WO2023178572A1

WO2023178572A1 - Methods, devices, and computer readable medium for communication

Info

Publication number: WO2023178572A1
Application number: PCT/CN2022/082601
Authority: WO
Inventors: Gang Wang; Da Wang
Original assignee: Nec Corporation
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2023-09-28

Abstract

Embodiments of the present disclosure relate to communications. According to embodiments of the present disclosure, a network device is to hand over from a source network device to a target network device. The network device transmits downlink control information comprising an indication associated with group mobility in a short message field to a terminal device. The downlink control information is generated by the source network device. The terminal device performs a cell reselection or a conditional handover based on the reception of the downlink control information. In other words, the cell reselection and conditional handover may be not triggered by changes in link quality. In this way, the terminal device is able to perform the cell reselection or conditional handover properly, thereby ensuring communication performances.

Description

METHODS, DEVICES, AND COMPUTER READABLE MEDIUM FOR COMMUNICATION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices, and computer readable medium for communication.

BACKGROUND

In recent communication networks, network speed has been improved. The communication networks are expected to provide low latency and reliability for consumers and industries. In order to achieve super-fast data rates and ultra-low latency, higher frequency electromagnetic waves (for example, millimeter waves) are introduced into the communication networks. However, signals transmitted with higher frequency electromagnetic waves are easily blocked by objects. In this situation, a technology of Integrated Access and Backhaul (IAB) has been introduced. In cellular telecommunication, a term “handover (HO) ” refers to a process of transferring an ongoing cell or data session from one channel to another channel. The handover procedures may be different in different scenarios. Therefore, applying the handover to the IAB scenario is worth studying.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for communication.

In a first aspect, there is provided a method for communication. The method comprises receiving, at a terminal device and from a network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from a source network device to a target network device and the downlink control information is generated by the source network device.

In a second aspect, there is provided a method for communication. The method comprises determining, at a source network device, that a network device is to handover from the source network device to a target network device based on a measurement report from the network device; determining downlink control information comprising an indication associated with group mobility in a short message field; and transmitting the downlink control information to the network device.

In a third aspect, there is provided a method for communication. The method comprises transmitting, at a network device, a measurement report to a source network device; receiving, from the source network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from the source network device to a target network device; and transmitting the downlink control information to a terminal device served by the network device.

In a fourth aspect, there is provided a terminal device. The terminal device comprises a processing unit; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the terminal device to perform acts comprising: receiving, from a network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from a source network device to a target network device and the downlink control information is generated by the source network device.

In a fifth aspect, there is provided a source network device. The source network device comprises a processing unit; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the source network device to perform acts comprising: determining that a network device is to handover from the source network device to a target network device based on a measurement report from the network device; determining downlink control information comprising an indication associated with group mobility in a short message field; and transmitting the downlink control information to the network device.

In a sixth aspect, there is provided a network device. The network device comprises a processing unit; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the network device to perform acts comprising: transmitting a measurement report to a source network device; receiving, from the source network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from the source network device to a target network device; and transmitting the downlink control information to a terminal device served by the IAB node.

In a seventh aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any one of the first aspect, second or third aspect.

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

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

Fig. 1 is a schematic diagram of a communication environment in which embodiments of the present disclosure can be implemented;

Fig. 2 illustrates a signaling flow for handover according to some embodiments of the present disclosure;

Fig. 3 illustrates a signaling flow for a cell reselection according to some embodiments of the present disclosure;

Fig. 4 illustrates a signaling flow for a conditional handover (CHO) according to some embodiments of the present disclosure;

Fig. 5 is a flowchart of an example method in accordance with an embodiment of the present disclosure;

Fig. 6 is a flowchart of an example method in accordance with an embodiment of the present disclosure;

Fig. 7 is a flowchart of an example method in accordance with an embodiment of the present disclosure; and

Fig. 8 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

Principle of the present disclosure will now be described with reference to some example 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 limitations 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.

As used herein, 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 NodeB in new radio access (gNB) a Remote Radio Unit (RRU) , a radio head (RH) , a remote radio head (RRH) , a low power node such as a femto node, a pico node, a satellite network device, an aircraft network device, and the like. For the purpose of discussion, in the following, some example embodiments will be described with reference to eNB as examples of the network device.

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, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, or image capture devices such as digital cameras, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

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 and the second network device. In one embodiment, a first information may be transmitted to the terminal device from the first network device and a 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.

Communications discussed herein may use conform to any suitable standards including, but not limited to, New Radio Access (NR) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , cdma2000, and Global System for Mobile Communications (GSM) and the like. Furthermore, the communications 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, 2.85G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) , and the sixth (6G) communication protocols. The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies.

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.

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 “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 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.

As mentioned above, IAB is an important feature in 5G New Radio (NR) that enables rapid and cost-effective millimeter wave deployments through self-backhauling in the same spectrum. The term “wireless self-backhauling” used herein refers to a technology that uses the same wireless channel for coverage and backhaul connectivity to other base stations. It can achieve greater performance, more efficient use of spectrum resources and lowers equipment costs, while also reduce the reliance on the availability of wired backhaul at each access node location. In an IAB system, there are two types of network devices, IAB node and IAB donor. In other words, IAB is a multi-hop approach to network deployment and allows deployment of millimeter wave base stations with or without fiber backhaul transport. It works by having a fraction of the deployed network device act as donor nodes, using a fiber/wired connection. The remainder without a wired connection is called IAB nodes. Both types of BSs generate an equivalent cellular coverage area and appear identical to user equipment (UE) in its coverage area. The Donor distributed unit (DU) is a conventional fiber-fed BS connected to the centralized unit (CU) using an F1 interface. The IAB node may serve as a first hop or second hop node. Both donor and IAB nodes also directly support UEs multiplexed with the backhaul Ur interface. The Uu interface is directly between a UE and an IAB or donor node. The channel between two IAB nodes can be called radio link control (RLC) channel.

When IAB node is serving a UE, it works as a distributed unit (DU) to the UE, and a mobile terminal (MT) to its parent IAB node. Backhaul RLC channel (s) are setup between the MT part and the parent nodes DU part and adaptation layer called Backhaul Adaptation Protocol (BAP) is agreed to be on top of the radio link control (RLC) layer. The IAB-node DU part connects to the IAB-donor CU with F1 interface which is enhanced to support IAB functions. F1 packets (GTP-U/UDP/IP for user plane (UP) and F1AP/SCTP/IP for control plane (CP) ) are transported on top of the adaptation layer. IAB thus implements L2 relaying. An IAB node represents a co-located resource providing NR access coverage and backhauling over the air interface. As such, an IAB node may take on both the personality of UE (MT part) for transferring backhaul traffic or that of gNB (or gNB-DU) serving connected UEs and forwarding backhaul traffic to the next hop.

According to conventional technologies, a conditional handover (CHO) has been introduced to reduce the service interruption and reduce the radio link failure (RLF) possibility. The network provides CHO triggering criteria, with the radio configuration of potential target gNBs. When the UE evaluates the criteria of the target gNB is fulfilled, the UE may complete the handover on its own, with a notification to the target gNB by RRC Reconfiguration Complete message.

Further, the introduction of inter-donor Integrated Access Backhaul (IAB) -node migration increases robustness and allows for more refined load-balancing and topology management. Reduction of service interruption time caused by IAB-node migration and backhaul (BH) RLF recovery improves network performance and allows network deployments to undergo more frequent topology changes, and provides stable backhaul performance.

Moreover, recent studies focus on the scenario of mobile-IAB-nodes mounted on vehicles providing 5G coverage/capacity enhancement to onboard and/or surrounding UEs. For example, in Release-18, mobile IAB may support in-band and out-of-band backhauling. Thee mobile IAB-node may have no descendent IAB-nodes, i.e., it serves only UEs. In this situation, if the IAB node is handed over from a source IAB donor to a target IAB donor, the UE connected to the IAB node may have some problems. Specifically, since the UE connects with the IAB node, the link quality between the UE and the IAB node may not change and the UE may not be aware of the handover of the IAB node. In such case, if the cell reselection or handover is triggered by the changed link quality, the UE cannot timely perform the cell reselection or handover. In other words, the conventional cell reselection and handover are not applicable. Therefore, a new solution on group mobility of mobile IAB node is needed.

In order to solve at least part of above and potential problems, a solution on group mobility of mobile network device is proposed. A network device is to hand over from a source network device to a target network device. The network device transmits downlink control information comprising an indication associated with group mobility in a short message field to a terminal device. The downlink control information is generated by the source network device. The terminal device performs a cell reselection or a conditional handover based on the reception of the downlink control information. In other words, the cell reselection and conditional handover may be not triggered by changes in link quality. In this way, the terminal device is able to perform the cell reselection or conditional handover properly, thereby ensuring communication performances.

Fig. 1 illustrates a schematic diagram of a communication system in which embodiments of the present disclosure can be implemented. The communication system 100, which is a part of a communication network, comprises a terminal device 110-1, a terminal device 110-2, . . ., a terminal device 110-N, which can be collectively referred to as “terminal device (s) 110. ” The number N can be any suitable integer number.

The communication system 100 further comprises a network device 120. In some embodiments, the network device may be any suitable network device. Only for the purpose of illustrations, the network device 120 may be an IAB node. As shown in Fig. 1, the communication system 100 also comprises a network device130-1 and a network device 130-2. Only for the purpose of illustrations, the network devices 130-1 and 130-2 may be IAB donors. It should be noted that the number of network devices shown in Fig. 1 is only an example. In the communication system 100, the network device 120 and the terminal devices 110 can communicate data and control information to each other. The donor CUs can also communicate with the network device 120. Only for the purpose of illustrations, the network device 120 can be handed over from the network device r 130-1 to the network device 130-2. Thus, the network device 130-1 can be regarded as a source network device and the network device 130-2 can be regarded as a target network device.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) , the fifth generation (5G) and the sixth generation (6G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Divided Multiple Address (CDMA) , Frequency Divided Multiple Address (FDMA) , Time Divided Multiple Address (TDMA) , Frequency Divided Duplexer (FDD) , Time Divided Duplexer (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Divided Multiple Access (OFDMA) and/or any other technologies currently known or to be developed in the future.

Embodiments of the present disclosure can be applied to any suitable scenarios. For example, embodiments of the present disclosure can be implemented at reduced capability NR devices. Alternatively, embodiments of the present disclosure can be implemented in one of the followings: NR multiple-input and multiple-output (MIMO) , NR sidelink enhancements, NR systems with frequency above 52.6GHz, an extending NR operation up to 71GHz, narrow band-Internet of Thing (NB-IOT) /enhanced Machine Type Communication (eMTC) over non-terrestrial networks (NTN) , NTN, UE power saving enhancements, NR coverage enhancement, NB-IoT and LTE-MTC, Integrated Access and Backhaul (IAB) , NR Multicast and Broadcast Services, or enhancements on Multi-Radio Dual-Connectivity.

The term “slot” used herein refers to a dynamic scheduling unit. One slot comprises a predetermined number of symbols. The term “downlink (DL) sub-slot” may refer to a virtual sub-slot constructed based on uplink (UL) sub-slot. The DL sub-slot may comprise fewer symbols than one DL slot. The slot used herein may refer to a normal slot which comprises a predetermined number of symbols and also refer to a sub-slot which comprises fewer symbols than the predetermined number of symbols.

Embodiments of the present disclosure will be described in detail below. Reference is first made to Fig. 2, which shows a signaling chart illustrating process 200 among devices according to some example embodiments of the present disclosure. Only for the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve the terminal device 110-1, the network device 120, and the network device 130-1 in Fig. 1. The network device 120 is serving the terminal device 110-1 and currently connecting with the network device 130-1. It should be noted that the process 200 is a general process according to embodiments of the present disclosure. In some embodiments, the process 200 may be implemented in a scenario of IAB communications. Alternatively, the process 200 may be implemented in a scenario of sidelink communications.

The network device 120 may perform measurements for the network device 130-1 (i.e., the source IAB donor) and the network device 130-2 (i.e., the target IAB donor) . The network device 120 may perform any suitable measurement events. For example, the network device 120 may perform Event A3 where a neighbor cell becomes better than a serving cell by an offset. The offset can be either positive or negative. In other words, the quality difference between the neighbor cell and the serving cell may be the offset value. Alternatively, the network device 120 may perform any one of: Event A1 where a serving cell becomes better than a threshold, Event A2 where the serving cell becomes worse than a threshold, Event A4 where the neighbor cell becomes better than a threshold, Event A5 wherein the serving cell becomes worse than threshold 1 and the neighbor cell becomes better than threshold A2, Event B1 wherein inter RAT neighbor becomes better than a threshold, and Event B2 where the serving cell becomes worse than threshold 1 and inter RAT neighbor becomes better than threshold 2. In some embodiments, the network device 120 may measure a reference signal received power (RSRP) . Alternatively, the network device 120 may measure a reference signal receiving quality (RSRQ) . The network device 120 may measure any suitable parameters.

The network device 120 transmits 2010 a measurement report to the network device 130-1. For example, the measurement report may indicate the RSRP associated with the network device 130-1 and the RSRP associated with the network device 130-2. Alternatively, the measurement report may indicate the RSRQ associated with the network device 130-1 and the RSRQ associated with the network device 130-2.

The network device 130-1 determines 2020 that the network device 120 is to hand over to the network device 130-2. The network device 130-1 may transmit a handover request for the network device 120 to the network device 130-2. The network device 130-2 may transmit a handover request acknowledgment to the network device 130-1 for the network device 120.

The network device 130-1 determines 2030 downlink control information. The downlink control information comprises an indication associated with group mobility in a short message field. This downlink control information may refer to a short message. The term “short message” used herein can refer to paging downlink control information which is scrambled by a paging radio network temporary identifier. The term “group mobility” used herein can refer to a mobility of a set of terminal devices which connect to one network device. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

The network device 130-1 transmits 2040 the downlink control information to the network device 120. The network device 120 then transmits 2050 the downlink control information to the terminal device 110-1.

As mentioned above, one or more reserved bits in the short message may be used for the group mobility indication. In this case, if the terminal device 110-1 is in an idle state or an inactive state the terminal device 110-1 may perform 2060 the cell reselection after receiving the downlink control information. For example, the terminal device 110-1 may perform a measurement on a neighbor cell with an intra-frequency or an inter-frequency with a priority below a threshold. The terminal device 110-1 may measure RSRP or RSRQ on the neighbor cell. The terminal device 110-1 may perform the cell reselection based on a result of the measurement.

Alternatively, if the terminal device 110-1 is in a connected state, the terminal device 110-1 may perform 2060 the CHO after receiving the downlink control information. The term “idle state” used herein can refer to a UE access stratum (AS) state in which the UE is switched on but does not have any established RRC connection. No RRC connection means that the presence of the UE is, in general, not known to the network at the cell level because the network device do not have any context for the UE. The term “connected state” can refer to a UE access stratum (AS) state in which the UE is switched on and has an established RRC connection.

In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit modified system information to the terminal device 110-1. In some embodiments, the system information may comprise an indication regarding the handover of the IAB node. Alternatively, the system information may comprise an implicit indication regarding the handover of the IAB node. For example, the system information may comprise a cell configuration of a cell to be reselected. If the terminal device 110-1 is in an idle state or an inactive state, the terminal device 110-1 may perform 2060 the cell reselection after receiving the downlink control information and the modified system information. Alternatively, if the terminal device 110-1 is in a connected state, the terminal device 110-1 may perform 2060 the CHO after receiving the downlink control information and the modified system information.

According to embodiments described with reference to Fig. 2, the cell reselection and the CHO may not be triggered by changes in link quality. The terminal device can perform the CHO and the cell reselection when the IAB node is to handover to another donor. In this way, communication performances can be ensured.

Embodiments of the present disclosure will be described in detail below. Reference is first made to Fig. 3, which shows a signaling chart illustrating process 300 among devices according to some example embodiments of the present disclosure. Only for the purpose of discussion, the process 300 will be described with reference to Fig. 1. The process 300 may involve the terminal device 110-1, the network device 120, the network device 130-1 and the network device 130-2 in Fig. 1. Fig. 3 shows the process 300 according to embodiments of the present disclosure where the terminal device 110-1 is in the idle state.

The network device 130-1 may transmit a measurement configuration to the network device 120. The measurement configuration may comprise one or more conditions for initiating the measurement.

The network device 120 may perform measurements for the network device 130-1 and the network device 130-2. The network device 120 may perform any suitable measurement events based on the measurement configuration. For example, the network device 120 may perform Event A3 where a neighbor cell becomes better than a serving cell by an offset. Alternatively, the network device 120 may perform any one of: Event A1 where a serving cell becomes better than a threshold, Event A2 where the serving cell becomes worse than a threshold, Event A4 where the neighbor cell becomes better than a threshold, Event A5 wherein the serving cell becomes worse than threshold 1 and the neighbor cell becomes better than threshold A2, Event B1 wherein inter RAT neighbor becomes better than a threshold, and Event B2 where the serving cell becomes worse than threshold 1 and inter RAT neighbor becomes better than threshold 2. In some embodiments, the network device 120 may measure a RSRP. Alternatively, the network device 120 may measure a RSRQ. The network device 120 may measure any suitable parameters.

The network device 120 may transmit 3005 a measurement report to the network device 130-1. For example, the measurement report may indicate the RSRP associated with the network device 130-1 and the RSRP associated with the network device 130-2. Alternatively, the measurement report may indicate the RSRQ associated with the network device 130-1 and the RSRQ associated with the network device 130-2.

The network device 130-1 may determine 3010 that the network device 120 is to hand over to the network device 130-2 based on the measurement report. The network device 130-1 may determine downlink control information. The downlink control information comprises an indication associated with group mobility in a short message field. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Table 1 below shows an example of the short message which comprises the group mobility indication. For example, as shown in Table 1, 5 ^th bit in the short message can be used for the group mobility indication.

Table 1

Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

The network device 130-1 may transmit 3015 the downlink control information to the network device 120. The network device 120 may forward 3016 the downlink control information to the terminal device 110-1. In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit 3017 modified system information to the terminal device 110-1 via the network device 120.

The terminal device 110-1 may monitor the downlink control information. As mentioned above, if the short message may comprise a modification in system information, the terminal device 110-1 may receive the modified system information from the network device 120. In this case, the terminal device 110-1 may perform 3020 the cell reselection after receiving the system information. In some embodiments, the system information may comprise an indication regarding the handover of the IAB node. Alternatively, the system information may comprise an implicit indication regarding the handover of the IAB node. For example, the system information may comprise a cell configuration of a cell to be reselected.

In some embodiments, if the terminal device 110-1 receives the short message which comprises the group mobility indication, the terminal device 110-1 may perform 3020 the cell reselection after receiving the downlink control information. For example, the terminal device 110-1 may perform a measurement on a neighbor cell with an intra-frequency or an inter-frequency with a priority below a threshold. The terminal device 110-1 may measure RSRP or RSRQ on the neighbor cell. The terminal device 110-1 may perform the cell reselection based on a result of the measurement. Table 2 below shows example behaviors of the terminal device 110-1 where the terminal device 110-1 receives the short message.

Table 2

In some embodiments, measurement rules for the cell reselection may also be changed. For example, if the serving cell serving cell fulfils Srxlev > S _IntraSearchP and Squal > S _IntraSearchQ, and the Groupmobilityindication bit of Short Message is not set, the terminal device 110-1may choose not to perform intra-frequency measurements. Otherwise, the terminal device 110-1 may perform intra-frequency measurements. The Srxlev value can be determined based on a measurement RSRP level and a minimum RSRP level for camping, such as, Srxlev = Qrxlevmeas -qRxLevMin, where Qrxlevemeas represents the measured RSRP level and qRxLevMin represents minimum RSRP level for camping. The SIntraSearchP can refer to a threshold of current cell Srxlev to perform intra-frequency. For example, if the current cell Srxleve is lower than this value, the terminal device 110-1 may perform measurement for intra-frequency. SIntraSearchQ can refer to a threshold of current cell Squal to perform intra-frequency. For example, if the current cell Squal is lower than this value, the terminal device 110-1 may perform measurement for intra-frequency. Table 3 below shows example measurement rules for the cell reselection.

Table 3

The network device 130-1 may transmit 3025 a handover request for the network device 120 to the network device 130-2. The network device 130-2 may transmit 3030 a handover request acknowledgment to the network device 130-1 for the network device 120. It should be noted that the cell reselection (3020) and the transmission (3025 and 3030) of the handover request and the handover request acknowledgment can be performed in any proper order. In other words, the cell reselection may be performed before or after the transmission of the handover request. The cell reselection and the transmission of the handover request may be performed simultaneously.

The network device 130-1 may transmit 3035 a reconfiguration message (for example, a RRC reconfiguration message) to the network device 130-2. The reconfiguration can be used to migrate from the network device 130-1 to the network device 130-2. The reconfiguration may be sent to activate the default radio bearer. The reconfiguration may also carry the Attach Accept message as non-access stratum (NAS) payload. The reconfiguration may comprise measurement objects for 5G NR frequencies. The network device 120 may transmit 3040 a reconfiguration complete message to the network device 130-2. In this way, since the reconfiguration is transmitted after the transmission of the downlink control information, it ensures that the terminal device can perform the cell reselection before the handover of the IAB node.

Embodiments of the present disclosure will be described in detail below. Reference is first made to Fig. 4, which shows a signaling chart illustrating process 400 among devices according to some example embodiments of the present disclosure. Only for the purpose of discussion, the process 400 will be described with reference to Fig. 1. The process 400 may involve the terminal device 110-1, the network device 120, the network device 130-1 and the network device 130-2 in Fig. 1. Fig. 4 shows the process 400 according to embodiments of the present disclosure where the terminal device 110-1 is in the connected state.

The DL/UL data packets may be transmitted 4005 between the terminal device 110-1 and the network device 130-1 via the network device 120. The network device 130-1 may configure a measurement configuration to the terminal device 110-1. The terminal device 110-1 may perform the measurement based on the measurement report. For example, the terminal device 110-1 may perform Event A3 where a neighbor cell becomes better than a serving cell by an offset. Alternatively, the terminal device 110-1 may perform any one of: Event A1 where a serving cell becomes better than a threshold, Event A2 where the serving cell becomes worse than a threshold, Event A4 where the neighbor cell becomes better than a threshold, Event A5 wherein the serving cell becomes worse than threshold 1 and the neighbor cell becomes better than threshold A2, Event B1 wherein inter RAT neighbor becomes better than a threshold, and Event B2 where the serving cell becomes worse than threshold 1 and inter RAT neighbor becomes better than threshold 2. In some embodiments, the network device 120 may measure a RSRP. Alternatively, the terminal device 110-1 may measure a RSRQ. The terminal device 110-1 may measure any suitable parameters. The terminal device 110-1 may transmit 4010 a measurement report of the terminal device 110-1 to the network device 130-1 through the network device 120.

The network device 130-1 may make 4015 the conditional handover decision. The network device 130-1 may also transmit a handover request to the network device 130-2. For example, the network device 130-1 may decide to use CHO and interactive information with candidate cell.

The network device 130-1 may transmit 4020 a reconfiguration message to the terminal device 110-1. In some embodiments, the reconfiguration may comprise a configuration of CHO candidate cell (s) . Alternatively or in addition, the reconfiguration may comprise one or more CHO execution conditions. The terminal device 110-1 may transmit 4025 a reconfiguration complete message to the network device 130-1.

The network device 120 may transmit 4030 a measurement report to the network device 130-1. For example, the measurement report may indicate the RSRP associated with the network device 130-1 and the RSRP associated with the network device 130-2. Alternatively, the measurement report may indicate the RSRQ associated with the network device 130-1 and the RSRQ associated with the network device 130-2.

The network device 130-1 may determine 4035 that the network device 120 is to hand over to the network device 130-2 based on the measurement report. The network device 130-1 may determine downlink control information. The downlink control information comprises an indication associated with group mobility in a short message field. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

The network device 130-1 may transmit 4040 the downlink control information to the terminal device 110-1 via the network device 120. In other words, the network device 120 may forward the downlink control information to the terminal device 110-1. In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit 4041 modified system information to the terminal device 110-1 via the network device 120.

The terminal device 110-1 may monitor the downlink control information. As mentioned above, if the short message may comprise a modification in system information, the terminal device 110-1 may receive the modified system information from the network device 120. In this case, the terminal device 110-1 may perform 4045 the CHO after receiving the system information.

In some embodiments, if the terminal device 110-1 receives the short message which comprises the group mobility indication, the terminal device 110-1 may perform 4045 the CHO after receiving the downlink control information. If the terminal device 110-1 is configured with the CHO, the terminal device 110-1 may select a suitable CHO candidate cell.

The network device 130-1 may transmit 4050 a handover request for the network device 120 to the network device 130-2. The network device 130-2 may transmit 4055 a handover request acknowledgment to the network device 130-1 for the network device 120. It should be noted that the CHO (4045) and the transmission (4050 and 4055) of the handover request and the handover request acknowledgment can be performed in any proper order. In other words, the CHO may be performed before or after the transmission of the handover request. The CHO and the transmission of the handover request may be performed simultaneously.

The network device 130-1 may transmit 4060 a reconfiguration message to the network device 130-2. The reconfiguration can be used to migrate from the network device 130-1 to the network device 130-2. The reconfiguration may be sent to activate the default radio bearer. The reconfiguration may also carry the Attach Accept message as non-access stratum (NAS) payload. The reconfiguration may comprise measurement objects for 5G NR frequencies. The network device 120 may transmit 4065 a reconfiguration complete message to the network device 130-2. In this way, since the reconfiguration is transmitted after the transmission of the downlink control information, it ensures that the terminal device can perform the cell reselection before the handover of the IAB node.

Fig. 5 shows a flowchart of an example method 500 in accordance with an embodiment of the present disclosure. The method 500 can be implemented at any suitable devices. Only for the purpose of illustrations, the method 500 can be implemented at a terminal device 110-1.

At block 510, the terminal device 110-1 receives downlink control information from the network device 120. The downlink control information comprises an indication associated with group mobility in a short message field. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

In some embodiments, at block 520, the terminal device 110-1 may perform a cell reselection or a conditional handover based on the reception of the downlink control information. As mentioned above, one or more reserved bits in the short message may be used for the group mobility indication. In this case, if the terminal device 110-1 is in an idle state, the terminal device 110-1 may perform the cell reselection after receiving the downlink control information. The terminal device 110-1 may exclude serving cell when the terminal device 110-1 ranks the cell based on the reselection criteria. For example, the terminal device 110-1 may perform a measurement on a neighbor cell with an intra-frequency or an inter-frequency with a priority below a threshold. The terminal device 110-1 may measure RSRP or RSRQ on the neighbor cell. The terminal device 110-1 may perform the cell reselection based on a result of the measurement. Alternatively, if the terminal device 110-1 is in a connected state, the terminal device 110-1 perform the CHO after receiving the downlink control information.

In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit modified system information to the terminal device 110-1. In some embodiments, the system information may comprise an indication regarding the handover of the IAB node. Alternatively, the system information may comprise an implicit indication regarding the handover of the IAB node. For example, the system information may comprise a cell configuration of a cell to be reselected. If the terminal device 110-1 is in an idle state or an inactive state, the terminal device 110-1 may perform the cell reselection after receiving the downlink control information and the modified system information. Alternatively, if the terminal device 110-1 is in a connected state, the terminal device 110-1 may perform the CHO after receiving the downlink control information and the modified system information.

Fig. 6 shows a flowchart of an example method 600 in accordance with an embodiment of the present disclosure. The method 600 can be implemented at any suitable devices. Only for the purpose of illustrations, the method 600 can be implemented at a network device 130-1.

In some embodiments, the network device 130-1 may configure a measurement configuration to the terminal device 110-1. The network device 130-1 may receive a measurement report of the terminal device 110-1 from the terminal device 110-1 through the network device 120.

The network device 130-1 may transmit a measurement configuration to the network device 120. The measurement configuration may comprise one or more conditions for initiating the measurement. The network device 130-1 may make the conditional handover decision. The network device 130-1 may also transmit a handover request to the network device 130-2. For example, the network device 130-1 may decide to use CHO and interactive information with candidate cell.

The network device 130-1 may transmit a reconfiguration message to the terminal device 110-1. In some embodiments, the reconfiguration may comprise a configuration of CHO candidate cell (s) . Alternatively or in addition, the reconfiguration may comprise one or more CHO execution conditions. The terminal device 110-1 may transmit 4025 a reconfiguration complete message to the network device 130-1.

At block 610, the network device 130-1 receives a measurement report from the network device 120. For example, the measurement report may indicate the RSRP associated with the network device 130-1 and the RSRP associated with the network device 130-2. Alternatively, the measurement report may indicate the RSRQ associated with the network device 130-1 and the RSRQ associated with the network device 130-2.

At block 620, the network device 130-1 may determine that the network device 120 is to hand over to the network device 130-2 based on the measurement report. The network device 130-1 may determine downlink control information. The downlink control information comprises an indication associated with group mobility in a short message field. This downlink control information may refer to a short message. The term “short message” used herein can refer to paging downlink control information which is scrambled by a paging radio network temporary identifier. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

At block 630, the network device 130-1 transmits the downlink control information to the network device 120. In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit modified system information to the terminal device 110-1 via the network device 120.

The network device 130-1 may transmit a handover request for the network device 120 to the network device 130-2. The network device 130-1 may receive a handover request acknowledgment from the network device 130-2 for the network device 120. The network device 130-1 may transmit a reconfiguration message to the network device 130-2. The reconfiguration can be used to migrate from the network device 130-1 to the network device 130-2. The reconfiguration may be sent to activate the default radio bearer. The reconfiguration may also carry the Attach Accept message as non-access stratum (NAS) payload. The reconfiguration may comprise measurement objects for 5G NR frequencies. In this way, since the reconfiguration is transmitted after the transmission of the downlink control information, it ensures that the terminal device can perform the cell reselection before the handover of the IAB node.

Fig. 7 shows a flowchart of an example method 700 in accordance with an embodiment of the present disclosure. The method 700 can be implemented at any suitable devices. Only for the purpose of illustrations, the method 700 can be implemented at the network device 120.

The network device 120 may perform measurements for the network device 130-1 (i.e., the source IAB donor) and the network device 130-2 (i.e., the target IAB donor) . The network device 120 may perform any suitable measurement events. For example, the network device 120 may perform Event A3 where a neighbor cell becomes better than a serving cell by an offset. Alternatively, the network device 120 may perform any one of: Event A1 where a serving cell becomes better than a threshold, Event A2 where the serving cell becomes worse than a threshold, Event A4 where the neighbor cell becomes better than a threshold, Event A5 wherein the serving cell becomes worse than threshold 1 and the neighbor cell becomes better than threshold A2, Event B1 wherein inter RAT neighbor becomes better than a threshold, and Event B2 where the serving cell becomes worse than threshold 1 and inter RAT neighbor becomes better than threshold 2. In some embodiments, the network device 120 may measure a reference signal received power (RSRP) . Alternatively, the network device 120 may measure a reference signal receiving quality (RSRQ) . The network device 120 may measure any suitable parameters.

At block 710, the network device 120 transmits a measurement report to the network device 130-1. For example, the measurement report may indicate the RSRP associated with the network device 130-1 and the RSRP associated with the network device 130-2. Alternatively, the measurement report may indicate the RSRQ associated with the network device 130-1 and the RSRQ associated with the network device 130-2.

At block 720, the network device 120 receives downlink control information from the network device 130-1. The downlink control information comprises an indication associated with group mobility in a short message field. In some embodiments, the short message may comprise a group mobility indication. For example, one or more reserved bits in the short message may be used for the group mobility indication. The group mobility indication may indicate the handover of the network device 120. Only as an example, if the group mobility indication is set to “1” , it may refer to that the IAB node 12 is to be handed over. Alternatively, the short message may comprise a modification in system information. For example, the “systeminfomodification” bit in the short message may be reused as the group mobility indication. In this case, in some embodiments, if this bit is set to “1” , it can refer to that the IAB node 12 is to be handed over.

At block 730, the network device 120 transmits the downlink control information to the terminal device 110-1. In some embodiments, if the short message may comprise a modification in system information, the network device 120 may also transmit modified system information to the terminal device 110-1. In some embodiments, the system information may comprise an indication regarding the handover of the IAB node. Alternatively, the system information may comprise an implicit indication regarding the handover of the IAB node. For example, the system information may comprise a cell configuration of a cell to be reselected.

In some embodiments, a terminal device comprises circuitry configured to perform: receiving, from a network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from a source network device to a target network device and the downlink control information is generated by the source network device.

In some embodiments, the indication associated with group mobility indicates the handover of the network device. In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with a determination that the terminal device is in an idle state or an inactive state, performing a cell reselection based on the reception of the downlink control information.

In some embodiments, the terminal device comprises circuitry configured to perform the cell reselection by: performing a measurement on a neighbor cell; and performing the cell reselection based on a result of the measurement.

In some embodiments, the neighbor cell is with an intra-frequency or an inter-frequency with a priority below a threshold.

In some embodiments, the indication associated with group mobility indicates the handover of the network device. In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with a determination that the terminal device is in a connected state, performing a conditional handover based on the reception of the downlink control information.

In some embodiments, the indication associated with group mobility indicates a modification in system information. In some embodiments, the terminal device comprises circuitry configured to perform: receiving system information from the network device, wherein the system information comprises one of: another indication regarding the handover of the network device, or a cell configuration of a cell to be reelected.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with a determination that the terminal device is in an idle state or an inactive state, performing a cell reselection.

In some embodiments, the terminal device comprises circuitry configured to perform in accordance with a determination that the terminal device is in a connected state, performing a conditional handover.

In some embodiments, a network device comprises circuitry configured to perform determining, at a source network device, that a network device is to handover from the source network device to a target network device based on a measurement report from the network device; determining downlink control information comprising an indication associated with group mobility in a short message field; and transmitting the downlink control information to the network device.

In some embodiments, the indication associated with group mobility indicates the handover of the network device, or the indication associated with group mobility indicates a modification in system information.

In some embodiments, the network device comprises circuitry configured to perform after the transmission of the downlink control information, transmitting a reconfiguration message to the network device; and receiving a reconfiguration complete message from the network device.

In some embodiments, a network device comprises circuitry configured to perform transmitting, at a network device, a measurement report to a source network device; receiving, from the source network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from the source network device to a target network device; and transmitting the downlink control information to a terminal device served by the network device.

In some embodiments, the indication associated with group mobility indicates the handover of the network device.

In some embodiments, the indication associated with group mobility indicates a modification in system information. In some embodiments, the network device comprises circuitry configured to perform transmitting system information to the terminal device, wherein the system information comprises one of: another indication regarding the handover of the network device, or a cell configuration of a cell to be reelected.

In some embodiments, the network device comprises circuitry configured to perform after the reception of the downlink control information, receiving a reconfiguration message from the source network device; and transmitting a reconfiguration complete message to the network device.

Fig. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 can be considered as a further example implementation of the terminal device, the IAB node or the IAB donor as shown in Fig. 1. Accordingly, the device 800 can be implemented at or as at least a part of the terminal device, the IAB node or the IAB donor.

As shown, the device 800 includes a processor 810, a memory 820 coupled to the processor 810, a suitable transmitter (TX) and receiver (RX) 840 coupled to the processor 810, and a communication interface coupled to the TX/RX 840. The memory 820 stores at least a part of a program 830. The TX/RX 840 is for bidirectional communications. The TX/RX 840 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 interface for bidirectional communications between eNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the eNB, Un interface for communication between the eNB and a relay node (RN) , or Uu interface for communication between the eNB and a terminal device.

The program 830 is assumed to include program instructions that, when executed by the associated processor 810, enable the device 800 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to Fig. 2 to 7. The embodiments herein may be implemented by computer software executable by the processor 810 of the device 800, or by hardware, or by a combination of software and hardware. The processor 810 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 810 and memory 820 may form processing means 850 adapted to implement various embodiments of the present disclosure.

The memory 820 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 820 is shown in the device 800, there may be several physically distinct memory modules in the device 800. The processor 810 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 800 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.

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 any of Figs. 2-7. 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.

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 incorporate 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 –7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz 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.

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.

Claims

A communication method, comprising:

receiving, at a terminal device and from a network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from a source network device to a target network device and the downlink control information is generated by the source network device.
The method of claim 1, wherein the indication associated with group mobility indicates the handover of the network device, and

wherein the method further comprises:

in accordance with a determination that the terminal device is in an idle state or an inactive state, performing a cell reselection based on the reception of the downlink control information.
The method of claim 2, wherein performing the cell reselection comprises:

performing a measurement on a neighbor cell; and

performing the cell reselection based on a result of the measurement.
The method of claim 3, wherein the neighbor cell is with an intra-frequency or an inter-frequency with a priority below a threshold.
The method of claim 1, wherein the indication associated with group mobility indicates the handover of the network device, and

wherein the method further comprises:

in accordance with a determination that the terminal device is in a connected state, performing a conditional handover based on the reception of the downlink control information.
The method of claim 1, wherein the indication associated with group mobility indicates a modification in system information, and

wherein the method further comprises:

receiving system information from the network device, wherein the system information comprises one of: another indication regarding the handover of the network device, or a cell configuration of a cell to be reelected.
The method of claim 6, wherein the method further comprises:

in accordance with a determination that the terminal device is in an idle state or an inactive state, performing a cell reselection.
The method of claim 7, wherein performing the cell reselection comprises:

performing a measurement on a neighbor cell; and

performing the cell reselection based on a result of the measurement.
The method of claim 8, wherein the neighbor cell is with an intra-frequency or an inter-frequency with a priority below a threshold.
The method of claim 6, wherein the method further comprises:

in accordance with a determination that the terminal device is in a connected state, performing a conditional handover.
A communication method, comprising:

determining, at a source network device, that a network device is to handover from the source network device to a target network device based on a measurement report from the network device;

determining downlink control information comprising an indication associated with group mobility in a short message field; and

transmitting the downlink control information to the network device.
The method of claim 11, wherein the indication associated with group mobility indicates the handover of the network device, or

the indication associated with group mobility indicates a modification in system information.
The method of claim 11, further comprising:

after the transmission of the downlink control information, transmitting a reconfiguration message to the network device; and

receiving a reconfiguration complete message from the network device.
A communication method, comprising:

transmitting, at a network device, a measurement report to a source network device;

receiving, from the source network device, downlink control information comprising an indication associated with group mobility in a short message field, wherein the network device is to handover from the source network device to a target network device; and

transmitting the downlink control information to a terminal device served by the network device.
The method of claim 14, wherein the indication associated with group mobility indicates the handover of the network device.
The method of claim 14, wherein the indication associated with group mobility indicates a modification in system information; and

wherein the method further comprises:

transmitting system information to the terminal device, wherein the system information comprises one of: another indication regarding the handover of the network device, or a cell configuration of a cell to be reelected.
The method of claim 16, further comprising:

after the reception of the downlink control information, receiving a reconfiguration message from the source network device; and

transmitting a reconfiguration complete message to the network device.
A terminal device comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the terminal device to perform the method according to any of claims 1-10.
A network device comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the network device to perform the method according to any of claims 11-13.
A network device comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the network device to perform the method according to any of claims 14-17.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method according to any of claims 1-10.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method according to any of claims 11-13.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method according to any of claims 14-17.