WO2022261930A1

WO2022261930A1 - Method and apparatus for beam determination

Info

Publication number: WO2022261930A1
Application number: PCT/CN2021/100874
Authority: WO
Inventors: Wei Ling; Chenxi Zhu; Bingchao LIU; Yi Zhang; Lingling Xiao
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2022-12-22

Abstract

Embodiments of the present application are related to a method and apparatus for beam determination. An exemplary method includes: receiving an indication indicating whether a downlink or joint common beam mechanism is applied for a subset of CORESETs of a set of CORESETs configured for a UE; and for a CORESET of the set of CORESETs, in the case that the CORESET is not included in the subset of CORESETs, monitoring PDCCHs in the CORESET according to a set of downlink RS regardless of the indication, and in the case that the CORESET is included in the subset of CORESETs, monitoring the PDCCHs in the CORESET according to the set of downlink RS based on the indication, wherein a DM-RS antenna port associated with PDCCH reception in the CORESET is quasi co-located with the set of downlink RS.

Description

METHOD AND APPARATUS FOR BEAM DETERMINATION

TECHNICAL FIELD

Embodiments of the present application are related to wireless communication technology, especially, related to a method and apparatus for beam determination.

BACKGROUND OF THE INVENTION

Regarding enhancements on multiple-input multiple-output (MIMO) for new radio (NR) , a work item description (WID) approved in NR R17 includes enhancement on multi-beam operation, mainly targeting frequency range (FR) 2 while also applicable to FR1. Wherein, a research topic is to identify and specify features to facilitate more efficient (lower latency and overhead) downlink/uplink (DL/UL) beam management to support higher intra-band and L1/L2-centric inter-cell mobility and/or a larger number of configured transmission configuration indication (TCI) states, including common beam for data and control transmission/reception for DL and UL, especially for intra-band carrier aggregation (CA) .

In addition, it has been agreed that downlink control information (DCI) format 1_1 and DCI format 1_2 can be reused for DL or joint common beam indication in RAN1 #103e, and the DL or joint common beam can be applied for physical downlink shared channel (PDSCH) and all or subset of control resource sets (CORESETs) . Given that, a UE may support both legacy beam indication (or determination) mode (e.g., the beam indication of R15/R16) and common beam indication (or determination) mode (e.g., common beam indication of R17) for transmission or reception.

Accordingly, how to determine the beam of a CORESET in view of the two indication modes, especially, how to determine the beam of a CORESET during switching between the legacy beam indication mode and common beam indication mode should be studied and determined.

SUMMARY

One objective of the embodiments of the present application is to provide a technical solution for beam determination, especially for beam determination in case of two beam indication modes being supported.

Some embodiments of the present application provide a method, which includes: receiving an indication indicating whether a downlink or joint common beam mechanism is applied for a subset of CORESETs of a set of CORESETs configured for a UE; and for a CORESET of the set of CORESETs, in the case that the CORESET is not included in the subset of CORESETs, monitoring physical downlink control channels (PDCCHs) in the CORESET according to a set of downlink reference signal (RS) regardless of the indication, and in the case that the CORESET is included in the subset of CORESETs, monitoring the PDCCHs in the CORESET according to the set of downlink RS based on the indication, wherein a demodulation-reference signal (DM-RS) antenna port associated with PDCCH reception in the CORESET is quasi co-located with the set of downlink RS.

Some other embodiments of the present application provide another method, which includes: transmitting an indication indicating whether a downlink or joint common beam mechanism is applied for a subset of CORESETs of a set of CORESETs configured for a UE; and for a CORESET of the set of CORESETs, in the case that the CORESET is not included in the subset of CORESETs, transmitting PDCCHs in the CORESET according to a set of downlink RS regardless of the indication, and in the case that the CORESET is included in the subset of CORESETs, transmitting the PDCCHs in the CORESET according to the set of downlink RS based on the indication, wherein a DM-RS antenna port associated with PDCCH transmission in the CORESET is quasi co-located with the set of downlink RS.

In some embodiments of the present application, in the case that the CORESET is not included in the subset of CORESETs and the CORESET is CORESET 0, the set of downlink RS is: a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no medium access control (MAC) control element (CE) activation command indicating a TCI state for the CORESET is received after the most recent random access procedure; or one or more downlink RSs configured by a TCI state, wherein the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.

In some other embodiments of the present application, in the case that the CORESET is not included in the subset of CORESETs and the CORESET is non-CORESET 0, the set of downlink RS is: a SSB identified by the UE during a most recent random access procedure, in the case that the UE has not been provided a configuration of TCI state (s) for the CORESET, or the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a MAC CE activation command for the CORESET; a SSB or a channel state information-reference signal (CSI-RS) resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as a part of the reconfiguration with sync procedure but has not received the MAC CE activation command; or one or more downlink RSs configured by a TCI state, wherein the TCI state is only one configured TCI state for the CORESET, or the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.

In some yet other embodiments of the present application, the indication is a configuration of radio resource control (RRC) parameter, indicating the downlink or joint common beam mechanism is applied for the subset of CORESETs in the case that the RRC parameter is configured as "enable. " According to some embodiments of the present application, the set of downlink RS is a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that the CORESET is included in the subset of CORESETs and: the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has not been provided a configuration of TCI state (s) for the CORESET; or the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a MAC CE activation command for the CORESET before receiving the configuration of the RRC parameter and after the most recent random access procedure; or the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter configured as "disable, " and no downlink or joint common TCI state indicated by DCI in a PDCCH is applicable. According to some other embodiments of the present application, the set of downlink RS is one or more downlink RS configured by a TCI state, in the case that the CORESET is included in the subset of CORESETs and the RRC parameter is not configured or configured as "disable" ; wherein the TCI state is only one configured TCI state for the CORESET or the TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET which is applicable. According to some yet other embodiments of the present application, in the case that the CORESET is included in the subset of CORESETs, the RRC parameter is configured as "enable, " and the indication is switched from a previous RRC parameter being not configured or configured as "disable, " before a downlink or joint common beam is applicable for the CORESET, the set of downlink RS is the one or more downlink RS configured by a most recent TCI state, wherein the most recent TCI state is a only configured TCI state for the CORESET or the most recent TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET. According to some yet other embodiments of the present application, the set of downlink RS is a SSB or a CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in the case that the CORESET is included in the subset of CORESETs and: the UE has been provided a configuration of more than one TCI states for the CORESET as part of the reconfiguration with sync procedure but has not received a MAC CE activation command for the CORESET before receiving the indication, the RRC parameter is configured as "disable" or not configured, and the indication is not switched from a previous RRC parameter configured with "enable" ; or the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter being configured as "disable, " and no downlink or joint common TCI state indicated by DCI in a PDCCH is applicable before receiving the configuration of the RRC parameter. According to some yet other embodiments of the present application, in the case that the RRC parameter is configured as "enable" and the CORESET is included in the subset of CORESETs, the set of downlink RS is one or more downlink RS configured by a TCI state applicable for the CORESET, wherein the TCI state is a downlink or joint common beam indicated by DCI in a PDCCH. According to some yet other embodiments of the present application, in the case that the RRC parameter is configured as "disable" or not configured, the indication is switched from a previous RRC parameter configured as "enable, " and the CORESET is included in the subset of CORESEs; the set of downlink RS is one or more downlink RS configured by a most recent TCI state before a TCI state activated by a MAC CE for the CORESET is applicable in the case that more than one TCI states are configured for the CORESET, wherein the most recent transmission configuration indication is indicated by DCI in a PDCCH which indicates a downlink or joint common beam before the indication is switched from a previous RRC parameter configured as "enable. "

In some yet other embodiments of the present application, the indication is a MAC CE activation command, and in the case that the MAC CE activation command is a MAC CE activation command activating a list of common beams, the MAC CE activation command indicates that a downlink or joint common beam in the list of common beams is applied for the subset of CORESETs; and in the case that the MAC CE activation command is a MAC CE activation command activating TCI state (s) for any of the set of CORESETs, or a MAC CE activation command activating TCI state (s) for PDSCH, the MAC CE activation command indicates that no downlink or joint common beam is applied for the subset of CORESET. According to some embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable, the set of downlink RS is: a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam is indicated before receiving the indication; or a SSB or CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as part of the reconfiguration with sync procedure but has not received a MAC CE activation command for the CORESET before receiving the indication and no downlink or joint common beam is indicated before receiving the indication. According to some other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is: one or more downlink RS configured by a most recent TCI state of the CORESET before the applicable time of the MAC CE activation command, wherein the most recent TCI state is the only one configured TCI state for the CORESET or the most recent TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI states are configured for the CORESET. According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is: one or more downlink RS configured by a downlink or joint common TCI state with a lowest codepoint in the MAC CE activation command. According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of CORESETs or activating TCI states for PDSCH and the CORESET is included in the subset of CORESETs, before an applicable time of the MAC CE activation command, the set of downlink RS is: a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam indication is received before receiving the indication; or a SSB or a CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that more than one TCI states are configured for the CORESET as part of the reconfiguration with sync procedure but no MAC CE activation command has been received for the CORESET before receiving the indication and no downlink or joint common beam indication is received before receiving the indication. According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH, and the CORESET is included in the subset of CORESETs, after the MAC CE activation command is applicable and before an applicable time of a MAC CE activation command for activating a TCI state for the CORESET, the set of downlink RS is: one or more downlink RS configured by a most recent downlink or joint common TCI state which is indicated before the applicable time of the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH in the case that another list of common beams has been received before receiving the indication.

Some yet other embodiments of the present application also provide an apparatus, including: at least one non-transitory computer-readable medium having stored thereon computer-executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry. The computer-executable instructions cause the at least one processor to implement any method according to an embodiment of the present application with the at least one receiving circuitry and the at least one transmitting circuitry.

Embodiments of the present application can solve the beam determination in view of the legacy beam indication mode and common beam indication mode, especially the beam determination during switching between the legacy beam indication mode and common beam indication mode for a UE, and thus will facilitate the deployment and implementation of the NR.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the present application can be obtained, a description of the present application is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the present application and are not therefore intended to limit the scope of the present application.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application;

FIG. 2 illustrates a flow chart of a method for beam determination according to some embodiments of the present application;

FIG. 3 illustrates an exemplary beam determination procedure in case of switching from a legacy beam indication mode to a common beam indication mode under a RRC based switching scheme according to some embodiments of the present application;

FIG. 4 illustrates an exemplary beam determination procedure in case of switching from a common beam indication mode to a legacy beam indication mode under a RRC based switching scheme according to some other embodiments of the present application;

FIG. 5 illustrates an exemplary beam determination procedure in case of switching from a legacy beam indication mode to a common beam indication mode under a MAC CE based switching scheme according to some embodiments of the present application;

FIG. 6 illustrates an exemplary beam determination procedure in case of switching from a common beam indication mode to a legacy beam indication mode under a MAC CE based switching scheme according to some other embodiments of the present application; and

FIG. 7 illustrates a simplified block diagram of an apparatus for beam determination according to some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3rd generation partnership project (3GPP) 5G, 3GPP long term evolution (LTE) Release 8 and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

FIG. 1 illustrates a schematic diagram of an exemplary wireless communication system 100 according to some embodiments of the present application.

As shown in FIG. 1, the wireless communication system 100 includes a UE 103 and a BS 101. Although merely one BS is illustrated in FIG. 1 for simplicity, it is contemplated that the wireless communication system 100 may include more BSs in some other embodiments of the present application. Similarly, although merely one UE is illustrated in FIG. 1 for simplicity, it is contemplated that the wireless communication system 100 may include more UEs in some other embodiments of the present application.

The BS 101 may also be referred to as an access point, an access terminal, a base, a macro cell, a node-B, an enhanced node B (eNB) , a gNB, a home node-B, a relay node, or a device, or described using other terminology used in the art. The BS 101 is generally part of a radio access network that may include a controller communicably coupled to the BS 101.

The UE 103 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to an embodiment of the present application, the UE 103 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments, the UE 103 may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the UE 103 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art.

The wireless communication system 100 is compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) -based network, a code division multiple access (CDMA) -based network, an orthogonal frequency division multiple access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.

Regarding the beam determination, e.g., for PDSCH, a legacy beam indication (or determination) mode is specified in TS 38.213 in R15/R16. Herein (throughout the specification) , the terminology "beam" can be represented by or associated with spatial relation information, TCI state, RS etc. For example, a beam for downlink transmission can be represented by a DM-RS antenna port associated with PDCCH reception in a CORESET which is quasi co-located with a set of downlink RS. Specifically, according to a UE procedure for determining PDCCH assignment in TS 38.213 in R15/R16,

For a CORESET other than a CORESET with index 0,

- if a UE has not been provided a configuration of TCI state (s) by tci-StatesPDCCH-ToAddList and tci-StatesPDCCH-ToReleaseList for the CORESET, or has been provided initial configuration of more than one TCI states for the CORESET by tci-StatesPDCCH-ToAddList and tci-StatesPDCCH-ToReleaseList but has not received a MAC CE activation command for one of the TCI states as described in [11, TS 38.321] , the UE assumes that the DM-RS antenna port associated with PDCCH receptions is quasi co-located with the SS/PBCH block the UE identified during the initial access procedure;

- if a UE has been provided a configuration of more than one TCI states by tci-StatesPDCCH-ToAddList and tci-StatesPDCCH-ToReleaseList for the CORESET as part of Reconfiguration with sync procedure as described in [12, TS 38.331] but has not received a MAC CE activation command for one of the TCI states as described in [11, TS 38.321] , the UE assumes that the DM-RS antenna port associated with PDCCH receptions is quasi co-located with the SS/PBCH block or the CSI-RS resource the UE identified during the random access procedure initiated by the Reconfiguration with sync procedure as described in [12, TS 38.331] .

For a CORESET with index 0, the UE assumes that a DM-RS antenna port for PDCCH receptions in the CORESET is quasi co-located with

- the one or more DL RS configured by a TCI state, where the TCI state is indicated by a MAC CE activation command for the CORESET, if any, or

- a SS/PBCH block the UE identified during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, if no MAC CE activation command indicating a TCI state for the CORESET is received after the most recent random access procedure.

For a CORESET other than a CORESET with index 0, if a UE is provided a single TCI state for a CORESET, or if the UE receives a MAC CE activation command for one of the provided TCI states for a CORESET, the UE assumes that the DM-RS antenna port associated with PDCCH receptions in the CORESET is quasi co-located with the one or more DL RS configured by the TCI state. For a CORESET with index 0, the UE expects that QCL-TypeD of a CSI-RS in a TCI state indicated by a MAC CE activation command for the CORESET is provided by a SS/PBCH block

- if the UE receives a MAC CE activation command for one of the TCI states, the UE applies the activation command in the first slot that is after slot

where k is the slot where the UE would transmit a PUCCH with HARQ-ACK information for the PDSCH providing the activation command and μ is the SCS configuration for the PUCCH. The active BWP is defined as the active BWP in the slot when the activation command is applied.

According to the above legacy specification, the beam of a CORESET is determined as the beam of an initial access, or the configured TCI state if only one TCI state is configured for the CORESET, or the TCI state activated by a MAC CE for the CORESET if multiple TCI states are configured for the CORESET.

On the other hand, in R17, common beam for data and control transmission/reception for DL and UL, especially for intra-band CA is introduced to improve latency and efficiency with more usage of dynamic control signaling. It has been agreed to reuse DCI format 1_1 and DCI format 1_2 for downlink or joint common beam indication. According to the agreement in R17, when a downlink or joint common beam is indicated by DCI in a PDCCH, it will be applied to all or subset of a set of CORESETs configured for a UE and all PDSCHs. Meanwhile, if the downlink or joint common beam is indicated by DCI in a PDCCH, it is valid for all or subset of the set of CORESETs starting from an applicable time which is the first slot that is at least a configured number of symbols or a configured number of milliseconds after the acknowledgement (ACK) of the DCI for indicating the downlink or joint common beam. However, when a UE is switched (or changed) from a legacy beam indication mode to a common beam indication mode, how to determine a beam for a CORESET before a downlink or joint common beam is applicable has not been solved yet. In addition, when the beam indication for all or subset of the set of CORESETs is switched from the common beam indication mode to the legacy beam indication mode, how to determine a beam for a CORESET before a TCI state activated by a MAC CE for the CORESET is applicable has not been solved yet either.

At least for solving the above technical problems, embodiments of the present application provide a technical solution for beam determination, especially for beam determination during switching between two beam indication modes, e.g., the legacy beam indication mode and the common beam indication mode.

FIG. 2 illustrates a flow chart of a method for beam determination according to some embodiments of the present application. Although the method is illustrated in a system level by a UE in a remote side (or UE side) and a BS in a network side (or BS side) , persons skilled in the art should understand that the method implemented in the remote side and that implemented in the network side can be separately implemented and incorporated by other apparatus with the like functions.

According to some embodiments of the present application, two beam indication modes, e.g., a legacy beam indication mode as provided in TS 38.213 and a common beam indication mode introduced in R17 are supported in a wireless system. The network side e.g., a BS 101 as shown in FIG. 1 will configure a set of CORESETs for a UE, e.g., a UE 101 as shown in FIG. 1, wherein the set of CORESETs includes one or more CORESETs (hereafter the same) . The network side e.g., the BS 101 as shown in FIG. 1 will indicate the UE which beam indication mode will be applied to a subset of the set of CORESETs, e.g., by a high layer signaling, wherein the subset of CORESETs includes all or part of the set of CORESETs (hereafter the same) according to a RRC configuration or a predefined rule.

For the subset of CORESETs, as shown in FIG. 2, in step 201, the network side, e.g., a BS 101 as shown in FIG. 1 will transmit an indication indicating whether a downlink or joint common beam mechanism is applied. Accordingly, in the remote side, the indication will be received from the network side in step 202 by the UE, e.g., the UE 103 as shown in FIG. 1, which indicates whether a downlink or joint common beam mechanism is applied for the subset of CORESETs of the set of CORESETs configured for the UE. When a downlink or joint common beam mechanism is applied for the subset of CORESETs, the common beam indication mode is applied. When a downlink or joint common beam mechanism is not applied for the subset of CORESETs, the legacy beam indication mode is applied.

In some embodiments of the present application, the high layer signaling transmitting the indication is a RRC signaling. For example, the indication is a configuration of RRC parameter. In the case that the RRC parameter is configured as "enable, " it indicates that the downlink or joint common beam mechanism, e.g., the common beam indication mode is applied for the subset of CORESETs. In the case that RRC parameter is configured as "disable, " or is not configured, it means that the legacy beam mechanism, e.g., the legacy beam indication mode is applied for the subset of CORESETs.

In some other embodiments of the present application, the high layer signaling transmitting the indication is a MAC CE. For example, the indication is a MAC CE activation command. In the case that the MAC CE activation command is a MAC CE activation command activating a list of common beams, the MAC CE activation command indicates that a downlink or joint common beam in the list of common beams will be applied for the subset of CORESETs, that is, the common beam indication mode will be applied for the subset of CORESET. The list of common beams includes one or more downlink or joint common beams (hereafter the same) . In the case that the MAC CE activation command is a MAC CE activation command activating TCI state (s) for any of the set of CORESETs, or a MAC CE activation command activating TCI state (s) for PDSCH, the MAC CE activation command indicates that no downlink or joint common beam will be applied for the subset of CORESET, that is, the legacy beam indication mode will be applied for the subset of CORESET.

The network side, e.g., the BS as shown in FIG. 1 will determine a beam for a CORESET of the set CORESETs, and transmit the PDCCHs in the CORESET according to a determined beam to transmit downlink control information in step 203. Similarly, the remote side, e.g., the UE 103 as shown in FIG. 1 will determine a beam for the CORESET of the set CORESETs, and monitor the PDCCHs in the CORESET according to a determined beam to receive downlink data (including control information etc. ) in step 204.

Specifically, according to current 3GPP specification (s) , receiving/transmitting a beam of downlink transmission can be represented by decoding/transmitting the resource elements (REs) of a DM-RS antenna port quasi co-located associated with a set of RS, e.g. a SSB or a CSI-RS resource, or one or more RSs configured by a TCI state. Considering whether a CORESET in the set of CORESETs is included in the subset of CORESETs, the set of RS associated with the beam can be determined in various manners.

Generally, for a CORESET not included in the subset of CORESETs, in the network side, a BS will transmit the PDCCHs in the CORESET according to a set of downlink RS regardless of the indication, wherein a DM-RS antenna port associated with PDCCH transmission in the CORESET is quasi co-located with the set of downlink RS. Similarly, for a CORESET not included in the subset of CORESETs, in the remote side, a UE will monitor the PDCCHs in the CORESET according to a set of downlink RS regardless of the indication, wherein a DM-RS antenna port associated with PDCCH reception in the CORESET is quasi co-located with the set of downlink RS. That is, for a CORESET not included in the subset of CORESETs, the legacy beam indication mode, e.g., the legacy beam indication schemes provided in TS 38.213 as descripted above, will always be applied regardless of the indication.

For example, in some embodiments of the present application, for a CORESET not included in the subset of CORESETs and being CORESET 0 (i.e., a CORESET with index 0) , the set of downlink RS is a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no MAC CE activation command indicating a TCI state for the CORESET is received after the most recent random access procedure. In some other embodiments of the present application, for a CORESET not included in the subset of CORESETs and being CORESET 0, the set of downlink RS is one or more downlink RSs configured by a TCI state, wherein the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.

In some embodiments of the present application, for a CORESET not included in the subset of CORESETs and not being CORESET 0 (i.e., a CORESET other than a CORESET with index 0) , the set of downlink RS is a SSB identified by the UE during a most recent random access procedure, in the case that the UE has not been provided a configuration of TCI state (s) for the CORESET, or in the case that the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a MAC CE activation command for the CORESET to activate a TCI state. In some other embodiments of the present application, for a CORESET not included in the subset of CORESETs and not being CORESET 0, the set of downlink RS is a SSB or a CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as a part of the reconfiguration with sync procedure but has not received the MAC CE activation command. In some yet other embodiments of the present application, for a CORESET not included in the subset of CORESETs and not being CORESET 0, the set of downlink RS is one or more downlink RSs configured by a TCI state, wherein the TCI state is the only one configured TCI state for the CORESET, or the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.

Persons skilled in the art should understand that, although the above descriptions on the legacy beam indication schemes are provided according to TS 38.213, they may be changed or updated as the evolution of 3GPP specifications or other related specifications/protocols, and thus should not be limited to the above. A legacy beam indication mode should be understood as a mode (or mechanism, or scheme etc. ) for a non-common (or specific, or legacy) beam, rather than the legacy contents provided in current TS 38.213.

On the other hand, for a CORESET included in the subset of CORESETS, in the network side, a BS will transmit the PDCCHs in the CORESET according to a set of downlink RS based on the indication, wherein a DM-RS antenna port associated with PDCCH transmission in the CORESET is quasi co-located with the set of downlink RS. Similarly, in the remote side, a UE will monitor the PDCCHs in the CORESET according to a set of downlink RS based on the indication, wherein a DM-RS antenna port associated with PDCCH reception in the CORESET is quasi co-located with the set of downlink RS. Considering that the indication indicating whether a downlink or joint common beam mechanism is applied for a subset of CORESETs, there will be a switching procedure between the legacy beam indication mode and the common beam indication mode if two adjacent indications are different.

More detailed embodiments will be illustrated in view of different high layer indication manners, e.g., configuration of RRC parameter (referred to as "RRC based switching scheme" ) and MAC CE activation command (referring to as "MAC CE based switching scheme" ) . Meanwhile, considering the consistency between the network side and the remote side, although the following descriptions are provided mainly concerning on the remote side for simplification, persons skilled in the art should well understand the corresponding operations in the network side.

RRC Based Switching scheme

As stated above, for a CORESET not included in the subset of CORSETs where a downlink or joint common beam mechanism can be applied, the beam determination of the CORESET will still follow the legacy beam indication mode regardless of the RRC parameter "enableCommonBeam. " While for a CORESET included in the subset of CORSETs where a downlink or joint common beam mechanism can be applied, the beam for the CORESET is determined at least based on the indication.

According to some embodiments of the present application, under the RRC based switching scheme, a new RRC parameter will be introduced to enable or disable a downlink or joint common beam mechanism. For example, the new RRC parameter can be named as "enableCommonBeam" or other names, and can be configured as either "enable" or "disable. " When the RRC parameter "enableCommonBeam" is not configured or is configured as "disable, " a legacy beam indication mode will be applied for the subset of CORESETs, which means the beam determination for a CORESET in the subset of CORESETS is the same as that specified in R15/R16 or the evaluation in the future. When the RRC parameter "enableCommonBeam" is configured as "enable, " the common beam indication mode will be applied for the subset of CORESETs where a downlink or joint common beam mechanism can be applied.

In some exemplary scenarios, the RRC parameter "enableCommonBeam" is configured as "enable" and the indication is changed from a not configured RRC parameter "enableCommonBeam" or a previous RRC parameter "enableCommonBeam" configured with "disable. " However, only after the RRC parameter "enableCommonBeam" is changed to "enable, " a downlink or joint common beam can be indicated by DCI in a PDCCH, e.g., by the TCI field in the DCI. The indicated downlink or joint common beam can only be applicable from an applicable time which is the first slot that is at least a configured number of symbols or a configured number of milliseconds after the ACK of a downlink or joint common beam indication, i.e., the DCI for indicating the downlink or joint common beam in such an exemplary embodiment.

Specifically, before the RRC parameter "enableCommonBeam" is configured as "enable, " the beam of the CORESET is determined according to the legacy beam indication mode in R15/R16. After the RRC parameter "enableCommonBeam" is configured as "enable" and before a downlink or joint common beam indicated by DCI in a PDCCH is applicable, the beam of the CORSET will not be changed from the latest beam of the CORESET before the RRC parameter is configured as "enable, " which means that the beam of the CORESET is determined based on the legacy beam indication mode. Only after the RRC parameter "enableCommonBeam" is configured as "enable, " DCI in a PDCCH can be used to indicate a downlink or joint common beam. After a downlink or joint common beam indicated by the DCI is applicable, the beam of the CORESET will be determined as the indicated downlink or joint common beam.

FIG. 3 illustrates an exemplary beam determination procedure in case of switching from a legacy beam indication mode to a common beam indication mode under a RRC based switching scheme according to some embodiments of the present application.

As shown in FIG. 3, before time t1, the RRC parameter "enableCommonBeam" is configured as "disable, " while after time t1 the RRC parameter "enableCommonBeam" is configured as "enable. " It is assumed that CORESET 0 and CORESET 1 are configured for a UE, wherein a downlink or joint common beam mechanism can be applied for CORESET 1 but not applied for CORESET 0. Therefore, the beam indication mode of CORESET 0 will always follow the legacy beam indication mode. It is also assumed that the latest beam of CORESET 0 is beam 1, which is a legacy beam and may be activated by a MAC CE for CORESET 0 before the RRC parameter "enableCommonBeam" is configured as "enable. " After time t1, the beam of CORESET 0 is still beam 1 or a new legacy beam updated by a MAC CE for CORESET 0 according to the legacy beam indication mode, regardless of the configuration of RRC parameter "enableCommonBeam. " It is also assumed that the latest beam of CORESET 1 is beam 2, which is a legacy beam and may be activated by a MAC CE for CORESET 1 before the RRC parameter "enableCommonBeam" is configured as "enable. " After the RRC parameter "enableCommonBeam" is configured as "enable, " a downlink or joint common beam, e.g., beam 3 is indicated by DCI in a PDCCH whose starting applicable time is t2 in FIG. 3. Thus, during time t1 and time t2, the RRC parameter "enableCommonBeam" is configured as "enable" while the indicated downlink or joint common beam, i.e., beam 3 is not applicable, and the beam of CORESET 1 is still beam 2. Only after the downlink or joint common beam is applicable, the beam of CORESET 1 will be the indicated common beam, i.e., beam 3.

In some other exemplary scenarios, the RRC parameter "enableCommonBeam" is configured as "disable" or is not configured and the indication is changed from a previous RRC parameter "enableCommonBeam" configured as "enable. "

For a CORESET included in the subset of CORSETs where a downlink or joint common beam mechanism can be applied, before the RRC parameter "enableCommonBeam" is configured as "disable, " the beam of the CORESET follows the latest applicable downlink or joint common beam when the RRC parameter is previously configured as "enable. " After the RRC parameter "enableCommonBeam" is configured as "disable" and before a beam is updated by a MAC CE for the CORESET, the beam of the CORSET will not change from the latest common beam of the CORESET before the RRC parameter "enableCommonBeam" is changed, which means the beam of the CORESET is determined as the latest downlink or joint common beam before the RRC parameter "enableCommonBeam" is configured as "disable" which is changed from "enable. " According to R15, a new beam activated by a MAC CE for the CORESET is applicable from the first slot that is after slot

wherein k is the slot where the UE will transmit a PUCCH with hybrid automatic repeat request (HARQ) -ACK information for the PDSCH carrying the MAC CE for the TCI state update of the CORESET and μ is the subcarrier spacing (SCS) configuration for the PUCCH. Thus, according to R15, the beam of the CORESET in the subset of CORESETs is the beam activated by a MAC CE from the first slot where the beam is applicable.

FIG. 4 illustrates an exemplary beam determination procedure in case of switching from a common beam indication mode to a legacy beam indication mode under a RRC based switching scheme according to some embodiments of the present application.

As shown in FIG. 4, before time t1, the RRC parameter "enableCommonBeam" is configured as "enable, " while after time t1 the RRC parameter "enableCommonBeam" is configured as "disable. " It is assumed that CORESET 0 and CORESET 1 are configured for a UE, wherein a downlink or joint common beam mechanism can be applied for CORESET 1 but not applied for CORESET 0. Therefore, the beam indication mode of CORESET 0 will always follow the legacy beam indication mode. It is assumed the latest beam of CORESET 0 is beam 1, which is a legacy beam and may be activated by a MAC CE before the RRC parameter "enableCommonBeam" is configured as "disable. " Then after time t1, the beam of CORESET 0 is still beam 1 or a new beam updated by a MAC CE for CORESET 0 according to the legacy scheme, regardless of the configuration of the RRC parameter "enableCommonBeam" . It is also assumed the latest beam of CORESET 1 is beam 2, which is a latest downlink or joint common beam indicated by DCI in a PDCCH before the RRC parameter "enableCommonBeam" is configured as "disable. " After the RRC parameter "enableCommonBeam" is configured as "disable, " a legacy beam, e.g., beam 3 is updated (or activated) for CORESET 1 by a MAC CE for CORESET 1, which is applicable starting from t2 as shown in FIG. 4. During time t1 and time t2, the RRC parameter "enableCommonBeam" is configured as "disable" while beam 3 activated by a MAC CE for CORESET 1 is not applicable, and thus the beam of CORESET 1 is still beam 2, which is the latest downlink or joint common beam. Only after the beam, i.e., beam 3 updated by a MAC CE for CORESET 1 is applicable, the beam of CORESET 1 will be beam 3.

Besides the above exemplary basic solutions, considering various application scenarios, for a CORESET in a subset of CORESETs where a downlink or joint mechanism can be applied, some embodiments of the present application provide exemplary beam determination manners as follows in view of the RRC based switching scheme, wherein the determined beam is associated with the set of downlink RS.

In some embodiments of the present application, the set of downlink RS is a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in any one of the following cases. The first one is that the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has not been provided a configuration of TCI state (s) for the CORESET. The second one is that the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a MAC CE activation command for the CORESET before receiving the configuration of the RRC parameter and after the most recent random access procedure. The third one is that the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter configured as "disable, " and no downlink or joint common TCI state indicated by DCI in a PDCCH is applicable.

According to some other embodiments of the present application, the set of downlink RS is one or more downlink RS configured by a TCI state, in the case that the RRC parameter is not configured or configured as "disable, " wherein the TCI state is only one configured TCI state for the CORESET or the TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET which is applicable.

According to some yet other embodiments of the present application, the RRC parameter is configured as "enable, " and the indication is switched from a previous RRC parameter being not configured or configured as "disable. " Before a downlink or joint common beam is applicable for the CORESET, the set of downlink RS is the one or more downlink RS configured by a most recent TCI state, wherein the most recent TCI state is a only configured TCI state for the CORESET or the most recent TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.

According to some yet other embodiments of the present application, the set of downlink RS is a SSB or a CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in any one of the following cases. The first one is that the UE has been provided a configuration of more than one TCI states for the CORESET as part of the reconfiguration with sync procedure but has not received a MAC CE activation command for the CORESET before receiving the indication, the RRC parameter is configured as "disable" or not configured, and the indication is not switched from a previous RRC parameter configured with "enable. " The second one is that the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter being configured as "disable, " and no downlink or joint common TCI state indicated by DCI in a PDCCH is applicable before receiving the configuration of the RRC parameter.

According to some yet other embodiments of the present application, in the case that the RRC parameter is configured as "enable" and the CORESET is included in the subset of CORESETs, the set of downlink RS is one or more downlink RS configured by a TCI state applicable for the CORESET, wherein the TCI state is a downlink or joint common beam indicated by DCI in a PDCCH.

According to some yet other embodiments of the present application, in the case that the RRC parameter is configured as "disable" or not configured, and the indication is switched from a previous RRC parameter configured as "enable, " the set of downlink RS is one or more downlink RS configured by a most recent TCI state before a TCI state activated by a MAC CE for the CORESET is applicable in the case that more than one TCI states are configured for the CORESET, wherein the most recent transmission configuration indication is indicated by DCI in a PDCCH which indicates a downlink or joint common beam before the indication is switched from a previous RRC parameter configured as "enable. "

MAC CE Based Switching Scheme

Similarly, under the MAC CE based switching scheme, for a CORESET not included in the subset of CORSETs where a downlink or joint common beam mechanism can be applied, the beam indication mode of the CORESET will still follow the legacy beam indication mode regardless of the indication. While for a CORESET included in the subset of CORSETs where a downlink or joint common beam mechanism can be applied, the beam is determined at least based on the indication.

According to some embodiments of the present application, a dedicated MAC CE activation command is introduced into the MAC CE based switching scheme, which is for activating a list of common beams (also referred to as "a MAC CE for common beam indication" ) . The list of common beams includes at least a downlink or joint common beam. In addition, for the legacy beam indication mode, there is a MAC CE activation command activating transmission configuration indication (TCI) state (s) for anyone of the set of CORESETs (also referred to as "a MAC CE for CORESET beam indication" ) , or a MAC CE activation command activating TCI state (s) for PDSCH (also referred to as "a MAC CE for PDSCH beam indication" ) . In other words, there may be a MAC CE for activating or updating a TCI state of a CORESET in case of more than one TCI states being configured for the CORESET in the legacy beam indication mode, or there may be a MAC CE for activating TCI states for PDSCH in the legacy beam indication mode. Both the MAC CE for CORESET beam indication and MAC CE for PDSCH beam indication indicate that no downlink or joint common beam is applied for the subset of CORESETs.

When a UE receives a MAC CE for common beam indication, i.e., a MAC CE activation command where at least a downlink or joint common beam is included, the beam determination for a CORESET of the subset of COREETs will be switched to the common beam indication mode. After the MAC CE activation command, DCI in a PDCCH will indicate a downlink or joint common TCI state which is applicable from an applicable time according to the capability of the UE for all PDSCHs and all or subset of the set of CORESETs. When the UE receives a MAC CE for CORESET beam indication or PDSCH beam indication, the beam determination for a CORESET of the subset of COREETs will be switched to the legacy beam indication mode. That is, when a UE receives a MAC CE activation command of TCI state for any CORESET included in the subset of CORESETs where a downlink or joint common beam mechanism can be applied or receives a MAC CE activation command of TCI state for PDSCH, the beam determination for the CORESET is switched to the legacy beam indication mode.

In some exemplary scenarios, the indication will switch from the legacy beam indication mode to the downlink or joint common beam indication mode.

According to some embodiments of the present application, a MAC CE for common beam indication is received in the UE, which activates a list of common beams including at least one downlink or joint common beam. After that, a downlink or joint common beam can be indicated by DCI in a PDCCH, e.g., by using the TCI field in the DCI. The indicated downlink or joint common beam can only be applicable from an applicable time which is the first slot that is at least a configured number of symbols or a configured number of milliseconds after the ACK of a downlink or joint common beam indication, i.e., the DCI for indicating the downlink or joint common beam in such an exemplary embodiment.

For a CORESET where a downlink or joint common beam mechanism can be applied, i.e., a CORESET included in the subset of CORESETs, before the MAC CE activation command for activating a list of common beams is applicable, the beam of the CORESET is determined according to the legacy beam indication mode. The MAC CE activation command is applicable from the first slot that is after slot

wherein k is the slot where the UE would transmit a PUCCH with HARQ-ACK information for the PDSCH carrying the MAC CE and μ is the SCS configuration for the PUCCH.

When the MAC CE for common beam indication is applicable and before a downlink or joint common beam indicated by DCI in a PDCCH is applicable, there are two alternatives for determining the beam for the CORSET. One is: the beam for the CORESET will be the latest legacy beam of the CORESET before the MAC CE for common beam indication is applicable (Alternative 1) . The other is: the beam for the CORESET will be a downlink or joint common beam with the lowest codepoint in the MAC CE for common beam indication (Alternative 2) .

When a downlink or joint common beam indicated by DCI in a PDCCH is applicable, the beam of the CORESET is determined as the downlink or joint common beam.

FIG. 5 illustrates an exemplary beam determination procedure in case of switching from a legacy beam indication mode to a common beam indication mode under a MAC CE based switching scheme according to some embodiments of the present application.

As shown in FIG. 5, starting from time t1, a MAC CE for common beam indication is applicable, which means the beam indication for the CORESET included in the subset of CORESETs will switch to the common beam indication mode. It is assumed that CORESET 0 and CORESET 1 are configured for a UE, wherein a downlink or joint common beam mechanism can be applied for CORESET 1 but not applied for CORESET 0. Therefore, the beam indication mode of CORESET 0 will always follow the legacy beam indication mode. Before time t1, the latest beam of CORESET 0 is beam 1 and the latest beam of CORESET 1 is beam 2 as shown in FIG. 5, and both of them are legacy beams. It is also assumed that a downlink or joint common beam, e.g., beam 3 is applicable from time t2, which is indicated by DCI in a PDCCH. Then the beam of CORESET 0 is beam 1 after time t1, and the beam of CORESET 1 after t2 is beam 3. During time t1 to time t2, the beam of CORESET 1 is beam 2 according to Alternative 1 which is the latest beam before t1, or is a downlink or joint common beam with the lowest codepoint in the MAC CE for common beam indication according to Alternative 2.

In some other scenarios, the indication will switch from the common beam indication mode to the legacy beam indication mode.

According to some embodiments of the present application, a MAC CE for common beam indication was received before a MAC CE for CORESET beam indication or PDSCH beam indication (a current MAC CE) is received. From the applicable time of the MAC CE for CORESET beam indication or the MAC CE for PDSCH beam indication, the beam determination for a CORESET of the subset of CORESETs where a downlink or common beam mechanism can be applied will switch to the legacy beam indication mode from the downlink or joint common beam indication mode.

Before the MAC CE for CORESET beam indication or PDSCH beam indication is applicable, the beam of the CORESET is determined as the latest downlink or joint common beam which may be indicated by DCI in a PDCCH. According to some embodiments of the present application, the MAC CE for CORESET beam indication or PDSCH beam indication is applicable from the first slot that is after slot

In the case that the current MAC CE is also a MAC CE activating a TCI state for the CORESET or only one TCI state is configured for the CORESET, the beam of the CORESET is the TCI state activated in the current MAC CE from the applicable time of the current MAC CE, which is the first slot that is after slot

wherein k is the slot where the UE will transmit a PUCCH with HARQ-ACK information for the PDSCH carrying the MAC CE and μ is the SCS configuration for the PUCCH or the TCI state configured for the CORESET respectively.

In the case that the current MAC CE is not a MAC CE activating a TCI state for the CORESET and more than one TCI state is configured for the CORESET, before a new MAC CE activating a TCI state for the CORESET is applicable and from the current MAC CE is applicable, the beam of the CORESET is the latest downlink or joint common beam before the current MAC CE is applicable. The beam of the CORESET is the TCI state activated by a new MAC CE for the CORESET TCI state activation from the new MAC CE for the CORESET TCI state activation is applicable.

FIG. 6 illustrates an exemplary beam determination procedure in case of switching from a common beam indication mode to a legacy beam indication mode under a MAC CE based switching scheme according to some other embodiments of the present application.

As shown in FIG. 6, starting from time t1, a MAC CE for PDSCH beam indication is applicable which means it will switch to the legacy beam indication mode. It is assumed that CORESET 0 and CORESET 1 are configured for a UE, wherein a downlink or joint common beam mechanism can be applied for CORESET 1 but not applied for CORESET 0. Therefore, the beam indication mode of CORESET 0 will always follow the legacy beam indication mode. Before time t1, the latest beam of CORESET 0 is beam 1, which is a legacy beam, while the latest beam of CORESET 1 is beam 2, which is a downlink or joint common beam. Then, the beam of CORESET 0 is beam 1 after t1 because it is not include in the subset of CORESETs where a downlink or joint common beam mechanism can be applied. It is also assumed that a legacy beam, e.g., beam 3 activated by another new MAC CE for CORESET 1 is applicable from t2. Then, the beam of CORESET 1 is beam 2 during time t1 to time t2, and the beam of CORESET 1 is beam 3 from time t2.

Besides the above exemplary basic solutions, for a CORESET included in a subset of CORESETs where a downlink or joint common beam mechanism can be applied, considering various application scenarios, some embodiments of the present application provide exemplary beam determination manners as follows in view of the MAC CE based switching scheme, wherein the determined beam is associated with the set of downlink RS.

In some embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable, the set of downlink RS is: a) a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam is indicated before receiving the indication; or b) a SSB or CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as part of the reconfiguration with sync procedure but has not received a MAC CE activation command for the CORESET before receiving the indication and no downlink or joint common beam is indicated before receiving the indication.

According to some other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is: one or more downlink RS configured by a most recent TCI state of the CORESET before the applicable time of the MAC CE activation command, wherein the most recent TCI state is the only one configured TCI state for the CORESET or the most recent TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI states are configured for the CORESET.

According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activating a list of common beams, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is: one or more downlink RS configured by a downlink or joint common TCI state with a lowest codepoint in the MAC CE activation command.

According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of CORESETs or activating TCI states for PDSCH, before an applicable time of the MAC CE activation command, the set of downlink RS is: a) a SSB identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam indication is received before receiving the indication; or b) a SSB or a CSI-RS resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that more than one TCI states are configured for the CORESET as part of the reconfiguration with sync procedure but no MAC CE activation command has been received for the CORESET before receiving the indication and no downlink or joint common beam indication is received before receiving the indication.

According to some yet other embodiments of the present application, in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH, after the MAC CE activation command is applicable and before an applicable time of a MAC CE activation command for activating a TCI state for the CORESET, the set of downlink RS is: one or more downlink RS configured by a most recent downlink or joint common TCI state which is indicated before the applicable time of the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH in the case that another list of common beams has been received before receiving the indication.

Embodiments of the present application also propose an apparatus for beam determination. For example, FIG. 7 illustrates a block diagram of an apparatus 700 for beam determination according to some embodiments of the present application.

As shown in FIG. 7, the apparatus 700 may include at least one non-transitory computer-readable medium 701, at least one receiving circuitry 702, at least one transmitting circuitry 704, and at least one processor 706 coupled to the non-transitory computer-readable medium 701, the receiving circuitry 702 and the transmitting circuitry 704. The apparatus 700 may be a network side apparatus (e.g., a BS) configured to perform a method illustrated in any one of FIGS. 2-6 and the like, or a remote unit (e.g., a UE) configured to perform a method illustrated in any one of FIGS. 2-6 or the like.

Although in this figure, elements such as the at least one processor 706, transmitting circuitry 704, and receiving circuitry 702 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present application, the receiving circuitry 702 and the transmitting circuitry 704 can be combined into a single device, such as a transceiver. In certain embodiments of the present application, the apparatus 700 may further include an input device, a memory, and/or other components.

For example, in some embodiments of the present application, the non-transitory computer-readable medium 701 may have stored thereon computer-executable instructions to cause a processor to implement the method with respect to the UE as described above. For example, the computer-executable instructions, when executed, cause the processor 706 interacting with receiving circuitry 702 and transmitting circuitry 704, so as to perform the steps with respect to the UE depicted in FIG. 2.

In some embodiments of the present application, the non-transitory computer-readable medium 701 may have stored thereon computer-executable instructions to cause a processor to implement the method with respect to the BS as described above. For example, the computer-executable instructions, when executed, cause the processor 706 interacting with receiving circuitry 702 and transmitting circuitry 704, so as to perform the steps with respect to the BS depicted in FIG. 2.

The method according to embodiments of the present application can also be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this application. For example, an embodiment of the present application provides an apparatus for PUSCH transmission with repetition, including a processor and a memory. Computer programmable instructions for implementing a method are stored in the memory, and the processor is configured to perform the computer programmable instructions to implement the method. The method may be a method as stated above or other method according to an embodiment of the present application.

An alternative embodiment preferably implements the methods according to embodiments of the present application in a non-transitory, computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by computer-executable components preferably integrated with a network security system. The non-transitory, computer-readable storage medium may be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical storage devices (CD or DVD) , hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a processor but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present application provides a non-transitory, computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement a method as stated above or other method according to an embodiment of the present application.

In addition, in this disclosure, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The terms "having, " and the like, as used herein, are defined as "including. "

Claims

A method, comprising:

receiving an indication indicating whether a downlink or joint common beam mechanism is applied for a subset of control resource sets (CORESETs) of a set of CORESETs configured for a user equipment (UE) ; and

for a CORESET of the set of CORESETs,

in the case that the CORESET is not included in the subset of CORESETs, monitoring physical downlink control channels (PDCCHs) in the CORESET according to a set of downlink reference signal (RS) regardless of the indication, and

in the case that the CORESET is included in the subset of CORESETs, monitoring the PDCCHs in the CORESET according to the set of downlink RS based on the indication,

wherein a demodulation-reference signal (DM-RS) antenna port associated with PDCCH reception in the CORESET is quasi co-located with the set of downlink RS.
The method of claim 1, wherein, in the case that the CORESET is not included in the subset of CORESETs and the CORESET is CORESET 0, the set of downlink RS is:

a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no medium access control (MAC) control element (CE) activation command indicating a transmission configuration indication (TCI) state for the CORESET is received after the most recent random access procedure; or

one or more downlink RSs configured by a TCI state, wherein the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.
The method of claim 1, wherein, in the case that the CORESET is not included in the subset of CORESETs and the CORESET is non-CORESET 0, the set of downlink RS is:

a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure, in the case that the UE has not been provided a configuration of transmission configuration indication (TCI) state (s) for the CORESET, or the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a medium access control (MAC) control element (CE) activation command for the CORESET;

a SSB or a channel state information-reference signal (CSI-RS) resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as a part of the reconfiguration with sync procedure but has not received the MAC CE activation command; or

one or more downlink RSs configured by a TCI state, wherein the TCI state is only one configured TCI state for the CORESET, or the TCI state is a TCI state activated by a MAC CE for the CORESET in the case that more than one TCI state is configured for the CORESET.
The method of claim 1, wherein the indication is a configuration of radio resource control (RRC) parameter, indicating the downlink or joint common beam mechanism is applied for the subset of CORESETs in the case that the RRC parameter is configured as "enable. "
The method of claim 4, wherein the set of downlink RS is a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that the CORESET is included in the subset of CORESETs and:

the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has not been provided a configuration of transmission configuration indication (TCI) state (s) for the CORESET; or

the RRC parameter is not configured or configured as "disable, " the indication is not switched from a previous RRC parameter configured as "enable, " and the UE has been provided an initial configuration of more than one TCI states for the CORESET but has not received a medium access control (MAC) control element (CE) activation command for the CORESET before receiving the configuration of the RRC parameter and after the most recent random access procedure; or

the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter configured as "disable" , and no downlink or joint common TCI state indicated by downlink control information (DCI) in a PDCCH is applicable.
The method of claim 4, wherein in the case that the CORESET is included in the subset of CORESETs, the RRC parameter is configured as "enable, " and the indication is switched from a previous RRC parameter being not configured or configured as "disable, "

before a downlink or joint common beam is applicable for the CORESET, the set of downlink RS is the one or more downlink RS configured by a most recent transmission configuration indication (TCI) state, wherein the most recent TCI state is a only configured TCI state for the CORESET or the most recent TCI state is activated by a medium access control (MAC) control element (CE) for the CORESET in the case that more than one TCI state is configured for the CORESET.
The method of claim 4, wherein the set of downlink RS is a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) or a channel state information-reference signal (CSI-RS) resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure, in the case that the CORESET is included in the subset of CORESETs and:

the UE has been provided a configuration of more than one transmission configuration indication (TCI) states for the CORESET as part of the reconfiguration with sync procedure but has not received a medium access control (MAC) control element (CE) activation command for the CORESET before receiving the indication, the RRC parameter is configured as "disable" or not configured, and the indication is not switched from a previous RRC parameter configured with "enable" ; or

the RRC parameter is configured as "enable, " the indication is not switched from a previous RRC parameter being configured as "disable, " and no downlink or joint common TCI state indicated by downlink control information (DCI) in a PDCCH is applicable before receiving the configuration of the RRC parameter.
The method of claim 4, wherein in the case that the RRC parameter is configured as "disable" or not configured, the indication is switched from a previous RRC parameter configured as "enable, " and the CORESET is included in the subset of CORESEs; the set of downlink RS is one or more downlink RS configured by a most recent transmission configuration indication (TCI) state before a TCI state activated by a medium access control (MAC) control element (CE) for the CORESET is applicable in the case that more than one TCI states are configured for the CORESET, wherein the most recent transmission configuration indication is indicated by downlink control information (DCI) in a PDCCH which indicates a downlink or joint common beam before the indication is switched from a previous RRC parameter configured as "enable. "
The method of claim 1, wherein the indication is a medium access control (MAC) control element (CE) activation command, and

in the case that the MAC CE activation command is a MAC CE activation command activating a list of common beams, the MAC CE activation command indicates that a downlink or joint common beam in the list of common beams is applied for the subset of CORESETs; and

in the case that the MAC CE activation command is a MAC CE activation command activating transmission configuration indication (TCI) state (s) for any of the set of CORESETs, or a MAC CE activation command activating TCI state (s) for physical downlink shared channel (PDSCH) , the MAC CE activation command indicates that no downlink or joint common beam is applied for the subset of CORESETs.
The method of claim 9, wherein in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by downlink control information (DCI) in a PDCCH is applicable, the set of downlink RS is:

a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam is indicated before receiving the indication; or

a SSB or a channel state information-reference signal (CSI-RS) resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that the UE has been provided a configuration of more than one TCI states for the CORESET as part of the reconfiguration with sync procedure but has not received a MAC CE activation command for the CORESET before receiving the indication and no downlink or joint common beam is indicated before receiving the indication.
The method of claim 9, wherein in the case that the MAC CE activation command is the MAC CE activation command activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by downlink control information (DCI) in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is:

one or more downlink RS configured by a most recent TCI state of the CORESET before the applicable time of the MAC CE activation command, wherein the most recent TCI state is the only one configured TCI state for the CORESET or the most recent TCI state is activated by a MAC CE for the CORESET in the case that more than one TCI states are configured for the CORESET.
The method of claim 9, wherein in the case that the MAC CE activation command is the MAC CE activating a list of common beams and the CORESET is included in the subset of CORESETs, before a downlink or joint common TCI state included in the list of common beams activated by the MAC CE activation command indicated by DCI in a PDCCH is applicable and after the MAC CE activation command is applicable, the set of downlink RS is:

one or more downlink RS configured by a downlink or joint common TCI state with a lowest codepoint in the MAC CE activation command.
The method of claim 9, wherein in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of CORESETs or activating TCI states for PDSCH and the CORESET is included in the subset of CORESETs, before an applicable time of the MAC CE activation command, the set of downlink RS is:

a synchronization signal (SS) /physical broadcast channel (PBCH) block (SSB) identified by the UE during a most recent random access procedure not initiated by a PDCCH order that triggers a contention-free random access procedure, in the case that no other MAC CE activation command indicating a TCI state for the CORESET is received before receiving the indication and after the most recent random access procedure, and no downlink or joint common beam indication is received before receiving the indication; or

a SSB or a channel state information-reference signal (CSI-RS) resource identified by the UE during a random access procedure initiated by a reconfiguration with sync procedure in the case that more than one TCI states are configured for the CORESET as part of the reconfiguration with sync procedure but no MAC CE activation command has been received for the CORESET before receiving the indication and no downlink or joint common beam indication is received before receiving the indication.
The method of claim 9, wherein in the case that the MAC CE activation command is the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH, and the CORESET is included in the subset of CORESETs, after the MAC CE activation command is applicable and before an applicable time of a MAC CE activation command for activating a TCI state for the CORESET, the set of downlink RS is:

one or more downlink RS configured by a most recent downlink or joint common TCI state which is indicated before the applicable time of the MAC CE activation command activating a TCI state for any CORESET in the subset of the CORESETs or activating TCI state (s) for PDSCH in the case that another list of common beams has been received before receiving the indication.
A method, comprising:

transmitting an indication indicating whether a downlink or joint common beam mechanism is applied for a subset of control resource sets (CORESETs) of a set of CORESETs configured for a user equipment (UE) ; and

for a CORESET of the set of CORESETs,

in the case that the CORESET is not included in the subset of CORESETs, transmitting physical downlink control channels (PDCCHs) in the CORESET according to a set of downlink reference signal (RS) regardless of the indication, and

in the case that the CORESET is included in the subset of CORESETs, transmitting the PDCCHs in the CORESET according to the set of downlink RS based on the indication,

wherein a demodulation-reference signal (DM-RS) antenna port associated with PDCCH transmission in the CORESET is quasi co-located with the set of downlink RS.