WO2023159434A1

WO2023159434A1 - Methods, devices, and computer readable medium for communication

Info

Publication number: WO2023159434A1
Application number: PCT/CN2022/077749
Authority: WO
Inventors: Gang Wang
Original assignee: Nec Corporation
Priority date: 2022-02-24
Filing date: 2022-02-24
Publication date: 2023-08-31

Abstract

Embodiments of the present disclosure relate to methods, devices, and computer readable medium for communication. According to embodiments of the present disclosure, a terminal device receives a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell from a network device. The terminal device receives SSB updating information from the network device. The SSB updating information indicates at least one target SSB configuration and a quasi co-location (QCL) relationship between the at least one target SSB and at least one active SSB. In this way, the terminal device is able to update the SSB configuration and corresponding TCI or spatial relation without traffic interruption.

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

Several technologies have been proposed to improve communication performances. For example, in previous releases of new radio (NR) , power saving at user equipment (UE) side has been intensively studied and specified. Moreover, a new study item of network energy saving also needs to be considered, which focuses on the energy saving at network device side. For example, for a network device with light-to-medium load, to reduce the energy consumption, the network device may temporarily stop its transmission/reception, or de-activate a portion of its antenna ports, or reduce its channel bandwidth.

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, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; receiving SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB; and determining, at the terminal device, the target SSB configuration to be activated and the active SSB configuration to be deactivate.

In a second aspect, there is provided a method for communication. The method comprises transmitting, at a network device and to a terminal device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; and transmitting SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB.

In a third 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, and from a network device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; receiving SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB; and determining, at the terminal device, the target SSB configuration to be activated and the active SSB configuration to be deactivate.

In a fourth 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, at a network device and to a terminal device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; and transmitting SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB.

In a fifth 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 the first or second 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 communications according to some embodiments of the present disclosure;

Fig. 3 illustrates a schematic diagram of panels according to some embodiments of the present disclosure;

Figs. 4A-4D illustrate schematic diagrams of resources according to some embodiments of the present disclosure, respectively;

Figs. 5A-5B illustrate schematic diagrams of beam switching according to some embodiments of the present disclosure, respectively;

Figs. 6A-6B illustrate schematic diagrams of activation and deactivation of SSB according to some embodiments of the present disclosure, respectively;

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

Fig. 8 is a flowchart of an example method in accordance with an embodiment 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

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 ‘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) , 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. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

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 Terahertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection 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 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) , and the like.

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, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

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 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.

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, a new study item of network energy saving also needs to be considered, which focuses on the energy saving at network device side. For example, for a network device with light-to-medium load, in order to reduce energy consumption, the network device may temporarily stop its transmission/reception, or de-activate a portion of its antenna ports, or reduce its channel bandwidth (by changing the bandwidth part (BWP) or switching-off some carrier components (CCs) ) . Moreover, the coverage and traffic continuity should be considered. For example, if the network device decides to switch-off some of its antenna ports (i.e., by switching off some radio frequency (RF) chains) to save energy, the transmission power can be reduced.

In new radio (NR) , a synchronization signal/physical broadcast channel (SS/PBCH) block (SSB) is used for cell search and beam management. A SSB may comprise a Physical Broadcast Chanel (PBCH) , a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) . One or more SSBs (i.e., a SSB burst, at most 64 SSBs for frequency range 2 (FR2) ) may be transmitted within a half frame (i.e., 5ms) , and each SSB is associated with a SSB index. The SSB burst can be repeated with a periodicity (e.g., 20ms, 160ms) . In practice, the network device may transmit the SSBs in a SSB burst with different beams. A terminal device may blind detect/search the SSBs and determine one or more SSBs with best beam quality, and the network device can be aware of the one or more best quality SSBs based on UE reporting or random access procedure.

For UL transmissions (for example, sounding reference signal (SRS) , physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) ) , “spatial relation” can be used to configure spatial settings (i.e., the transmitting beam) for the transmission. A physical channel or a physical signal can be associated with a spatial relation, and the spatial relation can be associated with a reference RS, and the reference RS can be one of SSB, channel state information-reference signal (CSI-RS) , or SRS. The terminal device should determine its spatial filter (i.e., beam configuration) to transmit the physical channel or the physical signal based on the indicated reference RS.

According to conventional technologies, a quasi co-location (QCL) state of many physical channels/signals is associated with a SSB. Thus, in order to enhance the traffic/measurement continuity and connection robustness, it is necessary to introduce a SSB updating mechanism. The term “quasi colocation (QCL) ” may be defined as follows: two antenna ports are said to be quasi co-located if properties of the channel over which a symbol on one antenna port is conveyed may be inferred from the channel over which a symbol on the other antenna port is conveyed. In NR, a TCI (transmission configuration indicator) state is used to configure a QCL relationship between one or two downlink reference signals (i.e., source reference signals (RSs) , can be SSB or channel state CSI-RS resource) and the demodulation reference signal (DM-RS) ports of the physical downlink shared channel (PDSCH) , the DM-RS port of physical downlink control channel (PDCCH) or the CSI-RS port (s) of a CSI-RS resource. The supported QCL relationship for a DMRS or a CSI-RS resource is dependent on the type of the DMRS or the CSI-RS.

For the network device which decides to switch off/on a portion of its antenna ports/panels to save energy, it may have to adjust its SSB transmission configuration due to the reduced/increased antenna ports/panels. However, for a terminal device served by the network device, at least a part of the TCI states may be associated with the SSBs. If the network device changes its SSB configuration without informing the terminal device the relationship between the new SSBs and the old SSBs, the terminal device may have to blind detect the new SSBs to re-construct the spatial settings (i.e., beams) for the TCI states, which is very time-consuming. Therefore, it is necessary to study and specify the enhancement on the SSB updating mechanism, in order to enable the terminal device to update the SSB configuration and corresponding TCI/spatial relation fast without traffic interruption.

In order to solve at least part of the above problems or other potential problems, solutions on SSB updating for network energy saving are proposed. According to embodiments of the present disclosure, a terminal device receives a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell from a network device. The plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs. The terminal device receives SSB updating information from the network device. The SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information. The target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB. The terminal device determines the target SSB configuration to be activated and the active SSB configuration to be deactivated and the active SSB configuration to be deactivate . In this way, the terminal device is able to update the SSB configuration and corresponding TCI or spatial relation without traffic interruption.

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. In the communication system 100, the network device 120 and the terminal devices 110 can communicate data and control information to each other. The numbers of terminal devices shown in Fig. 1 are given for the purpose of illustration without suggesting any limitations.

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) and the fifth generation (5G) 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 between the terminal device and the network device 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 110-1and the network device 120 in Fig. 1.

The network device 120 may have a plurality of antenna ports/panels. As shown in Fig. 3, the network device 120 may have two antenna panels 310-1 and 310-2. When the two antenna panels 310-1 and 310-2 are on, the antenna panels 310-1 can be associated with the SSBs 320-1, 320-2, 320-3 and 320-4 and the antenna panels 310-2 can be associated with the SSBs 321-1, 321-2, 321-3 and 321-4.

The network device 120 transmits 2010 a plurality of SSB configurations for a serving cell to the terminal device 110-1. The plurality of SSB configurations may at least comprise an active SSB configuration. In other words, the plurality of SSB configurations may comprise the currently used SSB configuration. The active SSB configuration indicates a plurality of active SSBs. The plurality of SSB configurations may comprise at least one inactive SSB configuration. In other words, the plurality of SSB configurations may comprise the not-used SSB configuration. In some embodiments, each of the plurality of SSB configurations may comprise a corresponding index. The serving cell may work on a frequency range.

In some embodiments, the SSB configuration may comprise a periodicity of SSB burst. Alternatively or in addition, the SSB configuration may comprise a subcarrier spacing (SCS) of the SSBs. In some other embodiments, the SSB configuration may comprise the number of SSB in a burst. In other embodiments, the SSB configuration may indicate positions of SSBs in a SSB burst. Alternatively or in addition, the SSB configuration may indicate time and/or frequency settings of the SSBs. In other embodiments, the SSB configuration may indicate power level of the SSBs. Only as an example, as shown in Figs. 4A-4D, a first SSB configuration may indicate that there may be the SSBs 411-1, 411-2, 411-3, ..., 411-N (collectively referred to as “SSBs 411” ) within the SSB burst 4111, wherein N can be an integer. The first SSB configuration may also indicate the periodicity 4110 of the SSB burst. A second configuration may indicate that there may be the SSBs 421-1, 421-2, 421-3, ..., 421-M (collectively referred to as “SSBs 421” ) within the SSB burst 4211, wherein M can be an integer. The first SSB configuration may also indicate the periodicity 4210 of the SSB burst.

Alternatively or in addition, the SSB configuration may be associated with a network energy saving configuration. In this case, in some embodiments, the network energy saving configuration may indicate a frame structure configuration, for example, DL-UL configuration and/or slot format configuration. In some embodiments, the network energy saving configuration can comprise a configuration of an energy saving level. Alternatively, the network energy saving configuration can comprise an energy saving configuration identity. The network energy saving level can indicate to what extend the energy at the network device is saved.

In some embodiments, the network energy saving configuration can comprise a configuration of maximum bandwidth. Alternatively, the network energy saving configuration can comprise a configuration of network device channel bandwidth. In some embodiments, the network energy saving configuration may also comprise a configuration of SSB. For example, the configuration of SSB may indicate a time or frequency resource of a SSB. Alternatively, the energy configuration can comprise a configuration of random access channel (RACH) . For example, the configuration of RACH may comprise RACH occasion configuration. In some embodiments, the configuration of RACH can comprise one or more of: BWP bandwidth size frequency location, and CORESET.

Alternatively or in addition, the network energy saving configuration can comprise a configuration of a power level. For example, the network energy saving configuration may indicate energy per resource element (EPRE) of SSB. Alternatively or in addition, the network energy saving configuration may indicate a power ratio or a power offset of channel state information reference signal (CS-RS) to SSB. It should be noted that the energy configuration may comprise other parameters related to the power level.

In other embodiments, the network energy saving configuration can comprise a configuration of maximum MIMO layer. For example, the configuration of maximum MIMO layer can be applied in in DL. Alternatively, the configuration of maximum MIMO layer can be applied in UL. In some embodiments, the configuration of maximum MIMO layer can be a cell specific maximum MIMO layer.

Back to Fig. 2, the network device 120 transmits 2020 SSB updating information to the terminal device 110-1. In this way, the terminal device 110-1 can acquire the beam setting for SSB reception without blind detection/searching, and then update the QCL relationship quickly. It is beneficial to avoid performance loss during the SSB switching (in other words, during the gNB antenna configuration switching to change its energy saving configuration) . On the other hand, the terminal device 110-1 can avoid using out-of-date QCL relationship after the SSB updating.

In some embodiments, a physical cell identity (PCI) carried by the plurality of target SSBs can be same as PCI carried by the plurality of active SSBs. In some example embodiments, the SSB updating information can be transmitted via RRC signaling. Alternatively, the SSB updating information can be transmitted via medium access control (MAC) signaling. In other embodiments, the SSB updating information may be transmitted via physical layer (PHY) signaling. For example, as shown in Fig. 3, the network device 120 can switch off the antenna panel 310-1 in order to save energy. In this case, the network device 120 may need to adjust the SSB transmission configuration. When the antenna panel 310-1 is off and the antenna panel 310-2 is on, the antenna panels 310-2 can be associated with the SSBs 330-1, 330-2, 330-3 and 330-4. In this situation, the terminal device 110-1 may also need to update the SSB configuration.

The SSB updating information indicates a target SSB configuration from the plurality of SSB configurations. The target SSB configuration may indicates a plurality of target SSBs. For example, the SSB updating information may comprise an index of the target SSB configuration. In some embodiments, one or more target SSBs and one or more active SSBs may have a same working frequency.

In some embodiments, a resource of the one or more target SSBs may be orthogonal with a resource of the at least one active SSB. For example, the resources of one or more target SSB and the resources the active SSBs do not overlap in time domain or frequency domain. For example, as shown in Fig. 4A, the SSBs 421 and the SSBs 411 are not overlapped in either time domain or frequency domain.

Alternatively, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the at least one active SSB. For example, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in time domain. Alternatively, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in frequency domain. In some other embodiments, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in time domain and frequency domain. For example, as shown in Fig. 4B, the resource of the SSBs 421 and the resource of the SSBs 411 are not overlapped in frequency domain. In other words, the SSBs 421 and the SSBs 411 can have overlapped frequency resources.

In some other embodiments, the resource of the one or more target SSBs may be a subset of the resource of the active SSBs. For example, as shown in Fig. 4C, the target SSBs may comprise the SSBs 411-1, 411-3, 411-5, ..., 411-N which are the subset of the active SSBs. Alternatively, the resource of the active SSBs may be a subset of the resource of the one or more target SSBs. For example, as shown in Fig. 4D, the active SSBs may comprise the SSBs 421-1, 421-3, 421-5, ..., 421-M which are the subset of the target SSBs. It should be noted that the resources of the active SSB refer to the resources which would be allocated to the active SSB assuming the active SSB is not deactivated.

The SSB updating information also indicates QCL information. The QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB. For example, the QCL relationship may indicate QCL type or a combination of QCL types. There can be several QCL types, for example, QCL type A, QCL type B, QCL type C and QCL type D. The QCL types and the corresponding QCL parameters can be: 'typeA' : {Doppler shift, Doppler spread, average delay, delay spread} , 'typeB' : {Doppler shift, Doppler spread} , 'typeC' : {Doppler shift, average delay} , 'typeD' : {Spatial Rx parameter} .

In some embodiments, different types of QCL relationship can be configured at the terminal device 110-1 with different indexes. In this case, the SSB updating information may indicate a corresponding index of the QCL relationship. Alternatively, the QCL relationship may be preconfigured for switching between the active SSB and the target SSB. Only as an example, the QCL relationship #1 can be preconfigured for the case where the SSB #1 is switched to the SSB #2, and the QCL relationship #2 can be preconfigured for the case where the SSB #1 is switched to the SSB #3.

In some embodiments, one target SSB may be quasi co-located (QCLed) with one active SSB. For example, the QCL relationship may be QCL typeA or QCL typeA + QCL typeD, which may imply the target SSB and the active SSB are transmitted with same antenna or beamforming configuration. As shown in Fig. 5A, the target SSB 511 and the active SSB 510 may be transmitted with same antenna for beamforming configuration.

Alternatively, the QCL relationship may be QCL typeC or QCL typeC + QCL typeD, which may imply the target SSB and the active SSB are transmitted by two beams with different beam widths respectively, and the wide beam can cover the narrow beam. As shown in Fig. 5B, the wide beam 522 can cover the narrow beams 520 and 521.

In some embodiments, one target SSB may be QCLed with more than one active SSB. In this case, the QCL relationship may be a QCL typeC or a new QCL type. It means that the new target uses a wide beam and the more than one active SSB may use narrow beams which are covered by the wide beam.

In other embodiments, more than one target SSB may be QCLed with one active SSB. In this case, the QCL relationship may be a QCL typeC or new QCL type. It may mean that the active SSB uses a wide beam, and the more than one target SSBs use narrow beams which are covered by the wide beam. Alternatively, none of the at least one target SSB may be QCLed with the at least one active SSB. In this case, the at least one target SSB can refer to all SSBs in the burst which is indicated by the target SSB configuration.

In some embodiments, the QCL information in the SSB updating information may indicate the QCL relationship between a target SSB and a CSI-RS resource. For example, a target SSB can also be QCLed with one or more CSI-RS resources, and the CSI-RS resource may be QCLed with an active SSB. In this case, the target SSB can be QCLed with one CSI-RS resource or with more than one CSI-RS resource. Alternatively, more than one target SSB can be QCLed with one CSI-RS resource or not QCLed with any CSI-RS resource.

In some embodiments, if a target SSB with a first SSB index is indicated to be associated with an active SSB with a second SSB index, the terminal device 110-1 may assume that the target SSB and the active SSB are QCLed. In this case, the first SSB index and the second SSB index can be same or different. Table 1 below shows an example of RRC control information element for QCL relationship of the target SSB.

Table 1

Alternatively, the terminal device 110-1 may also determine the QCL relationship of the target SSB based on the SSB index. For example, if there is an active SSB has same index as the target SSB, the terminal device 110-1 may assume that the active SSB and the target SSB are QCLed, and the QCL relationship can be QCL typeA or QCL typeA + QCL typeD. Alternatively, if there is no active SSB having same index as the target SSB, the terminal device 110-1 may assume that the target SSB is not QCLed with any active SSBs.

In some embodiments, the terminal device 110-1 may update a TCI state or a QCL relationship based on the SSB updating information. For example, the terminal device 110-1 may update the TCI state or the QCL relationship based on whether an active SSB is associated with a target SSB. Alternatively or in addition, the terminal device 110-1 may update the TCI state or the QCL relationship based on the type of QCL relationship. In this way, the terminal device 110-1 can avoid long time searching or detection of the target SSB, thereby the traffic interruption time can be avoided or reduced.

In some embodiments, if the QCL relationship indicates a QCL typeA or a QCL typeA + QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. Additionally, the terminal device 110-1 may apply receiving parameters associated with the TCI state or the QCL relationship. In other words, the terminal device 110-1 may not change its receiving parameters associated with the TCI state or the QCL relationship after the SSB updating. The receiving parameters can comprise one or more of: timing, center frequency or a spatial filter.

Alternatively, if the QCL relationship indicates a QCL typeC or both the QCL typeC and a QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. In this case, the terminal device 110-1 may perform a synchronization measurement and/or a beam measurement on the target SSB before it applies the TCI state or the QCL relationship with the target SSB. For example, the terminal device 110-1 may measure a reference signal received power (RSRP) on the target SSB. Additionally, the terminal device 110-1 may determine the TCI state or the spatial relation or the QCL configuration to be available after the synchronization measurement or the beam measurement. The terminal device 110-1 may also update receiving parameters associated with the TCI state or the QCL relationship based on synchronization measurement and/or beam measurement after the SSB updating. For example, the terminal device 110-1 may update a center frequency of the receiver or transmitter. Alternatively, the terminal device 110-1 may update a timing of the receiver or transmitter. In other embodiments, the terminal device 110-1 may update a phase of the spatial filer of the receiver or transmitter.

In other embodiments, if the QCL relationship indicates that multiple target SSBs is QCLed with one active SSB, the terminal device 110-1 may perform the synchronization measurement and/or the beam measurement on the multiple target SSBs. In this case, in some embodiments, the terminal device 110-1 may determine one target SSB from the multiple target SSBs. Alternatively, the terminal device 110-1 may report indexes of one or more target SSBs from the multiple target SSBs. The network device 120 may transmit an indication of one target SSB from the one or more target SSBs. The terminal device 110-1 may replace the active SSB with the one target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission.

In some embodiments, if the QCL relationship indicates that none target SSB is QCLed with the at least one active SSB, the terminal device 110-1 may determine at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission which is associated with the at least one active SSB to be not available. For example, the terminal device 110-1 may perform the synchronization measurement and/or the beam measurement on the plurality of target SSBs in a burst. The terminal device 110-1 may determine one or more target SSBs. The terminal device 110-1 may report indexes of the one or more target SSBs. In this case, the network device 120 may transmit an indication of a TCI state to replace a current TCI state of the active SSB.

Alternatively, the QCL relationship indicates that more than one active SSB is QCLed with the target SSB. In this case, if the QCL relationship indicates a QCL typeA or QCL typeA + QCL typeD, the terminal device 110-1 may replace an active SSB of the more than one active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. Additionally, the terminal device 110-1 may apply receiving parameters associated with the TCI state or the QCL relationship. In other words, the terminal device 110-1 may not change its receiving parameters associated with the TCI state or the QCL relationship after the SSB updating. Alternatively, if the QCL relationship indicates a QCL typeC or QCL typeC and QCL typeD, the terminal device 110-1 may replace an active SSB of the more than one active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. In this case, the terminal device 110-1 may perform a synchronization measurement and/or a beam measurement on the target SSB before it applies the TCI state or the QCL relationship with the target SSB. For example, the terminal device 110-1 may measure a reference signal received power (RSRP) on the target SSB. Additionally, the terminal device 110-1 may update a spatial filer associated with the TCI state or the QCL relationship based on synchronization measurement and/or beam measurement after the SSB updating. For example, the terminal device 110-1 may update a frequency of the receiver or transmitter. Alternatively, the terminal device 110-1 may update a timing of the receiver or transmitter. In other embodiments, the terminal device 110-1 may update a phase of the spatial filer of the receiver or transmitter.

Referring back to Fig. 2, the terminal device 110-1 determines 2030 the target SSB configuration to be activated and the active SSB configuration to be deactivated. The terminal device 110-1 may perform 2040 a communication with the network device 120 on the target SSB. In some embodiments, the network device 120 may start the transmission of the target SSB and stop the transmission of the active SSB at the same time. In this way, since there is no time domain overlap between the target SSB and the active SSB, it is easier to arrange the time and/or frequency resources of the target SSB without conflicting with the active SSB. Alternatively, the network device 120 may start the transmission of the target SSB before it stops the transmission of the active SSB. In this way, since the target SSB is started before the active SSB is stopped, the terminal device 110-1 may still use the current TCI state for transmission while measuring the target SSB to prepare for the TCI updating, thereby there can be no or short traffic interruption during the SSB switching.

In some embodiments, the network device 120 may activate the target SSB configuration and deactivate the active SSB configuration simultaneously. Alternatively, the network device 120 may activate the target SSB configuration after a first time period from the deactivation of the active SSB configuration. This means there will be no time domain overlap between the active SSBs and the target SSBs. In this case, the target SSBs can be arranged in any available time/frequency resources. As an example, the frequency resource of target SSBs can be same as the active SSBs, and the time domain resource of some active SSBs and some target SSBs can be overlapped, which may be beneficial for the idle UEs since they may still detect the SSB without retuning the center frequency of the receiver. The length of the first time period can be predefined or preconfigured. In this case, when the terminal device 110-1 receives the SSB updating information, the terminal device 110-1 may deactivate the active SSB configuration and activate the target SSB configuration immediately or after the first time period. In some embodiments, the terminal device 110-1 may not perform transmission or reception during the first timer period. Alternatively, the terminal device 110-1 may assume that the TCI state is associated with the active SSB, until the end of the first time period, or until a reception of a network indication, or until the terminal device 110-1 finishes the measurement of the target SSB. As shown in Fig. 6A, the old SSBs can be deactivated at the time instant 6010. The new SSBs can be activated at the time instant 6020 which is after the first time period 610 from the deactivation.

In some embodiments, the network device 120 may activate the target configuration before it deactivates the active SSB configuration. In this case, the target SSBs and the active SSBs may be both transmitted within a second time period, and then the network device 120 may deactivate the active SSBs. The resources of target SSBs and the active SSBs may be not overlapped. Alternatively, at least a portion of the target SSBs can be fully overlapped with active SSBs and the overlapped SSBs may have same SSB index. In some embodiments, the length of the second time period may be predefined or preconfigured. Alternatively, the length of the second time period may be based on a network indication. For example, if the network device 120 indicates the terminal device 110-1 a deactivation command, then the terminal device 110-1 may assume that the transmission of active SSBs is stopped. In other words, the second time period can be ended. During the second time period, the terminal device 110-1 may still assume the TCI state is associated with the active SSB. After the second time period ends, the terminal device 110-1 may assume that the TCI state is associated with the target SSB. As shown in Fig. 6B, the new SSBs can be activated at the time instant 6030 and the old SSBs can be deactivated at the time instant 6040. The new SSBs and the SSBs can be both transmitted within the second time period 620.

In other embodiments, the terminal device 110-1 may apply a target TCI state associated with the target SSB after a third time period (Ts) from a time instance (T0) . In some embodiments, the time instance may be the time when the SSB updating information is received. Alternatively, the time instance may be the time when the target SSB configuration is activated. In this case, if the target SSB is QCLed with an active SSB or a CSI-RS resource, the terminal device 110-1 may update the TCI state based on the QCL relationship without long time measurement. Thus, the third time period can be associated with the transmission time of the target SSB. Alternatively, the third time period can be zero. In other embodiments, the third time period can be associated with the processing time for the SSB updating information. In some embodiments, the third time period can be associated with the type of QCL relationship. Alternately, the third time period can be indicated by the network device with RRC information. In other embodiments, if the target SSB is not QCLed with the active SSB or a CSI-RS resource, the measurement of target SSBs may be needed. In this case, the third time period can be associated with the transmission time of the target SSB and the time for the measurement of the target SSB (i.e., the time for RX beam refinement) .

In some embodiments, the TCI state associated with one of the at least one target SSB may be considered as a known TCI state if the SSB associated with the TCI state is a target SSB, and the target SSB is QCLed with an active old SSB. Alternatively, the QCL type can be QCL typeD. The term “new SSB” refers to a SSB which is configured/activated by gNB not exceed a time instance (e.g., T0+Ts) , or a SSB which is not measured/detected by the UE yet. The term “old SSB” refers to a SSB which may be de-activated or will be deactivated by gNB, or a SSB which is measured/detected by the UE within a time duration.

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 a terminal device 110-1 as shown in Fig. 1.

At block 710, the terminal device 110-1 receives a plurality of SSB configurations from the network device 120. The plurality of SSB configurations may at least comprise an active SSB configuration. In other words, the plurality of SSB configurations may comprise the currently used SSB configuration. The active SSB configuration indicates a plurality of active SSBs. The plurality of SSB configurations may comprise at least one inactive SSB configuration. In other words, the plurality of SSB configurations may comprise the not-used SSB configuration. In some embodiments, each of the plurality of SSB configurations may comprise a corresponding index.

In some embodiments, the SSB configuration may comprise a periodicity of SSB burst. Alternatively or in addition, the SSB configuration may comprise a subcarrier spacing (SCS) of the SSBs. In some other embodiments, the SSB configuration may comprise the number of SSB in a burst. In other embodiments, the SSB configuration may indicate positions of SSBs in a SSB burst. Alternatively or in addition, the SSB configuration may indicate time and/or frequency settings of the SSBs. In other embodiments, the SSB configuration may indicate power level of the SSBs.

Alternatively or in addition, the network energy saving configuration can comprise a configuration of a power level. For example, the network energy saving configuration may indicate energy per resource element (EPRE) of SSB. Alternatively or in addition, the network energy saving configuration may indicate a power ratio or a power offset of channel state information reference signal (CS-RS) to SSB. It should be noted that the energy configuration may other parameters related to the power level.

At block 720, the terminal device 110-1 receives SSB updating information from the network device 120. In this way, the terminal device 110-1 can acquire the beam setting for SSB reception without blind detection/searching, and then update the QCL relationship quickly. It is beneficial to avoid performance loss during the SSB switching (in other words, during the gNB antenna configuration switching) . On the other hand, the terminal device 110-1 can avoid using out-of-date QCL relationship after the SSB updating.

In some embodiments, a physical cell identity (PCI) carried by the plurality of target SSBs can be same as PCI carried by the plurality of active SSBs. In some example embodiments, the SSB updating information can be transmitted via RRC signaling. Alternatively, the SSB updating information can be transmitted via medium access control (MAC) signaling. In other embodiments, the SSB updating information may be transmitted via physical layer (PHY) signaling.

The SSB updating information indicates a target SSB configuration from the plurality of SSB configurations. The target SSB configuration may indicates a plurality of target SSBs. For example, the SSB updating information may comprise an index of the target SSB configuration.

In some embodiments, a resource of the one or more target SSBs may be orthogonal with a resource of the at least one active SSB. For example, the resources of one or more target SSB and the resources the active SSBs do not overlap in time domain or frequency domain.

Alternatively, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the at least one active SSB. For example, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in time domain. Alternatively, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in frequency domain. In some other embodiments, at least a portion of the resource of the one or more target SSBs may be overlapped with the resource of the active SSBs in time domain and frequency domain.

In some other embodiments, the resource of the one or more target SSBs may be a subset of the resource of the active SSBs. Alternatively, the resource of the active SSBs may be a subset of the resource of the one or more target SSBs.

In some embodiments, one target SSB may be quasi co-located (QCLed) with one active SSB. For example, the QCL relationship may be QCL typeA or QCL typeA + QCL typeD, which may imply the target SSB and the active SSB are transmitted with same antenna or beamforming configuration.

Alternatively, the QCL relationship may be QCL typeC or QCL typeC + QCL typeD, which may imply the target SSB and the active SSB are transmitted by two beams with different beam widths respectively, and the wide beam can cover the narrow beam.

In some embodiments, if a target SSB with a first SSB index is indicated to be associated with an active SSB with a second SSB index, the terminal device 110-1 may assume that the target SSB and the active SSB are QCLed. In this case, the first SSB index and the second SSB index can be same or different.

In some embodiments, if the QCL relationship indicates a QCL typeA or QCL typeA + QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. Additionally, the terminal device 110-1 may apply receiving parameters associated with the TCI state or the QCL relationship. In other words, the terminal device 110-1 may not change its receiving parameters associated with the TCI state or the QCL relationship after the SSB updating. The receiving parameters can comprise one or more of: timing, center frequency or a spatial filter.

Alternatively, if the QCL relationship indicates a QCL typeC or QCL typeC and QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. In this case, the terminal device 110-1 may perform a synchronization measurement and/or a beam measurement on the target SSB before it applies the TCI state or the QCL relationship with the target SSB. For example, the terminal device 110-1 may measure a reference signal received power (RSRP) on the target SSB. Additionally, the terminal device 110-1 may determine the TCI state or the spatial relation or the QCL configuration to be available after the synchronization measurement or the beam measurement. The terminal device 110-1 may also update receiving parameters associated with the TCI state or the QCL relationship based on synchronization measurement and/or beam measurement after the SSB updating. For example, the terminal device 110-1 may update a center frequency of the spatial filer. Alternatively, the terminal device 110-1 may update a timing of the spatial filer. In other embodiments, the terminal device 110-1 may update a phase of the spatial filer.

In some embodiments, if the QCL relationship indicates that the target SSB is not QCLed with the active SSB, the terminal device 110-1 may determine at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission which is associated with the at least one active SSB to be not available. For example, the terminal device 110-1 may perform the synchronization measurement and/or the beam measurement on the target SSBs. The terminal device 110-1 may determine one or more target SSBs. The terminal device 110-1 may report indexes of the one or more target SSBs. In this case, the network device 120 may transmit an indication of a TCI state to replace a current TCI state of the active SSB.

Alternatively, the QCL relationship indicates that more than one active SSB is QCLed with the target SSB. In this case, if the QCL relationship indicates a QCL typeA or QCL typeA + QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. Additionally, the terminal device 110-1 may apply receiving parameters associated with the TCI state or the QCL relationship. In other words, the terminal device 110-1 may not change its receiving parameters associated with the TCI state or the QCL relationship after the SSB updating. Alternatively, if the QCL relationship indicates a QCL typeC or QCL typeC and QCL typeD, the terminal device 110-1 may replace the active SSB with the target SSB in one or more of: a TCI state, a spatial relation for an uplink transmission, or a QCL configuration for a downlink transmission. In this case, the terminal device 110-1 may perform a synchronization measurement and/or a beam measurement on the target SSB before it applies the TCI state or the QCL relationship with the target SSB. For example, the terminal device 110-1 may measure a reference signal received power (RSRP) on the target SSB. Additionally, the terminal device 110-1 may update a spatial filer associated with the TCI state or the QCL relationship based on synchronization measurement and/or beam measurement after the SSB updating. For example, the terminal device 110-1 may update a frequency of the spatial filer. Alternatively, the terminal device 110-1 may update a timing of the spatial filer. In other embodiments, the terminal device 110-1 may update a phase of the spatial filer.

At block 730, the terminal device 110-1 determines the target SSB configuration to be activated and the active SSB configuration to be deactivated. The terminal device 110-1 may perform a communication with the network device 120 on the target SSB.

In some embodiments, the network device 120 may activate the target SSB configuration and deactivate the active SSB configuration simultaneously. Alternatively, the network device 120 may activate the target SSB configuration after a first time period from the deactivation of the active SSB configuration. In this case, when the terminal device 110-1 receives the SSB updating information, the terminal device 110-1 may determine the target SSB configuration to be activated immediately or after the first time period from the deactivation of the active SSB configuration. In some embodiments, the terminal device 110-1 may not perform transmission or reception during the first timer period. Alternatively, the terminal device 110-1 may assume that the TCI state is associated with the active SSB, until the end of the first time period, or until a reception of a network indication, or until the terminal device 110-1 finishes the measurement of the target SSB.

In some embodiments, the network device 120 may activate the target configuration before it deactivates the active SSB configuration. In this case, the target SSBs and the active SSBs may be both transmitted within a second time period, and then the network device 120 may deactivate the active SSBs. The resources of target SSBs and the active SSBs may be not overlapped. Alternatively, at least a portion of the target SSBs can be fully overlapped with active SSBs and the overlapped SSBs may have same SSB index. In some embodiments, the length of the second time period may be predefined or preconfigured. Alternatively, the length of the second time period may be based on a network indication. For example, if the network device 120 indicates the terminal device 110-1 a deactivation command, then the terminal device 110-1 may assume that the transmission of active SSBs is stopped. In other words, the second time period can be ended. During the second time period, the terminal device 110-1 may still assume the TCI state is associated with the active SSB. After the second time period ends, the terminal device 110-1 may assume that the TCI state is associated with the target SSB. In this case, the terminal device 110-1 may determine the active SSB configuration to be deactivated after a second time period from the activation of the target SSB configuration. Additionally, the terminal device 110-1 may determine that the plurality of active SSBs and the plurality of target SSBs are available during the second time period.

In other embodiments, the terminal device 110-1 may determine a target TCI state associated with the at least one target SSB to be available after a third time period (Ts) from a time instance (T0) . In some embodiments, the time instance may be the time when the SSB updating information is received. Alternatively, the time instance may be the time when the target SSB configuration is activated. In this case, if the target SSB is QCLed with an active SSB or a CSI-RS resource, the terminal device 110-1 may update the TCI state based on the QCL relationship without long time measurement. Thus, the third time period can be associated with the transmission time of the target SSB. Alternatively, the third time period can be zero. In other embodiments, the third time period can be associated with the processing time for the SSB updating information. In some embodiments, the third time period can be associated with the type of QCL relationship. Alternately, the third time period can be indicated by the network device with a RRC information. In other embodiments, if the target SSB is not QCLed with the active SSB or a CSI-RS resource, the measurement of target SSBs may be needed. In this case, the third time period can be associated with the transmission time of the target SSB and the time for the measurement of the target SSB (i.e., the time for RX beam refinement) .

In some embodiments, the TCI state associated with one of the at least one target SSB may be considered as a known TCI state if the at least one target SSB is QCLed with the at least one active SSB. In other words, the TCI state may be known if the SSB associated with the TCI state is a target SSB, and the target SSB is QCLed with an active old SSB. Alternatively, the QCL type can be QCL typeD. The term “new SSB” refers to a SSB which is configured/activated by gNB not exceed a time instance (e.g., T0+Ts) , or a SSB which is not measured/detected by the UE yet. The term “old SSB” refers to a SSB which may be de-activated or will be deactivated by gNB, or a SSB which is measured/detected by the UE within a time duration.

Fig. 8 shows a flowchart of an example method 800 in accordance with an embodiment of the present disclosure. The method 800 can be implemented at any suitable devices. Only for the purpose of illustrations, the method 800 can be implemented at a network device 120 as shown in Fig. 1. The network device 120 may have a plurality of antenna ports/panels.

At block 810, the network device 120 transmits a plurality of SSB configurations to the terminal device 110-1. The plurality of SSB configurations may at least comprise an active SSB configuration. In other words, the plurality of SSB configurations may comprise the currently used SSB configuration. The active SSB configuration indicates a plurality of active SSBs. The plurality of SSB configurations may comprise at least one inactive SSB configuration. In other words, the plurality of SSB configurations may comprise the not-used SSB configuration. In some embodiments, each of the plurality of SSB configurations may comprise a corresponding index.

At block 820, the network device 120 transmits SSB updating information to the terminal device 110-1. In this way, the terminal device 110-1 can acquire the beam setting for SSB reception without blind detection/searching, and then update the QCL relationship quickly. It is beneficial to avoid performance loss during the SSB switching (in other words, during the gNB antenna configuration switching) . On the other hand, the terminal device 110-1 can avoid using out-of-date QCL relationship after the SSB updating.

In some embodiments, a target SSB can also be QCLed with one or more CSI-RS resources, and the CSI-RS resource may be QCLed with an active SSB. In this case, the target SSB can be QCLed with one CSI-RS resource or with more than one CSI-RS resource. Alternatively, more than one target SSB can be QCLed with one CSI-RS resource or not QCLed with any CSI-RS resource.

In some embodiments, the network device 120 may start the transmission of the target SSB and stop the transmission of the active SSB at the same time. In this way, since there is no time domain overlapped between the target SSB and the active SSB, it is easier to arrange the time and/or frequency resources of the target SSB without conflicting with the active SSB. Alternatively, the network device 120 may start the transmission of the target SSB before it stops the transmission of the active SSB. In this way, since the target SSB is started before the active SSB is stopped, the terminal device 110-1 may still use the current TCI state for transmission while measuring the target SSB to prepare for the TCI updating, thereby there can be no or short traffic interruption during the SSB switching.

In some embodiments, the network device 120 may activate the target SSB configuration and deactivate the active SSB configuration simultaneously. Alternatively, the network device 120 may activate the target SSB configuration after a first time period from the deactivation of the active SSB configuration. This means there will be no time domain overlap between the active SSBs and the target SSBs. In this case, the target SSBs can be arranged in any available time/frequency resources. As an example, the frequency resource of target SSBs can be same as the active SSBs, and the time domain resource of some active SSBs and some target SSBs can be overlapped, which may be beneficial for the idle UEs. The length of the first time period can be predefined or preconfigured.

In some embodiments, the network device 120 may activate the target configuration before it deactivates the active SSB configuration. In this case, the target SSBs and the active SSBs may be both transmitted within a second time period, and then the network device 120 may deactivate the active SSBs. The resources of target SSBs and the active SSBs may be not overlapped. Alternatively, at least a portion of the target SSBs can be fully overlapped with active SSBs and the overlapped SSBs may have same SSB index. In some embodiments, the length of the second time period may be predefined or preconfigured. Alternatively, the length of the second time period may be based on a network indication. For example, if the network device 120 indicates the terminal device 110-1 a deactivation command, then the terminal device 110-1 may assume that the transmission of active SSBs is stopped. In other words, the second time period can be ended. During the second time period, the terminal device 110-1 may still assume the TCI state is associated with the active SSB. After the second time period ends, the terminal device 110-1 may assume that the TCI state is associated with the target SSB.

In some embodiments, the TCI state may be known if the SSB associated with the TCI state is a target SSB, and the target SSB is QCLed with an active old SSB. Alternatively, the QCL type can be QCL typeD. The term “new SSB” refers to a SSB which is configured/activated by gNB not exceed a time instance (e.g., T0+Ts) , or a SSB which is not measured/detected by the UE yet. The term “old SSB” refers to a SSB which may be de-activated or will be deactivated by gNB, or a SSB which is measured/detected by the UE within a time duration.

It should be noted that embodiments described with reference to Figs. 2-8 can be implemented separately or together.

In some embodiments, a terminal device comprises circuitry configured to perform: receiving, at a terminal device and from a network device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; receiving SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB; and determining, at the terminal device, the target SSB configuration to be activated and the active SSB configuration to be deactivated.

In some embodiments, the plurality of SSB configurations comprises at least one inactive SSB configuration, and each of the plurality of SSB configurations is associated with a network energy saving configuration.

In some embodiments, a physical cell identity (PCI) carried by the plurality of target SSBs is same as PCI carried by the plurality of active SSBs.

In some embodiments, a resource of the at least one target SSB is orthogonal with a resource of the at least one active SSB, or at least a portion of the resource of the at least one target SSB is overlapped with the resource of the at least one active SSB, or the resource of the at least one target SSB is a subset of the resource of the at least one active SSB, or the resource of the at least one active SSB is a subset of the resource of the at least one target SSB.

In some embodiments, the QCL relationship between the at least one target SSB and the at least one active SSB comprises one of: one of the at least one target SSB is QCLed with one of the at least one active SSB, one of the at least one target SSB is QCLed with multiple active SSBs from the at least one active SSB, multiple target SSBs from the at least one target SSB is QCLed with one of the at least one active SSB, or none of the at least one target SSB is QCLed with the at least one active SSB.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with the QCL relationship indicates a QCL typeA or both the QCL typeA and a QCL typeD, replacing the at least one active SSB with the at least one target SSB in at least one of: a transmission configuration indicator (TCI) state, or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with the QCL relationship indicates a QCL typeC or both the QCL typeC and a QCL typeD, replacing the at least one active SSB with the at least one target SSB in at least one of a TCI state, or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission; performing at least one of: a synchronization measurement or a beam measurement on the at least one target SSB; and determining the TCI state or the spatial relation or the QCL configuration to be available after the synchronization measurement or the beam measurement.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with the QCL relationship indicates that multiple target SSBs are QCLed with one active SSB, performing at least one of: a synchronization measurement or a beam measurement on the multiple target SSBs; determining one target SSB from the multiple target SSBs; and replacing the one active SSB with the one target SSB in at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with the QCL relationship indicates that multiple target SSBs are QCLed with one active SSB, performing at least one of: a synchronization measurement or a beam measurement on the multiple target SSB; determining one or more target SSBs from the multiple target SSBs; reporting, to the network device, indexes of the one or more target SSBs; receiving, from the network device, an indication of one target SSB from the one or more target SSBs; and replacing the one active SSB with the one target SSB in at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.

In some embodiments, the terminal device comprises circuitry configured to perform: in accordance with the QCL relationship indicates that the at least one target SSB is not QCLed with the at least one active SSB, determining at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission which is associated with the at least one active SSB to be not available.

In some embodiments, the terminal device comprises circuitry configured to perform: determining the target SSB configuration to be activated after a first time period from the deactivation of the active SSB configuration.

In some embodiments, the terminal device comprises circuitry configured to perform: determining, the active SSB configuration to be deactivated after a second time period from the activation of the target SSB configuration; and determining that the plurality of active SSBs and the plurality of target SSBs are available during the second time period.

In some embodiments, the terminal device comprises circuitry configured to perform: determining a target TCI state associated with the at least one target SSB to be available after a third time period from a time instance, and wherein the time instance is a timing when the SSB updating information is received, or the time instance is a timing when the target SSB configuration is activated.

In some embodiments, in accordance with a determination that the at least one target SSB is QCLed with the at least one active SSB, the third time period is associated with one of: transmission time of the at least one target SSB, processing time for the SSB updating information, or the type of the QCL relationship; or in accordance with a determination that the at least one target SSB is QCLed with the at least one active SSB, the third time period is indicated by the network device.

In some embodiments, in accordance with a determination that none of the at least one target SSB is QCLed with the at least one active SSB, the third time period is associated with transmission time of the at least one target SSB and time for a measurement of the at least one target SSB.

In some embodiments, a TCI state associated with one of the at least one target SSB is considered as a known TCI state if the at least one target SSB is QCLed with the at least one active SSB.

In some embodiments, a network device comprises circuitry configured to perform transmitting, at a network device and to a terminal device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; and transmitting SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB.

In some embodiments, the plurality of SSB configurations comprises at least one non-active SSB configuration, and each of the plurality of SSB configurations is associated with a network energy saving configuration.

In some embodiments, the QCL relationship between the at least one target SSB and the at least one active SSB comprises one of: one of the at least one target SSB is QCLed with one of the at least one active SSB, one of the at least one target SSB is QCLed with multiple active SSBs from the at least one active SSB, multiple target SSBs B from the at least one target SSB is QCLed with one of the at least one active SSB, or none of the at least one target SSB is QCLed with the at least one active SSB.

In some embodiments, the network device comprises circuitry configured to perform receiving, from the terminal device, indexes of one or more target SSBs; and transmitting, to the terminal device, an indication of one target SSB from the one or more target SSBs.

In some embodiments, the network device comprises circuitry configured to perform receiving, from the terminal device, indexes of one or more target SSBs; and transmitting, to the terminal device, an indication of a TCI state to replace of a current TCI state of the at least one active SSB.

In some embodiments, the network device comprises circuitry configured to perform deactivating the active SSB configuration; and activating the target SSB configuration after a first time period from the deactivation of the active SSB configuration.

In some embodiments, the network device comprises circuitry configured to perform deactivating the active SSB configuration after a second time period from the activation of the target SSB configuration; transmitting, to the terminal device, the plurality of active SSBs and the plurality of target SSBs during the second time period.

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 terminal device 110-1 or the network device 120 as shown in Fig. 1. Accordingly, the device 900 can be implemented at or as at least a part of the terminal device 110-1 or the network device 120.

As shown, the device 900 includes a processor 910, a memory 920 coupled to the processor 910, a suitable transmitter (TX) and receiver (RX) 940 coupled to the processor 910, and a communication interface coupled to the TX/RX 940. The memory 920 stores at least a part of a program 930. 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 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 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 Fig. 2 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 1050 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 1200, 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.

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. 2 to 10. 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 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, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs;

receiving SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB; and

determining, at the terminal device, the target SSB configuration to be activated and the active SSB configuration to be deactivated.
The method of claim 1, wherein the plurality of SSB configurations comprises at least one inactive SSB configuration, and

wherein each of the plurality of SSB configurations is associated with a network energy saving configuration.
The method of claim 1, wherein a physical cell identity (PCI) carried by the plurality of target SSBs is same as PCI carried by the plurality of active SSBs.
The method of claim 1, wherein

a resource of the at least one target SSB is orthogonal with a resource of the at least one active SSB, or

at least a portion of the resource of the at least one target SSB is overlapped with the resource of the at least one active SSB, or

the resource of the at least one target SSB is a subset of the resource of the at least one active SSB, or

the resource of the at least one active SSB is a subset of the resource of the at least one target SSB.
The method of claim 1, wherein the QCL relationship between the at least one target SSB and the at least one active SSB comprises one of:

one of the at least one target SSB is QCLed with one of the at least one active SSB,

one of the at least one target SSB is QCLed with multiple active SSBs from the at least one active SSB,

multiple target SSBs from the at least one target SSB is QCLed with one of the at least one active SSB, or

none of the at least one target SSB is QCLed with the at least one active SSB.
The method of claim 1, further comprising:

in accordance with the QCL relationship indicates a QCL typeA or both the QCL typeA and a QCL typeD, replacing the at least one active SSB with the at least one target SSB in at least one of: a transmission configuration indicator (TCI) state, or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.
The method of claim 1, further comprising:

in accordance with the QCL relationship indicates a QCL typeC or both the QCL typeC and a QCL typeD, replacing the at least one active SSB with the at least one target SSB in at least one of: a TCI state, a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission;

performing at least one of: a synchronization measurement or a beam measurement on the at least one target SSB; and

determining the TCI state or the spatial relation or the QCL configuration to be available after the synchronization measurement or the beam measurement.
The method of claim 1, further comprising:

in accordance with the QCL relationship indicates that multiple target SSBs are QCLed with one active SSB, performing at least one of: a synchronization measurement or a beam measurement on the multiple target SSBs;

determining one target SSB from the multiple target SSBs; and

replacing the one active SSB with the one target SSB in at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.
The method of claim 1, further comprising:

in accordance with the QCL relationship indicates that multiple target SSBs are QCLed with one active SSB, performing at least one of: a synchronization measurement or a beam measurement on the multiple target SSB;

determining one or more target SSBs from the multiple target SSBs;

reporting, to the network device, indexes of the one or more target SSBs;

receiving, from the network device, an indication of one target SSB from the one or more target SSBs; and

replacing the one active SSB with the one target SSB in at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission.
The method of claim 1, further comprising:

in accordance with the QCL relationship indicates that the at least one target SSB is not QCLed with the at least one active SSB, determining at least one of: a TCI state or a spatial relation for an uplink transmission or a QCL configuration for a downlink transmission which is associated with the at least one active SSB to be not available.
The method of claim 1, further comprising:

determining the target SSB configuration to be activated after a first time period from the deactivation of the active SSB configuration.
The method of claim 1, further comprising:

determining, the active SSB configuration to be deactivated after a second time period from the activation of the target SSB configuration; and

determining that the plurality of active SSBs and the plurality of target SSBs are available during the second time period.
The method of claim 1, further comprising:

determining a target TCI state associated with the at least one target SSB to be available after a third time period from a time instance, and

wherein the time instance is a timing when the SSB updating information is received, or the time instance is a timing when the target SSB configuration is activated.
The method of claim 13, wherein in accordance with a determination that the at least one target SSB is QCLed with the at least one active SSB, the third time period is associated with one of: transmission time of the at least one target SSB, processing time for the SSB updating information, or the type of the QCL relationship; or

in accordance with a determination that the at least one target SSB is QCLed with the at least one active SSB, the third time period is indicated by the network device.
The method of claim 13, wherein in accordance with a determination that none of the at least one target SSB is QCLed with the at least one active SSB, the third time period is associated with transmission time of the at least one target SSB and time for a measurement of the at least one target SSB.
The method of claim 1, wherein a TCI state associated with one of the at least one target SSB is considered as a known TCI state if the at least one target SSB is QCLed with the at least one active SSB.
A communication method, comprising:

transmitting, at a network device and to a terminal device, a plurality of synchronization signal/physical broadcast channel block (SSB) configurations for a serving cell, wherein the plurality of SSB configurations at least comprise an active SSB configuration and the active SSB configuration indicates a plurality of active SSBs; and

transmitting SSB updating information from the network device, wherein the SSB updating information indicates a target SSB configuration from the plurality of SSB configurations and a quasi co-location (QCL) information, wherein the target SSB configuration indicates a plurality of target SSBs, and the QCL information indicates a QCL relationship between at least one target SSB and at least one active SSB.
The method of claim 17, wherein the plurality of SSB configurations comprises at least one non-active SSB configuration, and

wherein each of the plurality of SSB configurations is associated with a network energy saving configuration.
The method of claim 17, wherein a physical cell identity (PCI) carried by the plurality of target SSBs is same as PCI carried by the plurality of active SSBs.
The method of claim 17, wherein:

a resource of the at least one target SSB is orthogonal with a resource of the at least one active SSB, or

at least a portion of the resource of the at least one target SSB is overlapped with the resource of the at least one active SSB, or

the resource of the at least one target SSB is a subset of the resource of the at least one active SSB, or

the resource of the at least one active SSB is a subset of the resource of the at least one target SSB.
The method of claim 17, wherein the QCL relationship between the at least one target SSB and the at least one active SSB comprises one of:

one of the at least one target SSB is QCLed with one of the at least one active SSB,

one of the at least one target SSB is QCLed with multiple active SSBs from the at least one active SSB,

multiple target SSBs B from the at least one target SSB is QCLed with one of the at least one active SSB, or

none of the at least one target SSB is QCLed with the at least one active SSB.
The method of claim 17, further comprising:

receiving, from the terminal device, indexes of one or more target SSBs; and

transmitting, to the terminal device, an indication of one target SSB from the one or more target SSBs.
The method of claim 17, further comprising:

receiving, from the terminal device, indexes of one or more target SSBs; and

transmitting, to the terminal device, an indication of a TCI state to replace of a current TCI state of the at least one active SSB.
The method of claim 17, further comprising:

deactivating the active SSB configuration; and

activating the target SSB configuration after a first time period from the deactivation of the active SSB configuration.
The method of claim 17, further comprising:

deactivating the active SSB configuration after a second time period from the activation of the target SSB configuration; and

transmitting, to the terminal device, the plurality of active SSBs and the plurality of target SSBs during the second time period.
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 acts comprising the method according to any of claims 1-16.
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 acts comprising the method according to any of claims 17-25.
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 1-16 or any of claims 17-25.