WO2023248075A1 - Methods and apparatus of determining tci state for l1/l2 based inter-cell handover - Google Patents

Abstract

Methods and systems for applying a transmission configuration indicator (TCI) state when a user equipment (UE) switches serving cells is provided. For example, the UE receives, from a first serving cell, an indication to switch connection to a second serving cell. The UE receives a set of radio resource control (RRC) configurations and a first TCI state for switching to a second serving cell. The UE switches connection from the first serving cell to the second serving cell based on the RRC configurations and applies the first TCI state on reception or transmission channels of the second serving cell. In some embodiments, the UE is configured to operate a Level1/Level 2 inter-cell handover. In some embodiments, when the handover condition is met, the UE performs handover with a physical cell ID to a serving cell and determines a TCI state for receiving downlink channels/RS and/or transmitting uplink channel/RS after handover.

Description

METHODS AND APPARATUS OF DETERMINING TCI STATE

FOR L1/L2 BASED INTER-CELL HANDOVER

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63/366,821, filed on June 22, 2022, the contents of which are herein incorporated by reference in their entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to transmission configuration indicator (TCI) state indication of transmission configuration indicators and inter-cell mobility. In particular, the present disclosure describes methods for indicating and applying TCI state on downlink and uplink channels and/or reference signals during inter-cell mobility in a unified TCI framework or during user equipment-based conditional handover.

BACKGROUND

[0003] New radio (NR) and 5G systems supports the function of radio resource management (RRM) measurements. For instance, a system can request a user equipment (UE) to measure synchronization signal blocks (SSBs), physical broadcast channel (PBCH) blocks, and/or channel state information reference signals (CSI-RSs) for mobility of neighboring cells. The user equipment can report the measurement results to the system, which the system uses to determine inter-cell mobility. The system provides RRM measurement configuration to the UE through radio resource control (RRC), where the RRM measurement configuration includes a list of measurement objects, reporting configurations, measurement identities, quantity configurations and/or measurement gap configurations.

[0004] The NR systems support RRC-based handover for inter-cell mobility. In a general base station-controlled handover procedure, the serving base station (gNB) firsts sends a handover command to the UE through RRC signaling. The handover command delivers RRC reconfiguration information and information of target cell to the UE. Upon receiving the handover command, the UE starts the random-access procedure towards the target cell as indicated in the handover command. Through the random access, the UE can build the connection with the target cell. When the connection with the new cell is completed, the UE can send the handover message to the system to conclude the procedure of handover. However, using RRC in such instances use of Layer 3 (e.g., a network layer) to transmit data between nodes in the systems, which results in increased latency and signal overhead compared to not using Layer 3. Thus, systems and methods for RRC-based handover for inter-cell mobility that do not have a large latency and signal overhead are necessary.

SUMMARY

[0005] The present disclosure is related to systems and methods for transmission configuration (TCI) state indication and switching for inter-cell mobility. For instance, the systems and methods may apply a TCI state on downlink (DL) and/or uplink (UL) channels of a serving cell. The systems and methods may do this during Layer 1 (L1) and Layer 2 (L2) inter-cell mobility in a unified TCI framework and/or user equipmentbased conditional handover.

[0006] For example, in some embodiments, a gNB of a first serving cell can indicate to UE to switch from the first serving cell to a second serving cell. The UE can receive with a set of RRC configurations from the second serving cell and a first TCI state that is associated with the second serving cell. When the UE is requested to switch to the second serving cell, the UE can be requested to apply the RRC configurations associated with the second serving cell and the first TCI state on the reception of downlink channels of the second serving cell and/or transmission of uplink channels towards to the second serving cell.

[0007] In some embodiments, a UE can receive, from a first serving cell, an indication to switch connection to a second serving cell. The indication can be a switch or handover command. The UE can also receive a set of RRC configurations and a first TCI state for switching to the second serving cell. The UE may receive the first TCI state via a media access control (MAC) control element (CE) message or via downlink control information (DCI) signaling. The UE switches connection from the first serving cell to the second serving cell based on the RRC configurations and applies the first TCI state on reception or transmission channels of the second serving cell. For example, the UE can apply the first TCI state on the reception of downlink channels of the second serving cell and/or on the transmission of uplink channels of the second serving cell.

[0008] In further embodiments, the UE can receive a list of joint TCI states associated with the second serving cell. Each TCI state may contain one or more reference signals (RSs) providing reference for (quasi- co-location) QCL configuration for reception of downlink channels in the joint TCI state, and the first joint TCI state in the list of joint TCI states is the first TCI state received by the UE. The RSs can provide reference for determining a transmission spatial filter for uplink transmission. The UE can receive a request to apply the first TCI state on reception or transmission of common physical downlink control channel (PDCCH) and corresponding physical downlink shared channel (PDSCH).

[0009] In some embodiments, the present method can be implemented by a tangible, non-transitory, computer-readable medium having processor instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform one or more aspects/features of the method described herein. In other embodiments, the present method can be implemented by a system comprising a computer processor and a non-transitory computer-readable storage medium storing instructions that when executed by the computer processor cause the computer processor to perform one or more actions of the method described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] To describe the technical solutions in the implementations of the present disclosure more clearly, the following briefly describes the accompanying drawings. The accompanying drawings show merely some aspects or implementations of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0011] Fig. 1 is flowchart depicting a process for determining inter-cell mobility using RRC signaling used by prior art.

[0012] Fig. 2 is a schematic diagram of a wireless communication system in accordance with one or more implementations of the present disclosure. [0013] Fig. 3 is a schematic block diagram of a terminal device in accordance with one or more implementations of the present disclosure.

[0014] Fig. 4 is a flowchart of a method in accordance with one or more implementations of the present disclosure.

[0015] Fig. 5 is a flowchart of a method in accordance with one or more implementations of the present disclosure.

DETAILED DESCRIPTION

[0016] To describe the technical solutions in the implementations of the present disclosure more clearly, the following briefly describes the accompanying drawings. The accompanying drawings show merely some aspects or implementations of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0017] Fig. 1 is flowchart depicting a process for determining inter-cell mobility using RRC signaling used by prior art. For instance, a UE can receive 101 an RRM measurement configuration from an NR system using RRC. The measurement configuration can include a list of measurement object configurations, reporting configurations, measurement identities, quantity configurations and measurement gap configuration. The measurement object configurations can provide the configuration of SSBs, PBCH block, and/or CSI-RSs for mobility of one or more cells at one particular frequency point. Considering that the UE does not need to measure all the SSBs of one cell, the UE can receive a configuration of SS/PBCH Block Measurement Timing Configuration (SMTC) and only measures the SSBs within a SMTC.

[0018] Based on the RRM measurement configuration, the UE can measure 103parameters (e.g., Layer 3 reference signal received power [L3-RSRP], Layer 3 reference signal received quality [L3-RSRQ], or Layer 3 reference signal strength indicator [L3-RSSI]) of the SSBs, PBCH block, and/or CSI-RSs for mobility of some target cells provided in the RRM configuration. The UE can report 105 the measurement result to the NR system using RRC signaling. NR system can also support the function of measuring L1-RSRP of SSBs associated with a physical layer cell identity (PCI) that is different from that of the serving cell. The UE can receive 107 a request to measure multiple SSBs and report K = 1 , 2, 3 or 4 indicators of those SSBs and corresponding L1-RSRP measurement(s). The UE can report 109 these measurement results in uplink control information (UPI). For this, the NR system requires that the SSB associated with a PCI that is different from that of the serving cell is on same frequency and uses the same subcarrier spacing as the SSB of the serving cell. The NR system also needs to assume that the SSB associated with a different PCI has time synchronization with the serving cell.

[0019] Fig. 2 is a schematic diagram of a wireless communication system 200 in accordance with one or more implementations of the present disclosure. The wireless communication system 200 can implement the inter-cell mobility systems and methods discussed herein. As shown in Fig. 2, the wireless communications system 200 can include network devices (or base stations) 201 spaced apart in different serving cells 207 of a geographical region. Examples of a network device 201 A (201 B, 201 C) include a base transceiver station (Base Transceiver Station, BTS), a NodeB (NodeB, NB), an evolved Node B (eNB or eNodeB), a Next Generation NodeB (gNB or gNode B), a Wireless Fidelity (Wi-Fi) access point (AP), etc. In some embodiments, each network device 201 can include a relay station, an access point, an in-vehicle device, a wearable device, and the like. Each network device 201 can include wireless connection devices for communication networks such as: a Global System for Mobile Communications (GSM) network, a Code Division Multiple Access (CDMA) network, a Wideband CDMA (WCDMA) network, an LTE network, a cloud radio access network (Cloud Radio Access Network, CRAN), an Institute of Electrical and Electronics Engineers (IEEE) 802.11-based network (e.g., a Wi-Fi network), an Internet of Things (loT) network, a device-to-device (D2D) network, a next-generation network (e.g., a 5G network), a future evolved public land mobile network (Public Land Mobile Network, PLMN), or the like. A 5G system or network can be referred to as an NR system or network.

[0020] In Fig. 2, the wireless communications system 200 also includes a terminal device 203. The terminal device 203 can be an end-UE configured to facilitate wireless communication. The terminal device 203 can be configured to wirelessly connect to a network device 201 A (via, e.g., via a wireless channel 205A) according to one or more corresponding communication protocols/standards. The terminal device 203 may be mobile or fixed. The terminal device 203 can be a user equipment (UE), an access terminal, a user unit, a user station, a mobile site, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communications device, a user agent, or a user apparatus. Examples of the terminal device 203 include a modem, a cellular phone, a smartphone, a cordless phone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having a wireless communication function, a computing device or another processing device connected to a wireless modem, an in-vehicle device, a wearable device, an Internet-of-Things (loT) device, a device used in a 5G network, a device used in a public land mobile network, or the like. For illustrative purposes, Fig. 2 illustrates only one network device 201 and one terminal device 203 in the wireless communications system 200. However, in some instances, the wireless communications system 200 can include additional network device 201 and/or terminal device 203.

[0021] The terminal device 203 can be connected to a mobility server 209 via a wireless channel 205A to a network device 201 A, which is connected to the mobility server 209 via a wireless channel 205B. The mobility server 209 can communicate with the terminal device 203 via a first network device 201A. The mobility server 209 can send indications to the terminal device 203 to switch its connection between serving cells 207. For example, the mobility server 209 can cause the terminal device 203 to switch its connection from the first network device 201A of a first serving cell 207A (collectively referred to as the first serving cell 207A for simplicity) to a second network device 201 B of a second serving cell 207B (collectively referred to as the second serving cell 207B for simplicity).

[0022] The terminal device 203 can receive a set of RRC configurations from the second serving cell 207B. Examples of RRC configurations include states such as RRCJDLE, RRC_CONNECTED, and RRCJNACTIVE. The terminal device 203 can be provided with a first TCI state that is associated with the second serving cell 207B. The first TCI state can contain one or more RSs providing reference for QCL configuration for reception of downlink channels/reference signals. The RS(s)can also provide reference for QCL-typeD, which is used for determining an uplink transmission spatial filter for uplink transmission. When the terminal device 203 is requested to switch the second serving cell 207B, the terminal device 203 can apply the RRC configurations associated with the second serving cell 207B and apply the first TCI state on the reception of downlink channels of the second serving cell 207B and/or transmission of uplink channels towards to the second serving cell 207B.

[0023] The terminal device 203 can switch between serving cells 207 connected to the mobility server 209 upon request. Further methods employed by the mobility server 209 for inter-cell mobility are described in relation to the methods illustrated in Figs. 4-5.

[0024] Fig. 3 is a schematic block diagram of a terminal device 203 (e.g., which can implement the methods discussed herein) in accordance with one or more implementations of the present disclosure. As shown, the terminal device 203 includes a processing unit 310 (e.g., a DSP, a CPU, a GPU, etc.) and a memory 320. The processing unit 310 can be configured to implement instructions that correspond to the method 400 of Fig. 4, the method 500 of Fig. 5, and/or other aspects of the implementations described above. It should be understood that the processor 310 in the implementations of this technology may be an integrated circuit chip and has a signal processing capability. During implementation, the steps in the foregoing method may be implemented by using an integrated logic circuit of hardware in the processor 310 or an instruction in the form of software. The processor 310 may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or transistor logic device, and a discrete hardware component.

[0025] The general-purpose processor 310 may be a microprocessor, or the processor 310 may be alternatively any conventional processor or the like. The steps in the methods disclosed with reference to the implementations of this technology may be directly performed or completed by a decoding processor implemented as hardware or performed or completed by using a combination of hardware and software modules in a decoding processor. The software module may be located at a randomaccess memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, or another mature storage medium in this field. The storage medium is located at a memory 320, and the processor 310 reads information in the memory 320 and completes the steps in the foregoing methods in combination with the hardware thereof.

[0026] It may be understood that the memory 320 in the implementations of this technology may be a volatile memory or a non-volatile memory, or may include both a volatile memory and a non-volatile memory. The non-volatile memory may be a readonly memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory may be a random-access memory (RAM) and is used as an external cache. For exemplary rather than limitative description, many forms of RAMs can be used, and are, for example, a static random-access memory (SRAM), a dynamic random-access memory (DRAM), a synchronous dynamic random-access memory (SDRAM), a double data rate synchronous dynamic random-access memory (DDR SDRAM), an enhanced synchronous dynamic random-access memory (ESDRAM), a synchronous link dynamic random-access memory (SLDRAM), and a direct Rambus randomaccess memory (DR RAM). It should be noted that the memories in the systems and methods described herein are intended to include, but are not limited to, these memories and memories of any other suitable type. In some embodiments, the memory may be a non-transitory computer-readable storage medium that stores instructions capable of execution by a processor.

[0027] Fig. 4 is a flowchart of a method 400 in accordance with one or more implementations of the present disclosure. The method 400 can be implemented by a system (such as the wireless communications system 200). The method 400 may also be implemented solely by the terminal device 203. The method 400 is for switching connections of the terminal device 203 from a first serving cell 207A to a second serving cell 207B. Though described in relation to Fig. 2, in additional or alternative embodiments, the method 400 may be employed by other components or modules not shown in Fig. 2.

[0028] The method 400 includes, at block 401 , receiving 401 a list of joint TCI states that are associated with the second serving cell 207B. The terminal device 203 may receive the list from the mobility server 209 via the first network device 201A. Each joint TCI state contains one or more RSs providing reference for QCL configuration for reception of downlink channels/reference signals. Further, in each joint TCI state, the RS used to provide reference for QCL-typeD also provides reference for determining an uplink transmission spatial filter that may be used for uplink transmission. The method 400 continues with selecting (or receiving) a first joint TCI state and receiving 405 a request to apply the first joint TCI state when the terminal device 203 switches to the second serving cell 207B. The terminal device 203 may receive requests from the first serving cell 207A. The first joint TCI state may be associated with the second serving cell 207B, and the terminal device 203 may receive the request from the first serving cell 207A. In some embodiments, the first joint TCI state may be sent to the terminal device 203 through a MAC CE message or through DCI signaling. The first joint TCI state may be included in a handover command signal.

[0029] The method 400 includes receiving 407 a request to apply the first joint TCI state on reception of downlink channels/RSs and/or transmission of uplink channels/RS in response to the terminal device 203 switching to the second serving cell 207B. For example, the terminal device 203 may receive a request to apply the first joint TCI state on the reception of all or some of the PDCCH and/or the PDSCH associated with the second serving cell 207B. The terminal device 203 may also receive a request to apply the first joint TCI state on the reception of a CSI-RS resource that is configured to follow/use the first joint TCI state. The terminal device 203 may also apply the first joint TCI state on reception of common PDCCH and corresponding PDSCH associated with the second serving cell 207B.

[0030] The benefit of this method 400 is that handover only involves the common channels and the terminal device 203 is still able to receive terminal device-specific PDCCH and PDSCH from any transmission/reception point (e.g., network devices 201). For example, when the terminal device 203 switches to the second serving cell 207B, the terminal device 203 can receive a request to apply the first joint TCI state on the reception of PDCCH in a control resource set (CORESET) with index 0 and corresponding PDSCH and apply the first joint TCI state on the reception of PDCCH in a CORESET, other than a CORESET with index 0, associated with only a cluster switch system (CSS) set other than Type3-PDCCH CSS sets and the corresponding PDSCH CSS sets. In some instances, the method 4500 includes receiving a request to apply the first joint TCI state on the transmission of physical uplink shared channel (PLISCH) and physical uplink control channel (PLICCH) or to apply the first joint TCI state on the transmission of a sounding reference signal (SRS) resource that is configured to follow an indicated TCI state (for example, if the SRS resource is configured with higher layer parameter uselndicatedTCIState.)

[0031] In some embodiments, additional or alternative steps to those shown in Fig. 4 may be employed as part of the method 400. For example, in some embodiments, the method 400 includes the terminal device 203 receiving 401 a list of downlink TCI states that are associated with the second serving cell 207B. Each downlink TCI state may contain one or more RS providing reference for QCL configuration for reception of downlink channels/reference signals. The method 400 continues with the terminal device 203 selecting 403 or being indicated with a first downlink TCI state. The method includes the terminal device 203 receiving 405 a request to apply the first downlink TCI state when the terminal device 203 switches to the second serving cell 207B. In some embodiments, the first downlink TCI state is indicated to the terminal device 203 through a MAC CE message, through DCI signaling, or handover command signaling. The method 400 includes the terminal device 203 applying 407 the first downlink TCI state on reception of downlink channels/RSs in response to switching to the second serving cell 207B.

[0032] In some embodiments, the method 400 includes the terminal device 203 receiving a request apply the first downlink TCI state on the reception of all the PDCCH and the PDSCH or to apply the first downlink TCI state on the reception of CSI-RS resource that is configured to follow/use the first downlink TCI state. In some embodiments, the method 400 includes requesting the terminal device 203 to apply the first downlink TCI state on the reception of common PDCCH and corresponding PDSCH. This is an improvement ocer conventional systems in that the handover only involves the common channels and the terminal device 203 is still able to receive terminal device-specific PDCCH and PDSCH from any networking device 201 . For example, when the terminal device 203 switches to the second serving cell 207B, the terminal device 203 may receive a request to apply the first downlink TCI state on the reception of PDCCH in a CORESET with index 0 and corresponding PDSCH. The request may include requesting the terminal device 203 to apply the first joint TCI state on the reception of PDCCH in a CORESET, other than a CORESET with index 0, associated with only a CSS set other than Type3-PDCCH CSS sets and the corresponding PDSCH sets.

[0033] In some embodiments, the method 400 includes the first serving cell 207A providing the terminal device 203 with (e.g., the terminal device 203 receiving 401) a list of downlink TCI states and a list of uplink TCI states that are associated with the second serving cell 207B. Each downlink TCI state may contain one or more RSs providing reference for QCL configuration for reception of downlink channels/reference signals. Each uplink TCI state may contain one or more RSs providing reference for determining an uplink transmission spatial filter for uplink transmission. The method 400 continues with the terminal device 203 being indicated with a first downlink TCI state and a second uplink TCI state and the terminal device 203 receiving 405 a request to apply the first downlink TCI state and/or the second uplink TCI state when the terminal device 203 switches to the second serving cell 207B.

[0034] For example, the first downlink TCI state and the second uplink TCI state can be indicated to the terminal device 203 through a MAC CE message, DCI signaling, or handover command signaling. When the terminal device 203 switches to the second serving cell 207B, the terminal device 203 may receive a request to apply the first downlink TCI state on reception of downlink channels/RSs and/or the second uplink TCI state on the transmission of uplink channels/RS. In another example, the terminal device 203 receives a request to apply the first downlink TCI state on the reception of all the PDCCH and the PDSCH or of a CSI-RS resource that is configured to follow/use an indicated TCI state.

[0035] In another example, the method 400 includes the terminal device 203 being requested to apply the first downlink TCI state on the reception of common PDCCH and corresponding PDSCH. Again, this is an improvement over conventional methods since the handover only involves the common channels and the terminal device 203 is still able to receive UE-specific PDCCH and PDSCH from any netowkring device 201. For instance, when the terminal device 203 switches to the second serving cell 207B, the terminal device 203 may receive a request to apply the first downlink TCI state on the reception of PDCCH in a CORESET with index 0 and corresponding PDSCH and apply the first downlink TCI state on the reception of PDCCH in a CORESET, other than a CORESET with index 0, associated with only CSS set other than Type3-PDCCH CSS sets and the corresponding PDSCH. In one example, the terminal device 203 may receive a request to apply the second uplink TCI state on the transmission of PLISCH and PLICCH or on the transmission of an SRS resource that is configured to follow the indicated TCI state (for example, if the SRS resource is configured with higher layer parameter uselndicatedTCIState.)

[0036] In some embodiments, the terminal device 203 may be configured to operate a terminal device-initiated Levell/Level 2 (L1/L2) inter-cell handover as part of the method 400. For instance, as part of the method 400, the terminal device 203 may be provided with a list of candidate serving cells 207 and a set of RRC configurations for each candidate serving cell. The terminal device 203 may also be provided with a condition for measurement as part of the method 400. The terminal device 203 may conduct L1 measurement on those candidate serving cells, and when the configured condition for measurement is met, the terminal device 203 can choose one from the configured list of candidates serving cells to initiate the handover to. The terminal device 203 may receive a request to report the selected candidate serving cell to the system 200. For each candidate serving cell, the associated gNB (e.g., networking device 201) can provide one TCI state to the terminal device 203. The terminal device 203 can request to apply the provided TCI state on the reception of downlink channels/RS and/or transmission of uplink channels/RSs when the terminal device 203 switches serving cells 207. In one example, when the terminal device 203 determines one candidate serving cell 207 for handover, the terminal device 203 can also determine one TCI state that is going to be used when the terminal device 203 switches to the selected candidate serving cell 207. The terminal device 203 can report the selected TCI state to the gNB.

[0037] Fig. 5 is a flowchart of a method 500 in accordance with one or more implementations of the present disclosure. The method 500 can be implemented by a system (such as the wireless communications system 200). The method 500 may also be implemented solely by the terminal device 203. The method 500 may be used for determining and applying a TCI state when the terminal device 203 serving cells 207. Though described in relation to Fig. 2, in additional or alternative embodiments, the method 400 may be employed by other components or modules not shown in Fig.

2.

[0038] The method 500 includes receiving 501 , at the terminal device 203, configurations with a list of physical cell identities (IDs), which are applied to configure the terminal device 203. The first list of physical cell IDs may be associated with a candidate serving cell 207 that the terminal device 203 can handover to. The method 500 continues with receiving 503, at the terminal device 203, a set of RRC configurations for each of those physical cell IDs. If the terminal device 203 handovers to a serving cell 207 with a first physical cell ID, the terminal device 203 applies 505 the corresponding RRC configuration. For each physical cell ID, the terminal device 203 is also provided with a list of TCI states that are associated with this physical cell ID, where the TCI state can be:

- A joint TCI state in which one or more RSs are included to provided reference for QCL configuration. The RS configured for QCL-TypeD can also provide reference for determining an uplink transmission spatial filter for uplink transmission. Each joint TCI state may also be associated with a set of power control parameters for PLISCH, PLICCH, or SRS.

- A downlink TCI state in which one or more RSs are included to provide reference for QCL configuration.

- An uplink TCI state in which one RS is included to provide reference for determining an uplink transmission spatial filter for uplink transmission. Each uplink TCI state may also be associated with a set of power control parameters for PUSCH, PUCCH, or SRS.

[0039] The method 500 can include receiving 507, at the terminal device 203, a configuration of handover condition, for example, a threshold for a reference signal RSRP of a serving cell 207A and a threshold of a reference signal RSRP of a candidate serving cell 207B. When the handover condition is met, the method 500 continues with performing 509 handover with a physical cell ID in the first list of physical cell IDs to the serving cell 207A and receive a request to determine a TCI state for receiving downlink channels/RS and/or transmitting uplink channel/RS after handover. The terminal device 203 can receive a request to determine one joint TCI state and/or downlink TCI state and determine the requested TCI state.

[0040] In some embodiments, additional or alternative steps to those shown in Fig. 5 may be employed as part of the method 500. For instance, in some embodiments, the gNB of the serving cell 207A can indicate a TCI state that is associated with the first physical cell ID in the first list of physical cell IDs to the terminal device 203. When the terminal device 203 handovers to the serving cell 207B associated with the first physical cell ID, the terminal device 203 can apply the indicated TCI state that is associated with the first physical cell ID on reception of downlink channels/RSs and/or transmission of uplink channels/RSs after the handover.

[0041] In some embodiments, the indicated TCI state is a joint TCI state. The terminal device 203 can, in response to receiving a request, apply the indicated joint TCI state on the reception of all the PDCCH and the PDSCH after the terminal device 203 handovers to the serving cell 207A of the first physical cell ID. The terminal device 203 can also receive a request to apply the indicated joint TCI state on the reception of CSI-RS resource that is configured to follow/use the indicated TCI state. For example, the terminal device 203 can, in response to receiving a request, apply the indicated joint TCI state on the reception of common PDCCH and corresponding PDSCH, which provides the benefit over conventional systems of the handover only involving the common channels. Further, the terminal device 203 is still able to receive terminal device-specific PDCCH and PDSCH from any networking device 201.

[0042] For example, when the terminal device 203 can switch to the serving cell 207B of the first physical cell ID, the terminal device 203 can be requested to apply the first joint TCI state on the reception of PDCCH in a CORESET with index 0 and corresponding PDSCH and apply the first joint TCI state on the reception of PDCCH in a CORESET, other than a CORESET with index 0, associated with only CSS set other than Type3-PDCCH CSS sets and the corresponding PDSCH. In one example, the terminal device 203 can be requested to apply the indicated joint TCI state on the transmission of PLISCH and PLICCH. The terminal device 203 can also be requested to apply the indciated joint TCI state on the transmission of SRS resource that is configured to follow the indicated TCI state, for example if the SRS resource is configured with higher layer parameter uselndicatedTCIState. [0043] In some embodiments, the indicated TCI state can be a downlink TCI state. For instance, the terminal device 203 can, in response to a request, apply the indicated downlink TCI state on the reception of all the PDCCH and the PDSCH after the terminal device 203 handovers to the serving cell 207B of the first physical cell ID. The terminal device 203 can also be requested to apply the indicated downlink TCI state on the reception of CSI-RS resource that is configured to follow/use the indicated TCI state. In some instances, the terminal device 203 can be requested to apply the indicated downlink TCI state on the reception of common PDCCH and corresponding PDSCH. This again results in the benefit of the handover only involving the common channels, the first and second layer (rather than the third), and the terminal device 203 still being able to receive terminal device-specific PDCCH and PDSCH from any networking device 201. For example, when the terminal device 203 switches to the serving cell 207B of the first physical cell ID, the terminal device 203 can, in response to a request, apply the indicated downlink TCI state on the reception of PDCCH in a CORESET with index 0 and corresponding PDSCH and on the reception of PDCCH in a CORESET, other than a CORESET with index 0, associated with an only CSS set other than Type3-PDCCH CSS sets and the corresponding PDSCH sets.

[0044] In some embodiments, the indicated TCI state can be a downlink TCI state and an uplink TCI state. The terminal device 203 can, in response to one or more requests, apply the indicated downlink TCI state on the reception of all the PDCCH and the PDSCH after the terminal device 203 handovers to the serving cell 207B of the first physical cell ID and apply the indicated downlink TCI state on the reception of CSI-RS resource that is configured to follow/use the indicated TCI state. In some instances, the terminal device 203 receive a request to apply the indicated uplink TCI state on the transmission of PLISCH and PLICCH and facilitate such application. The terminal device 203 can also, in response to a request, apply the indicated uplink TCI state on the transmission of SRS resource that is configured to follow the indicated TCI state (for example, when the SRS resource is configured with higher layer parameter uselndicatedTCIState.)

[0045] In some instance, for a first physical cell ID in the first list of physical cell IDs, the terminal device 203 can determine one or more joint TCI states, one or more downlink TCI states, or one or more downlink TCI states and one or more uplink TCI states. When the terminal device 203 handovers to the serving cell 207B of the first physical cell ID, the terminal device 203 can apply the determined TCI state(s) that is associated with the first physical cell ID on reception of downlink channels/RSs and/or transmission of uplink channels/RSs after the handover. The terminal device 203 may report the determined TCI state(s) to the gNB of the serving cell 207B in response to a request for a report. For example, the terminal device 203 can report the ID of the determined joint TCI state and/or the ID of the downlink TCI state to the gNB in a MAC CE message, in a UCI message, or using RRC signaling. In another example, the terminal device 203 can report the ID of a reference signal that can be used as downlink QCL to the gNB. The terminal device 203 can report the ID of a reference signal that can be used to provide reference for uplink transmission spatial filter to the gNB. The terminal device 203 can report the ID in a MAC CE message, in a UCI message, or using RRC signaling.

[0046] Once the terminal device 203 has the determined joint TCI state, downlink TCI state, or uplink TCI state, the terminal device 203 shall apply the determined TCI state when the terminal device 203 handovers to the serving cell 207B of the first physical cell ID. The determined TCI state can be a joint TCI state and/or a downlink TCI state. The terminal device 203 receive a request to apply the determined TCI state on the reception of all the PDCCH and the PDSCH, on the reception of CSI-RS resource that is configured to follow/use the determined TCI state, and/or on the reception of common PDCCH and corresponding PDSCH. This allows the terminal device 203 to receive PDCCH and PDSCH from any networking device 203, even when the PDCCH and PDSCH is specific to a terminal device 203.

ADDITIONAL CONSIDERATIONS

[0047] The above Detailed Description of examples of the disclosed technology is not intended to be exhaustive or to limit the disclosed technology to the precise form disclosed above. While specific examples for the disclosed technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the described technology, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative implementations may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative implementations or subcombinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed or implemented in parallel, or may be performed at different times. Further, any specific numbers noted herein are only examples; alternative implementations may employ differing values or ranges.

[0048] In the Detailed Description, numerous specific details are set forth to provide a thorough understanding of the presently described technology. In other implementations, the techniques introduced here can be practiced without these specific details. In other instances, well-known features, such as specific functions or routines, are not described in detail in order to avoid unnecessarily obscuring the present disclosure. References in this description to “an implementation/embodiment,” “one implementation/embodiment,” or the like mean that a particular feature, structure, material, or characteristic being described is included in at least one implementation of the described technology. Thus, the appearances of such phrases in this specification do not necessarily all refer to the same implementation/embodiment. On the other hand, such references are not necessarily mutually exclusive either. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more implementations/embodiments. It is to be understood that the various implementations shown in the figures are merely illustrative representations and are not necessarily drawn to scale.

[0049] Several details describing structures or processes that are well-known and often associated with communications systems and subsystems, but that can unnecessarily obscure some significant aspects of the disclosed techniques, are not set forth herein for purposes of clarity. Moreover, although the following disclosure sets forth several implementations of different aspects of the present disclosure, several other implementations can have different configurations or different components than those described in this section. Accordingly, the disclosed techniques can have other implementations with additional elements or without several of the elements described below. [0050] Many implementations or aspects of the technology described herein can take the form of computer- or processor-executable instructions, including routines executed by a programmable computer or processor. Those skilled in the relevant art will appreciate that the described techniques can be practiced on computer or processor systems other than those shown and described below. The techniques described herein can be implemented in a special-purpose computer or data processor that is specifically programmed, configured, or constructed to execute one or more of the computer-executable instructions described below. Accordingly, the terms “computer” and “processor” as generally used herein refer to any data processor. Information handled by these computers and processors can be presented at any suitable display medium. Instructions for executing computer- or processorexecutable tasks can be stored in or on any suitable computer-readable medium, including hardware, firmware, ora combination of hardware and firmware. Instructions can be contained in any suitable memory device, including, for example, a flash drive and/or other suitable medium.

[0051] The term “and/or” in this specification is only an association relationship for describing the associated objects, and indicates that three relationships may exist, for example, A and/or B may indicate the following three cases: A exists separately, both A and B exist, and B exists separately.

[0052] These and other changes can be made to the disclosed technology in light of the above Detailed Description. While the Detailed Description describes certain examples of the disclosed technology, as well as the best mode contemplated, the disclosed technology can be practiced in many ways, no matter how detailed the above description appears in text. Details of the system may vary considerably in its specific implementation, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosed technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosed technology with which that terminology is associated. Accordingly, the invention is not limited, except as by the appended claims. In general, the terms used in the following claims should not be construed to limit the disclosed technology to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms.

[0053] A person of ordinary skill in the art may be aware that, in combination with the examples described in the implementations disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application.

[0054] Although certain aspects of the invention are presented below in certain claim forms, the applicant contemplates the various aspects of the invention in any number of claim forms. Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms, in either this application or in a continuing application.

Claims

I/We claim:

1. A method for applying a transmission configuration indicator (TCI) state when a user equipment (UE) switches serving cells, the method comprising: receiving, by the UE from a first serving cell, an indication to switch connection to a second serving cell; receiving, by the UE, a set of radio resource control (RRC) configurations and a first TCI state for switching to a second serving cell; switching, by the UE, connection from the first serving cell to the second serving cell based on the RRC configurations; and applying the first TCI state on reception or transmission channels of the second serving cell.

2. The method of claim 1 , wherein applying the first TCI state comprises: applying the first TCI state on the reception of downlink channels of the second serving cell.

3. The method of claim 1 , wherein applying the first TCI state comprises: applying the first TCI state on the transmission of uplink channels of the second serving cell.

4. The method of claim 1 , wherein the indication is a switch command.

5. The method of claim 1 , further comprising: receiving, at the UE, a list of joint TCI states associated with the second serving cell, wherein each TCI state contains one or more reference signals (RSs) providing reference for (quasi- co-location) QCL configuration for reception of downlink channels in the joint TCI state and the first TCI state is first in the list of joint TCI states.

6. The method of claim 5, wherein the RS further provides reference for determining a transmission spatial filter for uplink transmission.

7. The method of claim 1 , wherein the UE receives the first TCI state through a media access control (MAC) control element (CE) message.

8. The method of claim 1 , wherein the UE receives the first TCI state through downlink control information (DCI) signaling.

9. The method of claim 1 , wherein the UE receives the first TCI state with the indication.

11. The method of claim 1 , further comprising:

Receiving, at the UE, a request to apply the first TCI state on reception or transmission of common physical downlink control channel (PDCCH) and corresponding physical downlink shared channel (PDSCH).

12. A non-transitory computer-readable storage medium storing instructions that, when executed, cause a processor to perform actions comprising: receiving, by a user equipment (UE) from a first serving cell, an indication to switch connection to a second serving cell; receiving, by the UE, a set of radio resource control (RRC) configurations and a first transmission configuration indicator (TCI) state for switching to a second serving cell; switching, by the UE, connection from the first serving cell to the second serving cell based on the RRC configurations; applying the first TCI state on reception or transmission channels of the second serving cell.

13. The non-transitory computer-readable storage medium of claim 12, wherein applying the first TCI state comprises: applying the first TCI state on the reception of downlink channels of the second serving cell.

14. The non-transitory computer-readable storage medium of claim 12, wherein applying the first TCI state comprises: applying the first TCI state on the transmission of uplink channels of the second serving cell.

15. The non-transitory computer-readable storage medium of claim 12, wherein the indication is a switch command.

16. The non-transitory computer-readable storage medium of claim 12, the actions further comprising: receiving, at the UE, a list of joint TCI states associated with the second serving cell, wherein each TCI state contains one or more reference signals (RSs) providing reference for (quasi- co-location) QCL configuration for reception of downlink channels in the joint TCI state and the first TCI state is first in the list of joint TCI states.

17. The non-transitory computer-readable storage medium of claim 16, wherein the RS further provides reference for determining a transmission spatial filter for uplink transmission.

18. The non-transitory computer-readable storage medium of claim 12, wherein the UE receives the first TCI state through a media access control (MAC) control element (CE) message.

19. The non-transitory computer-readable storage medium of claim 12, wherein the UE receives the first TCI state through downlink control information (DCI) signaling.

20. A system for applying a transmission configuration indicator (TCI) state when a user equipment (UE) switches serving cells, the system comprising: a processor; and a memory configured to store instructions, when executed by the processor, to: receiving, by the UE from a first serving cell, an indication to switch connection to a second serving cell; receiving, by the UE, a set of radio resource control (RRC) configurations and a first TCI state for switching to a second serving cell; switching, by the UE, connection from the first serving cell to the second serving cell based on the RRC configurations; and applying the first TCI state on reception or transmission channels of the second serving cell.