in block 702B, candidate configuration 1 may include a first SCG configuration (an SCG-E configuration with candidate PSCell-1); candidate configuration 2 may include a second SCG configuration (an SCG-E configuration with candidate PSCell-2); and candidate configuration 3 may include a third SCG configuration (an SCG-E configuration with candidate PSCell-3). In some aspects of conditional procedures such as CHO, one or more conditional parameters (conditional trigger configuration 1, conditional trigger configuration 2) may also be included and associated with the candidate configuration ID. If the conditional parameters are present, conditional reconfiguration should be triggered.

[0062] In some aspects, it includes candidate configurations of the serving cell as an additional cell change candidate. For example, as shown in block 704A or 704B, in some aspects, the L2 mobility configuration IE may include an indicator (e.g., ServingCellAsCandidate). The indicator ServingCellAsCandidate is used to indicate using the serving cell as an additional candidate. If the indicator ServingCellAsCandidate is presented (e.g., indicated as "true"), the UE regards the current serving node as a candidate. If the indicator ServingCellAsCandidate is not presented (e.g., does not exist or is indicated as "false"), the UE does not regard the current serving node as a candidate.

[0063] In some additional aspects also shown in block 704A or 704B, the L2 mobility configuration IE may include a fixed configuration identifier (ID) associated with the serving cell as an additional candidate (e.g., ServingCellCandidateConfigID). The fixed configuration ID is not used by other candidate configurations. Through different mobility handovers, the ID pool and ID association remain the same. The network may use the RRC reconfiguration message to change the candidate configuration ID.

[0064] Figure 8 Another example of the serving configuration of the serving cell and the candidate configuration of the candidate list for SN handover according to various aspects is illustrated. For example, the serving configuration of the serving cell may have the IE RRCReconfiguration. For example, the candidate configuration of the candidate list may have the IE RRCReconfiguration or the IE CellGroupConfig. As Figure 8 shown, the configuration of the serving cell may include the MCG configuration (e.g., MCG-D configuration) and the SCG configuration (e.g., SCG-E configuration). The configuration of the candidate list may include various MCG configurations and SCG configurations associated with the candidate configuration ID.

[0065] For example, as shown in block 802, candidate configuration 1 may include an MCG configuration (MCG-A configuration) and a first SCG configuration (SCG-x configuration); candidate configuration 2 may include an MCG configuration (MCG-A configuration) and a second SCG configuration (SCG-y configuration); and candidate configuration 3 may include an MCG configuration (MCG-A configuration) and a third SCG configuration (SCG-z configuration). As another example for SN handover only, the MCG configuration may remain unchanged as MCG-D, and the candidate configurations may only include candidate configurations for the SCG. In some aspects of conditional procedures such as CHO, one or more conditional parameters (conditional trigger configuration 1, conditional trigger configuration 2) may also be included and associated with the candidate configuration ID. If the conditional parameters are presented, conditional reconfiguration should be triggered. The candidate configurations of the candidate list may be included in a candidate addition / modification parameter (e.g., SNSwithchCanididatesToAddModList) described similarly as associated with Figure 4 related.

[0066] In some aspects, candidate configurations including the serving cell as an additional cell change candidate are included. For example, as shown in block 804, in some aspects, the SN handover configuration IE may include an indicator (e.g., ServingCellAsCandidate). The indicator ServingCellAsCandidate is used to indicate using the serving cell as an additional candidate. If the indicator ServingCellAsCandidate is presented (e.g., indicated as "true"), the UE considers the current serving node (e.g., both MCG-D configuration and SCG-E configuration) as a candidate. If the indicator ServingCellAsCandidate is not presented (e.g., does not exist or is indicated as "false"), the UE does not consider the current serving node as a candidate.

[0067] In some additional aspects also shown in block 804, the SN handover configuration IE may include a fixed configuration identifier (ID) associated with the serving cell as an additional candidate (e.g., ServingCellCandidateConfigID). The fixed configuration ID is not used by other candidate configurations. Through different mobility handovers, the ID pool and ID association remain the same. The network may use an RRC reconfiguration message to change the candidate configuration ID.

[0068] Figure 9 Illustrates the use in the configuration information of pairs including the current serving cell (e.g., as associated with Figures 1 to 3Another configuration example of implicitly indicating the source BS 111-1 or source SN 113-1 described in association as an additional candidate for subsequent cell change. In some aspects, configuration parameters can be used as serving cell candidate indicators. For example, for mobility operations involving conditional triggering or execution, such as SN handover or conditional L2 mobility, if a conditional trigger / execution configuration is present in the configuration information without an explicit candidate configuration, this can imply that the source BS (e.g., as described in association with Figures 1 to 3 the source BS 111-1 or source SN 113-1 described in association) is used as an additional candidate for subsequent cell change. Thus, the conditional trigger / execution configuration is used as a serving cell candidate indicator. As shown in block 902, the candidate configuration list 904 can include a conditional trigger configuration (e.g., conditional trigger configuration 2) associated with a candidate configuration ID (e.g., candidate configuration 4), without an explicit candidate configuration. Then, the serving cell configuration (e.g., MCG-D configuration, SCG-E configuration) shown in block 906 can be used as a candidate configuration for the serving cell (e.g., source BS).

[0069] Figure 10 Illustrates a configuration example using an explicit candidate configuration of the current serving cell as an additional candidate. For example, the current serving cell can be the source BS 111-1 or source SN 113-1 described in association with Figures 1 to 3 As shown in block 1002, the explicit candidate configuration (e.g., MCG-D configuration, SCG-E configuration) is included in the candidate configuration list shown in block 1004. The explicit candidate configuration can be associated with a candidate configuration ID (e.g., candidate configuration 4) and can optionally be further associated with a conditional trigger configuration for conditional operation (e.g., conditional trigger configuration 3). In some aspects, the explicit candidate configuration is the same as the serving cell configuration shown in block 1006 (e.g., MCG-D configuration, SCG-E configuration). In other aspects, the explicit candidate configuration is different from the serving cell configuration, although the serving cell is used as an additional candidate cell.

[0070] Figures 11 to 12 Illustrates a configuration example using a mixture of implicit and explicit candidate configurations of the current serving cell as an additional candidate. For example, the current serving cell can be the source BS 111-1 or source SN 113-1 described in association with Figures 1 to 3 In some aspects, the additional candidate configuration can use the serving cell configuration as a reference and apply configuration changes to derive the candidate configuration. The derived candidate configuration is different from the previous serving cell configuration and can thus provide improved security.

[0071] For example, as shown in block 1102, a serving cell candidate indicator (e.g., SouceCellAssumeAsCanddiate: = TRUE) is presented in the configuration information and associated with a sourcecellcandidateconfigID (e.g., candidate configuration 4). The serving cell configuration (e.g., MCG-D configuration, SCG-E configuration) can be used as a reference for the candidate configuration of the current serving cell as an additional candidate. As shown in block 1106, an explicit candidate configuration (e.g., CandidateCellGroupConFigure [differential configuration]) is included in the candidate configuration list 1104. The explicit candidate configuration can be associated with a candidate configuration ID (e.g., candidate configuration 4) and can optionally be further associated with a conditional trigger configuration for conditional operation (e.g., conditional trigger configuration 2). In some aspects, the explicit candidate configuration is a differential candidate configuration. If the candidate configuration ID is the same as the sourcecellcandidateconfigID, then when considered as a candidate, the content in the explicit candidate configuration "replaces" the current serving cell configuration. The candidate configuration can be derived from the serving cell configuration and the differential candidate configuration.

[0072] Figure 13 FIG. is a schematic diagram illustrating signaling for communicating UE capability information between UE 101 and one or more BSs 111-1, 111-2. According to some aspects of the present disclosure, the UE capability information indicates UE capabilities for including the current serving cell as a candidate for subsequent cell changes. In some aspects, BS 111-1 can be a source BS, such as a source gNB for L2 mobility or an MN or source SN for SN handover. BS 111-2 can be a target BS, such as a target gNB or target SN for SN handover. BS 111-2' can be an additional target BS, such as a second target SN for SN handover.

[0073] As shown in action 1302, in some aspects, before receiving the configuration information, UE 101 can send UE capability information to source BS 111-1. The UE capability information includes an indication of whether UE 101 supports using the serving cell as an additional candidate. This indication can be listed separately for different mobility operations. For example, a first indication parameter (e.g., servingCellAsCandidateSupportL2Mobility) can be used to indicate whether UE 101 supports using the serving cell as an L2 mobility candidate. A second indication parameter (e.g., servingCellAsCandidateSupportSNMobility) can be used to indicate whether UE 101 supports using the serving cell as an SN handover candidate.

[0074] As shown by action 1304 and / or action 1304', in some aspects, after receiving UE capability information and before sending configuration information, source BS 111-1 may forward the UE capability information to one or more target BSs 111-2, 111-2'. The UE capability information may be forwarded via a UE capability container.

[0075] As shown by action 1306 and / or action 1306', in some aspects, after receiving UE capability information, target BSs 111-2, 111-2' may send an indication to source BS 111-1 to support the serving cell as an additional candidate. These indications are based on the capability information. In some aspects, target BSs 111-2, 111-2' may also send candidate configurations to source BS 111-1.

[0076] As shown by action 122, source BS 111-1 sends configuration information to UE 101. The configuration information may include serving cell configuration and candidate configurations for a first cell change and subsequent cell changes. Whether the serving cell is configured as an additional candidate for subsequent cell changes is based on the UE capability information. The configuration information may be sent after receiving an indication from at least one of target BSs 111-2, 111-2' to support the serving cell as an additional candidate.

[0077] Figure 14 FIG. is a diagram of an example of components of device 1400 that are in accordance with one or more specific implementations described herein. Device 1400 or its components may be or be included in a UE or a RAN node, such as UE 101 or RAN 110 or BSs 111-1, 111-2, 111-C1, 111-C2, as described throughout this disclosure. In some specific implementations, device 1400 may include at least application circuitry 1402, baseband circuitry 1404, RF circuitry 1406, front-end module (FEM) circuitry 1408, one or more antennas 1410, and power management circuitry (PMC) 1412 coupled together as shown. In some specific implementations, device 1400 may include fewer elements (e.g., a RAN node may not utilize application circuitry 1402 but include a processor / controller to process IP data received from a CN such as 5GC or evolved packet core (EPC)). In some specific implementations, device 1400 may include additional elements, such as, for example, memory / storage, a display, a camera, sensors (including one or more temperature sensors, such as a single temperature sensor, multiple temperature sensors at different locations in device 1400, etc.), or input / output (I / O) interfaces. In other specific implementations, the following components may be included in more than one device (e.g., the circuitry may be separately included in more than one device for cloud-RAN (C-RAN) implementations).

[0078] The application circuitry 1402 may include one or more application processors. For example, the application circuitry 1402 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processor may be coupled to the memory / storage or may include the memory / storage, and may be configured to execute instructions stored in the memory / storage to enable various applications or operating systems to run on the device 1400. In some specific implementations, the processor of the application circuitry 1402 may process IP data packets received from the CN.

[0079] The baseband circuitry 1404 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 1404 may include one or more baseband processors or control logic components to process baseband signals received from the receive signal path of the RF circuitry 1406 and generate baseband signals for the transmit signal path of the RF circuitry 1406. The baseband circuitry 1404 may interact with the application circuitry 1402 to generate and process baseband signals and control the operation of the RF circuitry 1406. For example, in some specific implementations, the baseband circuitry 1404 may include a 3G baseband processor 1404A, a 4G baseband processor 1404B, a 5G baseband processor 1404C, or other baseband processors 1404D for other existing generations, generations under development, or generations to be developed in the future (e.g., 6G, etc.). The baseband circuitry 1404 (e.g., one or more of the baseband processors 1404A to 1404D) may process various radio control functions that enable communication with one or more radio networks via the RF circuitry 1406. In other specific implementations, some or all of the functionality of the baseband processors 1404A to 1404D may be included in modules stored in the memory 1404G and executed via the central processing unit (CPU) 1404E. The radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some specific implementations, the modulation / demodulation circuitry of the baseband circuitry 1404 may include fast Fourier transform (FFT), pre-coding, or constellation mapping / demapping functionality. In some specific implementations, the encoding / decoding circuitry of the baseband circuitry 1404 may include convolutional, tail-biting convolutional, turbo, Viterbi, or low density parity check (LDPC) encoder / decoder functionality. The specific implementations of the modulation / demodulation and encoder / decoder functionality are not limited to these examples and may include other suitable functionality in other specific implementations.

[0080] In some specific embodiments, the baseband circuit 1404 may include one or more audio digital signal processors (DSPs) 1404F. The audio DSP 1404F may include elements for compression / decompression and echo cancellation, and in other specific embodiments may include other suitable processing elements. In some specific embodiments, the components of the baseband circuit may be appropriately combined in a single chip, a single chipset, or disposed on the same circuit board. In some specific embodiments, some or all of the constituent components of the baseband circuit 1404 and the application circuit 1402 may be implemented together, such as, for example, on a system-on-chip (SOC).

[0081] In some specific embodiments, the baseband circuit 1404 may provide communication compatible with one or more radio technologies. For example, in some specific embodiments, the baseband circuit 1404 may support communication with NG-RAN, evolved universal terrestrial radio access network (EUTRAN), or other wireless metropolitan area network (WMAN), wireless local area network (WLAN), wireless personal area network (WPAN), etc. Specific embodiments where the baseband circuit 1404 is configured to support radio communication of more than one wireless protocol may be referred to as multimode baseband circuits.

[0082] The RF circuit 1406 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various specific embodiments, the RF circuit 1406 may include switches, filters, amplifiers, etc. to facilitate communication with the wireless network. The RF circuit 1406 may include a receive signal path, which may include circuitry for downconverting the RF signal received from the FEM circuit 1408 and providing the baseband signal to the baseband circuit 1404. The RF circuit 1406 may also include a transmit signal path, which may include circuitry for upconverting the baseband signal provided by the baseband circuit 1404 and providing the RF output signal to the FEM circuit 1408 for transmission.

[0083] In some specific embodiments, the receive signal path of the RF circuit 1406 may include a mixer circuit 1406A, an amplifier circuit 1406B, and a filter circuit 1406C. In some specific embodiments, the transmit signal path of the RF circuit 1406 may include a filter circuit 1406C and a mixer circuit 1406A. The RF circuit 1406 may further include a synthesizer circuit 1406D that is configured to synthesize frequencies for use by the mixer circuit 1406A in the receive signal path and the transmit signal path. In some specific embodiments, the mixer circuit 1406A in the receive signal path may be configured to down-convert the RF signal received from the FEM circuit 1408 based on the synthesized frequency provided by the synthesizer circuit 1406D. The amplifier circuit 1406B may be configured to amplify the down-converted signal, and the filter circuit 1406C may be a low-pass filter (LPF) or a band-pass filter (BPF) that is configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal may be provided to the baseband circuit 1404 for further processing. In some specific embodiments, the output baseband signal may be a zero-frequency baseband signal, although this is not required. In some specific embodiments, the mixer circuit 1406A in the receive signal path may include a passive mixer, although the scope of the specific embodiments is not limited in this regard.

[0084] In some specific embodiments, the mixer circuit 1406A in the transmit signal path may be configured to up-convert the input baseband signal based on the synthesized frequency provided by the synthesizer circuit 1406D to generate an RF output signal for the FEM circuit 1408. The baseband signal may be provided by the baseband circuit 1404 and may be filtered by the filter circuit 1406C.

[0085] In some specific embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the specific embodiments is not limited in this regard. In some alternative specific embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative specific embodiments, the RF circuit 1406 may include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) circuit, and the baseband circuit 1404 may include a digital baseband interface for communicating with the RF circuit 1406.

[0086] In some dual-mode specific embodiments, a separate radio IC circuit may be provided to process signals for each spectrum, although the scope of the specific embodiments is not limited in this regard.

[0087] The FEM circuit 1408 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 1410, amplify the received signals, and provide an amplified version of the received signals to the RF circuit 1406 for further processing. The FEM circuit 1408 may also include a transmit signal path that may include circuitry configured to amplify transmit signals provided by the RF circuit 1406 for transmission via one or more of the one or more antennas 1410. In various embodiments, amplification through the transmit signal path or the receive signal path may be accomplished only in the RF circuit 1406, only in the FEM circuit 1408, or in both the RF circuit 1406 and the FEM circuit 1408.

[0088] In some embodiments, the PMC 1412 may manage power provided to the baseband circuit 1404. Specifically, the PMC 1412 may control power selection, voltage scaling, battery charging, or DC-DC conversion. When the device 1400 is capable of being battery powered, such as when the device is included in a UE, the PMC 1412 is typically included. The PMC 1412 may improve power conversion efficiency while providing desired embodiment size and thermal characteristics. While Figure 14 the PMC 1412 is shown coupled only to the baseband circuit 1404. However, in other embodiments, the PMC 1412 may additionally or alternatively be coupled to other components such as, but not limited to, the application circuit 1402, the RF circuit 1406, or the FEM circuit 1408 and perform similar power management operations.

[0089] The processors of the application circuit 1402 and the baseband circuit 1404 may be used to execute elements of one or more instances of a protocol stack. For example, the processors of the baseband circuit 1404 may be used alone or in combination to perform layer 3, layer 2, or layer 1 functionality, while the processors of the baseband circuit 1404 may utilize data received from these layers (e.g., packet data) and further perform layer 4 functionality (e.g., the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) layers of the transport protocol). As mentioned herein, layer 3 may include the RRC layer, layer 2 may include the Medium Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer, and layer 1 may include the physical (PHY) layer of the UE / RAN node.

[0090] Figure 15 is a diagram of an example interface of a baseband circuit in accordance with one or more embodiments described herein. As discussed above, Figure 14The baseband circuit 1404 may include processors 1404A - 1404E and a memory 1404G utilized by the processors. Each of the processors 1404A - 1404E may respectively include a memory interface 1504A - 1504E for transmitting / receiving data to / from the memory 1404G.

[0091] The baseband circuit 1404 may further include one or more interfaces for communicatively coupling to other circuits / devices, such as a memory interface 1512 (e.g., an interface for transmitting / receiving data to / from a memory external to the baseband circuit 1404), an application circuit interface 1514 (e.g., an interface for transmitting / receiving data to / from Figure 14 the application circuit 1402), an RF circuit interface 1516 (e.g., an interface for transmitting / receiving data to / from Figure 14 the RF circuit 1406), a wireless hardware connectivity interface 1518 (e.g., an interface for transmitting / receiving data to / from near - field communication (NFC) components, Bluetooth components, Wi - Fi components, and other communication components), and a power management interface 1520 (e.g., an interface for transmitting / receiving power or control signals to / from the PMC 1412).

[0092] Figure 16 is an illustration of a process flow of a cell change procedure for a UE to use a serving node as a candidate for a subsequent cell change according to some aspects of the present disclosure. Some details and additional optional steps have been discussed above and may be incorporated by reference with other appendices, and thus may be omitted hereinafter for simplicity. Figure 1 At action 1610, configuration information is received. The configuration information may include the serving cell configuration of the serving cell and the candidate configuration of the candidate cell list. The configuration information may be provided by

[0093] At action 1620, a first cell change from a source base station (BS) to a target BS is performed. The target BS is selected from the candidate cell list.

[0094] At action 1630, in the absence of another reconfiguration message, the candidate configuration of the candidate cell list is maintained for a subsequent cell change. Additionally, the serving cell may be added as an additional candidate to the candidate cell list for a subsequent cell change. The serving cell may be added based on an implicit indicator parameter or an explicit addition of the candidate configuration. In some aspects, the candidate configuration of the serving cell as an additional candidate may be the serving configuration. In other aspects, the candidate configuration of the serving cell as an additional candidate may be a new candidate configuration, where some parameters are changed based on a differential configuration using the serving configuration as a reference. The differential configuration may be included in the configuration information.

[0095] ​

[0096] At action 1640, in some aspects, a second cell change from a target BS to a subsequent target BS may be performed. The subsequent target BS is selected from a list of candidate cells that includes the serving cell as an additional candidate.

[0097] Figure 17 is an illustration of a process flow of a cell change procedure for a base station (BS) to configure a serving node as a candidate for a subsequent cell change according to some aspects of the present disclosure. Some details and additional optional steps have been discussed above and may be referenced in conjunction with other appended Figure 1 and are thus omitted hereinafter for simplicity.

[0098] At action 1710, configuration information is sent to a user equipment (UE). The configuration information includes the serving cell configuration of the serving cell and the candidate configuration of the list of candidate cells. As discussed in detail throughout the present disclosure, the configuration information may include using the serving cell as an additional candidate for a subsequent cell change via various configuration techniques such as implicit, explicit, or hybrid indicator parameters. In some aspects, the candidate configuration of the serving cell as an additional candidate may be the serving configuration. In other aspects, the candidate configuration of the serving cell as an additional candidate may be a new candidate configuration, where some parameters are changed based on a differential configuration using the serving configuration as a reference. The differential configuration may be included in the configuration information.

[0099] At action 1720, a first cell change from a source BS to a target BS is performed. The target BS is selected from the list of candidate cells. The configuration information may configure the serving cell as an additional candidate to be added to the list of candidate cells for a subsequent cell change from the target BS.

[0100] Embodiments herein may include subject matter such as a method, components for performing the actions or blocks of the method, at least one machine-readable medium including executable instructions that, when executed by a machine (e.g., a processor having a memory, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc.), cause the machine to perform the actions of a method or apparatus or system for concurrent communication using various communication techniques according to the specific implementations and embodiments described.

[0101] Embodiment 1 is a UE, the UE comprising: a memory; and a processor coupled to the memory and configured to execute instructions stored in the memory to cause the UE to: receive configuration information, the configuration information including a serving cell configuration of a serving cell and a candidate configuration of a candidate cell list; perform a first cell change from a source base station (BS) to a target BS, where the target BS is selected from the candidate cell list; maintain the candidate configuration of the candidate cell list for subsequent cell changes, and add the serving cell as an additional candidate to the candidate cell list for the subsequent cell changes; and perform a second cell change from the target BS to a subsequent target BS, where the subsequent target BS is selected from the candidate cell list including the serving cell as the additional candidate.

[0102] Embodiment 2 is a UE including the subject matter of Embodiment 1, where the first cell change and the second cell change are layer 2 (L2)-based cell handovers.

[0103] Embodiment 3 is a UE including the subject matter of Embodiment 1, where the first cell change and the second cell change are secondary node (SN) changes or additions for dual connectivity (DC).

[0104] Embodiment 4 is a UE including the subject matter of Embodiment 1, where the configuration information further includes an indicator parameter indicating using the serving cell configuration as the candidate configuration of the serving cell as the additional candidate.

[0105] Embodiment 5 is a UE including the subject matter of Embodiment 4, where the configuration information further includes a fixed configuration ID for identifying the serving cell as the additional candidate.

[0106] Embodiment 6 is a UE including the subject matter of Embodiment 4, where the configuration information further includes a dedicated configuration ID for the candidate configuration of the serving cell as the additional candidate; and where after performing the second cell change, the dedicated configuration ID is exchanged with the candidate configuration ID of the target BS.

[0107] Embodiment 7 is a UE including the subject matter of Embodiment 4, using a conditional trigger configuration without an explicit candidate configuration as the indicator parameter for SN handover or conditional L2 mobility.

[0108] Embodiment 8 is a UE including the subject matter of Embodiment 1, where the candidate configuration of the candidate cell list includes a differential candidate configuration of the serving cell as the additional candidate; and where the candidate configuration of the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

[0109] Embodiment 9 is a UE including the subject matter of Embodiment 1, wherein one or more of the master cell group (MCG) configuration and the secondary cell group (SCG) configuration related to L2 mobility or SN change of the source BS are assumed to be candidate configurations of the source BS.

[0110] Embodiment 10 is a UE including the subject matter of Embodiment 1, wherein the configuration of the candidate cell list includes an explicit candidate configuration of the serving cell as the additional candidate.

[0111] Embodiment 11 is a UE including the subject matter of Embodiment 10, wherein the explicit candidate configuration of the serving cell is identified by a fixed candidate configuration ID not used by other candidate configurations.

[0112] Embodiment 12 is a UE including the subject matter of Embodiment 1, wherein the UE is preconfigured to use the serving cell configuration as a candidate configuration of the serving cell as the additional candidate.

[0113] Embodiment 13 is a UE including the subject matter of Embodiment 1, and the UE is further configured to execute instructions from a memory to: before receiving configuration information, send UE capability information to the source BS, wherein whether the serving cell is configured as the additional candidate for the subsequent cell change is based on the UE capability information.

[0114] Embodiment 14 is a BS and includes: a memory; and a processor coupled to the memory and configured to execute instructions stored in the memory to cause the BS to: send configuration information to a user equipment (UE), the configuration information including a serving cell configuration of a serving cell and a candidate configuration of a candidate cell list; and perform a first cell change to a target BS selected from the candidate cell list; wherein the configuration information configures the serving cell as an additional candidate to be added to the candidate cell list for a subsequent cell change from the target BS.

[0115] Embodiment 15 is a BS including the subject matter of Embodiment 14, and the BS is further configured to: before sending the configuration information, receive UE capability information from the UE, the UE capability information including whether the UE supports using the serving cell as the additional candidate, wherein whether the serving cell is configured as the additional candidate for the subsequent cell change is based on the UE capability information.

[0116] Example 16 is a BS including the subject matter of Example 15, the BS being further configured to: forward the UE capability information to the candidate cell list after receiving the UE capability information and before transmitting the configuration information; receive the candidate configuration from the candidate cell list, the candidate configuration including an indication of support for using the serving cell as the additional candidate, where whether the serving cell is supported as the additional candidate is based on the UE capability information, and where the serving cell is configured as the additional candidate for the subsequent cell change if supported by at least one serving cell in the candidate cell list.

[0117] Example 17 is a BS including the subject matter of Example 14, where the configuration information further includes an indicator parameter indicating a candidate configuration for using the serving cell configured as the serving cell for the additional candidate.

[0118] Example 18 is a BS including the subject matter of Example 14, where a conditional trigger configuration with no explicit candidate configuration is used as the indicator parameter.

[0119] Example 19 is a BS including the subject matter of Example 14, where the configuration of the candidate cell list includes an explicit candidate configuration for the serving cell as the additional candidate.

[0120] Example 20 is a BS including the subject matter of Example 14, where the configuration of the candidate cell list includes a differential candidate configuration for the serving cell as the additional candidate; and where a candidate configuration for the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

[0121] Example 21 is a method for a user equipment (UE) to perform a cell change operation, and includes: receiving configuration information including a serving cell configuration of a serving cell and a candidate configuration of a candidate cell list; performing a first cell change from a source base station (BS) to a target BS, where the target BS is selected from the candidate cell list; and maintaining the candidate configuration of the candidate cell list for a subsequent cell change, and adding the serving cell as an additional candidate to the candidate cell list for the subsequent cell change based on the configuration information.

[0122] Example 22 is a method including the subject matter of Example 21, where the configuration information includes an indicator parameter indicating a candidate configuration for using the serving cell configuration as the serving cell for the additional candidate.

[0123] Example 23 is a method that includes the subject matter of Example 21, and uses a conditional trigger configuration without an explicit candidate configuration as an indicator parameter, where the indicator parameter indicates that if the conditions of the conditional trigger configuration are met, the serving cell configuration is used as the candidate configuration of the serving cell as the additional candidate.

[0124] Example 24 is a method that includes the subject matter of Example 21, and the method further includes: performing a second cell change from the target BS to a subsequent target BS, where the subsequent target BS is selected from a list of candidate cells that includes the serving cell as the additional candidate.

[0125] Example 25 is a method that includes the subject matter of Example 21, where the candidate configuration of the list of candidate cells includes a differential candidate configuration of the serving cell as the additional candidate; and where the candidate configuration of the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

[0126] Example 26 is a method that includes any action or combination of actions substantially described herein in the detailed description.

[0127] Example 27 is a method that is substantially described herein with reference to each or any combination of the figures included herein or with reference to each or any combination of the paragraphs in the detailed description.

[0128] Example 28 is a user equipment configured to perform any action or combination of actions substantially described herein in the detailed description included in the user equipment.

[0129] Example 29 is a network node configured to perform any action or combination of actions substantially described herein in the detailed description included in the network node.

[0130] Example 30 is a non - volatile computer - readable medium storing instructions that, when executed, cause any action or combination of actions substantially described herein in the detailed description to be performed.

[0131] Example 31 is a baseband processor of a user equipment configured to perform any action or combination of actions substantially described herein in the detailed description included in the user equipment.

[0132] Embodiment 32 is a baseband processor of a network node, and the baseband processor is configured to perform any action or combination of actions substantially described herein in the specific implementation included in the user equipment.

[0133] The above description of the exemplary examples, specific implementations, aspects, etc. of the subject matter of the present disclosure including the content described in the abstract of the specification is not intended to be exhaustive or to limit the disclosed aspects to the precise forms disclosed. Although specific examples, specific implementations, aspects, etc. are described herein for illustrative purposes, various modifications can be contemplated within the scope of such examples, specific implementations, aspects, etc. as would be recognized by those skilled in the relevant art.

[0134] In this regard, although the subject matter of the present disclosure has been described in connection with various examples, specific implementations, aspects, etc. and the corresponding drawings, it should be understood that, where applicable, other similar aspects can be used or modifications and additions can be made to the disclosed subject matter to perform the same, similar, alternative, or substitute functions of the subject matter without departing from the disclosed subject matter. Therefore, the disclosed subject matter should not be limited to any single example, specific implementation, or aspect described herein, but should be construed in accordance with the breadth and scope of the following appended claims.

[0135] Particularly with respect to the various functions performed by the above components or structures (components, devices, circuits, systems, etc.), unless otherwise specified, the terms used to describe such components (including references to "elements") are intended to correspond to any component or structure that performs the specified function of the component (e.g., functionally equivalent), even if not structurally equivalent to the disclosed structure that performs the function in the exemplary specific implementation illustrated herein. In addition, although a particular feature has been disclosed with respect to only one of the multiple specific implementations, for any given or particular application, such feature can be combined with one or more other features of one or more other specific implementations, which may be desirable and advantageous.

[0136] As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless stated otherwise or clear from the context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing instances. Additionally, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless stated otherwise or clearly apparent from the context to be referring to the singular form. Further, to the extent that the terms "comprising", "comprises", "having", "has", "with", or variants thereof are used in the detailed description and claims, such terms are intended to be inclusive in a manner similar to the term "including". Additionally, in the case of discussing one or more numbered items (e.g., "first X", "second X", etc.), generally, the one or more numbered items can be different or they can be the same, although in some cases the context may indicate that they are different or indicate that they are the same.

[0137] As is well known, the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of inadvertent or unauthorized access or use, and the nature of authorized use should be clearly explained to users.

Claims

1. A baseband processor for a user equipment (UE), the baseband processor being configured to execute instructions from a memory to: Receive configuration information, the configuration information including a serving cell configuration of a serving cell and a candidate configuration of a candidate cell list; Perform a first cell change from a source base station (BS) to a target BS, wherein the target BS is selected from the candidate cell list; Maintain the candidate configuration of the candidate cell list for subsequent cell changes, and add the serving cell as an additional candidate to the candidate cell list for the subsequent cell changes; And Perform a second cell change from the target BS to a subsequent target BS, wherein the subsequent target BS is selected from the candidate cell list including the serving cell as the additional candidate.

2. The baseband processor according to claim 1, wherein the first cell change and the second cell change are layer 2 (L2)-based cell handovers.

3. The baseband processor according to claim 1, wherein the first cell change and the second cell change are secondary node (SN) changes or additions for dual connectivity (DC).

4. The baseband processor according to claim 1, wherein the configuration information further includes an indicator parameter indicating that the serving cell configuration is used as the candidate configuration of the serving cell as the additional candidate.

5. The baseband processor according to claim 4, wherein the configuration information further includes a fixed configuration ID for identifying the serving cell as the additional candidate.

6. The baseband processor according to claim 4, Wherein the configuration information further includes a dedicated configuration ID for the candidate configuration of the serving cell as the additional candidate; and Wherein after performing the second cell change, the dedicated configuration ID is exchanged with the candidate configuration ID of the target BS.

7. The baseband processor according to claim 4, for SN handover or conditional L2 mobility, using a conditional trigger configuration without an explicit candidate configuration as the indicator parameter.

8. The baseband processor according to claim 1, Wherein the candidate configuration of the candidate cell list includes a differential candidate configuration of the serving cell as the additional candidate; and Wherein the candidate configuration of the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

9. The baseband processor according to claim 1, wherein one or more of a master cell group (MCG) configuration and a secondary cell group (SCG) configuration related to L2 mobility or SN change of the source BS are assumed as the candidate configuration of the source BS.

10. The baseband processor according to claim 1, wherein the candidate configuration of the candidate cell list includes an explicit candidate configuration of the serving cell as the additional candidate.

11. The baseband processor according to claim 10, wherein the explicit candidate configuration of the serving cell is identified by a fixed candidate configuration ID not used by other candidate configurations.

12. The baseband processor according to claim 1, wherein the UE is pre-configured to use the serving cell configuration as the candidate configuration of the serving cell as the additional candidate.

13. The baseband processor according to claim 1, the baseband processor being further configured to execute instructions from a memory to: Before receiving the configuration information, send UE capability information to the source BS; and Wherein whether the serving cell is configured as the additional candidate for the subsequent cell change is based on the UE capability information.

14. A base station, the base station comprising: A memory; And A processor coupled to the memory and configured to execute instructions stored in the memory to cause the base station to: Send configuration information to a user equipment (UE), the configuration information including the serving cell configuration of the serving cell and the candidate configuration of the candidate cell list; and Perform a first cell change to a target BS, the target BS being selected from the candidate cell list; and Wherein the configuration information configures the serving cell as an additional candidate to be added to the candidate cell list for a subsequent cell change from the target BS.

15. The base station according to claim 14, the base station being further configured to, before sending the configuration information: Receive UE capability information from the UE, the UE capability information including whether the UE supports using the serving cell as the additional candidate; and Wherein whether the serving cell is configured as the additional candidate for the subsequent cell change is based on the UE capability information.

16. The base station according to claim 15, the base station being further configured to, after receiving the UE capability information and before sending the configuration information: Forward the UE capability information to the candidate cell list; And Receive the candidate configuration from the candidate cell list, the candidate configuration including an indication of support for using the serving cell as the additional candidate, wherein whether the serving cell is supported as the additional candidate is based on the UE capability information; And Wherein if at least one serving cell in the candidate cell list supports it, the serving cell is configured as the additional candidate for the subsequent cell change.

17. The base station according to claim 14, wherein the configuration information further includes an indicator parameter indicating the candidate configuration of the serving cell configured to use the serving cell as the additional candidate.

18. The base station according to claim 17, wherein a conditional trigger configuration without an explicit candidate configuration is used as the indicator parameter.

19. The base station according to claim 14, wherein the candidate configuration of the candidate cell list includes an explicit candidate configuration of the serving cell as the additional candidate.

20. The base station according to claim 14, wherein the candidate configuration of the candidate cell list includes a differential candidate configuration of the serving cell as the additional candidate; and wherein a candidate configuration of the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

21. A method for a user equipment (UE) to perform a cell change procedure, the method comprising: receiving configuration information, the configuration information including a serving cell configuration of a serving cell and a candidate configuration of a candidate cell list; performing a first cell change from a source base station (BS) to a target BS, wherein the target BS is selected from the candidate cell list; and maintaining the candidate configuration of the candidate cell list for a subsequent cell change, and adding the serving cell as an additional candidate to the candidate cell list for the subsequent cell change based on the configuration information.

22. The method according to claim 21, wherein the configuration information includes an indicator parameter that indicates using the serving cell configuration as a candidate configuration of the serving cell as the additional candidate.

23. The method according to claim 21, using a conditional trigger configuration without an explicit candidate configuration as an indicator parameter that indicates that if the condition of the conditional trigger configuration is met, the serving cell configuration is used as a candidate configuration of the serving cell as the additional candidate.

24. The method according to claim 21, the method further comprising: performing a second cell change from the target BS to a subsequent target BS, wherein the subsequent target BS is selected from the candidate cell list including the serving cell as the additional candidate.

25. The method according to claim 21, wherein the candidate configuration of the candidate cell list includes a differential candidate configuration of the serving cell as the additional candidate; and wherein a candidate configuration of the serving cell as the additional candidate is derived from the serving cell configuration and the differential candidate configuration.

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