METHOD, DEVICE AND COMPUTER STORAGE MEDIUM OF COMMUNICATION

Embodiments of the present disclosure relate to methods, devices and computer readable media for communication. A terminal device receives a set of configurations for a set of candidate cells. The terminal device determines a reference configuration, and applies, based on the reference configuration, a configuration for a candidate cell in the set of configurations. In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices and computer storage media of communication for a radio resource control (RRC) configuration.

BACKGROUND

Currently, a delta configuration is supported for signaling amount reduction and lossless transmission. For example, in case of a handover (HO), a source network device may transmit, to a target network device, a current RRC configuration in a HO request message, and the target network device may respond with a delta configuration with respect to the current RRC configuration. As another example, in case of primary cell (PScell) of a secondary node (SN) change, a master node (MN) may provide current secondary cell group (SCG) configuration of a source SN to a target SN in a SCG addition request message, and the target SN may only provide a delta configuration with respect to the current SCG configuration.

However, in case of a subsequent cell change, e.g., for a conditional cell change, a layer 1 (L1)/layer 2 (L2) based mobility or the like, the above delta configuration behavior may result in wrong configuration being applied by a terminal device or even reconfiguration failure. This is because the delta configuration is built on the basis of a source cell, but the delta configuration will be applied at a terminal device to a current serving cell changing during the subsequent cell change.

SUMMARY

Embodiments of the present disclosure provide methods, devices and computer storage media of communication for a RRC configuration.

In a first aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a first network device, a set of configurations for a set of candidate cells; determining a reference configuration; and applying, based on the reference configuration, a configuration for a candidate cell in the set of configurations.

In a second aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a first network device, a set of configurations for a set of candidate cells; and in accordance with a determination that a cell change or addition to a candidate cell in the set of candidate cells is to be performed, applying a configuration for the candidate cell in the set of configurations, wherein the configuration for the candidate cell is the same as a configuration for a serving cell of the terminal device or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In a third aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a first network device, a set of full configurations for a set of candidate cells; and in accordance with a determination that a cell change or addition to a candidate cell in the set of candidate cells is to be performed, applying a configuration for the candidate cell in the set of full configurations.

In a fourth aspect, there is provided a method of communication. The method comprises: transmitting, at a first network device and to a terminal device, a set of configurations for a set of candidate cells, and an indication indicating a configuration for one of a set of candidate cells as a reference configuration.

In a fifth aspect, there is provided a method of communication. The method comprises: transmitting, at a first network device and to a terminal device, a set of configurations for a set of candidate cells, wherein a configuration for a candidate cell in the set of candidate cells is the same as a configuration for a serving cell of the terminal device or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In a sixth aspect, there is provided a method of communication. The method comprises: transmitting, at a first network device and to a terminal device, a set of configurations for a set of candidate cells, a configuration in the set of configurations being a full configuration for a candidate cell.

In a seventh aspect, there is provided a terminal device. The terminal device comprises a processor configured to cause the terminal device to perform the method according to any of the first to three aspects of the present disclosure.

In an eighth aspect, there is provided a network device. The network device comprises a processor configured to cause the network device to perform the method according to any of the fourth to sixth aspects of the present disclosure.

In a ninth aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method according to any of the first to three aspects of the present disclosure.

In a tenth aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method according to any of the fourth to sixth aspects of the present disclosure.

Other features of the present disclosure will become easily comprehensible through the following description.

DETAILED DESCRIPTION

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE), personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB), Small Data Transmission (SDT), mobility, Multicast and Broadcast Services (MBS), positioning, dynamic/flexible duplex in commercial networks, reduced capability (RedCap), Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS), extended Reality (XR) devices including different types of realities such as Augmented Reality (AR), Mixed Reality (MR) and Virtual Reality (VR), the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST), or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporated one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

The term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a next generation NodeB (gNB), a transmission reception point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS), Network-controlled Repeaters, and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency band larger than 100 GHz as well as Tera Hertz (THz). It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connections with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The network device may have the function of network energy saving, Self-Organising Networks (SON)/Minimization of Drive Tests (MDT). The terminal may have the function of power saving.

The embodiments of the present disclosure may be performed in test equipment, e.g. signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.

In one embodiment, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In one embodiment, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

As used herein, the singular forms ‘a’, ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to.’ The term ‘based on’ is to be read as ‘at least in part based on.’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment.’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment.’ The terms ‘first,’ ‘second,’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best,’ ‘lowest,’ ‘highest,’ ‘minimum,’ ‘maximum,’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

In the context of the present disclosure, the term “RRC configuration” may be interchangeably used with “radio resource configuration” or “configuration”. The term “delta configuration” may be interchangeably used with “delta radio resource configuration” or “delta RRC configuration”. The “RRC configuration” of one candidate cell is carried in one RRC Reconfiguration message when transmitted from a network device to the terminal device, or transmitted from one network device to another network device. “Applying one RRC configuration by the terminal device” can be referred to as “applying the RRC reconfiguration message”. The term “configuration for one candidate cell” may be referred to as “configuration associated with one candidate cell”.

As known, when a terminal device moves from a coverage area of one cell to that of another cell, a serving cell change needs to be performed at some point. Currently, a serving cell change is triggered by layer 3 (L3) measurements and is done by RRC signaling trigged reconfiguration with synchronization for change of a primary cell (PCell) of a MN and PSCell, as well as release for SCell if applicable. All these cases involve complete L2 and L1 resets, leading to a longer latency, larger overhead and longer interruption time than beam switch mobility. As a solution, a data transmission is performed with a change of a serving cell upon reception of a lower layer signaling such as L1 or L2 signaling, which is referred to as a L1/L2 based mobility. A goal of the L1/L2 based mobility is to enable a serving cell change via a lower layer signaling, in order to reduce the latency, overhead and interruption time.

For a conditional PSCell change (CPC)/conditional PSCell addition (CPA) in third generation partnership project (3GPP) Release 17, a CPC/CPA-configured terminal device has to release a CPC/CPA configuration when completing random access towards a target PSCell. Hence the terminal device has no chance to perform subsequent CPC/CPA without prior CPC/CPA reconfiguration and re-initialization from the network side. This will increase a delay for a cell change and increase signaling overhead, especially in the case of frequent SCG changes when operating in FR2. Therefore, multi-random access technology dual connectivity (MR-DC) with selective activation of cell groups aims at enabling subsequent CPC/CPA after SCG change, without reconfiguration and re-initialization on a CPC/CPA preparation from the network side. This results in a reduction of signaling overhead and an interrupting time for SCG change.

As mentioned above, a delta configuration is built on the basis of a source cell. For a subsequent CPC or subsequent L1/L2 based mobility, if a terminal device applies the delta configuration to the current serving cell and the current serving cell is different from the source cell, a wrong SCG configuration or even reconfiguration failure may occur.

Embodiments of the present disclosure provide solutions for a RRC configuration so as to solve the above or other potential issues. In one aspect, a terminal device receives a set of configurations for a set of candidate cells. The set of configurations are delta configurations. In this case, the terminal device determines a reference configuration, and applies a configuration for a candidate cell in the set of configurations based on the reference configuration. In this way, a delta configuration can be supported for a subsequent conditional PCell or PSCell change or subsequent L1/L2 based mobility.

In another aspect, a configuration for a candidate cell in the set of configurations is the same as a configuration for a serving cell of the terminal device or a configuration for a further candidate cell in the set of configurations, except for at least one of an identity, a timer, a dedicated random access channel configuration or a measurement configuration for a candidate cell. In this way, a delta configuration also can be supported for a subsequent conditional PCell or PSCell change or subsequent L1/L2 based mobility.

In still another aspect, configurations in the set of configurations are full configurations. In this way, the above issue for a delta configuration may be resolved.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

Example of Communication Network

FIG.1illustrates a schematic diagram of an example communication environment100in which embodiments of the present disclosure can be implemented. As shown inFIG.1, the communication environment100may comprise a network device110and a terminal device120. The network device110provides a cell111and the terminal device120is located in the cell111and served by the network device110.

The communication environment100may also comprise one or more other network devices such as network devices130,140and150. The network device130provides cells131,132and133. The network device140provides cells141,142and143, and the network device150provides cells151,152and153. It should be noted that the number of the cells are not limited to three, and more or less cells are also configured for the terminal device110.

Assuming that the terminal device120may establish a dual connection (i.e., simultaneous connection) with two network devices. For example, the network device110may serve as a MN (for convenience, also referred to as MN110below), and the network device130may serve as a SN (for convenience, also referred to as SN130below). Although only the cell111is shown, the MN110may provide multiple cells, and these cells may form a MCG for the terminal device120. Assuming that the cell111is a primary cell (i.e., PCell) in the MCG. Further, the cells131,132and133provided by the network device130may form a SCG for the terminal device120. Assuming that the cell131is a primary cell (i.e., PSCell) in the SCG.

The communication environment100may also comprise a core network160. The core network160may comprise a user port function (UPF)161and an access management function (AMF)162. It is to be understood that the core network160may also comprise any other suitable elements.

The SN130may communicate with the terminal device120via a channel such as a wireless communication channel. Similarly, the MN110may also communicate with the terminal device120via a channel such as a wireless communication channel. The SN130may communicate with the MN110via a control-plane interface such as Xn-C. The MN110may communicate with the core network160such as the AMF162via a control-plane interface such as NG-C. The SN130may also communicate with the MN110via a user plane interface such as Xn-U, and communicate with the core network160such as the UPF161via a user plane interface such as NG-U.

It is to be understood that the number of devices or cells inFIG.1is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication environment100may involve any suitable number of network devices and/or terminal devices and/or cells adapted for implementing implementations of the present disclosure.

The communications in the communication environment 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

Communication in a direction from the terminal device120towards the network device110,130,140or150is referred to as UL communication, while communication in a reverse direction from the network device110,130,140or150towards the terminal device120is referred to as DL communication. The terminal device120can move amongst the cells of the network devices110,130,140or150and possibly other network devices. In UL communication, the terminal device120may transmit UL data and control information to the network device110,130,140or150via a UL channel. In DL communication, the network device110,130,140or150may transmit DL data and control information to the terminal device120via a DL channel.

The communications in the communication network100A can be performed in accordance with UP and CP protocol stacks. Generally speaking, for a communication device (such as a terminal device or a network device), there are a plurality of entities for a plurality of network protocol layers in a protocol stack, which can be configured to implement corresponding processing on data or signaling transmitted from the communication device and received by the communication device.FIG.1Billustrates a schematic diagram100B illustrating network protocol layer entities that may be established for UP protocol stack at devices according to some embodiments of the present disclosure. For convenience, the following description is given by taking a communication between the terminal device120and the network device110as an example. It is to be understood that the following description is also suitable for the communication between the terminal device120and the network device130,140or150.

As shown inFIG.1B, in the UP, each of the terminal device120and the network device110may comprise an entity for the L1 layer, i.e., an entity for a physical (PHY) layer (also referred to as a PHY entity), and one or more entities for upper layers (L2 and layer 3 (L3) layers, or upper layers) including an entity for a media access control (MAC) layer (also referred to as a MAC entity), an entity for a radio link control (RLC) layer (also referred to as a RLC entity), an entity for a packet data convergence protocol (PDCP) layer (also referred to as a PDCP entity), and an entity for a service data application protocol (SDAP) layer (also referred to as a SDAP entity, which is established in 5G and higher-generation networks). In some cases, the PHY, MAC, RLC, PDCP, SDAP entities are in a stack structure.

FIG.1Cillustrates a schematic diagram100C illustrating network protocol layer entities that may be established for CP protocol stack at devices according to some embodiments of the present disclosure. As shown inFIG.1C, in the CP, each of the terminal device120and the network device110may comprise an entity for the L1 layer, i.e., an entity for a PHY layer (also referred to as a PHY entity), and one or more entities for upper layers (L2 and L3 layers) including an entity for a MAC layer (also referred to as a MAC entity), an entity for a RLC layer (also referred to as a RLC entity), an entity for a PDCP layer (also referred to as a PDCP entity), and an entity for a radio resource control (RRC) layer (also referred to as a RRC entity). The RRC layer may be also referred to as an access stratum (AS) layer, and thus the RRC entity may be also referred to as an AS entity. As shown inFIG.1C, the terminal device120may also comprise an entity for a non-access stratum (NAS) layer (also referred to as a NAS entity). An NAS layer at the network side is not located in a network device and is located in a core network (CN, not shown). In some cases, these entities are in a stack structure.

In the context of the present disclosure, L1 refers to the PHY layer, L2 refers to the MAC or RLC or PDCP or SDAP layer, and L3 refers to the RRC layer. In the context of the present disclosure, L1 or L2 may also be collectively referred to as a lower-layer, and L3 may also be referred to as a higher-layer. Accordingly, L1 or L2 signaling may be also referred to as a lower-layer signaling, and L3 signaling may be also referred to as a higher-layer signaling.

FIG.1Dillustrates a schematic diagram100D of a CU/DU architecture that may be established for a UP protocol stack at devices according to some embodiments of the present disclosure. The CU/DU architecture may be established at a network device. For illustration, the following description is given by taking the network device110as an example.

As shown inFIG.1D, in the UP, the network device110may comprise one or more CUs. Here, only one CU161is shown for convenience. Each CU161may communicate with multiple DUs. Here, two DUs171and172are shown for illustration. It is to be understood that more DUs may also be provided for implementation of embodiments of the present disclosure. As shown, CU161may be responsible for accomplishing the functionalities of the SDAP entity and the PDCP entity, and DU171or172may be responsible for accomplishing the functionalities of the RLC entity, the MAC entity and the PHY entity. DU171may communicate with transmission and reception points (TRPs)181and182. DU172may communicate with TRPs163and164. It is to be understood that this is merely an example, and more or less TRPs are also feasible. The terminal device120may communicate with any of these TRPs so as to communicate with the network device110.

In some embodiments, the terminal device120may switch from one TRP to another TRP under control of the same CU and same DU. For example, the terminal device120may be handed over from TRP181to TRP182. This is called as an intra-DU serving cell change. In some embodiments, the terminal device120may switch from one TRP to another TRP under control of the same CU and different DUs. For example, the terminal device120may be handed over from TRP182to TRP183. In this case, a cell change from DU181to DU182will occur. This is called as an inter-DU serving cell change. The cell change among DUs181,182,183and184is called as an intra-CU handover.

In some scenarios, the terminal device120may receive, from a network device as a MN or SN, a configuration of SSBs of cells with different PCIs for serving cell change and a RRC configuration for candidate cells, and store the RRC configuration of the candidate cells for L1/L2 based mobility. The terminal device120may perform a beam measurement for the candidate cells and report the beam measurement to the network device. The terminal device120may receive, from the network device, a L1 or L2signaling indicating a change of a serving cell to a selected candidate cell (i.e., new serving cell), and TCI state for the selected candidate cell is activated along with the serving cell change. This procedure may be called as a L1/L2 based mobility. The terminal device120may not need to discard the stored RRC configuration. If the terminal device120further receives, from the new serving cell, a L1 or L2 signaling indicating a change of a serving cell, the terminal device120may perform a data transmission with the change of the serving cell. This procedure may be called as a subsequent L1/L2 based mobility. The stored RRC configuration for the candidate cells may be used for the subsequent L1/L2based mobility procedures.

Return toFIG.1A, in some embodiments, the network device110may configure a conditional reconfiguration for the terminal device120. Assuming that the cells131-133,141-143and151-153are configured to the terminal device110as candidate cells. In some scenarios, the terminal device120may initially communicate with only the network device110. As the terminal device120moves, when a condition for a candidate cell (for example, the cell131) is fulfilled, the terminal device120may be caused to establish the dual connection with the network device110and the network device130. This process of SN addition may be called as a CPA.

In some scenarios, the terminal device120may establish a dual connection with the network devices110and130. The network device110serves as a MN and the network device130serves as a SN. As the terminal device120moves, when a condition for another candidate cell (for example, the cell142) is fulfilled, a SN serving the terminal device120may be changed from the network device130(also referred to as a source SN or current SN130) to the network device140(also referred to as a target SN140). This process of PScell change may be called as a CPC. In some scenarios, after the terminal device is configured with conditional reconfiguration and with subsequent CPC being enabled, and before at least one execution condition is fulfilled for any candidate PScell, the terminal device120may receive a RRC Reconfiguration message containing reconfiguration WithSync for SCG from the network device110, and the terminal device120may perform a PScell change or addition accordingly. This procedure is called as legacy PScell change or addition.

After the above CPA, CPC or legacy PSCell change/addition procedure, as the terminal device120further moves, when a condition for still another candidate cell (for example, the cell152) is fulfilled, a SN serving the terminal device120may be changed from the network device140to the network device150(also referred to as a target SN150). This process of SN change may be called as a subsequent CPC.

In 3GPP Release 18, a mechanism and procedure of NR-DC with selective activation of the cell groups (at least for SCG) will be specified by allowing subsequent cell group change after changing CG without reconfiguration and re-initiation of CPC/CPA. In this case, the terminal device120may not need to discard the CPC/CPA configuration after completion of PSCell change/addition procedure. The stored CPC/CPA configuration may be used for the subsequent CPC.

However, the terminal device120may be provided with a delta configuration with respect to a configuration of a source cell. A serving cell may keep changing during the subsequent CPC and may be different from the source cell. Thus, how to apply the delta configuration for the current serving cell becomes an issue.

Embodiments of the present disclosure provide a solution for solving the delta configuration issue for the above subsequent CPC or L1/L2 based mobility scenario or any other suitable scenarios. Its details will be described with reference toFIGS.2to5.

It is to be understood that the present solution may be applied in a SCG change, and also may be applied in a MCG change. That is, the present solution may be applied for a subsequent CPC or a subsequent conditional handover. The subsequent CPC or subsequent conditional handover may also be referred to as a selective activation of cell groups, a selective activation of SCGs, a subsequent SCG change, a subsequent cell group change or a subsequent conditional cell change. For convenience, embodiments of the present disclosure will be described by taking a subsequent CPC as an example.

Example Implementation of Applying Delta Configuration

FIG.2illustrates a schematic diagram illustrating a process200for communication according to embodiments of the present disclosure. For the purpose of discussion, the process200will be described with reference toFIG.1A. The process200may involve the terminal device120and the network device110as illustrated inFIG.1A. The network device110may be a MN or SN serving the terminal device120.

As shown inFIG.2, the network device110transmits210, to the terminal device120, a set of configurations for a set of candidate cells. Configurations in the set of configurations are delta configurations.

The terminal device120determines220a reference configuration. In some embodiments, the terminal device120may determine, as the reference configuration, the configuration used for a cell group serving the terminal device120. For example, upon reception of a RRC reconfiguration message comprising a configuration of an enabling of a subsequent conditional cell change or L1/L2 based mobility, the terminal device120may determine the current RRC configuration as the reference configuration.

In some embodiments, the network device110may transmit222, to the terminal device120, an indication indicating a configuration for one of the set of candidate cells as the reference configuration. In this case, the terminal device120may determine the configuration for the one of the set of candidate cells as the reference configuration based on the indication. For example, the network device110may obtain a RRC configuration (a full configuration) corresponding to a candidate cell which is used as basis of a delta configuration, and then provide the RRC configuration to at least one network device of at least one other candidate cell. Then each of the at least one network device may generate a delta configuration for a corresponding candidate cell using the provided RRC configuration as a basis. The network device120may transmit a RRC reconfiguration comprising conditional cell change or addition configuration or L1/L2 based mobility configuration to the terminal device110. The conditional cell change or addition configuration or L1/L2 based mobility configuration may consist of a set of RRC configurations for a set of candidate cells. The network device120may indicate, in the RRC reconfiguration, which entry in the set of RRC configurations is the basis of a delta configuration. For illustration, an example for a subsequent CPC will be given below with reference toFIG.3.

FIG.3illustrates a schematic diagram illustrating an example process300of indicating a reference configuration according to embodiments of the present disclosure. For the purpose of discussion, the process300will be described with reference toFIG.1A. The process300may involve the terminal device120and the network devices110,140and150as illustrated inFIG.1A. In this example, the network device110serves as a MN serving the terminal device120, the network device140serves as a potential target SN (denoted as T-SN), and the network device150serves as another potential target SN.

As shown inFIG.3, the network device110may transmit310, to the network device140, a SN addition request message comprising information of subsequent CPC and a candidate PScell #1. The network device140may transmit320, to the network device110, a SN addition request acknowledge message comprising a SCG configuration of the candidate PScell #1. In a subsequent CPC stage, the network device110may transmit330, to the network device140, a SN addition request message comprising information of the subsequent CPC, list of other candidate PSCells and a SCG configuration of the candidate PScell #1. The network device110may also transmit330′, to the network device150, a SN addition request message comprising information of the subsequent CPC, list of other candidate PSCells and a SCG configuration of the candidate PScell #1. The network device140may transmit340, to the network device110, a SN addition request acknowledge message comprising configurations of other candidate PScells, the configurations are delta configuration based on the SCG configuration of candidate PSCell #1. The network device150may also transmit340′, to the network device110, a SN addition request acknowledge message comprising configurations of other candidate PScells, and these configurations are delta configurations based on the SCG configuration of candidate PSCell #1. Then the network device110may transmit350, to the terminal device120, a RRC reconfiguration message comprising conditional reconfiguration, the conditional reconfiguration comprising configuration for the candidate PSCells and an indication indicating which entry in the CPC/CPA configurations is the basis of the delta configurations. It is to be understood that the process ofFIG.3is merely an example, and does not limit the present disclosure.

In some embodiments, the terminal device120may store221the reference configuration. For example, the reference configuration may be stored in one UE variable. For example, upon reception of a RRC reconfiguration message comprising a configuration of an enabling of a subsequent conditional cell change or L1/L2 based mobility, the terminal device120may store the RRC configuration corresponding to each candidate cell. The terminal device120may also store the reference configuration in one UE variable. In some embodiments, the terminal device120may replace a stored reference RRC configuration with the new received reference configuration. Then the terminal device120may transmit a RRC reconfiguration complete message to the network device110.

In some embodiments, the terminal device120may discard the stored reference RRC configuration if the cell group is released. In some embodiments, the terminal device120may discard the stored reference RRC configuration if a handover is performed, e.g., if a reconfigurationWithSync for MCG is performed. In some embodiments, the terminal device120may discard the stored reference RRC configuration upon if the configuration for the candidate cell is released, e.g., if a conditional reconfiguration or L1/L2 based mobility configuration is released. In some embodiments, the terminal device120may discard the stored reference RRC configuration if a subsequent conditional cell change is disabled. In this way, a storage resource may be well managed.

Upon determination of the reference configuration, the terminal device120applies230, based on the reference configuration, a configuration for a candidate cell in the set of configurations. In some embodiments for a subsequent conditional PSCell or PCell change, if at least one execution condition for the candidate cell (also referred to as a selected candidate cell) is fulfilled, the terminal device120may apply231the configuration for the candidate cell. In some embodiments for L1/L2 based mobility, the terminal device120may receive232, from the network device110, a lower layer signaling (for example, L1 or L2 signaling which can be medium access control (MAC) control element (CE) or downlink control information (DCI)) which indicates the candidate cell. In this case, the terminal device120may apply233the configuration for the candidate cell in response to the lower layer signaling.

In some embodiments where the current RRC configuration is stored as the reference configuration, the terminal device120may revert back (i.e., fallback) to the stored RRC configuration and then apply the configuration for the candidate cell. Alternatively, the terminal device120may generate an actual configuration (for convenience, also referred to as a first configuration herein) based on the reference configuration and the configuration for the candidate cell, and apply the first configuration for the candidate cell. In other words, the terminal device applies the first configuration for the candidate cell when an execution condition is fulfilled or a lower layer signaling is received.

In some embodiments, the terminal device120may generate a set of configurations (for convenience, also referred to as a set of second configurations) for the set of candidate cells based on the reference configuration and the set of configurations for the set of candidate cells, and store the set of second configurations. For example, upon reception of a RRC reconfiguration message comprising a set of configurations for a set of candidate cells, and the configurations of the candidate cells are delta configurations, the terminal device120may use or combine the reference RRC configuration and configuration corresponding to each candidate cell to generate a new or actual RRC configuration (i.e., the second configuration) corresponding to the candidate cell. Then the terminal device120may store the second configurations for the candidate cells in a variable of the terminal device120, or the terminal device120may replace or update the stored second RRC configurations with the newly generated second RRC configuration of the candidate cells. In these embodiments, the terminal device120may directly apply the currently stored second RRC configuration for the candidate cell upon an execution condition is fulfilled or a lower signaling is received.

So far, a solution for applying a delta configuration is described. In this way, a delta configuration may be supported for a subsequent conditional PCell or PSCell change or subsequent L1/L2 based mobility or any other suitable scenarios.

Example Implementation of Same Delta Configuration

Embodiments of the present disclosure also provide a solution of using substantially the same delta configuration for the set of candidate cells. For convenience, this solution will be described with reference toFIG.1A.

In this solution, the terminal device120receives, from the network device110, a set of configurations for a set of candidate cells, and if a cell change or addition to a candidate cell in the set of candidate cells is to be performed, the terminal device120applies a configuration for the candidate cell in the set of configurations. The configuration for the candidate cell is the same as a configuration for a cell group serving the terminal device or a configuration for a further candidate cell in the set of configurations, except for at least one of an identity, a timer, a dedicated random access channel (RACH) configuration or a measurement configuration for the terminal device120. In other words, the configurations of the all candidate cells from are the same as the current configuration or configuration one candidate cell, except for at least one of an identity, a timer, a dedicated RACH configuration or a measurement configuration. For example, the identity for the terminal device may be a cell-radio network temporary identifier (C-RNTI) of the terminal device120for a candidate cell. Of course, any other suitable forms are also feasible. The timer may be a T304 timer or any other similar timers.

For illustration, an example for a subsequent CPC will be given below with reference toFIG.4.FIG.4illustrates a schematic diagram illustrating an example process400of subsequent CPC according to embodiments of the present disclosure. For the purpose of discussion, the process400will be described with reference toFIG.1A. The process400may involve the terminal device120and the network devices110,130,140and150as illustrated inFIG.1A. In this example, the network device110serves as a MN serving the terminal device120, the network device130serves as a source SN (denoted as S-SN), the network devices140and150serve as potential target SNs (denoted as T-SN).

As shown inFIG.4, in a subsequent CPC stage, the network device110may transmit410, to the network device140, a SN addition request message comprising information of enabling subsequent CPC and the current SCG configuration of S-SN or a SCG configuration of one candidate PSCell. The network device110may also transmit410′, to the network device150, a SN addition request message comprising information of subsequent CPC and the current SCG configuration of S-SN or a SCG configuration of one candidate PSCell. The network device110may transmit420, to the network device130, an Xn message comprising information of the enabling of subsequent CPC. The network device140may transmit430, to the network device110, a SN addition request acknowledge message comprising only at least one of an identity, a timer, a dedicated random access channel configuration or a measurement configuration as a SCG configuration for each candidate PSCell. The network device150may also transmit430′, to the network device110, a SN addition request acknowledge message comprising only at least one of an identity, a timer, a dedicated RACH configuration or a measurement configuration as a SCG configuration for each candidate PSCell. The network device130may transmit440an Xn message for acknowledgement of the enabling of subsequent CPC comprising only at least one of an identity, a timer, a dedicated RACH configuration or a measurement configuration as a SCG configuration for each candidate PSCell. The network device110may transmit450, to the terminal device120, a RRC reconfiguration message comprising a set of configurations for a set of candidate cells, and a configuration for each candidate cell comprises only at least one of an identity, a timer, a dedicated RACH configuration or a measurement configuration as a SCG configuration for each candidate PSCell. It is to be understood that the process ofFIG.4is merely an example, and does not limit the present disclosure.

In some embodiments, if the configuration for the candidate cell is the same as the configuration for the further candidate cell in the set of candidate cells, the terminal device120may receive, from the network device110, an indication indicating the further candidate cell, and apply the configuration for the candidate cell based on the indication.

In some embodiments for a subsequent conditional PSCell or PCell change, if at least one execution condition for the candidate cell is fulfilled, the terminal device120may apply the configuration for the candidate cell. In some embodiments for L1/L2 based mobility, the terminal device120may receive, from the network device110, a lower layer signaling (for example, L1 or L2 signaling) which indicates the candidate cell. In this case, the terminal device120may apply the configuration for the candidate cell in response to the lower layer signaling.

In this way, a delta configuration also can be supported for a subsequent conditional PCell or PSCell change or subsequent L1/L2 based mobility.

Example Implementation of Full Configuration

Embodiments of the present disclosure also provide a solution of using a full configuration for each candidate cell in the set of candidate cells. For convenience, this solution will be described with reference toFIG.1A.

In this solution, the terminal device120receives, from the network device110, a set of configurations for a set of candidate cells, and each configuration in the set of configurations is a full configuration. In this way, if a cell change or addition to a candidate cell in the set of candidate cells is to be performed, the terminal device120directly applies a configuration for the candidate cell in the set of configurations.

For illustration, an example for a subsequent CPC will be given below with reference toFIG.5.FIG.5illustrates a schematic diagram illustrating another example process500of subsequent CPC according to embodiments of the present disclosure. For the purpose of discussion, the process500will be described with reference toFIG.1A. The process500may involve the terminal device120and the network devices110,130,140and150as illustrated inFIG.1A. In this example, the network device110serves as a MN serving the terminal device120, the network device130serves as a source SN (denoted as S-SN), the network devices140and150serve as potential target SNs (denoted as T-SN).

As shown inFIG.5, in a subsequent CPC stage, the network device110may transmit510, to the network device140, a SN addition request message comprising information of enabling subsequent CPC, wherein the SN addition request message does not include current SCG configuration because network device110uses a full configuration. The network device110may also transmit510′, to the network device150, a SN addition request message comprising information of subsequent CPC. The network device110may transmit520, to the network device130, an Xn message comprising information of the enabling of subsequent CPC, wherein the SN addition request message does not include current SCG configuration because network device110uses a full configuration. The network device140may transmit530, to the network device110, a SN addition request acknowledge message comprising a SCG configuration using a full configuration for each candidate PSCell. The network device150may also transmit530′, to the network device110, a SN addition request acknowledge message comprising a SCG configuration using a full configuration for each candidate PSCell. The network device130may transmit540an Xn message for acknowledgement of the enabling of subsequent CPC comprising a SCG configuration using a full configuration for each candidate PSCell. The network device110may transmit550, to the terminal device120, a RRC reconfiguration message comprising conditional reconfiguration for CPC/CPA, and the conditional reconfiguration comprises the configuration using a full configuration for each candidate PSCell. It is to be understood that the process ofFIG.5is merely an example, and does not limit the present disclosure.

In some embodiments for a subsequent conditional PSCell or PCell change, if at least one execution condition for the candidate cell is fulfilled, the terminal device120may apply the configuration for the candidate cell. In some embodiments for L1/L2 based mobility, the terminal device120may receive, from the network device110, a lower layer signaling (for example, L1 or L2 signaling) which indicates the candidate cell. In this case, the terminal device120may apply the configuration for the candidate cell in response to the lower layer signaling.

In this way, a full configuration also can be supported for a subsequent conditional PCell or PSCell change or subsequent L1/L2 based mobility.

Example Implementation of Dedicate RACH Configuration

Currently, a dedicated RACH configuration is to be configured for the reconfiguration WithSync procedure (e.g. for handover or PSCell change). If subsequent conditional cell change is enabled or if subsequent L1/L2 based cell change is configured for a terminal device, the dedicated RACH configuration needs to be reserved for a very long time. Thus, huge cost and resource waste will be caused.

In view of this, embodiments of the present disclosure also provide solutions for resource management. For convenience, these solutions will be described with reference toFIG.1A.

In some embodiments, a configuration for a candidate cell may comprise a dedicated RACH configuration for the candidate cell. In these embodiments, the terminal device120may perform the cell change or addition to the candidate cell based on the dedicated RACH configuration once. If a further cell change to the candidate cell is to be performed, the terminal device120may perform the further cell change without using the dedicated RACH configuration. For example, the terminal device120may perform the further cell change based on a contention based random access procedure. In this way, the dedicated RACH resource may be reserved for a short time.

In some embodiments, a configuration for a candidate cell may comprise a dedicated RACH configuration for a cell change or addition and a timer configured for the candidate cell. In these embodiments, if the configuration is received, the terminal device120may start the timer. If the timer expires, the terminal device120may release the dedicated RACH configuration. In this way, a timer is used to control the use of the dedicated RACH configuration, and thus the dedicated RACH resource also may be reserved for a short time.

In some embodiments, a configuration for a candidate cell may not comprise a dedicated RACH configuration for the candidate cell. In other words, the dedicated RACH configuration is not configured if subsequent CPC or lower layer signaling based mobility is configured. In these embodiments, the terminal device120may perform a cell change or cell addition to a candidate cell only based on a contention based random access procedure. In this way, the above issue related to a dedicated RACH configuration may also be resolved.

Example Implementation of Methods

Accordingly, embodiments of the present disclosure provide methods of communication implemented at a terminal device and a network device. These methods will be described below with reference toFIGS.6to11.

FIG.6illustrates an example method600of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method600may be performed at the terminal device120as shown inFIG.1A. For the purpose of discussion, in the following, the method600will be described with reference toFIG.1A. It is to be understood that the method600may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block610, the terminal device120receives, from a first network device (for example, the network device110) serving the terminal device120, a set of configurations for a set of candidate cells. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN.

At block620, the terminal device120determines a reference configuration. In some embodiments, the terminal device120may determine, as the reference configuration, a configuration of a cell group serving the terminal device120. In some embodiments, the terminal device120may receive, from the first network device, an indication indicating a configuration for one of the set of candidate cells as the reference configuration, and determine the reference configuration based on the indication.

In some embodiments, the terminal device120may store the reference configuration in a variable of the terminal device. In some embodiments, the terminal device120may discard the stored reference configuration in response to at least one of the following: the cell group being released; a handover being performed; the configuration for the candidate cell being released; or a subsequent conditional cell change being disabled.

At block630, the terminal device120applies, based on the reference configuration, a configuration for a candidate cell in the set of configurations. In some embodiments, if at least one execution condition for the candidate cell is fulfilled, the terminal device120may apply the configuration for the candidate cell. In some embodiments, if a lower layer signaling is received, the terminal device120may apply the configuration for the candidate cell.

In some embodiments, the terminal device120may revert back to the reference configuration, and apply the configuration for the candidate cell. In some embodiments, the terminal device120may generate a first configuration based on the reference configuration and the configuration for the candidate cell, and apply the first configuration for the candidate cell. In some embodiments, the terminal device120may generate a set of second configurations for the set of candidate cells based on the reference configuration and the set of configurations for the set of candidate cells, and store the set of second configurations. The terminal device120may directly apply a stored second configuration for the candidate cell.

In some embodiments where the configuration comprises a dedicated random access configuration for the candidate cell, the terminal device120may perform a cell change or addition to the candidate cell based on the dedicated random access configuration.

If a further cell change to the candidate cell is to be performed, the terminal device120may perform the further cell change without using the dedicated random access configuration.

In some embodiments where the configuration comprises a dedicated random access configuration for a cell change or addition and a timer configured for the candidate cell, if the configuration is received, the terminal device120may start the timer. If the timer expires, the terminal device120may release the dedicated random access configuration.

In some embodiments, the terminal device120may perform a cell change or cell addition to the candidate cell only based on a contention based random access procedure.

In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

FIG.7illustrates another example method700of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method700may be performed at the terminal device120as shown inFIG.1A. For the purpose of discussion, in the following, the method700will be described with reference toFIG.1A. It is to be understood that the method700may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block710, the terminal device120receives, from a first network device (for example, the network device110) serving the terminal device120, a set of configurations for a set of candidate cells. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN.

At block720, the terminal device120determines whether a cell change or addition to a candidate cell in the set of candidate cells is to be performed. If the cell change or addition to the candidate cell is to be performed, the process700proceeds to block730.

At block730, the terminal device120applies a configuration for a candidate cell in the set of configurations. The configuration for the candidate cell is the same as a configuration of a cell group serving the terminal device120or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In some embodiments where the configuration for the candidate cell is the same as the configuration for the further candidate cell in the set of candidate cells, the terminal device120may receive, from the first network device, an indication indicating the further candidate cell, and apply the configuration for the candidate cell based on the indication.

In some embodiments, if at least one execution condition for the candidate cell is fulfilled, the terminal device120may apply the configuration for the candidate cell. In some embodiments, if a lower layer signaling is received, the terminal device120may apply the configuration for the candidate cell.

In some embodiments where the configuration comprises a dedicated random access configuration for the candidate cell, the terminal device120may perform a cell change or addition to the candidate cell based on the dedicated random access configuration. If a further cell change to the candidate cell is to be performed, the terminal device120may perform the further cell change without using the dedicated random access configuration.

In some embodiments where the configuration comprises a dedicated random access configuration for a cell change or addition and a timer configured for the candidate cell, if the configuration is received, the terminal device120may start the timer. If the timer expires, the terminal device120may release the dedicated random access configuration.

In some embodiments, the terminal device120may perform a cell change or cell addition to the candidate cell only based on a contention based random access procedure.

In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

FIG.8illustrates still another example method800of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method800may be performed at the terminal device120as shown inFIG.1A. For the purpose of discussion, in the following, the method800will be described with reference toFIG.1A. It is to be understood that the method800may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block810, the terminal device120receives, from a first network device (for example, the network device110) serving the terminal device120, a set of full configurations for a set of candidate cells. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN.

At block820, the terminal device120determines whether a cell change or addition to a candidate cell in the set of candidate cells is to be performed. If the cell change or addition to the candidate cell is to be performed, the process800proceeds to block830.

At block830, the terminal device120applies a configuration for a candidate cell in the set of full configurations.

In some embodiments, if at least one execution condition for the candidate cell is fulfilled, the terminal device120may apply the configuration for the candidate cell. In some embodiments, if a lower layer signaling is received, the terminal device120may apply the configuration for the candidate cell.

In some embodiments where the configuration comprises a dedicated random access configuration for the candidate cell, the terminal device120may perform a cell change or addition to the candidate cell based on the dedicated random access configuration. If a further cell change to the candidate cell is to be performed, the terminal device120may perform the further cell change without using the dedicated random access configuration.

In some embodiments where the configuration comprises a dedicated random access configuration for a cell change or addition and a timer configured for the candidate cell, if the configuration is received, the terminal device120may start the timer. If the timer expires, the terminal device120may release the dedicated random access configuration.

In some embodiments, the terminal device120may perform a cell change or cell addition to the candidate cell only based on a contention based random access procedure.

In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

FIG.9illustrates an example method900of communication implemented at a network device in accordance with some embodiments of the present disclosure. The method900may be performed at a first network device. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN. For the purpose of discussion, the method900will be described with reference to inFIG.1A. It is to be understood that the method900may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

As shown inFIG.9, at block910, the first network device (for example, the network device110) transmits, to the terminal device120, a set of configurations for a set of candidate cells, and an indication indicating a configuration for one of a set of candidate cells as a reference configuration.

In some embodiments, the network device110may transmit the configuration for the one of the set of candidate cells to a set of second network devices (for example, the network devices140and150) providing the set of candidate cells, and receive, from the set of second network devices, the set of configurations generated based on the configuration for the one candidate cell as the reference configuration.

In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for the cell change or addition and a timer configured for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell does not comprise a dedicated random access configuration for the set of candidate cells.

In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

FIG.10illustrates another example method1000of communication implemented at a network device in accordance with some embodiments of the present disclosure. The method1000may be performed at a first network device. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN. For the purpose of discussion, the method1000will be described with reference to inFIG.1A. It is to be understood that the method1000may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

As shown inFIG.10, at block1010, the first network device (for example, the network device110) transmits, to the terminal device120, a set of configurations for a set of candidate cells. A configuration for a candidate cell in the set of candidate cells is the same as a configuration of a cell group serving the terminal device120or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In some embodiments, the network device110may receive the set of configurations from a set of second network devices (for example, the network devices140and150) providing the set of candidate cells.

In some embodiments where the configuration for the candidate cell is the same as the configuration for the further candidate cell in the set of candidate cells, the network device110may transmit, to the terminal device120, an indication indicating the further candidate cell.

In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for the cell change or addition and a timer configured for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell does not comprise a dedicated random access configuration for the set of candidate cells.

In this way, a delta configuration may be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

FIG.11illustrates still another example method1100of communication implemented at a network device in accordance with some embodiments of the present disclosure. The method1100may be performed at a first network device. In some embodiments for subsequent conditional cell change, the first network device may be a MN. In some embodiments for L1/L2 based mobility, the first network device may be a MN or a SN. For the purpose of discussion, the method1100will be described with reference to inFIG.1A. It is to be understood that the method1100may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

As shown inFIG.11, at block1110, the first network device (for example, the network device110) transmits, to the terminal device120, a set of configurations for a set of candidate cells. A configuration in the set of configurations is a full configuration for a candidate cell. That is, each configuration in the set of configurations is a full configuration.

In some embodiments, the network device110may receive the set of full configurations from a set of second network devices (for example, the network devices140and150) providing the set of candidate cells.

In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for the cell change or addition and a timer configured for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell does not comprise a dedicated random access configuration for the set of candidate cells.

In this way, a delta configuration may also be supported for subsequent conditional cell change or L1/L2 based mobility or any other suitable scenarios.

It is to be understood that the operations of methods600to1100are similar as that described in connection withFIGS.2to5, and thus other details are not repeated here for concise.

Example Implementation of Devices and Apparatuses

FIG.12is a simplified block diagram of a device1200that is suitable for implementing embodiments of the present disclosure. The device1200can be considered as a further example implementation of the terminal device120or the network devices110,130,140or150as shown inFIG.1A. Accordingly, the device1200can be implemented at or as at least a part of the terminal device120or the network devices110,130,140or150.

As shown, the device1200includes a processor1210, a memory1220coupled to the processor1210, a suitable transmitter (TX) and receiver (RX)1240coupled to the processor1210, and a communication interface coupled to the TX/RX1240. The memory1210stores at least a part of a program1230. The TX/RX1240is for bidirectional communications. The TX/RX1240has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME)/Access and Mobility Management Function (AMF)/SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN), or Uu interface for communication between the eNB/gNB and a terminal device.

The program1230is assumed to include program instructions that, when executed by the associated processor1210, enable the device1200to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference toFIGS.1A to11. The embodiments herein may be implemented by computer software executable by the processor1210of the device1200, or by hardware, or by a combination of software and hardware. The processor1210may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor1210and memory1220may form processing means1250adapted to implement various embodiments of the present disclosure.

The memory1220may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory1220is shown in the device1200, there may be several physically distinct memory modules in the device1200. The processor1210may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device1200may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

In some embodiments, a terminal device comprises circuitry configured to: receive, from a first network device, a set of configurations for a set of candidate cells; determine a reference configuration; and apply, based on the reference configuration, a configuration for a candidate cell in the set of configurations.

In some embodiments, the circuitry may be configured to determine, as the reference configuration, a configuration of a cell group serving the terminal device.

In some embodiments, the circuitry may be configured to determine the reference configuration by receiving, from the first network device, an indication indicating a configuration for one of the set of candidate cells as the reference configuration; and determining the reference configuration based on the indication.

In some embodiments, the circuitry may be configured to store the reference configuration in a variable of the terminal device.

In some embodiments, the circuitry may be further configured to discard the stored reference configuration in response to at least one of the following: the cell group being released; a handover being performed; the configuration for the candidate cell being released; or a subsequent conditional cell change being disabled.

In some embodiments, the circuitry may be configured to apply the configuration by: reverting back to the reference configuration; and applying the configuration for the candidate cell.

In some embodiments, the circuitry may be configured to apply the configuration by: generating a first configuration based on the reference configuration and the configuration for the candidate cell; and applying the first configuration for the candidate cell.

In some embodiments, the circuitry may be further configured to: generate a set of second configurations for the set of candidate cells based on the reference configuration and the set of configurations for the set of candidate cells; and store the set of second configurations. In these embodiments, the circuitry may be configured to apply the configuration by applying a stored second configuration for the candidate cell.

In some embodiments, a terminal device comprises a circuitry configured to: receive, from a first network device, a set of configurations for a set of candidate cells; and in accordance with a determination that a cell change or addition to a candidate cell in the set of candidate cells is to be performed, apply a configuration for the candidate cell in the set of configurations, wherein the configuration for the candidate cell is the same as a configuration of a cell group serving the terminal device or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In some embodiments where the configuration for the candidate cell is the same as the configuration for the further candidate cell in the set of candidate cells, the circuitry may be configured to apply the configuration by: receiving, from the first network device, an indication indicating the further candidate cell; and applying the configuration for the candidate cell based on the indication.

In some embodiments, a terminal device comprises a circuitry configured to: receive, from a first network device, a set of full configurations for a set of candidate cells; and in accordance with a determination that a cell change or addition to a candidate cell in the set of candidate cells is to be performed, apply a configuration for the candidate cell in the set of full configurations.

In some embodiments, the circuitry may be configured to apply the configuration by: in accordance with a determination that at least one execution condition for the candidate cell is fulfilled, applying the configuration for the candidate cell.

In some embodiments, the circuitry may be configured to apply the configuration by: in accordance with a determination that a lower layer signaling is received, applying the configuration for the candidate cell.

In some embodiments where the configuration comprises a dedicated random access configuration for the candidate cell, the circuitry may be further configured to: perform a cell change or addition to the candidate cell based on the dedicated random access configuration; and in accordance with a determination that a further cell change to the candidate cell is to be performed, perform the further cell change without using the dedicated random access configuration.

In some embodiments where the configuration comprises a dedicated random access configuration for a cell change or addition and a timer configured for the candidate cell, the circuitry may be further configured to: in accordance with a determination that the configuration is received, start the timer; and in accordance with a determination that the timer expires, release the dedicated random access configuration.

In some embodiments, the circuitry may be further configured to perform a cell change or cell addition to the candidate cell only based on a contention based random access procedure.

In some embodiments, a network device comprises a circuitry configured to: transmit, to a terminal device, a set of configurations for a set of candidate cells, and an indication indicating a configuration for one of a set of candidate cells as a reference configuration.

In some embodiments, the circuitry may be further configured to: transmit the configuration for the one of the set of candidate cells to a set of second network devices providing the set of candidate cells; and receive, from the set of second network devices, the set of configurations generated based on the configuration for the one candidate cell as the reference configuration.

In some embodiments, a network device comprises a circuitry configured to: transmit, to a terminal device, a set of configurations for a set of candidate cells, wherein a configuration for a candidate cell in the set of candidate cells is the same as a configuration of a cell group serving the terminal device or a configuration for a further candidate cell in the set of candidate cells, except for at least one of the following: an identity for a candidate cell in the set of candidate cells; a timer for a candidate cell in the set of candidate cells; a dedicated random access channel configuration for a candidate cell in the set of candidate cells; or a measurement configuration of a candidate cell in the set of candidate cells.

In some embodiments, the circuitry may be further configured to receive the set of configurations from a set of second network devices providing the set of candidate cells.

In some embodiments where the configuration for the candidate cell is the same as the configuration for the further candidate cell in the set of candidate cells, the circuitry may be further configured to transmit, to the terminal device, an indication indicating the further candidate cell.

In some embodiments, a network device comprises a circuitry configured to: transmit, to a terminal device, a set of configurations for a set of candidate cells, a configuration in the set of configurations being a full configuration for a candidate cell.

In some embodiments, the circuitry may be further configured to receive the set of full configurations from a set of second network devices providing the set of candidate cells.

In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell comprises a dedicated random access configuration for the cell change or addition and a timer configured for a candidate cell in the set of candidate cells. In some embodiments, the configuration for the candidate cell comprises no dedicated random access configuration for the set of candidate cells.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor(s), software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor(s) or a portion of a hardware circuit or processor(s) and its (or their) accompanying software and/or firmware.