Patent Publication Number: US-2022231807-A1

Title: Apparatus and method for configuring application of tci state to reference signal

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 119 from U.S. Provisional Application No. 63/137,781, entitled “Common TCI Framework,” filed on Jan. 15, 2021, the subject matter of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosed embodiments relate generally to wireless communication, and, more particularly, to application of TCI state to reference signal. 
     BACKGROUND 
     In conventional network of 3rd generation partnership project (3GPP) 5G new radio (NR), the user equipment (UE) can be configured, by the base station (BS), with a plurality of transmission configuration indication (TCI) states for downlink (DL) transmission and uplink (UL) transmission. After being configured, the UE may apply one or more indicated TCI states to: (1) UE-dedicated physical downlink control channel (PDCCH) reception and corresponding physical downlink share channel (PDSCH) reception; and (2) dynamic-grant/configured-grant based physical uplink share channel (PUSCH) and all dedicated physical uplink share channel (PUCCH) resources. 
     In some situations, the one or more indicated TCI states may be applied to some reference signals. However, how to indicate the UE to apply the one or more indicated TCI states to some reference signals has not been discussed yet. 
     SUMMARY 
     Apparatus and methods are provided for configuring application of transmission configuration indication (TCI) state to a reference signal (RS). In one novel aspect, a radio resource control (RRC) configuration may be introduced for indicating to a user equipment (UE) whether to apply an indicated TCI state to an RS. In particular, a base station (BS) can transmit an RRC configuration of an RS to a UE. The UE can receive the RRC configuration from the BS. After the transmission of the RRC configuration, the BS can transmit an indication of one or more TCI states to the UE. The UE can receive indication of the one or more TCI states from the BS. Then, the UE can apply the one or more TCI states to the reference signal when the RRC configuration indicates to the UE to apply the TCI state to the reference signal. 
     Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention. 
         FIG. 1  illustrates an exemplary 5G new radio network supporting application of TCI state activation to reference signal in accordance with embodiments of the current invention. 
         FIG. 2  is a simplified block diagram of the gNB and the UE in accordance with embodiments of the current invention. 
         FIG. 3A  illustrates one embodiment of message transmissions in accordance with embodiments of the current invention. 
         FIG. 3B  illustrates one embodiment of message transmissions in accordance with embodiments of the current invention. 
         FIG. 4  is a flow chart of a method of configuring application of TCI state to reference signal in accordance with embodiments of the current invention. 
         FIG. 5  is a flow chart of a method of configuring application of TCI state to reference signal in accordance with embodiments of the current invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
       FIG. 1  illustrates an exemplary 5G new radio (NR) network  100  supporting application of transmission configuration indication (TCI) state to reference signal (RS) in accordance with aspects of the current invention. The 5G NR network  100  includes a user equipment (UE)  110  communicatively connected to a gNB  121  operating in a licensed band (e.g., 30 GHz˜300 GHz for mmWave) of an access network  120  which provides radio access using a Radio Access Technology (RAT) (e.g., the 5G NR technology). The access network  120  is connected to a 5G core network  130  by means of the NG interface, more specifically to a User Plane Function (UPF) by means of the NG user-plane part (NG-u), and to a Mobility Management Function (AMF) by means of the NG control-plane part (NG-c). One gNB can be connected to multiple UPFs/AMFs for the purpose of load sharing and redundancy. The UE  110  may be a smart phone, a wearable device, an Internet of Things (IoT) device, and a tablet, etc. Alternatively, UE  110  may be a Notebook (NB) or Personal Computer (PC) inserted or installed with a data card which includes a modem and RF transceiver(s) to provide the functionality of wireless communication. 
     The gNB  121  may provide communication coverage for a geographic coverage area in which communications with the UE  110  is supported via a communication link  101 . The communication link  101  shown in the 5G NR network  100  may include uplink (UL) transmissions from the UE  110  to the gNB  121  (e.g., on the Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH)) or downlink (DL) transmissions from the gNB  121  to the UE  110  (e.g., on the Physical Downlink Control Channel (PDCCH) or Physical Downlink Shared Channel (PDSCH)). 
       FIG. 2  is a simplified block diagram of the gNB  121  and the UE  110  in accordance with embodiments of the present invention. For the gNB  121 , an antenna  197  transmits and receives radio signal. A radio frequency (RF) transceiver module  196 , coupled with the antenna, receives RF signals from the antenna, converts them to baseband signals and sends them to processor  193 . RF transceiver  196  also converts received baseband signals from the processor  193 , converts them to RF signals, and sends out to antenna  197 . Processor  193  processes the received baseband signals and invokes different functional modules and circuits to perform features in the gNB  121 . Memory  192  stores program instructions and data  190  to control the operations of the gNB  121 . 
     Similarly, for the UE  110 , antenna  177  transmits and receives RF signals. RF transceiver module  176 , coupled with the antenna, receives RF signals from the antenna, converts them to baseband signals and sends them to processor  173 . The RF transceiver  176  also converts received baseband signals from the processor  173 , converts them to RF signals, and sends out to antenna  177 . Processor  173  processes the received baseband signals and invokes different functional modules and circuits to perform features in the UE  110 . Memory  172  stores program instructions and data  170  to control the operations of the UE  110 . 
     The gNB  121  and the UE  110  also include several functional modules and circuits that can be implemented and configured to perform embodiments of the present invention. In the example of  FIG. 2 , the gNB  121  includes a set of control functional modules and circuit  180 . TCI handling circuit  182  handles TCI state(s) and associated network parameters for the UE  110 . Configuration and control circuit  181  provides different parameters to configure and control the UE  110 . The UE  110  includes a set of control functional modules and circuit  160 . TCI handling circuit  162  handles TCI state(s) and associated network parameters. Configuration and control circuit  161  handles configuration and control parameters from the gNB  121 . 
     Note that the different functional modules and circuits can be implemented and configured by software, firmware, hardware, and any combination thereof. The function modules and circuits, when executed by the processors  193  and  173  (e.g., via executing program codes  190  and  170 ), allow the gNB  121  and the UE  110  to perform embodiments of the present invention. 
       FIG. 3A  illustrates one embodiment of message transmissions in accordance with one novel aspect. In particular, the gNB  121  transmits a higher layer configuration  1210  of a reference signal (RS) to the UE  110 . The higher layer configuration  1210  indicates to the UE  110  a plurality of TCI states and indicates to the UE  110  whether to apply the plurality TCI states to the RS. The UE  110  receives the higher layer configuration  1210  from the gNB  121 . In some embodiments, the higher layer configuration  1210  may include a radio resource control (RRC) configuration. 
       FIG. 3B  illustrates one embodiment of message transmissions in accordance with one novel aspect. In particular, after the transmission of the higher layer configuration  1210 , the gNB  121  transmits a configuration  1214  to the UE  110 . The configuration  1214  includes an indication  1216  of one or more indicated TCI states of the plurality of TCI states. The UE  110  receives the configuration  1214 . In some embodiments, the configuration  1214  may include a downlink control information (DCI). In some embodiments, the configuration  1214  may include a media access control-control element (MAC-CE). 
     Then, the UE  110  can determine whether to apply the one or more indicated TCI states to the RS according to the higher layer configuration  1210 . In some embodiments, the higher layer configuration  1210  of the RS indicates to the UE  110  to apply the one or more indicated TCI states to the RS. Therefore, the UE  110  applies the one or more indicated TCI states to the RS. In some embodiments, the higher layer configuration  1210  indicates to the UE  110  not to apply the one or more indicated TCI states to the RS. Therefore, the UE  110  determines to transmit the RS without applying the one or more indicated TCI states to the RS. 
     In some embodiments, the RS may include a channel state information-RS (CSI-RS). In some cases, the higher layer configuration  1210  may include a parameter (e.g., an RRC parameter) for a CSI-RS resource configuration to indicate to the UE  110  to apply the one or more indicated TCI states to the CSI-RS. In some cases, the higher layer configuration  1210  may include a parameter (e.g., an RRC parameter) for a CSI-RS set resource configuration to indicate to the UE  110  to apply the one or more indicated TCI states to a CSI-RS set. 
     In some embodiments, the RS may include a sounding RS (SRS). In some cases, the higher layer configuration  1210  may include a parameter (e.g., an RRC parameter) for an SRS resource configuration to indicate to the UE  110  to apply the one or more indicated TCI states to the SRS. In some cases, the higher layer configuration  1210  may include a parameter (e.g., an RRC parameter) for an SRS set resource configuration to indicate to the UE  110  to apply the one or more indicated TCI states to an SRS set. 
     In some embodiments, the RS may include a first demodulation reference signal (DMRS) of a PDCCH on a control resource set (CORESET) and a second DMRS of a PDSCH corresponding to the PDCCH. The higher layer configuration  1210  may include a parameter (e.g., an RRC parameter) for a CORESET configuration to indicate to the UE  110  to apply the one or more TCI states to the first DMRS of the PDCCH on the CORESET and the second DMRS of the PDSCH corresponding to the PDCCH. 
       FIG. 4  is a flow chart of a method of configuring application of TCI state to RS from UE perspective in a 5G/NR network in accordance with one novel aspect. In step  401 , a UE receives an RRC configuration of an RS from a network. In step  402 , the UE receives an indication of one or more TCI states from the network. In step  403 , the UE determines whether to apply the one or more TCI states to the RS according to the RRC. 
     When the RRC configuration indicates to the UE to apply the one or more TCI states to the RS, in step  404 , the UE applies the one or more TCI states to the RS. When the RRC configuration indicates to the UE not to apply the one or more TCI states to the RS, in step  405 , the UE determines to transmit the RS without applying the one or more TCI states to the RS. 
       FIG. 5  is a flow chart of a method of configuring application of TCI state to RS from BS perspective in a 5G/NR network in accordance with one novel aspect. In step  501 , the BS transmits an RRC configuration of an RS to a UE. In step  502 , the BS transmits an indication of one or more TCI states to the UE so that the UE determines whether to apply the TCI state to the RS according to the RRC configuration of the RS. 
     In some embodiments, the indication is included in a DCI or a MAC-CE. The RS includes: (1) a CSI-RS; (2) an SRS; or (3) a first DMRS of a PDCCH on a CORESET and a second DMRS of a PDSCH corresponding to the PDCCH. 
     When the RS includes the CSI-RS, the RRC configuration may include: (1) an RRC parameter for a CSI-RS resource configuration to indicate to the UE to apply the one or more TCI states to the CSI-RS; or (2) an RRC parameter for a CSI-RS set resource configuration to indicate to the UE to apply the one or more TCI states to a CSI-RS set. 
     When the RS includes the SRS, the RRC configuration may include: (1) an RRC parameter for an SRS resource configuration to indicate to the UE to apply the one or more TCI states to the SRS; or (2) an RRC parameter for an SRS set resource configuration to indicate to the UE to apply the one or more TCI states to an SRS set. 
     When the RS includes the first DMRS of the PDCCH on the CORESET and the second DMRS of the PDSCH corresponding to the PDCCH, the RRC configuration may include an RRC parameter for a CORESET configuration to indicate to the UE to apply the one or more TCI states to the first DMRS of the PDCCH on the CORESET and the second DMRS of the PDSCH corresponding to the PDCCH. 
     Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.