WO2025218386A1 - Method and device used for mobility management in wireless communication - Google Patents

Abstract

The present application discloses a method and device used for mobility management in wireless communication. The method comprises: receiving first information, the first information indicating that a first MAC entity of a first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell, and the other is a target cell, and serving the first cell and the second cell comprises: receiving or sending an MAC PDU from or to the first cell, and receiving or sending an MAC PDU from or to the second cell. The present application can reduce the handover delay and ensure the continuity during handover, and is particularly suitable for non-RACH LTM cell handover.

Description

A method and device for mobility management in wireless communication

This application claims priority to the Chinese patent application filed with the China Patent Office on April 18, 2024, with application number 202410474211.2 and application name “A method and device for mobility management in wireless communications”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application relates to a method for mobility management in a cellular wireless communication system, and in particular to non-RACH layer 1 and layer 2 triggered mobility management.

Background Art

The application scenarios of future wireless communication systems are becoming increasingly diverse, and different scenarios place varying performance requirements on the systems. To meet the diverse performance demands of various application scenarios, the 3GPP (3rd Generation Partner Project) RAN (Radio Access Network) plenary meeting #72 decided to conduct research on New Radio (NR) (or Fifth Generation, 5G). The NR work item (WI) was approved at the 3GPP RAN plenary meeting #75, initiating standardization work on NR.

In communications, both LTE (Long Term Evolution) and 5G NR involve accurate reception of reliable information, optimized energy efficiency, determination of information validity, flexible resource allocation, scalable system structure, efficient non-access layer information processing, low service interruption and drop rate, and support for low power consumption. This is of great significance to the normal communication between base stations and user equipment, the reasonable scheduling of resources, and the balancing of system loads. It can be said to be the cornerstone of high throughput, meeting the communication needs of various services, improving spectrum utilization, and improving service quality. It is indispensable for eMBB (enhanced Mobile BroadBand), URLLC (Ultra Reliable Low Latency Communication) and eMTC (enhanced Machine Type Communication). At the same time, there are extensive demands in IIoT (Industrial Internet of Things), V2X (Vehicular to X), device-to-device communication, unlicensed spectrum communication, user communication quality monitoring, network planning and optimization, TN (Territial Network), dual connectivity systems, wireless resource management and multi-antenna codebook selection, signaling design, neighboring cell management, business management, and beamforming. Information is sent in two ways: broadcast and unicast. Both transmission methods are essential for 5G systems because they are very helpful in meeting the above requirements.

As the scenarios and complexity of the system continue to increase, higher requirements are placed on reducing interruption rates, reducing latency, enhancing reliability, enhancing system stability, business flexibility, and saving power. At the same time, compatibility between different system versions also needs to be considered during system design.

Summary of the Invention

Researchers found that in the 5G communication system, one MAC entity only serves one cell group, and when dual connectivity is not used, there is only one cell group, namely MCG; dual connectivity is usually used in the early stages of 5G network deployment, so a more typical scenario is to only connect to the 5G network, that is, there is only one cell group, that is, there is only one MAC entity; how to reduce data interruption during switching is an important issue, and a more specific issue is that when there is only one MAC entity, how to reduce the impact of cell switching on data transmission at the MAC sublayer is a problem that needs to be solved.

In response to the above-mentioned problems, this application provides a solution.

It should be noted that, in the absence of conflict, the embodiments and features of any node of the present application can be applied to any other node. In the absence of conflict, the embodiments and features of the embodiments of the present application can be arbitrarily combined with each other. At the same time, the method proposed in this application can also be used to solve other problems in communications, such as NR evolution and problems in 6G systems.

As an embodiment, the interpretation of terminology in this application refers to the definition of 3GPP specification protocol TS38 series.

As an example, the interpretation of the terms in this application refers to the definitions of the TS37 series of specification protocols of 3GPP.

The present application discloses a method in a first node for wireless communication, comprising:

Receive first information, the first information indicating that the first MAC entity of the first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the problem to be solved by the present application includes: how to reduce the impact of cell switching on data transmission when there is only one MAC entity.

As an embodiment, the benefits of the above method include: smoother switching, better support for LTM, better support for data continuity, better support for services with high requirements on latency, better support for inter-CU (inter control unit) and inter-DU (inter data unit) switching, reduced system complexity, and reduced network load.

Specifically, according to one aspect of the present application, the first information indicates that the second cell is added to the cell group to which the first cell belongs and remains in a deactivated state;

After the cell switching starts, the second cell is activated; when the cell switching is completed, the first cell is deactivated or released.

Specifically, according to one aspect of the present application, the first information indicates the reset uplink HARQ process of the first node.

Specifically, according to one aspect of the present application, the first cell and the second cell are a source cell and a target cell in a non-RACH LTM process.

Specifically, according to one aspect of the present application, first signaling and second signaling are received, wherein the first signaling includes a first parameter and at least one candidate configuration, the at least one candidate configuration includes a first candidate configuration, the first candidate configuration includes a second parameter, and the second signaling indicates the first candidate configuration and cell switching; performing the cell switching includes: setting a value of the second parameter to a value of the first parameter;

The serving of the first cell and the second cell depends on the second parameter being equal to the first parameter; the first signaling is the signaling of the RRC sublayer, and the second signaling is MAC CE.

Specifically, according to one aspect of the present application, the serving first cell and the second cell rely on the first timer being running.

Specifically, according to one aspect of the present application, along with the reception of the first information, a first timer is started, and the expiration of the first timer triggers RRC connection reconstruction; the stopping of the first timer triggers the first MAC entity to serve only one of the first cell and the second cell.

Specifically, according to one aspect of the present application, a first MAC CE is received;

In which, the first MAC entity indicates to a higher layer whether the first MAC CE is received from the first cell or the second cell.

Specifically, according to one aspect of the present application, the serving of the first cell and the second cell includes: receiving a MAC subPDU with an SRB associated with a logical channel identifier from the first cell and the second cell, and receiving a MAC subPDU with a MAC CE associated with a logical channel identifier only from one of the first cell and the second cell.

Specifically, according to one aspect of the present application, a third signaling is received, and the third signaling configures a first RLC bearer of the first cell and a second RLC bearer of the second cell, wherein the first RLC bearer of the first cell serves the SRB1 of the first cell, and the second RLC bearer of the second cell serves the SRB1 of the second cell, and the service of the first cell and the second cell includes simultaneously serving the SRB1 of the first cell and the SRB1 of the second cell.

Specifically, according to one aspect of the present application, the serving first cell and the second cell includes communicating with the first cell through a first radio bearer and communicating with the second cell through a second radio bearer, and the first radio bearer and the second radio bearer are respectively associated with different security contexts.

Specifically, according to one aspect of the present application, the first node is an Internet of Things terminal.

Specifically, according to one aspect of the present application, the first node is user equipment.

Specifically, according to one aspect of the present application, the first node is a vehicle-mounted terminal.

Specifically, according to one aspect of the present application, the first node is a mobile phone.

The present application discloses a first node used in wireless communication, comprising:

A first receiver receives first information, wherein the first information indicates that the first MAC entity of the first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an example, compared with traditional solutions, this application has the following advantages:

The difference between LTM (L1L2 Triggered Mobility) and traditional cell handovers is that they have shorter latency, especially non-RACH LTM. The main difference between non-RACH LTM cell handover and RACH-based LTM cell handover is that non-RACH LTM does not use or require the RACH process, which helps further shorten LTM cell handover latency; RACH-based LTM cell handover does require the RACH process. However, MAC sublayer communication interruptions weaken the advantages of LTM. This application helps fully utilize the advantages of LTM and reduce handover latency.

This helps to strike a good balance between network complexity and switching performance.

It can better support cell switching between inter-CU and inter-DU.

It can be accurately determined whether to allow simultaneous communication with the first cell and the second cell during the handover process.

When HARQ is supported, the data in the cache is very large and difficult to transfer between different network processing units. The method proposed in this application is helpful in solving this problem.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

FIG1 shows a schematic diagram of receiving first information according to an embodiment of the present application;

FIG2 shows a schematic diagram of a network architecture according to an embodiment of the present application;

FIG3 is a schematic diagram showing an embodiment of a radio protocol architecture of a user plane and a control plane according to an embodiment of the present application;

FIG4 shows a schematic diagram of a first communication device and a second communication device according to an embodiment of the present application;

FIG5 shows a flowchart of wireless signal transmission according to an embodiment of the present application;

FIG6 shows a flowchart of interaction between a first cell and a second cell according to an embodiment of the present application;

FIG7 is a schematic diagram showing the structure of a MAC PDU according to an embodiment of the present application;

FIG8 is a schematic diagram showing a serving first cell and a second cell depending on the operation of a first timer according to an embodiment of the present application;

FIG9 illustrates a schematic diagram of a processing device used in a first node according to an embodiment of the present application.

Implementation Method

The technical solution of the present application will be further described in detail below in conjunction with the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other in any way.

Example 1

Example 1 illustrates a flowchart of receiving first information according to an embodiment of the present application, as shown in Figure 1. In Figure 1, each box represents a step, and it is particularly important to emphasize that the order of the boxes in the figure does not represent the temporal sequence between the steps represented.

In embodiment 1, the first node in the present application receives first information in step 101.

The first information indicates that the first MAC entity of the first node serves the first cell and the second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the first node is UE (User Equipment).

As an embodiment, the first node is a terminal.

As an embodiment, those skilled in the art should understand that the source cell and the target cell refer to the source cell and the target cell in the handover process.

As an embodiment, LTM cell switch is a cell switch triggered by L1/L2 signaling.

As an embodiment, any operation performed in the MAC sublayer may also be understood as or referred to as any operation performed by the MAC entity.

As an embodiment, the lower layer at which the MAC sublayer performs operations is the physical layer.

As an embodiment, the higher layers when the MAC sublayer performs operations include the RLC sublayer, the RRC sublayer, and the PDCP sublayer.

Typically, the higher layer at which the MAC sublayer performs operations is the RRC sublayer.

As an embodiment, MAC CE is the control signaling of the MAC layer, which has the characteristics of fast speed but lower reliability than RRC signaling. RRC signaling is more reliable but slower than MAC CE. RRC signaling cannot replace MAC CE, and MAC CE cannot replace RRC signaling.

As an embodiment, the lower layers when the RRC sublayer performs operations include the physical layer, the MAC layer, the RLC sublayer, and the PDCP sublayer.

As an embodiment, the higher layer when the RRC sublayer performs an operation includes a non-access stratum.

As an embodiment, the higher layer signaling refers to RRC signaling or non-access stratum.

As an embodiment, in this application, if it is not specifically stated that it is executed in the MAC sublayer, it is executed in the RRC sublayer.

As an embodiment, access layer security of the first node is activated.

As an embodiment, the access stratum (AS) includes multiple protocol layers. For details, please refer to Example 3.

As an embodiment, the first node is in an RRC connected state.

As an embodiment, any parameter in the present application may be either configured by the network or generated by the first node according to an internal algorithm, such as random.

As an embodiment, the values of the timers in this application are all limited and do not exceed 2560 milliseconds.

As an embodiment, the value of the timer is the running time when the timer is not interfered with.

As an example, the value of any parameter in this application, including but not limited to the value of a timer and the value of a counter, is limited unless otherwise stated.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 1024 times of 65536.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 65536 or 65535.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 1024.

As a sub-embodiment of this embodiment, the upper limit of the value of any parameter in this application is 640 or 320.

As an embodiment, the present application is directed to NR.

As an embodiment, the present application is directed to a NR evolved wireless communication network.

As an embodiment, the serving cell refers to the cell where the UE resides. Performing a cell search includes the UE searching for a suitable cell of the selected PLMN (Public Land Mobile Network) or SNPN (Stand-alone Non-Public Network), selecting the suitable cell to provide available services, and monitoring the control channel of the suitable cell. This process is defined as camping on a cell; that is, a camped cell is the serving cell of the UE relative to the UE. Staying in a cell in RRC idle or RRC inactive state has the following benefits: it allows the UE to receive system messages from the PLMN or SNPN; after registration, if the UE wishes to establish an RRC connection or continue a suspended RRC connection, the UE can do so by performing initial access on the control channel of the cell where it is staying; the network can page the UE; and it allows the UE to receive ETWS (Earthquake and Tsunami Warning System) and CMAS (Commercial Mobile Alert System) notifications.

As an embodiment, for a UE in an RRC connected state that is not configured with CA/DC (carrier aggregation/dual connectivity), there is only one serving cell including a primary cell. For a UE in an RRC connected state that is configured with CA/DC (carrier aggregation/dual connectivity), the serving cell is used to indicate a set of cells including a special cell (SpCell) and all cells derived from the cells. The primary cell (Primary Cell) is an MCG (Master Cell Group) cell that operates on the primary frequency. The UE performs the initial connection establishment process or initiates connection reestablishment on the primary cell. For dual-connectivity operation, the special cell refers to the PCell (Primary Cell) of the MCG or the PSCell (Primary SCG Cell) of the SCG (Secondary Cell Group); if it is not a dual-connectivity operation, the special cell refers to the PCell.

As an embodiment, the operating frequency of SCell (Secondary Cell) is the secondary frequency.

As an embodiment, the first node is only configured with MCG.

As an example, the individual contents of an information element are referred to as fields.

As an embodiment, MR-DC (Multi-Radio Dual Connectivity) refers to dual connectivity between E-UTRA and NR nodes, or dual connectivity between two NR nodes.

As an embodiment, in MR-DC, the wireless access node that provides the control plane connection to the core network is a master node, which can be a master eNB, a master ng-eNB, or a master gNB.

As an embodiment, MCG refers to a group of serving cells associated with a master node in MR-DC, including SpCells, and may also, optionally, include one or more SCells.

As an embodiment, PCell is the SpCell of MCG.

As an embodiment, the PSCell is the SpCell of the SCG.

As an embodiment, in MR-DC, the radio access node that does not provide a control plane connection to the core network and provides additional resources to the UE is a slave node. The slave node can be an en-gNB, a slave ng-eNB, or a slave gNB.

As an embodiment, in MR-DC, a group of service cells associated with a slave node is an SCG (secondary cell group), which includes a SpCell and, optionally, one or more SCells.

As an embodiment, the SpCell is a PCell or the SpCell is a PSCell.

As an embodiment, only the former of the first cell and the second cell belongs to a first cell group, and the first cell group is one of the MCG or SCG of the first node.

As an embodiment, in the RRC inactive state, DC is not used.

As an example, in the RRC inactive state, CA is typically not used.

As an embodiment, the RRC information block refers to an information element in an RRC message.

As an embodiment, SSB may be referred to as SS\PBCH, or SS block.

As an embodiment, L1 is layer 1 (Layer-1) or physical layer.

As an example, L2 is Layer-2

As an embodiment, the present application is directed to NR and NR evolved networks, such as 6G networks.

As an embodiment, an RRC information block may include one or more RRC information blocks.

As an embodiment, an RRC information block may not include any RRC information block, but only include at least one parameter.

As an embodiment, the radio bearer includes at least a signaling radio bearer and a data radio bearer.

As an embodiment, a radio bearer is a service or service interface provided by the PDCP layer to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes one of the RRC sublayer, NAS, and SDAP layer.

As an embodiment, the signaling radio bearer is a service or service interface provided by PDCP to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes an RRC sublayer, at least the former in NAS.

As an embodiment, the data radio bearer is a service or an interface of services provided by PDCP to a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes an SDAP layer, at least the former in NAS.

As an embodiment, after the first node establishes an RRC connection with the network, the first node enters an RRC connection state.

As a sub-embodiment of this embodiment, the network is a radio access network (RAN).

As an embodiment, when the first node does not establish an RRC connection with the network, the first node is in an RRC idle state.

As a sub-embodiment of this embodiment, the network is a radio access network (RAN).

As an embodiment, when the RRC connection established between the first node and the network is suspended, the first node enters an RRC inactive state.

As a sub-embodiment of this embodiment, the network is a radio access network (RAN).

As an embodiment, different functions are supported in different RRC states.

As an embodiment, only very limited functions are supported in the non-RRC connected state.

As an embodiment, the non-RRC connected state is or includes an RRC idle state.

As an embodiment, the non-RRC connected state is or includes an RRC inactive state.

As an embodiment, the first node is not in limited service mode.

As an embodiment, the method proposed in this application and the scenario on which it is based are not targeted at emergency services.

As an embodiment, the first cell and the second cell are serving cells of the first node respectively.

As an embodiment, the first cell is a source cell.

As an embodiment, the second cell is a target cell.

As an embodiment, the first information is RRC signaling.

As an embodiment, the RRC signaling is RRC reconfiguration signaling.

As an embodiment, the RRC reconfiguration information is RRCReconfiguration.

As an embodiment, the first information is an indication from a higher layer to the MAC sublayer.

As an embodiment, the higher layer is the RRC sublayer.

As an embodiment, the first cell and the second cell do not belong to the same DU.

As an embodiment, the first cell and the second cell do not belong to the same CU.

As an embodiment, the first cell and the second cell are not synchronized.

As an embodiment, one advantage of the method proposed in the present application is that it is suitable for inter-CU or inter-DU cell switching, including LTM cell switching.

As an embodiment, the first cell and the second cell are the source cell and the target cell in a non-RACH LTM process.

As an embodiment, it is particularly necessary to further reduce the handover delay in non-RACH LTM.

As an embodiment, serving the first cell and the second cell refers to supporting serving the first cell and the second cell simultaneously.

As an embodiment, serving the first cell and the second cell means maintaining a connection relationship with the first cell and the second cell at the same time.

As an embodiment, serving the first cell and the second cell means that when serving the first cell and the second cell at the same time, if the first MAC entity of the first node receives a MAC PDU, this MAC PDU can be of the first cell or the second cell.

As an embodiment, serving the first cell and the second cell does not mean serving one cell first and then serving the other cell.

As an embodiment, serving the first cell and the second cell means that when serving one of the first cell and the second cell, the other cell of the first cell and the second cell may also be served.

As an embodiment, part of the HARQ process of the first MAC entity serves the first cell, and another part of the HARQ process serves the second service cell.

As an embodiment, the first information is information received by the MAC sublayer from a higher layer.

As a sub-embodiment of this embodiment, the higher layer includes an RRC sublayer.

As a sub-embodiment of this embodiment, the higher layer includes a non-access stratum.

As a sub-embodiment of this embodiment, the RRC sublayer of the first node receives network signaling, which triggers the RRC sublayer of the first node to send the first information to the MAC sublayer.

As a sub-embodiment of this embodiment, receiving the first information indicates that the negotiation between the first cell and the second cell has been completed.

As a sub-embodiment of this embodiment, receiving the first information indicates that the first node has received a configuration for supporting simultaneous service of the first cell and the second cell.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes configuration of the MAC sublayer.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes configuration of a radio bearer.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes configuration of an RLC bearer.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes a configuration of an identifier of the first node.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes a security configuration of the first node.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes the configuration of the logical channel identifier of the first node.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes the configuration of the PUCCH (physical uplink control channel) of the first node in the first cell and the second cell respectively.

As an embodiment, the first information indicates that the first MAC entity suspends or releases the configuration that causes a conflict in communication with the first cell and the second cell.

As a sub-embodiment of this embodiment, the conflicting configuration includes carrier or frequency configuration.

As a sub-embodiment of this embodiment, the conflicting configuration includes the configuration of the transceiver.

As a sub-embodiment of this embodiment, the configuration of the conflict includes the configuration of space parameters.

As a sub-embodiment of this embodiment, the conflicting configuration includes a MIMO (multiple in multiple out) configuration.

As an embodiment, the first information instructs the first MAC entity to stop performing the inter-frequency measurement configured for the first cell.

As a sub-embodiment of this embodiment, the advantage of the above method is that it can prevent the inter-frequency measurement configured in the first cell from interfering with the serving second cell.

As an embodiment, the configuration for supporting simultaneous service of the first cell and the second cell includes using one transceiver to serve the first cell and using another transceiver to serve the second cell.

As an embodiment, the first information indicates that a candidate configuration is used during simultaneous service of the first cell and the second cell.

As an embodiment, when stopping serving the first cell, the first node stops using the candidate configuration.

As an embodiment, the candidate configuration is a pre-selected configuration.

As an embodiment, the candidate configuration is a configuration stored after receiving.

As an embodiment, the candidate configuration is a temporary configuration.

As an embodiment, using the candidate configuration facilitates temporary simultaneous service of the first cell and the second cell, thereby avoiding conflicts.

As an embodiment, the meaning of the first information indicating that the first MAC entity of the first node serves the first cell and the second cell includes: the first information indicates that the conditions for the first MAC entity of the first node to serve the first cell and the second cell are met.

As an embodiment, the meaning of the first information indicating that the first MAC entity of the first node serves the first cell and the second cell includes: the first information indicates that the first MAC entity of the first node needs or is allowed to serve the first cell and the second cell.

As an embodiment, the meaning of the first information indicating that the first MAC entity of the first node serves the first cell and the second cell includes: the first information indicates to the first MAC entity of the first node the configuration information for serving the first cell and the second cell.

As an embodiment, receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell includes: receiving a MAC PDU from the first cell and receiving a MAC PDU from the second cell.

As an embodiment, receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell includes: receiving a MAC PDU from the first cell and sending a MAC PDU to the second cell.

As an embodiment, receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell includes: sending a MAC PDU to the first cell and receiving a MAC PDU from the second cell.

As an embodiment, receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell includes: sending a MAC PDU to the first cell and sending a MAC PDU to the second cell.

As an embodiment, receiving the MAC PDU from the first cell includes: receiving the MAC PDU using the configuration of the first cell.

As an embodiment, receiving the MAC PDU from the second cell includes: receiving the MAC PDU using the configuration of the second cell.

As an embodiment, receiving the MAC PDU from the first cell includes: receiving the MAC PDU on the resources of the first cell.

As an embodiment, receiving the MAC PDU from the second cell includes: receiving the MAC PDU on the resources of the second cell.

As an embodiment, sending the MAC PDU to the first cell includes: sending the MAC PDU using the configuration of the first cell.

As an embodiment, sending the MAC PDU to the second cell includes: sending the MAC PDU using the configuration of the second cell.

As an embodiment, the sending of the MAC PDU to the first cell includes: sending the MAC PDU according to the scheduling of the first cell.

As an embodiment, sending the MAC PDU to the second cell includes: sending the MAC PDU according to the scheduling of the second cell.

As an embodiment, the first node has only one MAC entity.

As an embodiment, the first MAC entity of the first node receives or sends a first type of MAC PDU from or to the first cell.

As an embodiment, the first MAC entity of the first node receives or sends a second type of MAC PDU from or to the second cell.

As an embodiment, the size of any MAC PDU in the second type of MAC PDU does not exceed a certain threshold.

As an embodiment, the advantage of the above method is that it can ensure communication with the second cell while preventing excessive resources from being occupied by the communication with the second cell.

As an embodiment, the first type of MAC PDU includes a MAC PDU carrying a MAC CE.

As an embodiment, the second type of MAC PDU does not include a MAC PDU carrying a MAC CE.

As an embodiment, the first type of MAC PDU and the second type of MAC PDU both include a MAC PDU carrying a MAC SDU.

As an embodiment, the first type of MAC PDU and the second type of MAC PDU both include a MAC PDU of a MAC SDU carrying an SRB (signaling radio bearer).

As an embodiment, the first type of MAC PDU and the second type of MAC PDU both include a MAC PDU of a MAC SDU carrying a DRB (data radio bearer).

As an embodiment, only one of the first type MAC PDU and the second type MAC PDU carries the MAC PDU of the MAC SDU of MRB (Multicast broadcast service radio bearer).

As an embodiment, the first type of MAC PDU includes at least one MAC PDU that does not belong to the second type of MAC PDU.

As an embodiment, the first type of MAC PDU and the second type of MAC PDU are different.

As an embodiment, the first type of MAC PDU and the second type of MAC PDU are not orthogonal.

As an embodiment, the benefits of supporting different categories of MAC PDUs for communicating with the first cell and the second cell include: ensuring service to both cells as much as possible while avoiding conflicts and interference when communicating with the two cells.

As an embodiment, the first information indicates that the second cell is added to the cell group to which the first cell belongs and remains in a deactivated state.

As an embodiment, after the cell switching starts, the second cell is activated.

As an embodiment, when the cell switching is completed, the first cell is deactivated or released.

As an embodiment, the benefits of the above method include: avoiding conflicts when serving the first cell and the second cell at the same time, and reducing implementation complexity.

As an embodiment, the cell group described in the first cell is MCG.

As an embodiment, when the second cell is added to the cell group of the first cell, at least one of a radio bearer and an RLC bearer is configured.

As an embodiment, when the second cell is added to the cell group of the first cell, the configuration parameters of the MAC layer and the physical layer are configured.

As an embodiment, during the period of serving the first cell and the second cell simultaneously, the first cell and the second cell are both PCells of the first node.

As an embodiment, during the period of serving the first cell and the second cell simultaneously, the first cell and the second cell are both serving cells of the first node.

As an embodiment, during the period of serving the first cell and the second cell simultaneously, one of the first cell and the second cell is a degraded PCell.

As an embodiment, execution of cell switching triggers activation of the second cell.

As an embodiment, completion of cell switching triggers the deactivation or release of the first cell.

As an embodiment, when the handover is completed, the first MAC entity copies the cache for communicating with the first cell to the cache for communicating with the second cell.

As an embodiment, the first MAC timer is a timer used when the first MAC entity of the first node communicates with the first cell. When the switching is completed, the first MAC entity starts a timer with the same name as the first MAC timer for communicating with the second cell, and sets the value to the remaining time of the first MAC timer.

As a sub-embodiment of this embodiment, the first MAC timer is in a running state during the switching process.

As an embodiment, the above method has the advantage of making the switching smoother.

As an embodiment, the first information indicates the reset uplink HARQ process of the first node.

As an embodiment, the reset uplink HARQ process is an uplink HARQ process whose transmission times are reset.

As an embodiment, the uplink HARQ process that is reset is an uplink HARQ (Hybrid Automatic Repeat Request) process in which the redundant version is reset.

As an embodiment, the uplink HARQ process that is reset is a HARQ process whose receiving and/or transmitting buffer is cleared.

As an embodiment, the uplink HARQ process that is reset is a HARQ process that is considered to have reached the maximum number of transmissions.

As an embodiment, when receiving the first scheduling indication for the reset uplink HARQ process, the first MAC entity determines that the NDI (new data indicator) is flipped.

As an embodiment, when receiving scheduling information for the HARQ process number of the uplink HARQ process, the first MAC entity determines that the NDI is flipped.

As a sub-embodiment of this embodiment, the scheduling information is the first scheduling information for the HARQ process number of the uplink HARQ process after receiving the first information.

As an embodiment, receiving the first information triggers flipping the value of the NDI field in the scheduling information associated with the HARQ process number of the reset uplink HARQ process indicated by the first information.

As a sub-embodiment of this embodiment, the associated scheduling information refers to scheduling information for the associated HARQ process number.

As an embodiment, receiving the first information triggers flipping the value of the NDI field in the scheduling information associated with the HARQ process number of the reset uplink HARQ process indicated by the first information.

As a sub-embodiment of this embodiment, the associated scheduling information refers to scheduling information for the associated HARQ process number.

As an embodiment, receiving the first information triggers flipping the value of the NDI associated with the HARQ process number of the reset uplink HARQ process indicated by the first information.

As a sub-embodiment of this embodiment, the scheduling information indicating the value of NDI of the HARQ process number associated with the reset uplink HARQ process is scheduled.

As a sub-embodiment of this embodiment, the first MAC entity determines whether the NDI value is flipped based on the scheduling information indication.

As an embodiment, the benefits of the above method include: it can avoid resetting the uplink HARQ process.

As an embodiment, the number of HARQ processes supported by the first node is configurable.

As an embodiment, the number of HARQ processes supported by the first node is no less than 8.

As an embodiment, the number of HARQ processes supported by the first node is no less than 16.

As an embodiment, the number of uplink HARQ processes of the first node that have not been reset is no more than 4.

As an embodiment, the number of uplink HARQ processes of the first node that have not been reset is no more than 2.

As an embodiment, the number of uplink HARQ processes of the first node that has not been reset is no more than one.

As an embodiment, the first information implicitly indicates that the target cell will continue the HARQ process of the first node that has not been reset.

As an embodiment, only part of the HARQ processes of the first node are reset.

As an embodiment, the first cell delivers the data of the uplink HARQ process of the first node that has not been reset to the second cell.

As an embodiment, the data of the uplink HARQ process that has not been reset includes data in the HARQ cache.

As an embodiment, in the above method, the benefits of only partially resetting the uplink HARQ process include: achieving a good balance between communication continuity and complexity, including network load overhead, during cell handover.

As an embodiment, the first information is based on signaling of the first cell.

As an embodiment, the first cell determines whether to reset the uplink HARQ process according to the reception status of the ongoing HARQ process.

As an embodiment, the receiving condition includes: a signal-to-noise ratio of the received data.

As an embodiment, the receiving condition includes: a bit error rate of the received data.

As an embodiment, the reception condition includes: the number of HARQ transmissions that have been received.

As an embodiment, the reception condition includes: a redundant version of the HARQ transmission that has been received.

As an embodiment, the network may determine the threshold for determining whether to reset the uplink HARQ process based on the above reception situation based on long-term statistics or simulation.

As an embodiment, the network may determine which uplink HARQ processes to reset based on the current network load condition, for example, the load condition of the communication link between the first cell and the second cell.

As an embodiment, the network may determine whether to reset each uplink HARQ process according to the amount of data buffered in the uplink HARQ process.

As an embodiment, the first information indicates that at least one downlink HARQ process of the first node is reset.

As an embodiment, the meaning of resetting at least one downlink HARQ process of the first node includes: resetting the number of retransmissions of the at least one downlink HARQ process.

As an embodiment, the meaning of resetting at least one downlink HARQ process of the first node includes: resetting the redundant version of the at least one downlink HARQ process.

As an embodiment, the meaning that at least one downlink HARQ process of the first node is reset does not include: clearing the cache of the at least one downlink HARQ process.

As an embodiment, the benefits of the above method include: increasing the reliability of data reception during switching, reducing latency, and avoiding RLC retransmission. When the maximum number of RLC retransmissions is reached, a wireless link failure will be triggered, and the above method avoids wireless link failure.

As an embodiment, the first cell and the second cell are the source cell and the target cell in a non-RACH LTM process.

As an embodiment, in a non-RACH LTM cell handover, the RLC bearer of the first cell is not reestablished or reset.

As an embodiment, in a non-RACH LTM cell handover, the PDCP of the first cell is not re-established or reset.

As an embodiment, serving the first cell and the second cell includes communicating with the first cell through a first radio bearer and communicating with the second cell through a second radio bearer, and the first radio bearer and the second radio bearer are respectively associated with different security contexts.

As an embodiment, the different security contexts include different keys.

As an embodiment, the advantage of the above method is that it better supports inter-CU and inter-DU cell switching.

As an embodiment, the cell switching performed by the first node does not include resetting the first MAC entity.

As an embodiment, the partial resetting of the first MAC entity accompanying the receiving of the first information includes: first resetting the first MAC entity, and then serving the first cell and the second cell.

As an embodiment, the partially resetting the first MAC entity accompanying the receiving of the first information includes: when resetting the first MAC entity, only serving one of the first cell and the second cell.

As a sub-embodiment of this embodiment, the one of the serving first cell and the second cell is the first cell, and the first cell is a source cell.

As an embodiment, the above method has the advantage of reducing the impact of cell switching on the serving first cell and the second cell.

Example 2

Example 2 illustrates a schematic diagram of a network architecture according to the present application, as shown in FIG2 .

FIG2 illustrates a diagram of a network architecture 200 for 5G NR, LTE (Long-Term Evolution), and LTE-A (Long-Term Evolution Advanced) systems. The 5G NR or LTE network architecture 200 may be referred to as a 5G System (5GS)/EPS (Evolved Packet System) 200 or some other suitable terminology. The 5GS/EPS 200 may include one or more user equipment (UE) 201, an NG-RAN (Next Generation Radio Access Network) 202, a 5G Core Network (5GC)/EPC (Evolved Packet Core) 210, a Home Subscriber Server (HSS)/UDM (Unified Data Management) 220, and internet services 230. The 5GS/EPS may interconnect with other access networks, but these entities/interfaces are not shown for simplicity. As shown, the 5GS/EPS provides packet-switched services, but those skilled in the art will readily appreciate that the various concepts presented throughout this disclosure can be extended to networks providing circuit-switched services or other cellular networks. The NG-RAN includes an NR Node B (gNB) 203 and other gNBs 204. The gNB 203 provides user and control plane protocol termination towards the UE 201. The gNB 203 can be connected to other gNBs 204 via an Xn interface (e.g., backhaul). The gNB 203 may also be referred to as a base station, base transceiver station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), TRP (transmitter receive node), or some other appropriate terminology. The gNB 203 provides an access point to the 5GC/EPC 210 for the UE 201. Examples of UE 201 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop computer, a personal digital assistant (PDA), a satellite radio, non-terrestrial base station communications, satellite mobile communications, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a drone, an aircraft, a narrowband Internet of Things device, a machine type communication device, a land vehicle, an automobile, a wearable device, or any other similarly functional device. Those skilled in the art may also refer to UE 201 as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. The gNB 203 connects to the 5GC/EPC 210 via the S1/NG interface. The 5GC/EPC 210 includes the MME (Mobility Management Entity)/AMF (Authentication Management Field)/SMF (Session Management Function) 211, other MMEs/AMFs/SMFs 214, the S-GW (Service Gateway)/UPF (User Plane Function) 212, and the P-GW (Packet Data Network Gateway)/UPF 213. The MME/AMF/SMF 211 is the control node that handles signaling between the UE 201 and the 5GC/EPC 210. Generally, the MME/AMF/SMF 211 provides bearer and connection management. All user IP (Internet Protocol) packets are transmitted through the S-GW/UPF 212, which is itself connected to the P-GW/UPF 213. The P-GW provides UE IP address allocation and other functions. The P-GW/UPF 213 is connected to the Internet Services 230. The Internet Services 230 includes the operator's corresponding Internet Protocol services, which may include the Internet, intranet, IMS (IP Multimedia Subsystem), and packet-switched streaming services.

As an embodiment, the first node in this application is UE201.

As an embodiment, the base station of the second node in this application is gNB203.

As an embodiment, the wireless link from the UE201 to the NR node B is an uplink.

As an embodiment, the wireless link from the NR Node B to the UE 201 is a downlink.

As an embodiment, the UE 201 includes a mobile phone.

As an embodiment, the UE 201 is a dedicated device or special device with communication function.

As an embodiment, the gNB203 is a micro cell base station.

As an embodiment, the gNB203 is a pico cell base station.

As an embodiment, the gNB203 is a base station used in a home network.

As an embodiment, the gNB203 is a base station used in a private network.

As an embodiment, the gNB203 is a base station used in an enterprise network.

Example 3

Embodiment 3 illustrates a schematic diagram of an embodiment of a radio protocol architecture for a user plane and a control plane according to the present application, as shown in FIG3 . FIG3 is a schematic diagram illustrating an embodiment of a radio protocol architecture for a user plane 350 and a control plane 300. FIG3 illustrates the radio protocol architecture of the control plane 300 for a first node (UE, gNB) and a second node (gNB, UE), or between two UEs, using three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowest layer and implements various PHY (physical layer) signal processing functions. The L1 layer will be referred to herein as PHY 301. Layer 2 (L2 layer) 305 is above PHY 301 and is responsible for the link between the first and second nodes, as well as between two UEs, via PHY 301. The L2 layer 305 includes the MAC (Medium Access Control) sublayer 302, the RLC (Radio Link Control) sublayer 303, and the PDCP (Packet Data Convergence Protocol) sublayer 304, which terminate at the second node. The PDCP sublayer 304 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 304 also provides security by encrypting data packets and supports inter-node mobility of the first node between the second nodes. The RLC sublayer 303 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to HARQ. The MAC sublayer 302 provides multiplexing between logical and transport channels. The MAC sublayer 302 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell between the first nodes. The MAC sublayer 302 is also responsible for HARQ operations. The RRC (Radio Resource Control) sublayer 306 in Layer 3 (L3) of the control plane 300 is responsible for obtaining radio resources (i.e., radio bearers) and configuring lower layers using RRC signaling between the second node and the first node. The PC5-S (PC5 Signaling Protocol) sublayer 307 is responsible for processing the signaling protocol of the PC5 interface. The radio protocol architecture of the user plane 350 includes Layer 1 (L1) and Layer 2 (L2). The radio protocol architecture for the first and second nodes in the user plane 350 is generally the same as the corresponding layers and sublayers in the control plane 300, including the physical layer 351, the PDCP sublayer 354 in the L2 layer 355, the RLC sublayer 353 in the L2 layer 355, and the MAC sublayer 352 in the L2 layer 355. However, the PDCP sublayer 354 also provides header compression for upper layer packets to reduce radio transmission overhead. The L2 layer 355 in the user plane 350 also includes the SDAP (Service Data Adaptation Protocol) sublayer 356, which is responsible for mapping QoS flows and data radio bearers (DRBs) to support service diversity. SRBs can be considered as services or interfaces provided by the PDCP layer to higher layers, such as the RRC sublayer. In the NR system, SRBs include SRB1, SRB2, and SRB3, each used to transmit different types of control signaling. SRBs are bearers between the UE and the access network, used to transmit control signaling, including RRC signaling, between the UE and the access network. SRB1 is of special significance to the UE. After each UE establishes an RRC connection, it uses SRB1 to transmit RRC signaling. Most signaling is transmitted over SRB1. If SRB1 is interrupted or unavailable, the UE must perform RRC re-establishment. SRB2 is generally used only to transmit NAS signaling or security-related signaling. The UE does not need to configure SRB3. Except for emergency services, the UE must establish an RRC connection with the network for subsequent communications. Although not shown, the first node may have several upper layers above the L2 layer 355. In addition, it also includes a network layer (e.g., IP layer) terminated at the P-GW on the network side and an application layer terminated at the other end of the connection (e.g., remote UE, server, etc.). The protocol layer can also be called a protocol sublayer. Figure 3 shows a general protocol layer structure, and the nodes used in this application may lack some protocol layers.

As an embodiment, the wireless protocol architecture in FIG3 is applicable to the first node in this application.

As an embodiment, the wireless protocol architecture in FIG3 is applicable to the second node in this application.

As an embodiment, the first information in this application is generated in MAC302 or RRC306.

As an embodiment, the at least one candidate configuration in the present application is generated in RRC306.

As an embodiment, the first signaling in this application is generated in RRC306.

As an embodiment, the second signaling in this application is generated by MAC302.

As an embodiment, the third signaling in this application is generated by MAC302.

As an embodiment, the first MAC CE in this application is generated in MAC302.

Example 4

Embodiment 4 shows a schematic diagram of a first communication device and a second communication device according to an embodiment of the present application, as shown in Figure 4. Figure 4 is a block diagram of a first communication device 450 and a second communication device 410 communicating with each other in an access network.

The first communication device 450 includes a controller/processor 459, a memory 460, a data source 467, a transmit processor 468, a receive processor 456, and optionally may also include a multi-antenna transmit processor 457, a multi-antenna receive processor 458, a transmitter/receiver 454 and an antenna 452.

The second communication device 410 includes a controller/processor 475 , a memory 476 , a receive processor 470 , a transmit processor 416 , and optionally may also include a multi-antenna receive processor 472 , a multi-antenna transmit processor 471 , a transmitter/receiver 418 and an antenna 420 .

During transmission from the second communication device 410 to the first communication device 450, upper layer data packets from the core network are provided to the controller/processor 475 at the second communication device 410. The controller/processor 475 implements Layer 2 (L2) functionality. During transmission from the second communication device 410 to the first communication device 450, the controller/processor 475 provides header compression, encryption, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation to the first communication device 450 based on various priority metrics. The controller/processor 475 is also responsible for retransmission of lost packets and signaling to the first communication device 450. The transmit processor 416 and the multi-antenna transmit processor 471 implement various signal processing functions for the Layer 1 (i.e., physical layer). The transmit processor 416 implements coding and interleaving to facilitate forward error correction (FEC) at the second communication device 410, as well as mapping of signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), and M-quadrature amplitude modulation (M-QAM)). The multi-antenna transmit processor 471 performs digital spatial precoding, including codebook-based and non-codebook-based precoding, and beamforming on the coded and modulated symbols to generate one or more spatial streams. The transmit processor 416 then maps each spatial stream to a subcarrier, multiplexes it with a reference signal (e.g., a pilot) in the time and/or frequency domain, and then uses an inverse fast Fourier transform (IFFT) to generate a physical channel carrying the time-domain multicarrier symbol stream. The multi-antenna transmit processor 471 then performs transmit analog precoding/beamforming operations on the time-domain multicarrier symbol stream. Each transmitter 418 converts the baseband multi-carrier symbol stream provided by the multi-antenna transmit processor 471 into a radio frequency stream, and then provides it to a different antenna 420.

During transmission from the second communication device 410 to the first communication device 450, at the first communication device 450, each receiver 454 receives a signal via its corresponding antenna 452. Each receiver 454 recovers the information modulated onto the RF carrier and converts the RF stream into a baseband multi-carrier symbol stream, which is provided to the receive processor 456. The receive processor 456 and the multi-antenna receive processor 458 implement various L1 signal processing functions. The multi-antenna receive processor 458 performs receive analog precoding/beamforming operations on the baseband multi-carrier symbol stream from the receiver 454. The receive processor 456 converts the baseband multi-carrier symbol stream, after the receive analog precoding/beamforming operations, from the time domain to the frequency domain using a fast Fourier transform (FFT). In the frequency domain, the receive processor 456 demultiplexes the physical layer data signal and reference signal, where the reference signal is used for channel estimation. The data signal undergoes multi-antenna detection in the multi-antenna receive processor 458 to recover any spatial streams destined for the first communication device 450. The symbols on each spatial stream are demodulated and recovered in the receive processor 456, and soft decisions are generated. The receive processor 456 then decodes and deinterleaves the soft decisions to recover the upper layer data and control signals transmitted by the second communication device 410 on the physical channel. The upper layer data and control signals are then provided to the controller/processor 459. The controller/processor 459 implements the functions of the L2 layer. The controller/processor 459 may be associated with a memory 460 that stores program code and data. The memory 460 may be referred to as a computer-readable medium. During transmission from the second communication device 410 to the second communication device 450, the controller/processor 459 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover upper layer data packets from the core network. The upper layer data packets are then provided to all protocol layers above the L2 layer. Various control signals may also be provided to the L3 layer for L3 processing.

During transmission from the first communication device 450 to the second communication device 410, a data source 467 is used at the first communication device 450 to provide upper layer data packets to the controller/processor 459. The data source 467 represents all protocol layers above the L2 layer. Similar to the transmission functionality at the second communication device 410 described in the transmission from the second communication device 410 to the first communication device 450, the controller/processor 459 implements header compression, encryption, packet segmentation and reordering, and multiplexing between logical and transport channels based on radio resource allocation, implementing L2 layer functions for the user plane and control plane. The controller/processor 459 is also responsible for retransmission of lost packets and signaling to the second communication device 410. The transmit processor 468 performs modulation mapping and channel coding, while the multi-antenna transmit processor 457 performs digital multi-antenna spatial precoding, including codebook-based and non-codebook-based precoding, and beamforming. The transmit processor 468 then modulates the resulting spatial stream into a multi-carrier/single-carrier symbol stream. After analog precoding and beamforming operations in the multi-antenna transmit processor 457, the stream is provided to different antennas 452 via the transmitter 454. Each transmitter 454 first converts the baseband symbol stream provided by the multi-antenna transmit processor 457 into a RF symbol stream before providing it to the antenna 452.

During transmission from the first communications device 450 to the second communications device 410, the functionality at the second communications device 410 is similar to the reception functionality at the first communications device 450 described for transmission from the second communications device 410 to the first communications device 450. Each receiver 418 receives RF signals via its corresponding antenna 420, converts the received RF signals into baseband signals, and provides the baseband signals to a multi-antenna receive processor 472 and a receive processor 470. The receive processor 470 and the multi-antenna receive processor 472 collectively implement L1 layer functionality. A controller/processor 475 implements L2 layer functionality. The controller/processor 475 may be associated with a memory 476 storing program codes and data. The memory 476 may be referred to as a computer-readable medium. During transmission from the first communications device 450 to the second communications device 410, the controller/processor 475 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover upper layer data packets from the UE 450. Upper layer packets from controller/processor 475 may be provided to the core network.

As an embodiment, the first communication device 450 apparatus includes: at least one processor and at least one memory, the at least one memory including computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor, and the first communication device 450 apparatus at least: receives first information, the first information indicating that the first MAC entity of the first node serves the first cell and the second cell, wherein one of the first cell and the second cell is the source cell and the other is the target cell; the serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the first communication device 450 includes: a memory storing a computer-readable instruction program, the computer-readable instruction program generating an action when executed by at least one processor, the action including: receiving first information, the first information indicating that the first MAC entity of the first node serves the first cell and the second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the first communication device 450 corresponds to the first node in this application.

As an embodiment, the second communication device 410 corresponds to the second node in this application.

As an embodiment, the first communication device 450 is a UE.

As an embodiment, the first communication device 450 is a mobile phone.

As an embodiment, the second communication device 450 is a relay.

As an embodiment, the second communication device 410 is a base station.

As an embodiment, the receiver 454 (including the antenna 452 ), the receive processor 456 , and the controller/processor 459 are used to receive the at least one candidate configuration in the present application.

As an embodiment, the receiver 454 (including the antenna 452 ), the receiving processor 456 and the controller/processor 459 are used to receive the first signaling in this application.

As an embodiment, the receiver 454 (including the antenna 452 ), the receiving processor 456 and the controller/processor 459 are used to receive the second signaling in this application.

As an embodiment, the receiver 454 (including the antenna 452 ), the receiving processor 456 and the controller/processor 459 are used to receive the third signaling in this application.

As an embodiment, the receiver 454 (including the antenna 452 ), the receiving processor 456 and the controller/processor 459 are used to receive the first information in the present application.

As an embodiment, a receiver 454 (including an antenna 452), a receiving processor 456 and a controller/processor 459 are used to receive the first MAC CE in this application.

As an embodiment, the transmitter 454 (including the antenna 452), the transmit processor 468 and the controller/processor 459 are used to send the second MAC CE in the present application.

Example 5

Example 5 illustrates a wireless signal transmission flow chart according to an embodiment of the present application, as shown in Figure 5. In Figure 5, U01 corresponds to the first node of the present application. It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present application, wherein the steps in F51 and F52 are optional.

For the first node U01 , the first signaling is received in step S5101; the second signaling is received in step S5102; the first information is received in step S5103; the cell switching is performed in step S5104; the first MAC entity serves the first cell and the second cell in step S5105; the first MAC CE is received in step S5106; the cell switching is completed in step S5107; and the first MAC entity serves the second cell in step S5108.

For the second node U02 , the first signaling is sent in step S5201; the second signaling is sent in step S5202; and the first information is sent in step S5203.

In Example 5, the first information indicates that the first MAC entity of the first node serves the first cell and the second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the second node U02 is a base station corresponding to the PCell of the first node U01.

As an embodiment, the second node U02 is the service cell of the first node or the base station corresponding to the service cell.

As an embodiment, the second node U02 belongs to a cellular network.

As an embodiment, the second node U02 corresponds to the source cell.

As an embodiment, the second signaling U02 is the first cell or the base station corresponding to the first cell.

As an embodiment, the numbering sequence of the steps shown in FIG5 is the chronological sequence.

As an embodiment, the second node U02 sends the at least one candidate configuration through the first signaling.

As an embodiment, before step S5101, the first node U01 indicates to the second node U02 that LTM cell switching is supported.

As an embodiment, before step S5101, the first node U01 indicates to the second node U02 that non-RACH LTM cell switching is supported.

As an embodiment, before step S5101, the first node U01 indicates to the second node U02 that UE-based timing advance is supported.

As an embodiment, the first signaling is RRC signaling.

As an embodiment, the first signaling is unicast.

As an embodiment, the second signaling is MAC layer control signaling.

As an embodiment, the first signaling includes a first parameter and at least one candidate configuration.

As an embodiment, the first parameter is for the first cell.

As an embodiment, the first candidate configuration is for the second cell.

As an embodiment, any candidate configuration of the at least one candidate configuration is for a candidate target cell.

As an embodiment, any candidate configuration among the at least one candidate configuration is used to configure unlimited resources of the candidate target cell.

As an embodiment, any candidate configuration of the at least one candidate configuration is used to configure system information of the candidate target cell.

As an embodiment, any candidate configuration of the at least one candidate configuration is used to configure the PUCCH of the first node U01 in the candidate target cell.

As an embodiment, any candidate configuration of the at least one candidate configuration is used to configure the identifier of the first node U01 in the candidate target cell.

As an embodiment, any candidate configuration of the at least one candidate configuration is used to configure a timer of the candidate target cell for detecting radio link failure.

As an embodiment, any candidate configuration of the at least one candidate configuration is used to configure the beam or spatial parameters of the candidate target cell.

As an embodiment, the at least one candidate configuration includes a first candidate configuration.

As an embodiment, the first candidate configuration includes a second parameter.

As an embodiment, the second signaling indicates the first candidate configuration.

As an embodiment, the second signaling indicates cell switching.

As an embodiment, the second signaling triggers step S5104.

As an embodiment, step S5104 includes: setting the value of the second parameter to the value of the first parameter.

As an embodiment, the serving first cell and the second cell depend on the second parameter being equal to the first parameter.

As an embodiment, the serving of the first cell and the second cell depends on the second parameter being equal to the first parameter, including: when the value of the first parameter is equal to the second parameter, the first MAC entity serves the first cell and the second cell.

As an embodiment, the serving of the first cell and the second cell depends on the second parameter being equal to the first parameter, including: when the value of the first parameter is not equal to the second parameter, the first MAC entity only serves one of the first cell and the second cell.

As an embodiment, the above method has the following advantages: it can effectively control the source cell and candidate target cells that are served simultaneously; it can support continuous LTM cell switching, reduce signaling overhead, and shorten switching delay.

As an embodiment, the first information is received after step S5102.

As an embodiment, the first information is received before step S5102, and after the second signaling is received, the signaling indicated by the first information is executed.

As an embodiment, the first information is received from the second node U02.

As an embodiment, the first information is triggered or generated by signaling received from the second node U02.

As an embodiment, step S5104 refers to triggering or starting to execute cell switching.

As an embodiment, step S5104 will last for a certain period of time, and the cell switching process may be performed in parallel with step S5105 and/or S5106.

As an embodiment, step S5108 is performed later than step S5107.

As an embodiment, completion of the cell switching triggers the first MAC entity to serve the second cell and no longer serve the first cell.

As an embodiment, the first MAC entity indicates to a higher layer whether the first MAC CE is received from the first cell or the second cell.

As an embodiment, the first MAC entity indicating to a higher layer includes: indicating to the RRC sublayer.

As an embodiment, the benefits of the above method include: being conducive to simultaneously supporting the reception of MAC CE from the first cell and the second cell, and avoiding interference between the two cells.

As an embodiment, the first MAC CE is received from the second node U02.

As an embodiment, the first MAC CE is received from the second cell.

As an embodiment, the logical channel of MAC CE is fixed, so it is necessary to indicate to the higher layer which cell it is received from to avoid misoperation.

As an embodiment, the first cell and the second cell independently send MAC CE.

As an embodiment, the first MAC CE is any MAC CE received by the first node during the service of the first cell and the second cell.

As an embodiment, during the service of the first cell and the second cell, the first node only receives some types of MAC CEs sent by the second cell.

As an embodiment, during the service of the first cell and the second cell, the first node only receives some types of MAC CEs sent by the first cell.

As an embodiment, the benefits of the above method include: reducing complexity.

Example 6

Example 6 illustrates a flowchart of the interaction between the first cell and the second cell according to an embodiment of the present application, as shown in Figure 6. In Figure 6, U11 corresponds to the first cell of the present application, and U12 corresponds to the second cell of the present application. It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present application.

For the first cell U11 , first configuration information is sent in step S6101; and a handover completion indication is received in step S6102.

For the second cell U12 , first configuration information is received in step S6201; and a handover completion indication is sent in step S6202.

As an embodiment, the first configuration information is sent before the first node performs cell switching.

As an embodiment, the first configuration information is sent before the second signaling.

As an embodiment, the first configuration information is sent before the first signaling.

As an embodiment, the first configuration information is sent after the first signaling.

As an embodiment, the first configuration information is sent through an interface between cells.

As an embodiment, the first configuration information is sent via an interface between wireless access networks.

As an embodiment, the first configuration information queries whether the first node is allowed to serve the first cell and the second cell simultaneously.

As an embodiment, the first configuration information indicates that the first node will be allowed to serve the first cell and the second cell simultaneously.

As an embodiment, the first configuration information indicates frequency information when the second cell communicates with the first node.

As an embodiment, the first configuration information indicates frequency information when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates a radio bearer when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates an identifier of a radio bearer when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates an identifier of an RLC bearer when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates an identifier of a signaling radio bearer when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates a logical channel identifier used when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates a logical channel identifier allocated by the first cell to the first node.

As an embodiment, the first configuration information indicates the capacity occupied by the first cell when communicating with the first node.

As an embodiment, the first configuration information indicates the expected capacity of the second cell to be occupied when communicating with the first node.

As an embodiment, the first configuration information indicates expected power information of the second cell when communicating with the first node.

As an embodiment, the first configuration information indicates power information when the first cell communicates with the first node.

As an embodiment, the first configuration information indicates resources that are prohibited from being used when the second cell communicates with the first node.

As an embodiment, the first configuration information indicates a configuration that is prohibited from being used when the second cell communicates with the first node.

As an embodiment, the first configuration information indicates the maximum number of HARQ processes when the second cell communicates with the first node.

As an embodiment, the first configuration information indicates an upper limit of resources that can be used by the second cell when communicating with the first node.

As an embodiment, the first configuration information indicates that the second cell can communicate with the first node at a highest bit rate.

As an embodiment, the first configuration information indicates the configuration of the measurement gap when the second cell communicates with the first node.

As an embodiment, when the first MAC entity is in a non-RACH LTM cell switching period, the first MAC entity monitors the PDCCH within the measurement gap.

As an embodiment, the first configuration information indicates the search space or PDCCH configuration when the second cell communicates with the first node.

As an embodiment, the first configuration information indicates the PUCCH configuration when the second cell communicates with the first node.

As an embodiment, the communication between the second cell and the first cell indicated by the first configuration information refers to the communication between the first node and the second cell when the first node serves the first cell and the second cell simultaneously.

As an embodiment, the first configuration information indicates the maximum number of SCells allowed to be configured in the second cell during the switching process.

As an embodiment, the first configuration information indicates the maximum number of SCells used by the first cell during the switching process.

As an embodiment, the first configuration information indicates the number of deactivated cells used by the first cell during the switching process.

As an embodiment, the first configuration information indicates the measurement configuration of the first cell configuration.

As an embodiment, sharing measurement configuration is beneficial to avoiding repeated configuration of measurements and saving resources.

As an embodiment, the first configuration information may include multiple sub-information.

As an embodiment, the first configuration information indicates whether the first MAC entity is reset.

As an embodiment, the first configuration information indicates whether layer 2 of the first node is reset.

As an embodiment, the first configuration information indicates a recommended count (COUNT).

As an embodiment, the recommended count is used for encryption when the second cell communicates with the first node.

As an embodiment, upon receiving an indication of completion of the connection, the first cell stops sending to the first node.

As an embodiment, upon receiving an indication of completion of the integration, the first cell stops receiving from the first node.

As an embodiment, upon receiving an indication of completion of the integration, the first cell releases resources of the first node.

Example 7

Example 7 illustrates a schematic diagram of the structure of a MAC PDU according to an embodiment of the present application, as shown in Figure 7.

As an embodiment, Figure 7 shows the structure of the MAC PDU applicable to this application.

As an embodiment, the MAC header in a MAC PDU may be missing, that is, a MAC PDU only includes at least one MAC sub-PDU (subPDU).

As an embodiment, the structure of the MAC PDU in FIG7 is conducive to speeding up processing.

As an embodiment, each MAC sub-PDU includes a MAC sub-header or a header of a MAC sub-PDU.

As an embodiment, each MAC sub-PDU may include only a MAC sub-header, or may also include a MAC CE of size 0.

As an embodiment, each MAC sub-PDU includes only one MAC CE or one MAC SDU.

As an embodiment, the MAC SDU corresponds to RLC PDU.

As an embodiment, a MAC PDU carries either data of the first cell or data of the second cell.

As an embodiment, the MAC PDU may also include padding bits.

As an embodiment, when a MAC sub-PDU is received and the MAC sub-PDU carries a MAC CE, the first MAC entity reports to a higher layer, such as the RRC sublayer, whether the received MAC CE is from the first cell or the second cell.

As an embodiment, the higher layers of the first MAC entity only process some types of MAC CEs from the first cell.

As an embodiment, the partial type includes deactivated SCell or SCG.

As an embodiment, the partial type includes deactivating PDCP duplication.

As an embodiment, the partial type includes timing advance signaling.

As an embodiment, the first node sends a second MAC CE while serving the first cell and the second cell during switching.

As an embodiment, during serving the first cell and the second cell in switching, the first node only sends some types of MAC CE to the first cell.

As a sub-embodiment of this embodiment, the second MAC CE is only allowed to be the said part of types of MAC CE for the first cell.

As an embodiment, during serving the first cell and the second cell in switching, the first node only sends some types of MAC CE to the second cell.

As a sub-embodiment of this embodiment, the second MAC CE is only allowed to be the said part of types of MAC CE for the second cell.

As an embodiment, during serving the first cell and the second cell in switching, the partial type of MAC CE sent by the first MAC entity to the first cell includes at least one MAC CE that does not belong to the partial type sent to the second cell.

As an embodiment, during serving the first cell and the second cell in switching, the partial type of MAC CE sent by the first MAC entity to the second cell includes at least one MAC CE that does not belong to the partial type sent to the first cell.

As an embodiment, the above method has the advantage of avoiding interference between two cells during communication and reducing complexity.

As an embodiment, the serving of the first cell and the second cell includes: receiving MAC subPDUs with logical channel identifiers associated with SRBs (signaling radio bearers) from the first cell and the second cell, and receiving MAC subPDUs with logical channel identifiers associated with MAC CEs only from one of the first cell and the second cell.

As an embodiment, the meaning of receiving the MAC subPDU of the logical channel identifier associated SRB from the first cell and the second cell includes: the first node receives the RRC signaling of the first cell and also receives the RRC signaling of the second cell.

As an embodiment, the logical channel identifier associated SRB received from the first cell and the second cell includes one of SRB1, SRB2, SRB3, SRB4, and SRB5.

As an embodiment, the receiving of the logical channel identifier associated SRB from the first cell and the second cell means that the logical channel is for the SRB.

As an embodiment, the receiving of the logical channel identifier associated SRB from the first cell and the second cell means that the logical channel identifier associated with the SRB1 of the first cell is different from the logical channel identifier associated with the SRB1 of the second cell.

As an embodiment, the receiving of logical channel identifier associated SRBs from the first cell and the second cell means that the RRC signaling of the first cell is sent to the first node through SRB1, and the RRC signaling of the second cell is sent to the first node through an SRB other than SRB1.

As an embodiment, the receiving of logical channel identifier associated SRBs from the first cell and the second cell means that the RRC signaling of the first cell is sent to the first node through SRB2, and the RRC signaling of the second cell is sent to the first node through an SRB other than SRB2.

As an embodiment, the receiving of logical channel identifier associated SRBs from the first cell and the second cell means that the RRC signaling of the first cell is sent to the first node through SRB3, and the RRC signaling of the second cell is sent to the first node through SRB other than SRB3.

As an embodiment, the benefit of the above method is that it reduces the complexity of signaling reception.

As an embodiment, the first node only receives the MAC subPDU of the logical channel identifier associated MAC CE from one of the first cell and the second cell.

As an embodiment, the meaning of the first node receiving the MAC subPDU of the logical channel identifier associated MAC CE only from one of the first cell and the second cell is: the first node receives the MAC CE only from the first cell, but not from the second cell, or the first node receives the MAC CE only from the second cell, but not from the first cell.

As an embodiment, the above method has the advantage of reducing the complexity of control during switching.

Example 8

Embodiment 8 illustrates a schematic diagram of serving a first cell and a second cell depending on the running of a first timer according to an embodiment of the present application, as shown in FIG8 .

As an embodiment, the serving of the first cell and the second cell depends on the first timer being running, which means that when the first timer is running, the first MAC entity serves the first cell and the second cell.

As an embodiment, the serving of the first cell and the second cell depends on the first timer being running, which means that when the first timer is not running, the first MAC entity serves one of the first cell and the second cell.

As an embodiment, the serving of the first cell and the second cell depends on the running of the first timer, which means that the first timer stops triggering the first MAC entity to stop serving the first cell.

As an embodiment, the serving of the first cell and the second cell depends on the running of the first timer, which means that the expiration of the first timer triggers the first MAC entity to stop serving the first cell.

As an embodiment, a first timer is started along with the receiving of the first information.

As an embodiment, the first timer is started when a cell handover is performed.

As an embodiment, the first timer is stopped when the cell switching is completed.

As an embodiment, when the first timer expires, the cell switching fails.

As an embodiment, expiration of the first timer triggers RRC connection reestablishment.

As an embodiment, the stopping of the first timer triggers the first MAC entity to serve only one of the first cell and the second cell.

As an embodiment, the first timer is T304.

As an embodiment, the first timer is T304a.

As an embodiment, the first timer is T304b.

As an embodiment, the first timer is for LTM cell switching.

As an embodiment, the first timer is for non-RACH LTM cell switching.

Example 9

Embodiment 9 illustrates a structural block diagram of a processing device in a first node according to an embodiment of the present application, as shown in FIG9 . In FIG9 , the processing device 900 in the first node includes a first receiver 901 and a first transmitter 902 .

In Example 9, a first receiver 1001 receives first information, wherein the first information indicates that a first MAC entity of the first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.

As an embodiment, the first information indicates that the second cell is added to the cell group to which the first cell belongs and remains in a deactivated state;

After the cell switching starts, the second cell is activated; when the cell switching is completed, the first cell is deactivated or released.

As an embodiment, the first information indicates the reset uplink HARQ process of the first node.

As an embodiment, the first cell and the second cell are the source cell and the target cell in a non-RACH LTM process.

As an embodiment, the first receiver 1001 receives first signaling and second signaling, wherein the first signaling includes a first parameter and at least one candidate configuration, the at least one candidate configuration includes a first candidate configuration, the first candidate configuration includes a second parameter, and the second signaling indicates the first candidate configuration and cell switching; performing the cell switching includes: setting the value of the second parameter to the value of the first parameter;

The serving of the first cell and the second cell depends on the second parameter being equal to the first parameter; the first signaling is the signaling of the RRC sublayer, and the second signaling is MAC CE.

As an embodiment, the serving first cell and the serving second cell rely on the first timer being running.

As an embodiment, the first receiver 1001 starts a first timer along with the reception of the first information, and the expiration of the first timer triggers RRC connection reconstruction; the stopping of the first timer triggers the first MAC entity to serve only one of the first cell and the second cell.

As an embodiment, the first receiver 1001 receives a first MAC CE;

In which, the first MAC entity indicates to a higher layer whether the first MAC CE is received from the first cell or the second cell.

As an embodiment, the serving of the first cell and the second cell includes: receiving a MAC subPDU with an SRB associated with a logical channel identifier from the first cell and the second cell, and receiving a MAC subPDU with a MAC CE associated with a logical channel identifier only from one of the first cell and the second cell.

As an embodiment, the first receiver 901 receives a third signaling, and the third signaling configures a first RLC bearer of the first cell and a second RLC bearer of the second cell, wherein the first RLC bearer of the first cell serves the SRB1 of the first cell, and the second RLC bearer of the second cell serves the SRB1 of the second cell, and the service of the first cell and the second cell includes simultaneously serving the SRB1 of the first cell and the SRB1 of the second cell.

As an embodiment, serving the first cell and the second cell includes communicating with the first cell through a first radio bearer and communicating with the second cell through a second radio bearer, and the first radio bearer and the second radio bearer are respectively associated with different security contexts.

As an embodiment, the first node is a user equipment (UE).

As an embodiment, the first node is a mobile phone.

As an embodiment, the first node is a communication device that supports low latency.

As an embodiment, the first node is an industrial communication device.

As an embodiment, the first node is an Internet of Things terminal or an industrial Internet of Things terminal.

As an embodiment, the first receiver 901 includes at least one of the antenna 452, receiver 454, receiving processor 456, multi-antenna receiving processor 458, controller/processor 459, memory 460, or data source 467 in Example 4.

As an embodiment, the first transmitter 902 includes at least one of the antenna 452, transmitter 454, transmit processor 468, multi-antenna transmit processor 457, controller/processor 459, memory 460, or data source 467 in Example 4.

A person skilled in the art will understand that all or part of the steps in the above method can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a hard disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module unit in the above embodiment can be implemented in the form of hardware or in the form of a software functional module. The present application is not limited to any specific form of combination of software and hardware. The user equipment, terminal and UE in the present application include but are not limited to drones, communication modules on drones, remote-controlled aircraft, aircraft, small aircraft, mobile phones, tablet computers, notebooks, vehicle-mounted communication equipment, wireless sensors, network cards, Internet of Things terminals, RFID terminals, NB-IoT terminals, MTC (Machine Type Communication) terminals, eMTC (enhanced MTC) terminals, data cards, network cards, vehicle-mounted communication equipment, low-cost mobile phones, low-cost tablet computers, satellite communication equipment, ship communication equipment, NTN user equipment and other wireless communication equipment. The base stations or system equipment in this application include but are not limited to macrocell base stations, microcell base stations, home base stations, relay base stations, gNB (NR Node B) NR Node B, TRP (Transmitter Receiver Point), NTN base stations, satellite equipment, flight platform equipment and other wireless communication equipment.

The present invention may be implemented in other specific forms without departing from its core or essential characteristics. Therefore, the presently disclosed embodiments should be considered in all respects as illustrative and not restrictive. The scope of the invention is determined by the appended claims, not the foregoing description, and all modifications that come within the meaning and range of equivalents are intended to be embraced therein.

Claims (10)

A first node used for mobility management in wireless communication, comprising: A first receiver receives first information, wherein the first information indicates that the first MAC entity of the first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell. The first node according to claim 1, characterized in that The first information indicates that the second cell is added to the cell group to which the first cell belongs and remains in a deactivated state; After the cell switching starts, the second cell is activated; when the cell switching is completed, the first cell is deactivated or released. The first node according to claim 1 or 2, characterized in that The first information indicates the reset uplink HARQ process of the first node. The first node according to any one of claims 1 to 3, characterized in that The first cell and the second cell are a source cell and a target cell in a non-RACH LTM process. The first node according to any one of claims 1 to 4, characterized by comprising: the first receiver, receiving first signaling and second signaling, wherein the first signaling includes a first parameter and at least one candidate configuration, the at least one candidate configuration includes a first candidate configuration, the first candidate configuration includes a second parameter, and the second signaling indicates the first candidate configuration and cell switching; performing the cell switching, comprising: setting the value of the second parameter to the value of the first parameter; The serving of the first cell and the second cell depends on the second parameter being equal to the first parameter; the first signaling is the signaling of the RRC sublayer, and the second signaling is MAC CE. The first node according to any one of claims 1 to 5, characterized in that The serving first cell and the second cell depend on the first timer being running. The first node according to any one of claims 1 to 6, characterized in that it comprises: The first receiver starts a first timer along with the reception of the first information, and the expiration of the first timer triggers RRC connection reconstruction; the stopping of the first timer triggers the first MAC entity to serve only one of the first cell and the second cell. The first node according to any one of claims 1 to 7, characterized in that it comprises: The first receiver receives a first MAC CE; In which, the first MAC entity indicates to a higher layer whether the first MAC CE is received from the first cell or the second cell. The first node according to any one of claims 1 to 8, characterized in that The serving of the first cell and the second cell includes: receiving MAC subPDUs with logical channel identifiers associated with SRBs from the first cell and the second cell, and receiving MAC subPDUs with logical channel identifiers associated with MAC CEs only from one of the first cell and the second cell. A method in a first node for mobility management in wireless communication, comprising: Receive first information, the first information indicating that the first MAC entity of the first node serves a first cell and a second cell, wherein one of the first cell and the second cell is a source cell and the other is a target cell; serving the first cell and the second cell includes: receiving a MAC PDU from the first cell or sending a MAC PDU to the first cell, and receiving a MAC PDU from the second cell or sending a MAC PDU to the second cell.