WO2021186206A1

WO2021186206A1 - Search space group switching for pdcch monitoring

Info

Publication number: WO2021186206A1
Application number: PCT/IB2020/000463
Authority: WO
Inventors: Hao Lin
Original assignee: Orope France Sarl
Priority date: 2020-03-20
Filing date: 2020-03-20
Publication date: 2021-09-23

Abstract

An apparatus and a method of communication of the same are provided. A method of communication of a user equipment (UE) includes receiving, by the UE, a first information, and the first information corresponds to search space group monitoring for a first serving cell. This provides a search space group indication and further provides a method of search space group switching.

Description

SEARCH SPACE GROUP SWITCHING FOR PDCCH MONITORING

BACKGROUND OF DISCLOSURE

1. Field of the Disclosure

[0001] The present disclosure relates to the field of communication systems, and more particularly, to an apparatus and a method of communication of the same, which can provide a good communication performance and high reliability.

2. Description of the Related Art

[0002] In an unlicensed band, an unlicensed spectrum is a shared spectrum. Communication equipments in different communication systems can use the unlicensed spectrum as long as the unlicensed meets regulatory requirements set by countries or regions on a spectrum. There is no need to apply for a proprietary spectrum authorization from a government.

[0003] In order to allow various communication systems that use the unlicensed spectrum for wireless communication to coexist friendly in the spectrum, some countries or regions specify regulatory requirements that must be met to use the unlicensed spectrum. For example, a communication device follows a listen before talk (LBT) procedure, that is, the communication device needs to perform a channel sensing before transmitting a signal on a channel. When an LBT outcome illustrates that the channel is idle, the communication device can perform signal transmission; otherwise, the communication device cannot perform signal transmission. In order to ensure fairness, once a communication device successfully occupies the channel, a transmission duration cannot exceed a maximum channel occupancy time (MCOT). [0004] On an unlicensed carrier, for a channel occupation time obtained by a base station, it may share the channel occupation time to a user equipment (UE) for transmitting an uplink signal or an uplink channel. In other words, when the base station shares its own channel occupancy time with the UE, the UE can use an LBT mode with higher priority than that used by the UE itself to obtain the channel, thereby obtaining the channel with greater probability.

[0005] In Releasel6, the UE can have different search space groups for physical downlink control channel (PDCCH) monitoring. However, how to provide a search space group indication to indicate the UE which search space group should be monitored and how to provide a method of search space group switching are still open issues.

[0006] Therefore, there is a need for an apparatus and a method of communication of the same, which can solve issues in the prior art, provide a search space group indication, and further provide a method of search space group switching.

SUMMARY

[0007] An object of the present disclosure is to propose an apparatus such as a user equipment (UE) and/or a base station (BS) and a method of communication of the same, which can solve issues in the prior art, provide a search space group indication, and further provide a method of search space group switching. [0008] In a first aspect of the present disclosure, a method of communication of a user equipment (UE) includes receiving, by the UE, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

[0009] In a second aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to control the transceiver to receive a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

[0010] In a third aspect of the present disclosure, a method of communication of a UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in the DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the first slot where a timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell that is indicated by the DCI format 2_0.

[0011] In a fourth aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in the DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the first slot where a timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell that is indicated by the DCI format 2_0.

[0012] In a fifth aspect of the present disclosure, a method of communication of a UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on a first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration.

[0013] In a sixth aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on a first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration.

[0014] In a seventh aspect of the present disclosure, a method of communication of a UE includes if the UE detects a first information, the UE starts monitoring a PDCCH according to search space set with a first target search space group.

[0015] In an eighth aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform the following: if the UE detects a first information, the UE starts monitoring a PDCCH according to search space set with a first target search space group.

[0016] In a ninth aspect of the present disclosure, a method of communication of a UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with the search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1, on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where a timer expires or after the last symbol of the remaining channel occupancy duration for the first serving cell.

[0017] In a tenth aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1, and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with the search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1, on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where a timer expires or after the last symbol of the remaining channel occupancy duration for the first serving cell.

[0018] In an eleventh aspect of the present disclosure, a method of communication of a UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and stops monitoring the PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space set with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1, and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1, on the first group of serving cells, and/or on a first serving cell, at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after the last symbol of a first remaining channel occupancy duration. [0019] In a twelfth aspect of the present disclosure, a UE includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and stops monitoring the PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space set with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the first group of serving cells, and/or on a first serving cell, at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after the last symbol of a first remaining channel occupancy duration.

[0020] In a thirteenth aspect of the present disclosure, a method of communication of a base station (BS) includes transmitting, by the BS, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

[0021] In a fourteenth aspect of the present disclosure, a BS includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to control the transceiver to transmit a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

[0022] In a fifteenth aspect of the present disclosure, a non-transitory machine-readable storage medium has stored thereon instructions that, when executed by a computer, cause the computer to perform the above method.

[0023] In a sixteenth aspect of the present disclosure, a chip includes a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the above method. [0024] In a seventeenth aspect of the present disclosure, a computer readable storage medium, in which a computer program is stored, causes a computer to execute the above method.

[0025] In an eighteenth aspect of the present disclosure, a computer program product includes a computer program, and the computer program causes a computer to execute the above method.

[0026] In a nineteenth aspect of the present disclosure, a computer program causes a computer to execute the above method.

BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present disclosure or related art, the following figures will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present disclosure, a person having ordinary skill in this field can obtain other figures according to these figures without paying the premise.

[0028] FIG. 1 is a block diagram of a user equipments (UE) and a base station (BS) (e.g., gNB) of communication in a communication network system according to an embodiment of the present disclosure. [0029] FIG. 2 is a flowchart illustrating a method of communication of a UE according to an embodiment of the present disclosure.

[0030] FIG. 3 is a flowchart illustrating a method of communication of a BS according to an embodiment of the present disclosure.

[0031] FIG. 4 is a schematic diagram illustrating search space group switching according to an embodiment of the present disclosure.

[0032] FIG. 5 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0033] FIG. 6 is a schematic diagram illustrating a cell group according to another embodiment of the present disclosure.

[0034] FIG. 7 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0035] FIG. 8 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0036] FIG. 9 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0037] FIG. 10 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0038] FIG. 11 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure.

[0039] FIG. 12 is a schematic diagram illustrating search space group switching according to another embodiment of the present disclosure. [0040] FIG. 13 is a block diagram of a system for wireless communication according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0041] Embodiments of the present disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present disclosure are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

[0042] In Release 16, a user equipment (UE) can have different search space groups for physical downlink control channel (PDCCH) monitoring. A base station such as a gNB can indicate the UE which search space group should be monitored. In addition, how to provides a search space group indication to indicate the UE which search space group should be monitored and how to provide a method of search space group switching are still open issues. Some embodiments of the present disclosure can provide technical solutions to resolve the issues, provide a search space group indication, and further provide a method of search space group switching. Further, some embodiments of the present disclosure present a method of a search space group indication and the UE switches from one search space group to another. [0043] FIG. 1 illustrates that, in some embodiments, a user equipment (UE) 10 and a base station (BS) (e.g., gNB) 20 of communication in a communication network system 30 according to an embodiment of the present disclosure are provided. The communication network system 30 includes one or more UEs 10 of a cell and the BS 20. The UE 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12, the transceiver 13. The base station 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22, the transceiver 23. The processor 11 or 21 may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 is operatively coupled with the processor 11 or 21 and stores a variety of first information to operate the processor 11 or 21. The transceiver 13 or 23 is operatively coupled with the processor 11 or 21, and the transceiver 13 or 23 transmits and/or receives a radio signal.

[0044] The processor 11 or 21 may include application-specific integrated circuit (ASIC), other chipset, logic circuit and/or data processing device. The memory 12 or 22 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and/or other storage device. The transceiver 13 or 23 may include baseband circuitry to process radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 can be implemented within the processor 11 or 21 or external to the processor 11 or 21 in which case those can be communicatively coupled to the processor 11 or 21 via various means as is known in the art.

[0045] In some embodiments, the processor 11 is configured to control the transceiver 13 to receive a first information, wherein the first information corresponds to search space group monitoring for a first serving cell. This can provide a search space group indication, and further provide a method of search space group switching.

[0046] In some embodiments, the processor 21 is configured to control the transceiver 23 to transmit a first information, wherein the first information corresponds to search space group monitoring for a first serving cell. This can provide a search space group indication, and further provide a method of search space group switching.

[0047] FIG. 2 illustrates a method 200 of communication of a UE according to an embodiment of the present disclosure. In some embodiments, the method 200 includes: a block 202, receiving, by a UE, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell. This can provide a search space group indication, and further provide a method of search space group switching.

[0048] FIG. 3 illustrates a method 300 of communication of a BS according to an embodiment of the present disclosure. In some embodiments, the method 300 includes: a block 302, transmitting, by a BS, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell. This can provide a search space group indication, and further provide a method of search space group switching.

[0049] In some embodiments, the first information comprises a first indication field, and the first indication field indicates a first target search space group. This solution gives a clear indication of the target search space group. Thus there is no ambiguity for the UE to determine the target search space group. In details, the first information is a DCI format 2_0, the UE determines the first target search space group based on the indication in the DCI format 2_0. In some embodiments, the first indication field has 1 bit, and a value of the 1 bit corresponds to a target search space group index of the first target search space group. In details, the first indication field, such as a search space set switching field, is 1 bit, if it is 0, target search space group 0, if it is 1, target search space group 1. In some embodiments, a location of the first indication field corresponds to the first serving cell. In details, the target search group is applied for the first serving cell. In some embodiments, a location of the first indication field corresponds to a first cell group, which includes a group of serving cells, and the first cell group comprises the first serving cell. In details, the first target search space group is applied for a group of cells, where the group includes the first serving cell. The advantage of this solution is that all the serving cells within the same group will be applied for the target search space group, so that the network does not need to indicate the search space group switching for each of these serving cell. In some embodiments, the correspondence between the first indication field and the first serving cell is indicated by a second information. In details, association is between the search space set switching field and the first serving cell. In some embodiments, the second information comprises a parameter, SlotF ormatlndicator IE. In some embodiments, the second information associates a position of the first indication field in the first information with an identity of the first serving cell. In details, positionlnDCI and servingCellld association, where servingCellld is the identity of the first serving cell. In details, positionlnDCI is corresponding bit position of the search space set switching field in the DCI format 2_0. In some embodiments, the second information associates a position of the first indication field in the first information with an identity of the first cell group. In details, positionlnDCI and cell group ID, SearchSpaceSwitchingGroup-rl6, group id, or searchSpaceSwitchingGroupList-rl6 has two sequences, the first sequence is group id=0. In some embodiments, the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceS witchingGroup-r 16.

[0050] In some embodiments, the first information comprises a downlink control information (DCI) format 2_0. In some embodiments, the UE starts to monitor the first target search space group from a first slot. In some embodiments, the first slot is the earliest slot that is at least a given interval after a first symbol. In some embodiments, the first symbol is the last symbol of a physical downlink control channel (PDCCH) that carries the first information. In details, reference starting symbol is the last symbol of PDCCH. In some embodiments, a second symbol is the last symbol of a remaining channel occupancy duration for a given serving cell. In details, reference symbol is same as a last symbol of the channel occupancy time (COT) end. In some embodiments, if the UE is monitoring a PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or a first group of serving cells, from a second slot. In some embodiments, the second target search space group is different from the first target search space group. [0051] In some embodiments, the given serving cell is the first serving cell. In details, the given serving cell has the information about the remaining channel occupancy time duration (COT duration). In some embodiments, the given serving cell is a second serving cell. In details, the COT duration of the given serving cell is referred to the last end COT duration among all the serving cells of the same cell group. The reasoning of this solution is that the UE can maximally taek advantage of the COT duration before applying the search space group switching. But alternatively, in some embodiments, the COT duration is referred to the earliest end COT duration among all the serving cells of the same cell group. In some embodiments, the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell is different from (less than or greater than) that of the first serving cell. In some embodiments, a second symbol is the last symbol of a slot where a given timer expires. In details, reference symbol is equal to a slot end (the last symbol of a slot) where a timer expires. In some embodiments, the given timer is a timer of the first serving cell. In details, the timer is same as a serving cell own timer or the last expired timer of all serving cells of the same cell group. In some embodiments, the timer can be started or re-started in different conditions. The timer is used for the UE to determine when to switch the search space group 1 back to search space group 0. The idea is that if in the search space group 1, there is no PDCCH detected for a while the UE will switch back to search space group 0. Here the measure ‘for a while’ is controlled by the timer. The timer is counting-down (decremented by 1) for every slot until it expires, when UE detects a DCI format in a slot, the timer will not be decremented. In some embodiments, if search space switching is per serving cell, each serving cell has a dedicated timer. The timer is started if the UE has detected a dedicated DCI format, e.g. format 2_0, or other DCI format when UE is monitoring PDCCH according to the search space set with group 0. Similarly, when UE is monitoring PDCCH according to the search space set with group 1, the timer is re-started if the UE detects a DCI format when monitoring PDCCH according to the search space with group 1.

[0052] In some embodiments, the given timer is a timer of a third serving cell. In some embodiments, the third serving cell and the first serving cell are in the same cell group, and the timer of the third serving cell expires in a different slot than that the timer of the first serving cell expires. This solution is suitable for the search space group switching is per cell group, i.e. a group of serving cells. It is in particular for the case where UE has more than one serving cell for downlink transmission. And thus, there are more than one timer, one for each serving cell. When the search space group switching is based on the timer expiration, the network can decide to base this switching on the latest expired timer or the earliest expired timer. For the solution that is based on the latest expired timer, the network intends to keep the search space group as much as possible before it switches back to the default search space group. Here we can assume that the default search space group is group 0. For the solution that is based on the earliest expired timer, the network might want the UE switch back to the default search space group as quickly as possible. For the timer start or restart, each serving cell has a dedicated timer. For a timer of a given serving cell, it is restarted if the UE detects a DCI format when monitoring PDCCH according to the search space set with group 1 on this serving cell. But in some other embodiments, the network may want to synchronize the timers of different serving cells, thus, it might be the case that if UE detects a DCI format when monitoring PDCCH according to the search space set with group 1 on one serving cell, the timers of all the serving cells should be re started. For the timer starting, in some embodiments, the timers of a group serving cells will be started when UE stops monitoring PDCCH according to the search space set with group 0 and starts monitoring PDCCH according to the search space set with group 1 on a group of serving cells. In some embodiments, the given timer is a timer of the first cell group. This is an alternative solution to synchronize the timers of a group of serving cells. In this case, there is a unique timer a group of serving cells. Thus, it makes the timer updating mechanism simpler. In details, in some cases, even the UE has more than one downlink serving cell, there might still be possible to have a unique timer and this timer can be used for a group of serving cells of this UE. In this case, each time when UE stops monitoring PDCCH according to the search space set with group 0 and starts monitoring PDCCH according to the search space set with group 1 on a group of serving cells, this timer is started. Moreover, if UE detects a DCI format when monitoring PDCCH according to the search space set with group 1 on one serving cell, the timer is re-started. In some embodiments, the start or re-start of the timer means that the timer is given with a value that is configured by a parameter, searchSpaceSwitchingTimer-rl6. In some embodiments, the same value is provided by searchSpaceSwitchingTimer-rl6 for the timers of different serving cells. In some embodiments, searchSpaceSwitchingTimer-rl6 can provide different values for different timers of different serving cells. In some embodiments, the given interval is a length of P symbols, where P is an integer. This interval is expected to cover the time needed for the UE to decode a PDCCH or process some other downlink data. In some embodiments, the P symbols are derived based on a reference subcarrier spacing (SCS). In some embodiments, the reference SCS is a SCS of the first serving cell. In some embodiments, the reference SCS is a SCS of a fourth serving cell. In some embodiments, the reference SCS has a pre-defined value. In some embodiments, the pre-defined value is 15 kHz or 30Khz or 60Khz. In some embodiments, the fourth serving cell and the first serving cell are in the same cell group, and the fourth serving cell has a different SCS from that of the first serving cell. In some embodiments, the UE cannot monitor PDCCH according to search space sets with more than one search space group. If there are two search space groups, e.g. group 0 and group 1 , it requires the UE either to monitor in group 0 or in group 1. This solution can greatly reduce the UE monitoring complexity.

[0053] In some embodiments, a method of communication of the UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in the DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the first slot where a timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell that is indicated by the DCI format 2_0. This can provide a search space group indication, and further provide a method of search space group switching.

[0054] In some embodiments, the first indication field comprises a search space switching field. In some embodiments, the first indication field has 1 bit, whose value is 0 or 1. In some embodiments, a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell. In some embodiments, the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell is provided by a parameter, SlotFormat Indicator IE.

[0055] In some embodiments, a method of communication of the UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on a first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration. This can provide a search space group indication, and further provide a method of search space group switching.

[0056] In some embodiments, the first indication field comprises a search space switching field. In some embodiments, the first indication field has 1 bit, whose value is 0 or 1. In some embodiments, a location of the first indication field in the DCI format 2_0 corresponds to the first group or a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell. In some embodiments, the first group comprises the first group serving cells. In some embodiments, the first serving cell belongs to the first group. In some embodiments, the first group has a group index. In some embodiments, the correspondence between the location of the first indication field in the DCI format 2_0 and the first group is provided by a parameter, SlotFormat Indicator IE, and the location of the first indication field in the DCI format 2_0 corresponds to the group index of the first group. In some embodiments, the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell and the correspondence between the first group and the first serving cell are provided by a parameter, SlotF ormatlndicator IE. In some embodiments, a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells. In some embodiments, a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells. In some embodiments, a symbol duration of the P symbols is based on a pre-defined SCS. In some embodiments, the pre-defined SCS is 15 khz or 30 Khz or 60 Khz. In some embodiments, the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the slot where a timer of the first cell group expires. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is indicated by the DCI format 2_0. In some embodiments, the UE is provided with a parameter, searchSpaceSwitchingGroupList-rl6. [0057] In some embodiments, a method of communication of the UE includes if the UE detects a first information, the UE starts monitoring a PDCCH according to search space set with a first target search space group. This can provide a search space group indication, and further provide a method of search space group switching.

[0058] In some embodiments, the first information comprises a first DCI format. In details, the first information is a DCI format 2_0, the UE determines the first target search space group based on the indication in the DCI format 2_0. In some embodiments, the first DCI format is detected by the UE by monitoring the PDCCH according to search space set with search space group index 0. In details, search space set switching field is 1 bit, if it is 0, target search space group 0, if it is 1 , target search space group 1. In some embodiments, the first DCI format is detected by the UE by monitoring the PDCCH in any search space set. In details, the target search group is applied for the first serving cell. In some embodiments, the first information comprises a downlink signal or channel or downlink transmission. In some embodiments, the downlink signal or channel or downlink transmission comprises a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). In some embodiments, the first target search space group comprises search space group index 1. In some embodiments, the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first serving cell. In some embodiments, the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first group of serving cells (a first cell group). In some embodiments, the first cell group comprises the first serving cell. In some embodiments, the first serving cell associated with the first cell group is configured by a second information. In some embodiments, the second information comprises a parameter, SlotF ormatlndicator IE. In some embodiments, the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-rl6. In some embodiments, the UE starts monitoring the PDCCH according to search space set with the first target search space group from a first slot. In some embodiments, the first slot is the earliest slot that is at least a given interval after a first symbol. In some embodiments, the first symbol is the last symbol of the PDCCH that carries the first information. In some embodiments, the first symbol is the last symbol of the signal or channel or downlink transmission that carries the first information. In some embodiments, if a UE is monitoring the PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or the first group of serving cells, from a second slot. [0059] In some embodiments, the second target search space group comprises search space group index 0. In some embodiments, the second slot is the earliest slot that is at least the given interval after a second symbol. In some embodiments, the second symbol is the last symbol of a first remaining channel occupancy duration. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of the first serving cell. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells. In some embodiments, the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0, or slot format indication (SFI)-index field in the DCI format 2_0, or maximum channel occupancy time provided in a parameter, semiStaticChannelAccessConfig-rl6. In some embodiments, the second symbol is the last symbol of a reference slot. In some embodiments, the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the slot where a timer of the first cell group expires.

[0060] In some embodiments, the reference slot is a slot where a timer of the first serving cell expires. In some embodiments, the given interval is a length of P symbols, where P is an integer. In some embodiments, a symbol duration of the P symbols is based on a reference SCS. In some embodiments, the reference SCS is a SCS of the first serving cell. In some embodiments, the reference SCS is 15 Khz. In some embodiments, the reference SCS is a SCS of a second serving cell. In some embodiments, the second serving cell and the first serving cell are in the same cell group, and the second serving cell has a different SCS from that of the first serving cell. In some embodiments, the second slot is at the earliest slot in every periodic channel occupancy, and the periodic channel occupancy is provided by a parameter, semiStaticChannelAccessConfig-rl6. In some embodiments, the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', by a system information block 1 (SIB1) or a dedicated configuration.

[0061] In some embodiments, a method of communication of the UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1, and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with the search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1, on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where a timer expires or after the last symbol of the remaining channel occupancy duration for the first serving cell. This can provide a search space group indication, and further provide a method of search space group switching.

[0062] In some embodiments, the remaining channel occupancy duration is indicated by a DCI format 2_0. In some embodiments, the remaining channel occupancy duration is indicated by SFI-index field in the DCI format 2_0. In some embodiments, the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0. In some embodiments, the remaining channel occupancy duration is indicated by a parameter, semiStaticChannelAccessConfig-rl6. In some embodiments, the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', by a SIB1 or a dedicated configuration. In some embodiments, the UE is not provided with a parameter, SearchSpaceSwitchTrigger-r 16.

[0063] In some embodiments, a method of communication of the UE includes at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1, and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and stops monitoring the PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space set with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1, and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the first group of serving cells, and/or on a first serving cell, at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after the last symbol of a first remaining channel occupancy duration. In some embodiments, the first serving cell belongs to the first group of serving cells. This can provide a search space group indication, and further provide a method of search space group switching.

[0064] In some embodiments, the first group of serving cells is provided by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-rl6. In some embodiments, a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells. In some embodiments, a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells. In some embodiments, a symbol duration of the P symbols is based on a pre -defined SCS. In some embodiments, the pre-defined SCS is 15 khz or 30 Khz or 60 Khz. In some embodiments, the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires. In some embodiments, the reference slot is the slot where a timer of the first cell group expires. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is indicated by a DCI format 2_0. In some embodiments, the first remaining channel occupancy duration is indicated by a SFI-index field in the DCI format 2_0. In some embodiments, the first remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0. In some embodiments, the first remaining channel occupancy duration is indicated by a parameter, semiStaticChannelAccessConfig-rl6. In some embodiments, the UE is provided with a parameter, searchSpaceSwitchingGroupList-rl6. In some embodiments, the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic' by a SIB1 or a dedicated configuration. In some embodiments, the UE is not provided with a parameter, SearchSpaceSwitchTrigger-rl6. In some embodiments, the reference slot is the slot where a timer of the first serving cell expires. In some embodiments, the reference slot is the slot where a timer of the first cell group expires. In some embodiments, the timer of the first cell group is provided by RRC configuration. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer- rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer- rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer- rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1. In some embodiments, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set.

[0065] In some embodiments, the method of the UE determines the search space group in which the UE monitors the PDCCH comprising the UE receives a first information and the first information is related to the search space group in which the PDCCH monitoring is performed for a first serving cell. In some embodiments, the first information is in downlink control indicator (DCI) format 2_0, and the DCI format 2_0 will indicate the UE the first target search space group for PDCCH monitoring. In some embodiments, the first information is any DCI format. In some embodiments, the first target search space group (SSG) has SSG index. The SSG index is 0 or 1. In some embodiments, DCI format 2_0 includes a first indication field, the field is used to indicate the target SSG. The indication field can be 1-bit indication with ’ indicating the target SSG index 0 and with ‘1’ indicating the target SSG index 1. In some embodiments, the first indication field is called search space group switch trigger. In some embodiments, the first indication field is corresponding to the first serving cell. This means that the indicated target SSG is applied for the first serving cell. In some other embodiments, the first indication field is corresponding to a cell group, and the cell group includes the first serving cell. Thus, the correspondence between the first indication field and the first serving cell is derived via the cell group.

[0066] In some embodiments, the correspondence between the first indication field and the serving cell is given by a second information, which is SlotF ormatlndicator IE in RRC configuration. In SlotF ormatlndicator IE, one parameter positionlnDCI represents the first indication field position in DCI format 2_0. Another parameter is servingCellld, representing the identity of the serving cell. These two parameters are associated together to establish the correspondence between the first indication field and the first serving cell. In some embodiments, the correspondence between the first indication field and the serving cell is given by a second information, which is SlotF ormatlndicator IE in RRC configuration. In SlotF ormatlndicator IE, one parameter positionlnDCI represents the first indication field position in DCI format 2_0. Another parameter is cell group id, representing the identity of the cell group. Moreover, a third parameter SearchSpaceSwitchingGroup-rl6 includes a group of identity of the serving cells and the cell group id. Therefore, UE can rely on the association between the first indication field and configured cell group id, and further on the association between the cell group id and the included serving cell id to determine the linkage between the first indication field and the first serving cell.

[0067] In some embodiments, the correspondence between the first indication field and the serving cell is given by a second information, which is SlotF ormatlndicator IE in RRC configuration. In SlotF ormatlndicator IE, one parameter positionlnDCI represents the first indication field position in DCI format 2_0. Another parameter is cell group id, representing the identity of the cell group. Moreover, a third parameter SearchSpaceSwitchingGroup-rl6 includes a group of identity of the serving cells. A fourth parameter SearchSpaceSwitchingGroupList-rl6 includes one or more groups of serving cells. The one or more groups correspond to the cell group id that is associated with the positionlnDCI. Therefore, UE can rely on the association between the first indication field and configured cell group id, where the cell group id corresponds to the ordering of the groups configured in SearchSpaceSwitchingGroupList-rl6 to further determine the linkage between the first indication field and the first serving cell.

[0068] In some embodiments, the UE starts to monitor the target SSG from a first slot boundary, where the first slot boundary is the earliest slot boundary that is at least after a given interval from a first symbol. In some embodiments, the first symbol is the last symbol of the PDCCH. The PDCCH is used to transmit DCI format 2_0. In some embodiments, the first symbol is the last symbol of the remaining channel occupancy duration for a given serving cell. The remaining channel occupancy duration is indicated in DCI format 2_0. And the given serving cell can be the first serving cell or a second serving cell, that the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell ends later than that of the first serving cell. In some embodiments, the first symbol is the last symbol of the slot where the given timer expires, where the given timer is the timer of the first serving cell or the given timer is the timer of a third serving cell. The third serving cell and the first serving cell are in the same cell group, and the timer of the third serving cell expires later than that of the first serving cell. In some embodiments, the timer is configured by searchSpaceSwitchingTimer-rl6. [0069] In some embodiments, the given interval is a length of P symbols, where P is an integer. The P symbols are calculated based on a reference subcarrier spacing (SCS). In some embodiments, the reference SCS is the SCS of the first serving cell or the reference SCS is the SCS of a fourth serving cell, where the fourth serving cell and the first serving cell are in the same cell group, and the fourth serving cell has different SCS from the first serving cell. In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring PDCCH in any search space set, the UE starts monitoring PDCCH according to search space set with search space group 1 , and stops monitoring PDCCH according to search space set with the search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format. In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring PDCCH according to search space sets with search space group 0, the UE starts monitoring PDCCH according to search space set with search space group 1, and stops monitoring PDCCH according to search space set with the search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format.

[0070] In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1, and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring PDCCH according to search space set with search space group 1 , and stops monitoring PDCCH according to search space set with the search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission. In some embodiment, If the UE monitors PDCCH on a first serving cell according to search space sets with group index 1, the UE starts monitoring PDCCH on the serving cell according to search space sets with group index 0, and stops monitoring PDCCH according to search space sets with group index 1, on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where the timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell. In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring PDCCH in any search space set, the UE starts monitoring PDCCH according to search space set with search space group 1 , and stops monitoring PDCCH according to search space set with the search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format.

[0071] In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring PDCCH according to search space set with search space group 0, the UE starts monitoring PDCCH according to search space set with search space group 1, and stops monitoring PDCCH according to search space set with the search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format. In some embodiments, If a UE is not monitoring PDCCH according to search space sets with search space group 1, and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring PDCCH according to search space set with search space group 1 , and stops monitoring PDCCH according to search space set with the search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission. In some embodiments, the first group of serving cells are provided by searchSpaceSwitchingGroupList-rl6 parameter and/or SearchSpaceSwitchingGroup-rl6, where a list of the serving cells, with respective serving cell identities, are configured to be grouped together.

[0072] In some embodiments, If the UE monitors PDCCH on a first serving cell according to search space sets with group index 1, the UE starts monitoring PDCCH on the serving cell according to search space sets with group index 0, and stops monitoring PDCCH according to search space sets with group index 1 , on a first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration. In some embodiments, the symbol duration of the P symbols are based on the smallest SCS among the serving cells in the first group of serving cells. In some embodiments, the symbol duration of the P symbols are based on the largest SCS among the serving cells in the first group of serving cells. In some embodiments, the symbol duration of the P symbols are based on a pre-defined value. In some embodiments, the reference slot is the latest slot where the timer of a serving cell, among a first group of serving cells, expires. In some embodiments, the reference slot is the earliest slot where the timer of a serving cell, among a first group of serving cells, expires.

[0073] In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells. In some embodiments, the first remaining channel occupancy duration is indicated by DCI format 2_0, by SFI-index field or channel occupancy duration field. In some embodiments, when UE is provided by higher layer parameters ChannelAccessMode-rl6 ='semistatic', the remaining channel occupancy duration can also be provided by semiStaticChannelAccessConfig-rl6. In some embodiments, the UE is provided by higher layer parameters ChannelAccessMode-rl6 ='semistatic' by SIB1 or dedicated configuration. In some embodiments, the UE is not provided with SearchSpaceSwitchTrigger-rl6.

[0074] FIG. 4 illustrates search space group switching according to an embodiment of the present disclosure. FIG. 4 illustrates that, in some embodiments, a UE receives a DCI format 2_0, the DCI format 2_0 contains a 1-bit flag to indicate that a first target search space group (SSG) is SSG 0 or SSG 1. When the flag indicates 1, the target SSG is SSG 1. The UE will start to monitor a PDCCH in SSG 1 starting from the earliest slot boundary that is at least P symbols after the last PDCCH that carries the DCI format 2_0. FIG. 4 illustrates that, in some embodiments, the UE initially monitors SSG 0 and it will switch to SSG 1 from the slot n+2. In this embodiment, the search space group switching happens from SSG 0 to SSG 1. [0075] FIG. 5 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 5 illustrates that, in some embodiments, in the DCI format 2_0, the flag=0, the UE will continue monitoring SSG 0 if the UE initially monitors SSG 0 as illustrated in FIG. 5. Thus, the SSG switching does not happen. But if the UE initially monitors SSG 1, then the SSG switching will happen from SSG 1 to SSG 0. The flag is an indication field in the DCI format 2_0, which is corresponding to a serving cell or a group of serving cell. If the flag is corresponding to a serving cell. The association can be given in the RRC configuration under SlotF ormatlndicator IE and searchSpaceSwitchTrigger-rl6 parameter, such as:

[0076]

[0077] Where positionlnDCI is the flag field position in DCI format 2_0 and the servingCellld is the specific serving cell id that is associated with the flag field. Thus, the flag indication is applied for this associated serving cell. In this case, the indicated target SSB as illustratedin FIG. 4 and 5, are applied only for the associated serving cell. This is called per serving cell search space group switching. When the flag is corresponding to a group of serving cells. The association between the cell group and the flag field is given in searchSpaceSwitchTrigger-rl6 parameter, such as:

[0078]

[0079] Where the groupld is the cell group id, which can further be configured by two parameters under PDCCH-config IE, such as:

[0080]

[0081] Where searchSpaceSwitchingGroupList-rl6 configures one or more cell groups and the configuration of each cell group is further configured by SearchSpaceSwitchingGroup-rl6, where a list of serving cell id are included in the cell group. The linkage between groupld and the configured one or more cell groups can be following the increasing ordering. For instance, when searchSpaceSwitchingGroupList- rl6 configures one cell group, it then has the groudld=0. When searchSpaceSwitchingGroupList-rl6 configures two cell groups, the first configured cell group has groudld=0 and the second cell group has groudId=l. To make the linkage more obvious, a groudld can be directly configured under cell group configuration, i.e. for each cell group it has a dedicated group id. Then in searchSpaceSwitchingGroupList- rl6, it indicates which group id is associated with the flag field. When the flag field is associated with a cell group, the indicated target SSG is applied for a group of serving cells that within the same cell group that associated with the flag field. This is called per cell group search space group switching.

[0082]

[0083] To allow a network to have more flexibility, the searchSpaceSwitchingGroupList-rl6 can select other the field is associated with one serving cell or a group of serving cells (a cell group), such as:

[0084]

[0085] In another example, the cell group id is not configured to be associated with flag field, the per group SSG switching can also be realized. If the UE is provided with searchSpaceSwitchingGroupList-rl6, this means that the cell group is configured, which includes a group of serving cells. Then even though the association in searchSpaceSwitchTrigger-rl6 is between flag field and serving cell id. If the UE knows the cell group that the associated serving cell belongs to, the flag field can still be applied for the cell group. For example, the cell group configured by searchSpaceSwitchingGroupList-rl6 and searchSpaceSwitchingGroup-rl6 includes serving cell id= 1,2,3. And the flag field is associated with 2. Then once the UE receives the flag field associated to serving cell id=2, the corresponding SSG switching behavior will be applied for serving cell id=l ,2,3.

[0086]

[0087] FIG. 4 and FIG. 5 illustrate that, in some embodiments, the UE starts to monitor the target SSG in a slot boundary that must satisfy a time interval which is defined by P symbols (P is an integer, which can be in the range of (2~30)). For per serving cell SSG switching is configured, e.g. when searchSpaceSwitchingGroupList-rl6 parameter is not provided, the P symbols should be calculated as the symbol for the associated serving cell with the flag field. On the other hand, if per cell group SSG switching is applied, e.g. when searchSpaceSwitchingGroupList-rl6 parameter is provided, since the SSG switching is applied for a group of serving cells instead of one serving cell, the P symbols should be calculated based on the serving cell which has the smallest subcarrier spacing.

[0088] FIG. 6 illustrates a cell group according to another embodiment of the present disclosure. FIG. 6 illustrates that, in some embodiments, assuming that a cell group contains serving cell 1 and serving cell 2 whose SCS are SCSI > SCS2. If P=8, then the time interval should be calculated as 8 symbols of serving cell 2 for all serving cells. The principle is that the time interval must be satisfied for all the serving cells within the cell group. If it is calculated the interval based on serving cell 1 , as can be easily seen that for serving cell 2, the interval is not enough. FIG. 7 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 7 illustrates, in some embodiments, the UE will switch from SSG 1 to SSG 0 when the channel occupancy duration is end (COT end). In this case, the UE will start to monitor SSG 0 from the earliest slot boundary, as illustrates in Fig. 7, at least P symbols after the COT end. This SSG switching can also be either per serving cell switching or per cell group switching similar to previous examples.

[0089] FIG. 8 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 8 illustrates, in some embodiments, for per cell group switching, the COT end is referred to the latest COT end (can also be the earliest COT end) among all the serving cells in the same cell group. FIG. 8 illustrates, in some embodiments, the COT end should be referred to the COT end for serving cell 2 instead of serving cell 1. And the P symbols should be calculated from the COT end of the serving cell 2. The channel occupancy duration can be indicated by SFI-index field in DCI format 2_0 if the UE is provided by slotFormatCombinations, or be indicated by channel occupancy duration field in DCI format 2_0, if the UE is provided by CO-DurationPerCell-rl6. At least one of these two parameters should be provided to the UE if the UE is not provided by higher layer parameters ChannelAccessMode-rl6 ='semistatic'. On the other hand, when the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', and if none of CO-DurationPerCell-rl6 and slotFormatCombinations is provided to the UE, the channel occupancy duration is provided by semiStaticChannelAccessConfig-rl6. But if either CO-DurationPerCell-rl6 or slotFormatCombinations is provided to the UE, the channel occupancy duration should follow the indication in DCI format 2_0. If both CO-DurationPerCell-rl6 and slotFormatCombinations are provided to the UE, the channel occupancy duration is indicated by channel occupancy duration field in DCI format 2_0.

[0090] FIG. 9 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 9 illustrates, in some embodiments, the UE will switch from SSG 1 to SSG 0 when a timer expires. In this case, the UE will start to monitor SSG 0 from the earliest slot boundary, as illustrates in FIG. 9, at least P symbols after the end of the slot where the timer is expired. This SSG switching can also be either per serving cell switching or per cell group switching similar to previous examples. FIG. 10 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 10 illustrates, in some embodiments, for per cell group switching, the slot that timer expires is referred to the latest slot (can also be the earliest slot) among all the serving cells in the same cell group. FIG. 10 illustrates, in some embodiments, the timer of serving cell 2 expires in slot n+1, and for serving cell 1 the timer expires in slot n, then the slot n+1 should be used for calculating P symbols. FIG. 11 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 11 illustrates, in some embodiments, the UE is not provided with SearchSpaceSwitchTrigger-rl6 but the UE is provided by searchSpaceGroupIdEist-rl6, in this case, the UE will not monitor DCI format 2_0 in order to decide which search space group is target search space group. Instead, if the UE is monitoring PDCCF1 according to the search space set with search space group 0, if UE detects a DCI format, which is not necessarily format 2_0, the UE will start monitoring the PDCCH according to the search space set with search space group 1 and stops monitoring PDCCH according to the search space set with search space group 0.

[0091] FIG. 12 illustrates search space group switching according to another embodiment of the present disclosure. FIG. 12 illustrates, in some embodiments, the detected signal does not need to be always DCI format, but it can be other downlink transmissions, such as downlink reference signal CSI-RS or SSB. Moreover, this is suitable for a frame-based equipment (FBE) system where UE is provided by higher layer parameters ChannelAccessMode-rl6 ='semistatic'. FIG. 12 illustrates, in some embodiments, in FBE system the UE will be provided with periodic channel occupancy by semiStaticChannelAccessConfig-rl6, it is also called fixed frame period (FFP). Thus, the UE starts monitoring the PDCCH according to the search space set with search space group 0 always from the first slot of every FFP or every period channel occupancy, if the UE detects a downlink transmission, the UE will start monitoring the PDCCH according to the search space set with search space group 1 and the UE will stop monitoring the PDCCH according to the search space set with search space group 1 from the first slot that is at least P symbols after the last symbol of the detected downlink transmission. Here, the downlink transmission can be DCI format 2_0 or other DCI format or other downlink signal or channel, as illustrated in FIG. 12.

[0092] Commercial interests for some embodiments are as follows. 1. providing a search space group indication. 2. providing a method of search space group switching. 3. providing a good communication performance. 4. providing a high reliability. 5. Some embodiments of the present disclosure are used by 5G-NR chipset vendors, V2X communication system development vendors, automakers including cars, trains, trucks, buses, bicycles, moto-bikes, helmets, and etc., drones (unmanned aerial vehicles), smartphone makers, communication devices for public safety use, AR/VR device maker for example gaming, conference/seminar, education purposes. Some embodiments of the present disclosure are a combination of “techniques/processes” that can be adopted in 3GPP specification to create an end product. Some embodiments of the present disclosure could be adopted in the 5G NR unlicensed band communications. Some embodiments of the present disclosure propose technical mechanisms.

[0093] FIG. 13 is a block diagram of an example system 700 for wireless communication according to an embodiment of the present disclosure. Embodiments described herein may be implemented into the system using any suitably configured hardware and/or software. FIG. 13 illustrates the system 700 including a radio frequency (RF) circuitry 710, a baseband circuitry 720, an application circuitry 730, a memory/storage 740, a display 750, a camera 760, a sensor 770, and an input/output (I/O) interface 780, coupled with each other at least as illustrated. The application circuitry 730 may include a circuitry such as, but not limited to, one or more single -core or multi-core processors. The processors may include any combination of general-purpose processors and dedicated processors, such as graphics processors, application processors. The processors may be coupled with the memory/storage and configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems running on the system. [0094] The baseband circuitry 720 may include circuitry such as, but not limited to, one or more single core or multi-core processors. The processors may include a baseband processor. The baseband circuitry may handle various radio control functions that enables communication with one or more radio networks via the RF circuitry. The radio control functions may include, but are not limited to, signal modulation, encoding, decoding, radio frequency shifting, etc. In some embodiments, the baseband circuitry may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. In various embodiments, the baseband circuitry 720 may include circuitry to operate with signals that are not strictly considered as being in a baseband frequency. For example, in some embodiments, baseband circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency. The RF circuitry 710 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. In various embodiments, the RF circuitry 710 may include circuitry to operate with signals that are not strictly considered as being in a radio frequency. For example, in some embodiments, RF circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

[0095] In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of the RF circuitry, the baseband circuitry, and/or the application circuitry. As used herein, “circuitry” may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or a memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the electronic device circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, some or all of the constituent components of the baseband circuitry, the application circuitry, and/or the memory/storage may be implemented together on a system on a chip (SOC). The memory/storage 740 may be used to load and store data and/or instructions, for example, for system. The memory/storage for one embodiment may include any combination of suitable volatile memory, such as dynamic random access memory (DRAM)), and/or non-volatile memory, such as flash memory.

[0096] In various embodiments, the I/O interface 780 may include one or more user interfaces designed to enable user interaction with the system and/or peripheral component interfaces designed to enable peripheral component interaction with the system. User interfaces may include, but are not limited to a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. Peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power supply interface. In various embodiments, the sensor 770 may include one or more sensing devices to determine environmental states and/or location first information related to the system. In some embodiments, the sensors may include, but are not limited to, a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, the baseband circuitry and/or RF circuitry to communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite. In various embodiments, the display 750 may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system 700 may be a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, an ultrabook, a smartphone, a AR/VR glasses, etc. In various embodiments, system may have more or less components, and/or different architectures. Where appropriate, methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

[0097] A person having ordinary skill in the art understands that each of the units, algorithm, and steps described and disclosed in the embodiments of the present disclosure are realized using electronic hardware or combinations of software for computers and electronic hardware. Whether the functions run in hardware or software depends on the state of application and design requirement for a technical plan. A person having ordinary skill in the art can use different ways to realize the function for each specific application while such realizations should not go beyond the scope of the present disclosure. It is understood by a person having ordinary skill in the art that he/she can refer to the working processes of the system, device, and unit in the above-mentioned embodiment since the working processes of the above-mentioned system, device, and unit are basically the same. For easy description and simplicity, these working processes will not be detailed. It is understood that the disclosed system, device, and method in the embodiments of the present disclosure can be realized with other ways. The above-mentioned embodiments are exemplary only. The division of the units is merely based on logical functions while other divisions exist in realization. It is possible that a plurality of units or components are combined or integrated in another system. It is also possible that some characteristics are omitted or skipped. On the other hand, the displayed or discussed mutual coupling, direct coupling, or communicative coupling operate through some ports, devices, or units whether indirectly or communicatively by ways of electrical, mechanical, or other kinds of forms. The units as separating components for explanation are or are not physically separated. The units for display are or are not physical units, that is, located in one place or distributed on a plurality of network units. Some or all of the units are used according to the purposes of the embodiments. Moreover, each of the functional units in each of the embodiments can be integrated in one processing unit, physically independent, or integrated in one processing unit with two or more than two units.

[0098] If the software function unit is realized and used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical plan proposed by the present disclosure can be essentially or partially realized as the form of a software product. Or, one part of the technical plan beneficial to the conventional technology can be realized as the form of a software product. The software product in the computer is stored in a storage medium, including a plurality of commands for a computational device (such as a personal computer, a server, or a network device) to run all or some of the steps disclosed by the embodiments of the present disclosure. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk, or other kinds of media capable of storing program codes.

[0099] While the present disclosure has been described in connection with what is considered the most practical and preferred embodiments, it is understood that the present disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

What is claimed is:

1. A method of communication of a user equipment (UE), comprising: receiving, by the UE, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

2. The method of claim 1, wherein the first information comprises a first indication field, and the first indication field indicates a first target search space group.

3. The method of claim 2, wherein the first indication field has 1 bit, and a value of the 1 bit corresponds to a first target search space group index of the first target search space group.

4. The method of claim 2 or 3, wherein a location of the first indication field corresponds to the first serving cell.

5. The method of claim 2 or 3, wherein a location of the first indication field corresponds to a first cell group, and the first cell group comprises the first serving cell.

6. The method of any one of claims 2 to 5, wherein the correspondence between the first indication field and the first serving cell is indicated by a second information.

7. The method of claim 6, wherein the second information comprises a parameter, SlotF ormatlndicator IE.

8. The method of claim 6 or 7, wherein the second information associates a position of the first indication field in the first information with an identity of the first serving cell.

9. The method of claim 6 or 7, wherein the second information associates a position of the first indication field in the first information with an identity of the first cell group.

10. The method of claim 9, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceS witchingGroup-r 16.

11. The method of any one of claims 1 to 10, wherein the first information comprises a downlink control information (DCI) format 2_0.

12. The method of any one of claims 2 to 11 , wherein the UE starts to monitor the first target search space group from a first slot.

13. The method of claim 12, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

14. The method of claim 13, wherein the first symbol is the last symbol of a physical downlink control channel (PDCCH) that carries the first information.

15. The method of any one of claims 1 to 14, wherein if the UE is monitoring PDCCH according to search space set with the first target space group, the UE starts monitoring PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or a first group of serving cells, from a second slot.

16. The method of claim 15, wherein the second target search space group is different from the first target search space group.

17. The method of claim 13, wherein a second symbol is the last symbol of a remaining channel occupancy duration for a given serving cell.

18. The method of claim 17, wherein the given serving cell is the first serving cell.

19. The method of claim 17, wherein the given serving cell is a second serving cell.

20. The method of claim 19, wherein the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell is different from that of the first serving cell.

21. The method of claim 13, wherein a second symbol is the last symbol of a slot where a given timer expires.

22. The method of claim 21, wherein the given timer is a timer of the first serving cell.

23. The method of claim 21, wherein the given timer is a timer of a third serving cell.

24. The method of claim 21, wherein the given timer is a timer of the first cell group.

25. The method of claim 23, wherein the third serving cell and the first serving cell are in the first cell group, and the timer of the third serving cell expires in a different slot than that the timer of the first serving cell expires.

26. The method of claim 13 or 17, wherein the given interval is a length of P symbols, where P is an integer.

27. The method of claim 26, wherein the P symbols are derived based on a reference subcarrier spacing (SCS).

28. The method of claim 27, wherein the reference SCS is a SCS of the first serving cell.

29. The method of claim 27, wherein the reference SCS is a SCS of a fourth serving cell.

30. The method of claim 27, wherein the reference SCS has a pre -defined value.

31. The method of claim 30, wherein the pre-defined value is 15 kHz or 30Khz or 60Khz

32. The method of claim 29, wherein the fourth serving cell and the first serving cell are in the first cell group, and the fourth serving cell has a different SCS from that of the first serving cell.

33. The method of any one of claims 1 to 11, wherein the UE cannot monitor a PDCCH according to search space sets with more than one search space group.

34. A method of communication of a UE, comprising at least one of the followings: a) if a UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if a UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in the DCI format 2_0 is 0; or c) if a UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the first slot where a timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell that is indicated by the DCI format 2_0.

35. The method of claim 34, wherein the first indication field comprises a search space switching field.

36. The method of claim 34 or 35, wherein the first indication field has 1 bit, whose value is 0 or 1.

37. The method of any one of claims 34 to 36, wherein a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell.

38. The method of claim 37, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell is provided by a parameter, SlotF ormatlndicator IE.

39. A method of communication of a UE, comprising at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is l; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on a first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration.

40. The method of claim 39, wherein the first indication field comprises a search space switching field.

41. The method of claim 39 or 40, wherein the first indication field has 1 bit, whose value is 0 or 1.

42. The method of any one of claims 39 to 41, wherein a location of the first indication field in the DCI format 2_0 corresponds to the first group or a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell

43. The method of claim 42, wherein the first group comprises the first group serving cells.

44. The method of claim 43, wherein the first serving cell belongs to the first group.

45. The method of claim 43, wherein the first group has a group index.

46. The method of any one of claims 42 to 45, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first group is provided by a parameter, SlotFormat Indicator IE, and the location of the first indication field in the DCI format 2_0 corresponds to the group index of the first group.

47. The method of any one of claims 42 to 45, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell and the correspondence between the first group and the first serving cell are provided by a parameter, SlotF ormatlndicator IE.

48. The method of any one of claims 39 to 46, wherein a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells.

49. The method of any one of claims 39 to 46, wherein a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells.

50. The method of any one of claims 39 to 46, wherein a symbol duration of the P symbols is based on a pre-defined SCS.

51. The method of claim 50, wherein the pre-defined SCS is 15 khz or 30 Khz or 60 Khz.

52. The method of any one of claims 39 to 49, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

53. The method of any one of claims 39 to 49, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

54. The method of any one of claims 39 to 51 , wherein the reference slot is the slot where a timer of the first cell group expires.

55. The method of any one of claims 39 to 51, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

56. The method of any one of claims 39 to 51, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

57. The method of any one of claims 39 to 52, wherein the first remaining channel occupancy duration is indicated by DCI format 2_0.

58. The method of any one of claims 39 to 52, wherein the UE is provided with a parameter, searchSpaceS witchingGroupList-r 16.

59. A method of communication of a UE, comprising: if the UE detects a first information, the UE starts monitoring a PDCCH according to search space set with a first target search space group.

60. The method of claim 59, wherein the first information comprises a first DCI format.

61. The method of claim 59 or 60, wherein the first DCI format is detected by the UE by monitoring the PDCCH according to search space set with search space group index 0.

62. The method of claim 59 or 60, wherein the first DCI format is detected by the UE by monitoring the PDCCH in any search space set.

63. The method of claim 59, wherein the first information comprises a downlink signal or channel or downlink transmission.

64. The method of claim 63, wherein the downlink signal or channel or downlink transmission comprises a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS).

65. The method of any one of claims 59 to 64, wherein the first target search space group comprises search space group index 1.

66. The method of any one of claims 59 to 65, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first serving cell.

67. The method of any one of claims 59 to 65, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first group of serving cells (a first cell group).

68. The method of claim 67, wherein the first cell group comprises the first serving cell.

69. The method of claim 68, wherein the first serving cell associated with the first cell group is configured by a second information.

70. The method of claim 69, wherein the second information comprises a parameter, SlotFormat Indicator IE.

71. The method of claim 69 or 70, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-r 16.

72. The method of any one of claims 59 to 71, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group from a first slot.

73. The method of claim 72, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

74. The method of claim 73, wherein the first symbol is the last symbol of the PDCCH that carries the first information.

75. The method of claim 72, wherein the first symbol is the last symbol of the signal or channel or downlink transmission that carries the first information.

76. The method of any one of claims 59 to 75, wherein if a UE is monitoring the PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or the first group of serving cells, from a second slot.

77. The method of claim 76, wherein the second target search space group comprises search space group index 0.

78. The method of claim 76 or 77, wherein the second slot is the earliest slot that is at least the given interval after a second symbol.

79. The method of claim 78, wherein the second symbol is the last symbol of a first remaining channel occupancy duration.

80. The method of claim 79, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of the first serving cell.

81. The method of claim 79, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

82. The method of claim 79, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

83. The method of any one of claims 79 to 82, wherein the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0, or slot format indication (SFI)-index field in the DCI format 2_0, or maximum channel occupancy time provided in a parameter, semiStaticChannel AccessConfig-r 16.

84. The method of claim 78, wherein the second symbol is the last symbol of a reference slot.

85. The method of claim 84, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

86. The method of claim 84, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

87. The method of claim 84, wherein the reference slot is the slot where a timer of the first cell group expires.

88. The method of claim 84, wherein the reference slot is a slot where a timer of the first serving cell expires.

89. The method of any one of claims 73 to 84, wherein the given interval is a length of P symbols, where P is an integer.

90. The method of claim 85, wherein a symbol duration of the P symbols is based on a reference SCS.

91. The method of claim 86, wherein the reference SCS is a SCS of the first serving cell.

92. The method of claim 86, wherein the reference SCS has a pre -defined value.

93. The method of claim 92, wherein the pre -defined value is 15Khz or 30Khz or 60Khz.

94. The method of claim 86, wherein the reference SCS is a SCS of a second serving cell.

95. The method of claim 94, wherein the second serving cell and the first serving cell are in the same cell group, and the second serving cell has a different SCS from that of the first serving cell.

96. The method of claim 78 or 79, wherein the second slot is at the earliest slot in every periodic channel occupancy, and the periodic channel occupancy is provided by a parameter, semiStaticChannel AccessConfig-r 16.

97. The method of any one of claims 59 to 96, wherein the UE is provided by a higher layer parameter, ChanneIAccessMode-rl6 ='semistatic', by a system information block 1 (SIB1) or a dedicated configuration.

98. A method of communication of a UE, comprising at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with the search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where a timer expires or after the last symbol of the remaining channel occupancy duration for the first serving cell.

99. The method of claim 98, wherein the remaining channel occupancy duration is indicated by a DCI format 2_0.

100. The method of claim 98, wherein the remaining channel occupancy duration is indicated by SFI-index field in the DCI format 2_0.

101. The method of claim 98, wherein the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0.

102. The method of claim 98, wherein the remaining channel occupancy duration is indicated by a parameter, semiStaticChannelAccessConfig-rl6.

103. The method of any one of claims 98 to 102, wherein the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', by a SIB1 or a dedicated configuration.

104. The method of any one of claims 98 to 103, wherein the UE is not provided with a parameter, SearchSpaceSwitchTrigger-r 16.

105. A method of communication of a UE, comprising at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space set with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the first group of serving cells, and/or on a first serving cell, at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after the last symbol of a first remaining channel occupancy duration.

106. The method of claim 105, wherein the first serving cell belongs to the first group of serving cells.

107. The method of claim 105 or 106, wherein the first group of serving cells is provided by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-rl6.

108. The method of any one of claims 105 to 107, wherein a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells.

109. The method of any one of claims 105 to 107, wherein a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells.

110. The method of any one of claims 105 to 107, wherein a symbol duration of the P symbols is based on a pre-defined SCS.

111. The method of claim 110, wherein the pre-defined SCS is 15 khz or 30 khz or 60 khz

112. The method of any one of claims 105 to 111, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

113. The method of any one of claims 105 to 111, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

114. The method of any one of claims 105 to 111 , wherein the reference slot is the slot where a timer of the first serving cell expires.

115. The method of any one of claims 105 to 111 , wherein the reference slot is the slot where a timer of the first cell group expires.

116. The method of claim 105, wherein the timer of the first cell group is provided by RRC configuration.

117. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set.

118. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1.

119. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set.

120. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set.

121. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1.

122. The method of claim 116, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set.

123. The method of claim 105 to 122, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

124. The method of claim 105 to 122, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

125. The method of claim 105 to 124, wherein the first remaining channel occupancy duration is indicated by a DCI format 2_0.

126. The method of claim 105 to 124, wherein the first remaining channel occupancy duration is indicated by a SFI-index field in the DCI format 2_0.

127. The method of claim 105 to 124, wherein the first remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0.

128. The method of claim 105 to 124, wherein the first remaining channel occupancy duration is indicated by a parameter, semiStaticChannelAccessConfig-rl6.

129. The method of claim 105 to 128, wherein the UE is provided with a parameter, searchSpaceSwitchingGroupList-rl6.

130. The method of claim 105 to 129, wherein the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic' by a SIB1 or a dedicated configuration.

131. The method of claim 105 to 130, wherein the UE is not provided with a parameter, SearchSpaceSwitchTrigger-r 16.

132. A method of communication of a base station (BS), comprising: transmitting, by the BS, a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

133. The method of claim 132, wherein the first information comprises a first indication field, and the first indication field indicates a first target search space group.

134. The method of claim 133, wherein the first indication field has 1 bit, and a value of the 1 bit corresponds to a first target search space group index of the first target search space group.

135. The method of claim 133 or 134, wherein a location of the first indication field corresponds to the first serving cell.

136. The method of claim 133 or 134, wherein a location of the first indication field corresponds to a first cell group, and the first cell group comprises the first serving cell.

137. The method of any one of claims 133 to 136, wherein the correspondence between the first indication field and the first serving cell is indicated by a second information.

138. The method of claim 137, wherein the second information comprises a parameter, SlotFormat Indicator IE.

139. The method of claim 137 or 138, wherein the second information associates a position of the first indication field in the first information with an identity of the first serving cell.

140. The method of claim 137 or 138, wherein the second information associates a position of the first indication field in the first information with an identity of the first cell group.

141. The method of claim 140, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceS witchingGroup-r 16.

142. The method of any one of claims 132 to 141, wherein the first information comprises a downlink control information (DCI) format 2_0.

143. The method of any one of claims 133 to 142, wherein the first target search space group is started to be monitored from a first slot.

144. The method of claim 143, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

145. The method of claim 144, wherein the first symbol is the last symbol of a physical downlink control channel (PDCCH) that carries the first information.

146. The method of any one of claims 132 to 145, wherein if the UE is monitoring a PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or a first group of serving cells, from a second slot.

147. The method of claim 146, wherein the second target search space group is different from the first target search space group.

148. The method of claim 144, wherein a second symbol is the last symbol of a remaining channel occupancy duration for a given serving cell.

149. The method of claim 148, wherein the given serving cell is the first serving cell.

150. The method of claim 148, wherein the given serving cell is a second serving cell.

151. The method of claim 150, wherein the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell is different from that of the first serving cell.

152. The method of claim 144, wherein a second symbol is the last symbol of a slot where a given timer expires.

153. The method of claim 152, wherein the given timer is a timer of the first serving cell.

154. The method of claim 152, wherein the given timer is a timer of a third serving cell.

155. The method of claim 152, wherein the given timer is a timer of the first cell group.

156. The method of claim 154, wherein the third serving cell and the first serving cell are in the same cell group, and the timer of the third serving cell expires in a different slot than that the timer of the first serving cell expires.

157. The method of claim 144, wherein the given interval is a length of P symbols, where P is an integer.

158. The method of claim 157, wherein the P symbols are derived based on a reference subcarrier spacing (SCS).

159. The method of claim 158, wherein the reference SCS is a SCS of the first serving cell.

160. The method of claim 158, wherein the reference SCS is a SCS of a fourth serving cell.

161. The method of claim 158, wherein the reference SCS has a pre-defined value.

162. The method of claim 161, wherein the pre-defined value is 15 kHz or 30Khz or 60Khz.

163. The method of claim 160, wherein the fourth serving cell and the first serving cell are in the same cell group, and the fourth serving cell has a different SCS from that of the first serving cell.

164. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to control the transceiver to receive a first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

165. The UE of claim 164, wherein the first information comprises a first indication field, and the first indication field indicates a first target search space group.

166 The UE of claim 165, wherein the first indication field has 1 bit, and a value of the 1 bit corresponds to a first target search space group index of the first target search space group.

167. The UE of claim 165 or 166, wherein a location of the first indication field corresponds to the first serving cell.

168. The UE of claim 165 or 166, wherein a location of the first indication field corresponds to a first cell group, and the first cell group comprises the first serving cell.

169. The UE of any one of claims 165 to 168, wherein the correspondence between the first indication field and the first serving cell is indicated by a second information.

170. The UE of claim 169, wherein the second information comprises a parameter, SlotF ormatlndicator IE.

171. The UE of claim 169 or 170, wherein the second information associates a position of the first indication field in the first information with an identity of the first serving cell.

172. The UE of claim 169 or 170, wherein the second information associates a position of the first indication field in the first information with an identity of the first cell group.

173. The UE of claim 170, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-r 16.

174. The UE of any one of claims 164 to 173, wherein the first information comprises a downlink control information (DCI) format 2_0.

175. The UE of any one of claims 165 to 174, wherein the UE starts to monitor the first target search space group from a first slot.

176. The UE of claim 175, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

177. The UE of claim 176, wherein the first symbol is the last symbol of a physical downlink control channel (PDCCH) that carries the first information.

178. The UE of any one of claims 164 to 177, wherein if the UE is monitoring a PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or a first group of serving cells, from a second slot.

179. The UE of claim 202, wherein the second target search space group is different from the first target search space group.

180. The UE of claim 176, wherein a second symbol is the last symbol of a remaining channel occupancy duration for a given serving cell.

181. The UE of claim 180, wherein the given serving cell is the first serving cell.

182. The UE of claim 180, wherein the given serving cell is a second serving cell.

183 The UE of claim 181, wherein the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell is different from that of the first serving cell.

184. The UE of claim 176, wherein a second symbol is the last symbol of a slot where a given timer expires.

185. The UE of claim 184, wherein the given timer is a timer of the first serving cell.

186. The UE of claim 184, wherein the given timer is a timer of a third serving cell.

187. The UE of claim 184, wherein the given timer is a timer of the first cell group.

188. The UE of claim 186, wherein the third serving cell and the first serving cell are in the same cell group, and the timer of the third serving cell expires in a different slot than that the timer of the first serving cell expires.

189. The UE of claim 176, 180, or 184, wherein the given interval is a length of P symbols, where P is an integer.

190. The UE of claim 189, wherein the P symbols are derived based on a reference subcarrier spacing (SCS).

191. The UE of claim 190, wherein the reference SCS is a SCS of the first serving cell.

192. The UE of claim 190, wherein the reference SCS is a SCS of a fourth serving cell.

193. The UE of claim 190, wherein the reference SCS has a pre -defined value.

194. The UE of claim 193, wherein the pre-defined value is 15 kHz or 30Khz or 60Khz.

195. The UE of claim 192, wherein the fourth serving cell and the first serving cell are in the same cell group, and the fourth serving cell has a different SCS from that of the first serving cell.

196. The UE of any one of claims 164 to 174, wherein the UE cannot monitor a PDCCH according to search space sets with more than one search space group.

197. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is 1 ; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1 , on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in the DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1, on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the first slot where a timer expires or after a last symbol of a remaining channel occupancy duration for the first serving cell that is indicated by the DCI format 2_0.

198. The UE of claim 197, wherein the first indication field comprises a search space switching field.

199. The UE of claim 197 or 198, wherein the first indication field has 1 bit, whose value is 0 or 1.

200. The UE of any one of claims 197 to 199, wherein a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell.

201. The UE of claim 200, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell is provided by a parameter, SlotFormat Indicator IE.

202. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with a DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and a value of a first indication field in the DCI format 2_0 is l; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 0, and the UE stops monitoring the PDCCH according to search space set with search space group 1, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format 2_0, if the UE detects the DCI format 2_0 in a slot and the value of the first indication field in DCI format 2_0 is 0; or c) if the UE monitors the PDCCH on a first serving cell according to search space sets with group index 1 , the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on first group serving cells at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after a last symbol of a first remaining channel occupancy duration.

203. The UE of claim 202, wherein the first indication field comprises a search space switching field.

204. The UE of claim 202 or 203, wherein the first indication field has 1 bit, whose value is 0 or 1.

205. The UE of any one of claims 202 to 204, wherein a location of the first indication field in the DCI format 2_0 corresponds to the first group or a location of the first indication field in the DCI format 2_0 corresponds to the first serving cell.

206. The UE of claim 205, wherein the first group comprises the first group serving cells.

207. The method of claim 206, wherein the first serving cell belongs to the first group.

208. The UE of claim 206 or 207, wherein the first group has a group index.

209. The UE of any one of claims 205 to 208, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first group is provided by a parameter, SlotFormat Indicator IE, and the location of the first indication field in the DCI format 2_0 corresponds to the group index of the first group.

210. The UE of any one of claims 205 to 208, wherein the correspondence between the location of the first indication field in the DCI format 2_0 and the first serving cell and the correspondence between the first group and the first serving cell are provided by a parameter, SlotF ormatlndicator IE.

211. The UE of any one of claims 202 to 209, wherein a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells.

212. The UE of any one of claims 202 to 209, wherein a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells.

213. The UE of any one of claims 202 to 209, wherein a symbol duration of the P symbols is based on a pre-defined SCS.

214. The UE of claim 213, wherein the pre-defined SCS is 15 khz or 30 Khz or 60 Khz.

215. The method of any one of claims 202 to 212, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

216. The UE of any one of claims 202 to 212, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

217. The UE of any one of claims 202 to 214, wherein the reference slot is the slot where a timer of the first cell group expires.

218. The UE of any one of claims 202 to 214, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

219. The UE of any one of claims 202 to 214, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

220. The UE of any one of claims 202 to 215, wherein the first remaining channel occupancy duration is indicated by DCI format 2_0.

221. The UE of any one of claims 202 to 215, wherein the UE is provided with a parameter, searchSpaceS witchingGroupList-r 16.

222. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform the following: if the UE detects a first information, the UE starts monitoring a PDCCH according to search space set with a first target search space group.

223. The UE of claim 222, wherein the first information comprises a first DCI format.

224. The UE of claim 222 or 223, wherein the first DCI format is detected by the UE by monitoring the PDCCH according to search space set with search space group index 0.

225. The UE of claim 222 or 223, wherein the first DCI format is detected by the UE by monitoring the PDCCH in any search space set.

226. The UE of claim 222, wherein the first information comprises a downlink signal or channel or downlink transmission.

227. The UE of claim 226, wherein the downlink signal or channel or downlink transmission comprises a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS).

228. The UE of any one of claims 222 to 227, wherein the first target search space group comprises search space group index 1.

229. The UE of any one of claims 222 to 228, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first serving cell.

230. The UE of any one of claims 222 to 228, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group on a first group of serving cells (a first cell group).

231. The UE of claim 230, wherein the first cell group comprises the first serving cell.

232. The UE of claim 231, wherein the first serving cell associated with the first cell group is configured by a second information.

233. The UE of claim 231, wherein the second information comprises a parameter, SlotF ormatlndicator IE.

234. The UE of claim 232 or 233, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceS witchingGroup-r 16.

235. The UE of any one of claims 222 to 234, wherein the UE starts monitoring the PDCCH according to search space set with the first target search space group from a first slot.

236. The UE of claim 235, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

237. The UE of claim 236, wherein the first symbol is the last symbol of the PDCCH that carries the first information.

238. The UE of claim 235, wherein the first symbol is the last symbol of the signal or channel or downlink transmission that carries the first information.

239. The UE of any one of claims 222 to 238, wherein if a UE is monitoring the PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or the first group of serving cells, from a second slot.

240. The UE of claim 239, wherein the second target search space group comprises search space group index 0.

241. The UE of claim 239 or 240, wherein the second slot is the earliest slot that is at least the given interval after a second symbol.

242. The UE of claim 241, wherein the second symbol is the last symbol of a first remaining channel occupancy duration.

243. The UE of claim 242, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of the first serving cell.

244. The UE of claim 242, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

245. The UE of claim 242, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

246. The UE of any one of claims 242 to 245, wherein the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0, or slot format indication (SFI)-index field in the DCI format 2_0, or maximum channel occupancy time provided in a parameter, semiStaticChannel AccessConfig-r 16.

247. The UE of claim 241, wherein the second symbol is the last symbol of a reference slot.

248. The UE of claim 247, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

249. The UE of claim 247, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

250. The UE of claim 247, wherein the reference slot is the slot where a timer of the first cell group expires.

251. The UE of claim 247, wherein the reference slot is a slot where a timer of the first serving cell expires.

252. The UE of any one of claims 236 to 247, wherein the given interval is a length of P symbols, where P is an integer.

253. The UE of claim 248, wherein a symbol duration of the P symbols is based on a reference SCS.

254. The UE of claim 249, wherein the reference SCS is a SCS of the first serving cell.

255. The UE of claim 249, wherein the reference SCS is 15 Khz.

256. The UE of claim 249, wherein the reference SCS is a SCS of a second serving cell.

257. The UE of claim 256, wherein the second serving cell and the first serving cell are in the same cell group, and the second serving cell has a different SCS from that of the first serving cell.

258. The UE of claim 241 or 242, wherein the second slot is at the earliest slot in every periodic channel occupancy, and the periodic channel occupancy is provided by a parameter, semiStaticChannel AccessConfig-r 16.

259. The UE of any one of claims 222to 258, wherein the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', by a system information block 1 (SIB1) or a dedicated configuration.

260. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and the UE stops monitoring the PDCCH according to search space set with search space group 0, on a first serving cell at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space sets with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with the search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on the first serving cell at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and stops monitoring the PDCCH according to search space sets with group index 1 , on the serving cell at the beginning of the first slot that is at least P symbols after the last symbol of the slot where a timer expires or after the last symbol of the remaining channel occupancy duration for the first serving cell.

261. The UE of claim 260, wherein the remaining channel occupancy duration is indicated by a DCI format

2_0.

262. The UE of claim 260, wherein the remaining channel occupancy duration is indicated by SFI-index field in the DCI format 2_0.

263. The UE of claim 260, wherein the remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0.

264. The UE of claim 260, wherein the remaining channel occupancy duration is indicated by a parameter, semiStaticChannel AccessConfig-r 16.

265. The UE of any one of claims 260 to 264, wherein the UE is provided by a higher layer parameter, ChannelAccessMode-rl6 ='semistatic', by a SIB1 or a dedicated configuration.

266. The UE of any one of claims 260 to 263, wherein the UE is not provided with a parameter, SearchSpaceSwitchTrigger-r 16.

267. A UE, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform at least one of the followings: a) if the UE is not monitoring a PDCCH according to search space sets with search space group 1 , and if the UE detects a DCI format by monitoring the PDCCH in any search space set, the UE starts monitoring the PDCCH according to search space set with search space group 1, and stops monitoring the PDCCH according to search space set with search space group 0, on a first group of serving cells at a first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; b) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects the DCI format by monitoring the PDCCH according to search space set with search space group 0, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the PDCCH with the DCI format; c) if the UE is not monitoring the PDCCH according to search space sets with search space group 1 , and if the UE detects any downlink signal or channel or downlink transmission, the UE starts monitoring the PDCCH according to search space set with search space group 1 , and the UE stops monitoring the PDCCH according to search space set with search space group 0, on the first group of serving cells at the first slot that is at least P symbols after the last symbol of the downlink signal or channel or downlink transmission; or d) if the UE monitors the PDCCH on the first serving cell according to search space sets with group index 1, the UE starts monitoring the PDCCH on a serving cell according to search space sets with group index 0, and the UE stops monitoring the PDCCH according to search space sets with group index 1 , on the first group of serving cells, and/or on a first serving cell, at the beginning of the first slot that is at least P symbols after the last symbol of a reference slot or after the last symbol of a first remaining channel occupancy duration.

268. The UE of claim 267, wherein the first serving cell belongs to the first group of serving cells.

269. The UE of claim 267 or 268, wherein the first group of serving cells is provided by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceSwitchingGroup-rl6.

270. The UE of any one of claims 267 to 269, wherein a symbol duration of the P symbols is based on the smallest SCS among the serving cells in the first group of serving cells.

271. The UE of any one of claims 267 to 269, wherein a symbol duration of the P symbols is based on the largest SCS among the serving cells in the first group of serving cells.

272. The UE of any one of claims 267 to 269, wherein a symbol duration of the P symbols is based on a pre-defined SCS.

273. The UE of claim 272, wherein the pre-defined SCS is 15 khz or 30 Khz or 60 Khz.

274. The UE of claim 267 to 273, wherein the reference slot is the latest slot where a timer of a serving cell, among the first group of serving cells, expires.

275. The UE of claim 267 to 273, wherein the reference slot is the earliest slot where a timer of a serving cell, among the first group of serving cells, expires.

276. The UE of any one of claims 267 to 273, wherein the reference slot is the slot where a timer of the first serving cell expires.

277. The UE of any one of claims 267 to 273, wherein the reference slot is the slot where a timer of the first cell group expires.

278. The UE of claim 267, wherein the timer of the first cell group is provided by RRC configuration.

279. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set.

280. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1.

281. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first serving cell, if the UE detects a DCI format by monitoring PDCCH in any search space set.

282. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set.

283. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in search space set with search space group 1.

284. The UE of claim 278, the UE sets the timer value to the value provided by searchSpaceSwitchingTimer-rl6 for the first cell group, if the UE detects a DCI format by monitoring PDCCH in any search space set.

285. The UE of claim 267 to 275, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the latest among the first group of serving cells.

286. The UE of claim 267 to 275, wherein the first remaining channel occupancy duration is the remaining channel occupancy duration of a serving cell that ends the earliest among the first group of serving cells.

287. The UE of claim 267 to 286, wherein the first remaining channel occupancy duration is indicated by a DCI format 2_0.

288. The UE of claim 267 to 286, wherein the first remaining channel occupancy duration is indicated by a SFI-index field in the DCI format 2_0.

289. The UE of claim 267 to 286, wherein the first remaining channel occupancy duration is indicated by channel occupancy duration field in the DCI format 2_0.

290. The UE of claim 267 to 286, wherein the first remaining channel occupancy duration is indicated by a parameter, semiStaticChanneIAccessConfig-rl6.

291. The UE of claim 267 to 288, wherein the UE is provided with a parameter, searchSpaceSwitchingGroupList-rl6.

292. The UE of claim 267 to 288, wherein the UE is provided by a higher layer parameter, ChanneIAccessMode-rl6 ='semistatic' by a SIB1 or a dedicated configuration.

293. The UE of claim 267 to 292, wherein the UE is not provided with a parameter, SearchSpaceSwitchTrigger-r 16.

294. A BS, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to control the transceiver to transmit first information, wherein the first information corresponds to search space group monitoring for a first serving cell.

295. The method of claim 294, wherein the first information comprises a first indication field, and the first indication field indicates a first target search space group.

296. The method of claim 295, wherein the first indication field has 1 bit, and a value of the 1 bit corresponds to a first target search space group index of the first target search space group.

297. The method of claim 295 or 296, wherein a location of the first indication field corresponds to the first serving cell.

298. The method of claim 295 or 296, wherein a location of the first indication field corresponds to a first cell group, and the first cell group comprises the first serving cell.

299. The method of any one of claims 295 to 298, wherein the correspondence between the first indication field and the first serving cell is indicated by a second information.

300. The method of claim 299, wherein the second information comprises a parameter, SlotFormat Indicator IE.

301. The method of claim 299 or 300, wherein the second information associates a position of the first indication field in the first information with an identity of the first serving cell.

302. The method of claim 299 or 300, wherein the second information associates a position of the first indication field in the first information with an identity of the first cell group.

303 The method of claim 302, wherein the second information further associates the first cell group with the first serving cell by a parameter, searchSpaceSwitchingGroupList-rl6 and/or a parameter, SearchSpaceS witchingGroup-r 16.

304. The method of any one of claims 294 to 303, wherein the first information comprises a downlink control information (DCI) format 2_0.

305. The method of any one of claims 295 to 304, wherein the first target search space group is started to be monitored from a first slot.

306. The method of claim 305, wherein the first slot is the earliest slot that is at least a given interval after a first symbol.

307. The method of claim 306, wherein the first symbol is the last symbol of a physical downlink control channel (PDCCH) that carries the first information.

308. The method of any one of claims 294 to 307, wherein if the UE is monitoring a PDCCH according to search space set with the first target space group, the UE starts monitoring the PDCCH according to search space set with a second target search space group and stops monitoring the PDCCH according to search space set with the first target search space group, on the first serving cell or a first group of serving cells, from a second slot.

309. The method of claim 308, wherein the second target search space group is different from the first target search space group.

310. The method of claim 306, wherein a second symbol is the last symbol of a remaining channel occupancy duration for a given serving cell.

311. The method of claim 310, wherein the given serving cell is the first serving cell.

312. The method of claim 310, wherein the given serving cell is a second serving cell.

313. The method of claim 312, wherein the second serving cell and the first serving cell are in the first cell group and the remaining channel occupancy duration for the second serving cell is different from that of the first serving cell.

314. The method of claim 306, wherein a second symbol is the last symbol of a slot where a given timer expires.

315. The method of claim 314, wherein the given timer is a timer of the first serving cell.

316. The method of claim 314, wherein the given timer is a timer of a third serving cell.

317. The method of claim 314, wherein the given timer is a timer of the first cell group.

318. The method of claim 316, wherein the third serving cell and the first serving cell are in the same cell group, and the timer of the third serving cell expires in a different slot than that the timer of the first serving cell expires.

319. The method of claim 306 or 310, wherein the given interval is a length of P symbols, where P is an integer.

320. The method of claim 319, wherein the P symbols are derived based on a reference subcarrier spacing (SCS).

321. The method of claim 320, wherein the reference SCS is a SCS of the first serving cell.

322. The method of claim 320, wherein the reference SCS is a SCS of a fourth serving cell.

323. The method of claim 320, wherein the reference SCS has a pre-defined value.

324. The method of claim 323, wherein the pre-defined value is 15 kHz or 30Khz or 60Khz.

325. The method of claim 322, wherein the fourth serving cell and the first serving cell are in the same cell group, and the fourth serving cell has a different SCS from that of the first serving cell.

326. A non-transitory machine -readable storage medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 163.

327. A chip, comprising: a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the method of any one of claims 1 to 163.

328. A computer readable storage medium, in which a computer program is stored, wherein the computer program causes a computer to execute the method of any one of claims 1 to 163.

329. A computer program product, comprising a computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 163.

330. A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 163.