WO2024093154A1

WO2024093154A1 - Devices and methods of communication

Info

Publication number: WO2024093154A1
Application number: PCT/CN2023/088782
Authority: WO
Inventors: Congchi ZHANG; Lianhai WU; Mingzeng Dai; Shuigen Yang; Le Yan
Original assignee: Lenovo (Beijing) Limited
Priority date: 2023-04-17
Filing date: 2023-04-17
Publication date: 2024-05-10

Abstract

Embodiments of the present disclosure relate to devices and methods of communication. In one aspect, an MN transmits, to a first SN, a first message comprising a first set of candidate cells associated with a set of second SNs and receives, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells. The MN transmits, to a terminal device, a configuration for a subsequent conditional cell addition or change comprising at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells. In this way, execution conditions for a subsequent conditional cell addition or change may be configured by a candidate SNs.

Description

DEVICES AND METHODS OF COMMUNICATION

FIELD

Embodiments of the present disclosure generally relate to the field of communication, and in particular to devices and methods of communication for dual connectivity (DC) operation.

BACKGROUND

For DC operation, it has been proposed to support secondary cell group (SCG) selective activation during which after accessing to a candidate primary secondary cell (PSCell) , a terminal device keeps conditional reconfigurations of other candidate PSCells for subsequent conditional switch. That is, the terminal device may further execute a conditional switch according to the conditional reconfigurations received previously. However, solutions of the SCG selective activation are still incomplete and need to be further developed.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer readable media of communication for DC operation.

In a first aspect, there is provided a master node (MN) . The MN comprises a processor and a transceiver coupled to the processor. The processor is configured to: transmit, via the transceiver to a first secondary node (SN) , a first message comprising a first set of candidate cells associated with a set of second SNs; receive, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells; and transmit, to a terminal device, a configuration for a subsequent conditional cell addition or change, the configuration comprising at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells.

In a second aspect, there is provided a first SN. The first SN comprises a processor and a transceiver coupled to the processor. The processor is configured to: receive, via the transceiver from a MN, a first message comprising a first set of candidate cells associated with a set of second SNs; and transmit, to the MN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells.

In a third aspect, there is provided a terminal device. The terminal device comprises a processor and a transceiver coupled to the processor. The processor is configured to: receive, via the transceiver from a MN, a configuration for a subsequent conditional cell addition or change, the configuration comprising, for a first SN, at least part of a set of execution conditions associated with some or all of at least part of a first set of candidate cells, the first set of candidate cells being associated with a set of second SNs.

In a fourth aspect, there is provided a method of communication. The method comprises: transmitting, at a MN and to a first SN, a first message comprising a first set of candidate cells associated with a set of second SNs; receiving, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells; and transmitting, to a terminal device, a configuration for a subsequent conditional cell addition or change, the configuration comprising at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells.

In a fifth aspect, there is provided a method of communication. The method comprises: receiving, at a first SN and from a MN, a first message comprising a first set of candidate cells associated with a set of second SNs; and transmitting, to the MN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells.

In a sixth aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a MN, a configuration for a subsequent conditional cell addition or change, the configuration comprising, for a first SN, at least part of a set of execution conditions associated with some or all of at least part of a first set of candidate cells, the first set of candidate cells being associated with a set of second SNs.

In a seventh 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.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments will now be described with reference to the accompanying drawings in which:

Fig. 1 illustrates an example communication environment in which some embodiments of the present disclosure can be implemented;

Fig. 2 illustrates a schematic diagram illustrating a process of communication according to embodiments of the present disclosure;

Fig. 3A illustrates a schematic diagram illustrating an example process of communication in a conditional primary secondary cell (PSCell) addition (CPA) scenario according to embodiments of the present disclosure;

Fig. 3B illustrates a schematic diagram illustrating another example process of communication in a CPA-like scenario according to embodiments of the present disclosure;

Fig. 4A illustrates a schematic diagram illustrating an example process of communication in an MN-initiated conditional primary secondary cell (PSCell) change (CPC) -like scenario according to embodiments of the present disclosure;

Fig. 4B illustrates a schematic diagram illustrating another example process of communication in an MN-initiated CPC-like scenario according to embodiments of the present disclosure;

Fig. 5A illustrates a schematic diagram illustrating an example process of communication in an SN-initiated CPC-like scenario according to embodiments of the present disclosure;

Fig. 5B illustrates a schematic diagram illustrating another example process of communication in an SN-initiated CPC-like scenario according to embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of an example method of communication implemented at a MN in accordance with some embodiments of the present disclosure;

Fig. 7 illustrates a flowchart of an example method of communication implemented at an SN in accordance with some embodiments of the present disclosure;

Fig. 8 illustrates a flowchart of an example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure; and

Fig. 9 is a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principles of the present disclosure will now be described with reference to some embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below. In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an example embodiment, ” “an embodiment, ” “some embodiments, ” and the like indicate that the embodiment (s) described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment (s) . Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” or the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could also be termed as a second element, and similarly, a second element could also be termed as a first element, without departing from the scope of embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms. In some examples, values, procedures, or apparatuses 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.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments. 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. It will be further understood that the terms “comprises, ” “comprising, ” “has, ” “having, ” “includes” and/or “including, ” when used herein, specify the presence of stated features, elements, components and/or the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. For example, 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 “based at least in part 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 use of an expression such as “A and/or B” can mean either “only A” or “only B” or “both A and B. ” Other definitions, explicit and implicit, may be included below.

As used herein, the term “communication environment” refers to a network following any suitable communication standards, such as, 5G NR, Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , and so on. Further, the communications between a terminal device and a network device in the communication environment may be performed according to any suitable generation communication protocols, including 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) , the sixth generation (6G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will also be future type communication technologies and systems in which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned systems.

As used herein, the term “network device” generally refers to a node in a communication environment via which a terminal device can access the communication environment and receive services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , a radio access network (RAN) node, an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , an infrastructure device for a V2X (vehicle-to-everything) communication, a transmission and reception point (TRP) , a reception point (RP) , a remote radio head (RRH) , a relay, an integrated access and backhaul (IAB) node, a low power node such as a femto BS, a pico BS, and so forth, depending on the applied terminology and technology.

As used herein, the term “terminal device” generally refers to any end device that may be capable of wireless communications. By way of example rather than a limitation, a terminal device may also be referred to as a communication device, a user equipment (UE) , an end user device, a subscriber station (SS) , an unmanned aerial vehicle (UAV) , a portable subscriber station, a mobile station (MS) , or an access terminal (AT) . The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA) , a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback appliance, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , a USB dongle, a smart device, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device (for example, a remote surgery device) , an industrial device (for example, a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms: “terminal device, ” “communication device, ” “terminal, ” “user equipment” and “UE, ” may be used interchangeably.

In legacy CPA/CPC, a terminal device releases conditional configurations after switching to a candidate PSCell. In this case, the terminal device has no change to perform subsequent CPA/CPC without CPA/CPC reconfiguration and re-initialization from a network side.

Thus, it is proposed to support SCG selective activation as enhancement on top of the legacy CPA/CPC. Basically, a terminal device (that has connected to any SN or has not connected to any SN) may be configured with conditional reconfigurations of a list of candidate PSCells/SCGs, and each candidate PSCell/SCG is associated with an execution condition. The terminal device may keep evaluating link quality of the candidate PSCell/SCG. Once the associated execution condition is fulfilled (e.g., the link quality is better than a threshold) , the terminal device may trigger random access and connect to that candidate PSCell/SCG. After accessing to the candidate PSCell/SCG, the terminal device may keep conditional reconfigurations of other candidate cells for subsequent conditional switch, and the candidate PSCell/SCG becomes a new source PSCell/SCG for the next conditional switch. That is, the terminal device may further execute conditional switch from the new source PSCell/SCG to other candidate PSCell (s) /SCG (s) according to the conditional reconfigurations received previously.

Embodiments of the present disclosure provide a solution of communication for subsequent conditional switch. In the solution, a MN transmits, to an SN (for convenience, also referred to as a first SN herein) , a message (for convenience, also referred to as a first message herein) comprising a set of candidate cells (for convenience, also referred to as a first set of candidate cells herein) associated with a set of other SNs (for convenience, also referred to as second SNs herein) . The SN transmits, to the MN, another message (for convenience, also referred to as a second message herein) comprising a set of execution conditions associated with the first set of candidate cells. The MN transmits, to a terminal device, a configuration for a subsequent conditional cell addition or change. The configuration comprising at least part of the set of execution conditions associated with at least part of the first set of candidate cells.

In this way, execution conditions for SCG selective activation may be configured by candidate SNs. In other words, an execution condition for each conditional switch from a source PSCell during SCG selective activation may be configured by an SN associated with the source PSCell. The source PSCell may be one of candidate PSCells configured for SCG selective activation. Thus, the SCG selective activation may be well supported.

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 CPA/CPC or a subsequent conditional handover. In the context of the present disclosure, the term “subsequent conditional cell addition or change” may be interchangeably used with “subsequent conditional switch” or “subsequent CPA/CPC” or “consecutive CPA/CPC” or “consecutive conditional switch” or “SCG selective activation” or “a selective activation of cell groups” . For convenience, embodiments of the present disclosure will be described by taking a subsequent CPA/CPC as an example.

In the context of the present disclosure, the term “candidate PSCells” may be interchangeably used with “candidate PSCells/SCGs” . In the context of the present disclosure, the term “candidate PSCells” may refer to candidate PSCells for the overall SCG selective activation procedure, or candidate PSCells for each conditional switch during the SCG selective activation.

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

Fig. 1 illustrates a schematic diagram of an example communication environment 100 in which embodiments of the present disclosure can be implemented. As shown in Fig. 1, the communication environment 100 may comprise a network device 110 and a terminal device 120. The network device 110 provides a cell 111 and the terminal device 120 is located in the cell 111 and served by the network device 110.

The communication environment 100 may also comprise one or more other network devices such as network devices 130, 140 and 150. The network device 130 provides cells 131 and 132. The network device 140 provides cells 141 and 142, and the network device 150 provides cells 151 and 152. It should be noted that the number of the cells are not limited to three, and more or less cells may be provided by the network devices 130, 140 and 150.

It is assumed that the terminal device 120 may establish connections with two network devices simultaneously (i.e., DC) . For example, the network device 110 may serve as a MN (for convenience, also referred to as MN 110 below) , and any of the network devices 130, 140 and 150 may serve as a SN (for convenience, also referred to as SN 130, 140 or 150 below) . Although only the cell 111 is shown, the MN 110 may provide multiple cells, and these cells may form a MCG for the terminal device 120. Assuming that the cell 111 is a primary cell (i.e., PCell) in the MCG. Further, the cells 131 and 132 provided by the network device 130 may form a SCG for the terminal device 120. Assuming that the cell 131 is a primary cell (i.e., PSCell) in the SCG. Similarly, the cells 141 and 142 provided by the network device 140 may form a SCG for the terminal device 120. The cells 151 and 152 provided by the network device 150 may also form a SCG for the terminal device 120.

Any of the SN 130, 140 or 150 may communicate with the terminal device 120 via a channel such as a wireless communication channel. Similarly, the MN 110 may also communicate with the terminal device 120 via a channel such as a wireless communication channel. Any of the SN 130, 140 or 150 may communicate with the MN 110 via an Xn interface.

It is to be understood that the number of devices or cells in Fig. 1 is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication environment 100 may include any suitable number of network devices and/or terminal devices and/or cells adapted for implementing embodiments 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.

In some embodiments, the network device 110 may configure conditional reconfiguration for the terminal device 120. Assuming that the cells 131-132, 141 and 151-152 are configured to the terminal device 120 as candidate PSCells.

In some scenarios, the terminal device 120 may initially communicate with only the network device 110. As the terminal device 120 moves, when a condition for a candidate PSCell (for example, the cell 131) is fulfilled, the terminal device 120 may be caused to establish a simultaneous connection with the network device 110 and the network device 130. This process of SN addition may be called as a CPA.

In some scenarios, the terminal device 120 may establish a simultaneous connection with the network devices 110 and 130. The network device 110 serves as a MN and the network device 130 serves as a SN. As the terminal device 120 moves, a SN serving the terminal device 120 may be changed from the network device 130 (also referred to as a source SN) to the network device 140 (also referred to as a target SN) . This process of PSCell change may be called as a CPC.

In some scenarios, before any CPA/CPC execution condition is satisfied, upon reception of, the terminal device 120 may receive PSCell addition/change command or PCell addition/change command from the network device 110, and the terminal device 120 may perform a PSCell addition/change or PCell addition/change accordingly. This procedure is called as legacy PSCell change/addition.

After the above CPA, CPC or legacy PSCell change/addition procedure, the terminal device 120 does not release conditional configurations of other candidate PSCells, and continues evaluating execution conditions of other candidate PSCells. When a condition for a candidate PSCell (for example, the cell 151) is fulfilled, a SN serving the terminal device 120 may be changed from the network device 140 to the network device 150. This process of SN change may be called as a subsequent CPC.

As shown in Fig. 1, the terminal device 120 may move out of coverage of a SN. The network device 110 (i.e., the MN) may indicate the terminal device 120 to release a previous SN (e.g., the network device 150) . In this case, the terminal device 120 may not release the conditional reconfigurations, and continue a conditional reconfiguration evaluation. When a condition for a candidate cell (for example, the cell 152) is fulfilled, the terminal device 120 may be caused to establish a dual connection with the network device 110 and the network device 150. This process may be called as a subsequent CPA.

For convenience, CPA, CPC, subsequent CPA or subsequent CPC may also be called as a conditional switch. For each time of conditional switch, associated candidate PSCells are configured with corresponding execution conditions. For the first time conditional switch, it may be clear that it is an MN or source SN that configures execution conditions for the first time conditional switch.

However, it is still unclear which network node provides the execution conditions for subsequent conditional switches, especially considering that a source/serving PSCell will change (in other words, any candidate PSCell may become a serving/source PSCell) . In addition, all execution conditions for the overall SCG selective activation need to be provided in the same RRC reconfiguration message when NW configures a terminal device with SCG selective activation.

As an option, it is considered that for each candidate PSCell, it is upon a candidate SN associated with the candidate PSCell to prepare execution conditions for switching to other candidate PSCells for subsequent conditional switches when the candidate PSCell becomes a serving/source PSCell. In the configuration of a candidate PSCell belonging to this candidate SN, the candidate SN will decide triggering events (i.e., execution conditions) for the associated neighbour candidate PSCells, which are also decided by the candidate SN. However, the configuration does not include execution conditions for candidate PSCells that are not neighbours of that candidate PSCell.

Thus, there is one issue to be resolved if an SN of one candidate PSCell is caused to generate execution conditions for switching to other candidate PSCells when the candidate PSCell becomes a serving/source PSCell. Because, in legacy CPA/CPC procedures, the SN of the candidate PSCell does not know the existence of other candidate PSCells belonging to other SNs. In legacy, only MN or the source SN knows the full list of candidate PSCells belonging to different candidate SNs. For example, a candidate target SN does not know the candidate PSCells prepared by another candidate target SN, and thus cannot prepare execution conditions when considering the PSCells belonging to the another candidate target SN as candidate PSCells.

In view of this, embodiments of the present disclosure provide solutions of communication for subsequent CPA/CPC (also referred to as subsequent conditional switch herein) so as to solve the above and other potential issues. The solutions will be described in connection with Fig. 2 below.

Fig. 2 illustrates a schematic diagram illustrating a process 200 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve the terminal device 120, the MN 110, and the SN 130 as illustrated in Fig. 1. It is to be understood that the steps and the order of the steps in Fig. 2 are merely for illustration, and not for limitation. In some embodiments, the SN 130 may be a source SN. In some embodiments, the SN 130 may be a candidate SN.

As shown in Fig. 2, the MN 110 transmits 210, to a first SN (e.g., the SN 130) , a first message comprising a first set of candidate cells associated with a set of second SNs (e.g., the SN 140 and 150) . In other words, the first message may comprise a set of candidate cells associated with other SNs, i.e., a set of candidate cells possibly prepared by other SNs.

In some embodiments, the first set of candidate cells may comprise a subset of candidate cells associated with a second SN (e.g., each SN) of the set of second SNs. For example, the first set of candidate cells may be presented as a list as below:

{

SN 140: {cell 141}

SN 150: {cell 151, cell 152}

}

In some embodiments, the subset of candidate cells may be associated with a candidate cell (e.g., each candidate cell) in a second set of candidate cells associated with the SN 130. In other words, the subset of candidate cells includes candidate cells that the terminal device 120 will conditionally switch to when the terminal device 120 is connected to the candidate cell associated with the SN 130. The second set of candidate cells is suggested by the MN 110. For example, the second set of candidate cells may be presented as a list: {cell 131, cell 132, cell 141, cell 151, cell 152} . In this case, the first set of candidate cells may be presented as a list below:

In some embodiments, the first message may comprise an SN addition request message. In some embodiments, the first set of candidate cells may be carried as an XnAP message information element (IE) in the SN addition request message. In some embodiments, the first set of candidate cells may be carried as a radio resource control (RRC) field in cell group (CG) configuration IE (e.g., CG-ConfigInfo) in the SN addition request message.

In some embodiments, the first message may comprise an SN modification request message. It is to be understood that any other suitable messages are also feasible.

Continue to refer to Fig. 2, the SN 130 transmits 220, to the MN 110, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells. In some embodiments, the set of execution conditions may be associated with a part of the first set of candidate cells. In some embodiments, the set of execution conditions may be associated with all the first set of candidate cells.

In some embodiments, the first set of candidate cells may be suggested for the set of second SNs by the MN 110. In some embodiments, the first set of candidate cells may be suggested for the set of second SNs by a source SN. In this case, the SN 130 may generate and transmit an execution condition for any possible candidate cell for subsequent conditional switch even if the candidate cell is not prepared by the SN 130 eventually.

In some embodiments, the first set of candidate cells may be configured by the set of second SNs. In other words, the first set of candidate cells may be prepared by the set of second SNs. In this case, the SN 130 may generate and transmit execution conditions for switching to only prepared candidate cells of the set of second SNs.

In some embodiments, for each candidate cell prepared by the SN 130, the SN 130 may generate execution conditions for switching to possible other candidate cells when the candidate cell prepared by the SN 130 becomes a serving/source cell. In some embodiments, if the SN 130 decides to prepare one cell (e.g., the cell 131) in the second set of candidate cells suggested by the MN 110 and reject to prepare other cells (e.g., the cell 132) in the second set of candidate cells, the SN 130 may decide and configure execution conditions for switching to possible other candidate cells (belonging to the SN 130 or not) when the cell 131 becomes a serving/source cell.

In some embodiments, the possible other candidate cells may comprise a candidate cell in the second set of candidate cells associated with the SN 130, that is prepared by the SN 130 and different from the cell 131. In some embodiments, the possible other candidate cells may comprise a candidate cell in the first set of candidate cells associated with other SNs (i.e., the set of second SNs) . In some embodiments, the possible other candidate cells may comprise a candidate cell in the first set of candidate cells associated with other SNs (i.e., the set of second SNs) per candidate cell of the SN 130.

For example, the set of execution conditions may be presented as a list below:

It is to be understood that the set of execution conditions may comprise Event A3, Event A4, Event A5, Event B1 or any other suitable events existing or to be developed in future. Any combination of these events is also feasible.

In some embodiments where the first message comprises an SN addition request message, the second message comprises an SN addition request acknowledgement (ACK) message. In some embodiments where the first message comprises an SN modification request message, the second message comprises an SN modification request ACK message. It is to be understood that any other suitable messages are also feasible.

In some embodiments, the set of execution conditions may be comprised in an RRC reconfiguration field of an RRC container. In some embodiments, the set of execution conditions may be contained in the RRC reconfiguration field of a CG configuration RRC container. The RRC reconfiguration is generated by the SN 130.

For example, an example CG configuration message may be configured as below.

In this example, the set of execution conditions is included in an IE “scg-CellGroupConfig” .

In some embodiments, the set of execution conditions may be comprised in the RRC container and outside of the RRC reconfiguration field. In some embodiments, the set of execution conditions may be contained in the CG configuration RRC container and outside of the RRC reconfiguration field. The RRC reconfiguration is generated by the SN 130. For example, an example CG configuration message may be configured as below.

In this example, the set of execution conditions is included in an IE “ScgSelectiveActivationConfigurationPerCandidateCell-r18” .

Continue to refer to Fig. 2, the MN 110 transmits 230, to the terminal device 120, a configuration for a subsequent conditional cell addition or change (i.e., subsequent conditional switch) . The configuration comprises, for the SN 130, at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells. In some embodiments, the configuration may comprise, for the SN 130, all the set of execution conditions associated with all the at least part of the first set of candidate cells. In some embodiments, the configuration may comprise, for the SN 130, a part of the set of execution conditions associated with some of the at least part of the first set of candidate cells.

In some embodiments where the set of execution conditions is comprised in the RRC reconfiguration field of the RRC container, the MN 110 may transmit 231 the configuration comprising the set of execution conditions associated with the first set of candidate cells. In other words, the MN 110 cannot understand and process the set of execution conditions. The MN 110 may only forward the set of execution conditions to the terminal device 120.

With reference to Fig. 2, in some embodiments where the set of execution conditions is comprised in the RRC container and outside of the RRC reconfiguration field, the MN 110 may determine 232, for each candidate cell in the first set of candidate cells, whether both an execution condition associated with the candidate cell and RRC reconfiguration information associated with the candidate cell are received.

In some embodiments, the MN 110 may also receive a list of prepared candidate cells from the SN 130, i.e. RRC reconfiguration information of the prepared candidate cells. Based on the list of prepared candidate cells, the MN 110 may determine whether both an execution condition and RRC reconfiguration information are received for a candidate cell.

If both the execution condition and the RRC reconfiguration information are received for the candidate cell, the MN 110 may transmit 233 the configuration comprising the execution condition associated with the candidate cell. In this way, the MN 110 may only provide the execution conditions of the eventually prepared candidate cells to the terminal device 120.

It is to be understood that although the above procedure is described in connection with the SN 130, the same procedure may also be applied to other SNs. The MN 110 may cause the set of execution conditions for each SN of all possible candidate SNs to be comprised in the configuration for subsequent conditional cell addition or change.

Accordingly, the terminal device 120 receives the configuration for subsequent conditional cell addition or change. As shown in Fig. 2, the terminal device 120 may perform 240 evaluation on a candidate cell. In some embodiments, the terminal device 120 may determine 241 whether the configuration comprises an execution condition associated with a candidate cell and RRC reconfiguration information associated with the candidate cell. In other words, the terminal device 120 may determine whether a candidate cell configured with an execution condition is a valid candidate.

In some embodiments, if the configuration comprises the execution condition associated with the candidate cell and the RRC reconfiguration information associated with the candidate cell (i.e., the candidate cell is a valid candidate) , the terminal device 120 may evaluate 242 the candidate cell based on the execution condition. In some embodiments, if RRC reconfiguration information associated with the candidate cell is stored at the terminal device 120, the terminal device 120 may determine that the candidate cell is a valid candidate and evaluate the candidate cell based on the execution condition.

In some embodiments where the set of execution conditions is comprised in the RRC container and outside of the RRC reconfiguration field, for a candidate cell configured with an execution condition, the terminal device 120 may evaluate the candidate cell based on the execution condition.

With the process 200, execution conditions for SCG selective activation may be configured by candidate SNs, and thus SCG selective activation is well supported. The process 200 may be carried out in any suitable scenarios. For illustration, some example embodiments in different scenarios will be further described in connection with Figs. 3A to 5B below.

Fig. 3A illustrates a schematic diagram illustrating a process 300A of communication in a CPA-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 300A will be described with reference to Fig. 1. The process 300A may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SNs 130 and 140 serve as candidate SNs. It is assumed that the MN 110 initiates SCG selective activation via a CPA-like procedure with suggested candidate cells: cells 131 and 132 of SN 130; cells 141 and 142 of SN 140.

As shown in Fig. 3A, the MN 110 may transmit 310, to the SN 130, an SN addition request message comprising a suggested set of candidate PSCells (e.g., cells 131 and 132) for the SN 130 and a suggested set of candidate PSCells for each of other SNs (e.g., cells 141 and 142 for the SN 140) . The MN 110 may transmit 311, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., cells 141 and 142) for the SN 141 and a suggested set of candidate PSCells for each of other SNs (e.g., cells 131 and 132 for the SN 130) .

It is assumed that the cell 131 is a candidate PSCell eventually prepared by the SN 130, and the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 3A, the MN 110 may receive 312, from the SN 130, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 131) and execution conditions for switching to other candidate PSCells (i.e., the cells 141 and 142) when the cell 131 is a serving/source PSCell. The MN 110 may receive 313, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) and execution conditions for switching to other candidate PSCells (i.e., the cells 131 and 132) when the cell 141 is a serving/source PSCell.

With reference to Fig. 3A, the MN 110 may generate 314 a conditional reconfiguration including all execution conditions for switching to suggested candidate PSCells (i.e., the cells 141 and 142) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and all execution conditions for switching to suggested candidate PSCells (i.e., the cells 131 and 132) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. Alternatively, the MN 110 may generate 314’ a conditional reconfiguration including an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. In this way, an efficient evaluation for SCG selective activation may be facilitated.

The MN 110 may transmit 315 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform 316 evaluation on a candidate PSCell. In some embodiments, for a candidate PSCell configured with an execution condition, the terminal device 120 may determine whether RRC reconfiguration information of the candidate PSCell is received. If the RRC reconfiguration information of the candidate PSCell is received, the terminal device 120 may evaluate the candidate PSCell based on the execution condition. In this way, an efficient evaluation for SCG selective activation may be achieved.

With the process 300A, a candidate SN may configure execution conditions of all candidate PSCells of other SNs even if some of the candidate PSCells may not be prepared eventually.

Fig. 3B illustrates a schematic diagram illustrating another process 300B of communication in a CPA-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 300B will be described with reference to Fig. 1. The process 300B may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SNs 130 and 140 serve as candidate SNs. It is assumed that the MN 110 initiates SCG selective activation via a CPA-like procedure with suggested candidate cells: cells 131 and 132 of SN 130; cells 141 and 142 of SN 140.

As shown in Fig. 3B, the MN 110 may transmit 320, to the SN 130, an SN addition request message comprising a suggested set of candidate PSCells (e.g., cells 131 and 132) for the SN 130. The MN 110 may transmit 321, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., cells 141 and 142) for the SN 141.

It is assumed that the cell 131 is a candidate PSCell eventually prepared by the SN 130, and the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 3B, the MN 110 may receive 322, from the SN 130, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 131) . The MN 110 may receive 323, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) .

As shown in Fig. 3B, the MN 110 may transmit 324, to the SN 130, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 141 prepared by the SN 140) . The MN 110 may transmit 325, to the SN 140, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 131 prepared by the SN 130) .

With reference to Fig. 3B, the MN 110 may receive 326, from the SN 130, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the cell 131 is a serving/source PSCell. The MN 110 may receive 327, from the SN 140, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the cell 141 is a serving/source PSCell.

With reference to Fig. 3B, the MN 110 may generate 328 a conditional reconfiguration including the execution condition of the prepared candidate PSCell (i.e., the cells 141) of the SN 140 for the prepared candidate PSCell (i.e., the cell 131) of the SN 130 and the execution condition of the prepared candidate PSCell (i.e., the cell 131) of the SN 130 for the prepared candidate PSCell (i.e., the cell 141) of the SN 140. The MN 110 may transmit 329 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform evaluation on each candidate PSCell.

With the process 300B, a candidate SN may configure execution conditions of only prepared candidate PSCells of other SNs.

Fig. 4A illustrates a schematic diagram illustrating a process 400A of communication in an MN-initiated CPC-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 400A will be described with reference to Fig. 1. The process 400A may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SN 130 serves as a source SN which the terminal device 120 has already connected to, and the SN 140 serves as a candidate target SN. It is assumed that the MN 110 initiates SCG selective activation via a CPC-like procedure with suggested candidate cells: cells 131 and 132 of SN 130; cells 141 and 142 of SN 140.

As shown in Fig. 4A, the MN 110 may transmit 410, to the SN 130, an SN modification request message comprising a suggested set of candidate PSCells (e.g., the cells 131 and 132) for the SN 130 and a suggested set of candidate PSCells for each of other SNs (e.g., the cells 141 and 142 for the SN 140) . The MN 110 may transmit 411, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., the cells 141 and 142) for the SN 141 and a suggested set of candidate PSCells for each of other SNs (e.g., the cells 131 and 132 for the SN 130) .

It is assumed that the cell 131 is a candidate PSCell eventually prepared by the SN 130, and the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 4A, the MN 110 may receive 412, from the SN 130, an SN modification request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 131) and execution conditions for switching to other candidate PSCells (i.e., the cells 141 and 142) when the cell 131 is a serving/source PSCell. The MN 110 may receive 413, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) and execution conditions for switching to other candidate PSCells (i.e., the cells 131 and 132) when the cell 141 is a serving/source PSCell.

With reference to Fig. 4A, the MN 110 may generate 414 a conditional reconfiguration including all execution conditions for switching to suggested candidate PSCells (i.e., the cells 141 and 142) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and all execution conditions for switching to suggested candidate PSCells (i.e., the cells 131 and 132) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. Alternatively, the MN 110 may generate 414’ a conditional reconfiguration including an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. In this way, an efficient evaluation for SCG selective activation may be facilitated.

The MN 110 may transmit 415 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform 416 evaluation on a candidate PSCell. In some embodiments, for a candidate PSCell configured with an execution condition, the terminal device 120 may determine whether RRC reconfiguration information of the candidate PSCell is received. If the RRC reconfiguration information of the candidate PSCell is received, the terminal device 120 may evaluate the candidate PSCell based on the execution condition. In this way, an efficient evaluation for SCG selective activation may be achieved.

With the process 400A, a candidate SN may configure execution conditions of all candidate PSCells of other SNs even if some of the candidate PSCells may not be prepared eventually.

Fig. 4B illustrates a schematic diagram illustrating another process 400B of communication in an MN-initiated CPC-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 400B will be described with reference to Fig. 1. The process 400B may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SN 130 serves as a source SN which the terminal device 120 has already connected to, and the SN 140 serves as a candidate target SN. It is assumed that the MN 110 initiates SCG selective activation via a CPC-like procedure with suggested candidate cells: cells 131 and 132 of SN 130; cells 141 and 142 of SN 140.

As shown in Fig. 4B, the MN 110 may transmit 420, to the SN 130, an SN modification request message comprising a suggested set of candidate PSCells (e.g., the cells 131 and 132) for the SN 130. The MN 110 may transmit 421, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., the cells 141 and 142) for the SN 141.

It is assumed that the cell 131 is a candidate PSCell eventually prepared by the SN 130, and the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 4B, the MN 110 may receive 422, from the SN 130, an SN modification request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 131) . The MN 110 may receive 423, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) .

As shown in Fig. 4B, the MN 110 may transmit 424, to the SN 130, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 141 prepared by the SN 140) . The MN 110 may transmit 425, to the SN 140, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 131 prepared by the SN 130) .

With reference to Fig. 4B, the MN 110 may receive 426, from the SN 130, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the cell 131 is a serving/source PSCell. The MN 110 may receive 427, from the SN 140, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the cell 141 is a serving/source PSCell.

With reference to Fig. 4B, the MN 110 may generate 428 a conditional reconfiguration including the execution condition of the prepared candidate PSCell (i.e., the cells 141) of the SN 140 for the prepared candidate PSCell (i.e., the cell 131) of the SN 130 and the execution condition of the prepared candidate PSCell (i.e., the cell 131) of the SN 130 for the prepared candidate PSCell (i.e., the cell 141) of the SN 140. The MN 110 may transmit 429 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform evaluation on each candidate PSCell.

With the process 400B, a candidate SN may configure execution conditions of only prepared candidate PSCells of other SNs.

Fig. 5A illustrates a schematic diagram illustrating a process 500A of communication in an SN-initiated CPC-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 500A will be described with reference to Fig. 1. The process 500A may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SN 130 serves as a source SN which the terminal device 120 has already connected to, and the SN 140 serves as a candidate target SN. It is assumed that the SN 130 initiates SCG selective activation via a CPC-like procedure with suggested candidate cells: cell 131 of the SN 130; and cells 141 and 142 of the SN 140.

As shown in Fig. 5A, the SN 130 may transmit 510, to the MN 110, an SN change required message comprising a configuration of a candidate PSCell (i.e., the cell 131) prepared by the SN 130 and execution conditions for switching to candidate PSCells of other SNs (e.g., the cells 141 and 142 of the SN 140) when the cell 131 is a serving/source PSCell. Then the MN 110 may determine that a suggested set of candidate cells of SNs includes the cell 131 of the SN 130 and the cells 141 and 142 of the SN 140.

The MN 110 may transmit 511, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., the cells 141 and 142) for the SN 140 and a suggested set of candidate PSCells for each of other SNs (e.g., the cell 131 of the SN 130) .

It is assumed that the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 5A, the MN 110 may receive 512, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) and execution conditions for switching to other candidate PSCells (i.e., the cell 131) when the cell 141 is a serving/source PSCell.

With reference to Fig. 5A, the MN 110 may generate 513 a conditional reconfiguration including all execution conditions for switching to suggested candidate PSCells (i.e., the cells 141 and 142) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and all execution conditions for switching to suggested candidate PSCells (i.e., the prepared cell 131) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. Alternatively, the MN 110 may generate 513’ a conditional reconfiguration including an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the prepared candidate PSCell (i.e., the cell 131) of the SN 130 is a serving/source PSCell, and an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the prepared candidate PSCell (i.e., the cell 141) of the SN 140 is a serving/source PSCell. In this way, an efficient evaluation for SCG selective activation may be facilitated.

The MN 110 may transmit 514 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform 515 evaluation on a candidate PSCell. In some embodiments, for a candidate PSCell configured with an execution condition, the terminal device 120 may determine whether RRC reconfiguration information of the candidate PSCell is received. If the RRC reconfiguration information of the candidate PSCell is received, the terminal device 120 may evaluate the candidate PSCell based on the execution condition. In this way, an efficient evaluation for SCG selective activation may be achieved.

With the process 500A, a candidate SN may configure execution conditions of all candidate PSCells of other SNs even if some of the candidate PSCells may not be prepared eventually.

Fig. 5B illustrates a schematic diagram illustrating another process 500B of communication in an SN-initiated CPC-like scenario according to embodiments of the present disclosure. For the purpose of discussion, the process 500B will be described with reference to Fig. 1. The process 500B may involve the terminal device 120, the MN 110, and the SNs 130 and 140 as illustrated in Fig. 1. In this example, the SN 130 serves as a source SN which the terminal device 120 has already connected to, and the SN 140 serves as a candidate target SN. It is assumed that the SN 110 initiates SCG selective activation via a CPC-like procedure with suggested candidate cells: cell 131 of SN 130; cells 141 and 142 of SN 140.

As shown in Fig. 5B, the SN 130 may transmit 520, to the MN 110, an SN change required message comprising a configuration of a candidate PSCell (i.e., the cell 131) prepared by the SN 130.

The MN 110 may transmit 521, to the SN 140, an SN addition request message comprising a suggested set of candidate PSCells (e.g., cells 141 and 142) for the SN 141. It is assumed that the cell 141 is a candidate PSCell eventually prepared by the SN 140. With reference to Fig. 5B, the MN 110 may receive 522, from the SN 140, an SN addition request ACK message comprising a configuration of the prepared candidate PSCell (i.e., the cell 141) .

As shown in Fig. 5B, the MN 110 may transmit 523, to the SN 130, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 141 prepared by the SN 140) . The MN 110 may transmit 524, to the SN 140, an SN modification request message comprising a candidate PSCell prepared by each of other SNs (e.g., the cell 131 prepared by the SN 130) .

With reference to Fig. 5B, the MN 110 may receive 525, from the SN 130, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 141) of the SN 140 when the cell 131 is a serving/source PSCell. The MN 110 may receive 526, from the SN 140, an SN modification request ACK message comprising an execution condition for switching to the prepared candidate PSCell (i.e., the cell 131) of the SN 130 when the cell 141 is a serving/source PSCell.

With reference to Fig. 5B, the MN 110 may generate 527 a conditional reconfiguration including the execution condition of the prepared candidate PSCell (i.e., the cells 141) of the SN 140 for the prepared candidate PSCell (i.e., the cell 131) of the SN 130 and the execution condition of the prepared candidate PSCell (i.e., the cell 131) of the SN 130 for the prepared candidate PSCell (i.e., the cell 141) of the SN 140. The MN 110 may transmit 528 the conditional reconfiguration (i.e., a configuration for subsequent conditional cell addition or change) to the terminal device 120. Based on the conditional reconfiguration, the terminal device 120 may perform evaluation on each candidate PSCell.

With the process 500B, a candidate SN may configure execution conditions of only prepared candidate PSCells of other SNs. It is to be understood that the operations described in connection with the process 200 may be carried out in any of the processes 300A to 500B in any suitable ways.

Corresponding to the above processes, embodiments of the present disclosure provide methods of communication implemented at an MN, an SN and a terminal device. These methods will be described below with reference to Figs. 6 to 8.

Fig. 6 illustrates a flowchart of an example method 600 of communication implemented at an MN in accordance with some embodiments of the present disclosure. For example, the method 600 may be performed at the MN 110 as shown in Fig. 1. For the purpose of discussion, in the following, the method 600 will be described with reference to Fig. 1. It is to be understood that the method 600 may 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 block 610, the MN 110 transmits, to a first SN (e.g., the SN 130) , a first message comprising a first set of candidate cells associated with a set of second SNs (e.g., the SNs 140 and 150) . In some embodiments, the set of second SNs is different from the first SN.

In some embodiments, the first set of candidate cells may comprise a subset of candidate cells associated with a second SN of the set of second SNs. In some embodiments, the subset of candidate cells may be associated with a candidate cell in a second set of candidate cells associated with the first SN. The second set of candidate cells is suggested for the first SN by the MN 110. The subset of candidate cells may include candidate cells that the terminal device 120 will conditionally switch to when the terminal device 120 is connected to a candidate cell associated with the first SN in the second set of candidate cells.

In some embodiments, the first set of candidate cells may be suggested by the MN for the set of second SNs, e.g., in a CPA-like scenario or MN-initiated CPC-like scenario as described in Figs. 3A or 4A. In some embodiments, the first set of candidate cells may be suggested by a third SN (i.e., a source SN) different from the first SN, e.g., in an SN-initiated CPC-like scenario as described in Fig. 5A. In some embodiments, the first set of candidate cells may be configured by the set of second SNs, e.g., as described in Figs. 3B, 4B or 5B.

In some embodiments, the first message may comprise an SN addition request message. In some embodiments, the first message may comprise an SN modification request message.

At block 620, the MN 110 receives, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells. In some embodiments where the first message comprises an SN addition request message, the second message may comprise an SN addition request ACK message. In some embodiments where the first message comprises an SN modification request message, the second message may comprise an SN modification request ACK message.

In some embodiments, the set of execution conditions may be comprised in an RRC reconfiguration field of an RRC container. In some embodiments, the set of execution conditions may be comprised in an RRC container and outside of an RRC reconfiguration field.

At block 630, the MN 110 transmits, to the terminal device 120, a configuration for a subsequent conditional cell addition or change. The configuration comprises at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells.

In some embodiments where the set of execution conditions is comprised in an RRC reconfiguration field of an RRC container, the MN 110 may transmit the configuration comprising the set of execution conditions associated with all of the at least part of the first set of candidate cells.

In some embodiments where the set of execution conditions is comprised in an RRC container and outside of an RRC reconfiguration field, the MN 110 may determine whether an execution condition associated with a candidate cell and RRC reconfiguration information associated with the candidate cell are received. If the execution condition associated with the candidate cell and the RRC reconfiguration information associated with the candidate cell are received, the MN 110 may transmit the configuration comprising the execution condition associated with the candidate cell.

With the method 600, a configuration for a subsequent conditional cell addition or change (e.g., SCG selective activation) may be enhanced.

Fig. 7 illustrates a flowchart of an example method 700 of communication implemented at an SN (i.e., a first SN) in accordance with some embodiments of the present disclosure. For example, the method 700 may be performed at the SN 130, 140 or 150 as shown in Fig. 1. For the purpose of discussion, in the following, the method 700 will be described with reference to the SN 130 of Fig. 1. It is to be understood that the method 700 may 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 block 710, a first SN (e.g., the SN 130) receives, from the MN 110, a first message comprising a first set of candidate cells associated with a set of second SNs (e.g., the SNs 140 and 150) . In some embodiments, the set of second SNs is different from the first SN.

In some embodiments, the first set of candidate cells may comprise a subset of candidate cells associated with a second SN of the set of second SNs. In some embodiments, the subset of candidate cells may be associated with a candidate cell in a second set of candidate cells associated with the SN 130. The second set of candidate cells is suggested for the SN 130 by the MN 110. The subset of candidate cells may include candidate cells that the terminal device 120 will conditionally switch to when the terminal device 120 is connected to a candidate cell associated with the first SN in the second set of candidate cells.

At block 720, the SN 130 transmits, to the MN 110, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells. In some embodiments where the first message comprises an SN addition request message, the second message may comprise an SN addition request ACK message. In some embodiments where the first message comprises an SN modification request message, the second message may comprise an SN modification request ACK message.

With the method 700, a candidate SN may configure execution conditions for switching to candidate cells of other SNs when a candidate cell of the candidate SN is a serving/source cell.

Fig. 8 illustrates a flowchart of an example method 800 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 800 may be performed at the terminal device 120 as shown in Fig. 1. For the purpose of discussion, in the following, the method 800 will be described with reference to Fig. 1. It is to be understood that the method 800 may 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 block 810, the terminal device 120 receives, from a master node (MN) , a configuration for a subsequent conditional cell addition or change. The configuration comprises, for a first SN (e.g., the SN 130) , at least part of a set of execution conditions associated with some or all of at least part of a first set of candidate cells, the first set of candidate cells being associated with a set of second SNs (e.g., the SNs 140 and 150) .

In some embodiments, if the configuration comprises an execution condition associated with a candidate cell and RRC reconfiguration information associated with the candidate cell, the terminal device 120 may evaluate the candidate cell based on the execution condition. In some embodiments, for a candidate cell configured with an execution condition, if RRC reconfiguration information associated with the candidate cell is stored at the terminal device 120, the terminal device 120 may evaluate the candidate cell based on the execution condition.

With the method 800, execution conditions for a subsequent conditional cell addition or change (e.g., SCG selective activation) may be configured.

It is to be understood that operations of the methods 600 to 800 correspond to that described in connection with Figs. 2 to 5B, and thus other details are not repeated here for concise.

Fig. 9 is a simplified block diagram of a device 900 that is suitable for implementing embodiments of the present disclosure. The device 900 can be considered as a further example implementation of the MN 110 or the terminal device 120 or the SN 130 or 140 or 150 as shown in Fig. 1. Accordingly, the device 900 can be implemented at or as at least a part of the MN 110 or the terminal device 120 or the SN 130 or 140 or 150.

As shown, the device 900 includes a processor 910, a memory 920 coupled to the processor 910, a suitable transmitter (TX) and receiver (RX) (e.g., a transceiver) 940 coupled to the processor 910, and a communication interface coupled to the TX/RX 940. The memory 910 stores at least a part of a program 1130. The TX/RX 940 is for bidirectional communications. The TX/RX 940 has 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 program 930 is assumed to include program instructions that, when executed by the associated processor 910, enable the device 900 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to Figs. 1 to 8. The embodiments herein may be implemented by computer software executable by the processor 910 of the device 900, or by hardware, or by a combination of software and hardware. The processor 910 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 910 and memory 920 may form processing means 950 adapted to implement various embodiments of the present disclosure.

The memory 920 may 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 memory 920 is shown in the device 900, there may be several physically distinct memory modules in the device 900. The processor 910 may 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 device 900 may 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 summary, embodiments of the present disclosure provide the following solutions.

In one solution, a terminal device comprising: a processor; and a transceiver coupled to the processor. The processor is configured to: transmit, via the transceiver to a first secondary node (SN) , a first message comprising a first set of candidate cells associated with a set of second SNs; receive, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells; and transmit, to a terminal device, a configuration for a subsequent conditional cell addition or change, the configuration comprising at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells.

In some embodiments, the first set of candidate cells comprises a subset of candidate cells associated with a second SN of the set of second SNs.

In some embodiments, the subset of candidate cells is associated with a candidate cell in a second set of candidate cells associated with the first SN, the second set of candidate cells being suggested by the MN.

In some embodiments, the first set of candidate cells is suggested by the MN or a third SN different from the first SN, or the first set of candidate cells is configured by the set of second SNs.

In some embodiments, the set of execution conditions is comprised in a radio resource control (RRC) reconfiguration field of an RRC container. In some embodiments, the processor is configured to transmit the configuration by: transmitting the configuration comprising the set of execution conditions associated with all of the at least part of the first set of candidate cells.

In some embodiments, the set of execution conditions is comprised in a radio resource control (RRC) container and outside of a radio resource control (RRC) reconfiguration field. In some embodiments, the processor is configured to transmit the configuration by: in accordance with a determination that an execution condition associated with a candidate cell and radio resource control (RRC) reconfiguration information associated with the candidate cell are received, transmitting the configuration comprising the execution condition associated with the candidate cell.

In some embodiments, the first message comprises an SN addition request message, and the second message comprises an SN addition request acknowledgement message.

In some embodiments, the first message comprises an SN modification request message, and the second message comprises an SN modification request acknowledgement message.

In another solution, a first secondary node (SN) comprises: a processor; and a transceiver coupled to the processor. The processor is configured to: receive, via the transceiver from a master node (MN) , a first message comprising a first set of candidate cells associated with a set of second SNs; and transmit, to the MN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells.

In some embodiments, the set of execution conditions is comprised in a radio resource control (RRC) reconfiguration field of an RRC container.

In some embodiments, the set of execution conditions is comprised in a radio resource control (RRC) container and outside of a radio resource control (RRC) reconfiguration field.

In another solution, a terminal device comprises: a processor; and a transceiver coupled to the processor. The processor is configured to: receive, via the transceiver from a master node (MN) , a configuration for a subsequent conditional cell addition or change, the configuration comprising, for a first secondary node (SN) , at least part of a set of execution conditions associated with some or all of at least part of a first set of candidate cells, the first set of candidate cells being associated with a set of second SNs.

In some embodiments, the first set of candidate cells is suggested by the MN or a third SN different from the first SN, or the set of candidate cells is configured by the set of second SNs.

In some embodiments, the processor is further configured to: in accordance with a determination that the configuration comprises an execution condition associated with a candidate cell and radio resource control (RRC) reconfiguration information associated with the candidate cell, evaluate the candidate cell based on the execution condition.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to Figs. 1 to 8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A master node (MN) comprising:

a processor; and

a transceiver coupled to the processor,

wherein the processor is configured to:

transmit, via the transceiver to a first secondary node (SN) , a first message comprising a first set of candidate cells associated with a set of second SNs;

receive, from the first SN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells; and

transmit, to a terminal device, a configuration for a subsequent conditional cell addition or change, the configuration comprising at least part of the set of execution conditions associated with some or all of the at least part of the first set of candidate cells.
The MN of claim 1, wherein the first set of candidate cells comprises a subset of candidate cells associated with a second SN of the set of second SNs.
The MN of claim 2, wherein the subset of candidate cells is associated with a candidate cell in a second set of candidate cells associated with the first SN, the second set of candidate cells being suggested by the MN.
The MN of claim 1, wherein the first set of candidate cells is suggested by the MN or a third SN different from the first SN, or

wherein the first set of candidate cells is configured by the set of second SNs.
The MN of claim 1, wherein the set of execution conditions is comprised in a radio resource control (RRC) reconfiguration field of an RRC container.
The MN of claim 5, wherein the processor is configured to transmit the configuration by:

transmitting the configuration comprising the set of execution conditions associated with all of the at least part of the first set of candidate cells.
The MN of claim 1, wherein the set of execution conditions is comprised in a radio resource control (RRC) container and outside of a radio resource control (RRC) reconfiguration field.
The MN of claim 7, wherein the processor is configured to transmit the configuration by:

in accordance with a determination that an execution condition associated with a candidate cell and radio resource control (RRC) reconfiguration information associated with the candidate cell are received, transmitting the configuration comprising the execution condition associated with the candidate cell.
A first secondary node (SN) , comprising:

a processor; and

a transceiver coupled to the processor,

wherein the processor is configured to:

receive, via the transceiver from a master node (MN) , a first message comprising a first set of candidate cells associated with a set of second SNs; and

transmit, to the MN, a second message comprising a set of execution conditions associated with at least part of the first set of candidate cells.
The first SN of claim 9, wherein the first set of candidate cells comprises a subset of candidate cells associated with a second SN of the set of second SNs.
The first SN of claim 10, wherein the subset of candidate cells is associated with a candidate cell in a second set of candidate cells associated with the first SN, the second set of candidate cells being suggested by the MN.
The first SN of claim 9, wherein the first set of candidate cells is suggested by the MN or a third SN different from the first SN, or

wherein the first set of candidate cells is configured by the set of second SNs.
A terminal device comprising:

a processor; and

a transceiver coupled to the processor,

wherein the processor is configured to:

receive, via the transceiver from a master node (MN) , a configuration for a subsequent conditional cell addition or change, the configuration comprising, for a first secondary node (SN) , at least part of a set of execution conditions associated with some or all of at least part of a first set of candidate cells, the first set of candidate cells being associated with a set of second SNs.
The terminal device of claim 13, wherein the first set of candidate cells is suggested by the MN or a third SN different from the first SN, or

wherein the set of candidate cells is configured by the set of second SNs.
The terminal device of claim 13, wherein the processor is further configured to:

in accordance with a determination that the configuration comprises an execution condition associated with a candidate cell and radio resource control (RRC) reconfiguration information associated with the candidate cell, evaluate the candidate cell based on the execution condition.