Patent Publication Number: US-2023135408-A1

Title: Methods and apparatus for beam determination for physical uplink control channel (pucch) transmission

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/108,500, filed Nov. 2, 2020, which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     This application relates to the communications field, and more specifically, to a wireless communications system, method, and device. 
     BACKGROUND 
     Rapid growth in computing technology is creating a greater demand for data communication. The increasing demand in turn drives further growth in communication technology, including multi-beam communication or operations. New radio (NR) or 5th generation (5G) communication system supports uplink power control on uplink physical uplink control channel (PUSCH) transmission and sounding reference signal (SRS) transmission. Pathloss of transmission can be estimated based on measuring a downlink reference signal. For example, a channel-state information reference signal (CSI-RS) or a Synchronization Signal/Physical Broadcast Channel (SS/PBCH) block can be configured as pathloss reference signal. 
     For each physical uplink control channel (PUCCH) resource, a Radio Resource Control (RRC) parameter can be used to provide (i) one reference signal to provide spatial relation information and (ii) one downlink reference signal to provide path loss reference signal for that PUCCH resource. However, when a beam failure occurs, there would be no reference signal available and thus there is no mechanism to recover the transmission beam of uplink channels. Therefore, it is advantageous to have improved methods or systems to address the foregoing issue. 
     SUMMARY 
     The present disclosure provides methods and systems for beam determination for a PUCCH transmission, in response to detecting a beam failure event. The present methods can be implemented by a user equipment (UE). The methods include, for example, (1) upon detecting beam failure of a serving cell, starting a contention-based random-access channel (RACH); (2) transmitting a medium access control (MAC) control element (CE); (3) determining completion of the contention-based RACH based on receipt of a physical downlink control channel (PDCCH); and (4) after receiving one or more of the last symbols of the PDCCH, determining a default transmission (Tx) beam for each resource of a PUCCH that includes a PUCCH spatial relation information parameter. 
     In some embodiments, the MAC CE signals the beam failure of the serving cell in a message of the contention-based RACH. In some embodiments, the default transmission beam matches a spatial-domain filter used in the latest physical RACH (PRACH) transmission. 
     The methods can further include determining, after receiving one or more of the last symbols of the PDCCH, one or more power control parameters. The power control parameters includes a reference signal (RS) resource index for uplink, “q u ,” an RS resource index for downlink, “q d ,” and/or a PUCCH power control adjustment state, “I.” In some embodiments, the RS resource index for uplink “q u ” can be set to “0.” The RS resource index for downlink “q d ” can be set to a RS selected for a preamble (“Msg1”) transmission in the PRACH “q new .” The PUCCH power control adjustment state “I ” can be set to “0.” 
     The methods can further include receiving, from a next-generation node B base station (gNB), one or more PUCCH resources. One or more of the PUCCH resources can include the PUCCH spatial relation information parameter. 
     Another aspect of the present disclosure includes a UE configured to (1) start a contention-based RACH upon detecting beam failure of a serving cell; (2) transmit a MAC CE (the MAC CE signals the beam failure of the serving cell in a message of the contention-based RACH); (3) determine completion of the contention-based RACH based on receipt of a PDCCH; and (4) after receiving one or more of the last symbols of the PDCCH, determine a default transmission beam for each resource of a PUCCH that includes a PUCCH spatial relation information parameter. 
     In some embodiment, the present method can be implemented by a tangible, non-transitory, computer-readable medium having processor instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform one or more aspects/features of the method described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To describe the technical solutions in the implementations of the present disclosure more clearly, the following briefly describes the accompanying drawings. The accompanying drawings show merely some aspects or implementations of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG.  1    is a schematic diagram of a wireless communication system in accordance with one or more implementations of the present disclosure. 
         FIG.  2    is a flowchart of a method in accordance with one or more implementations of the present disclosure. 
         FIG.  3    is a flowchart of a method in accordance with one or more implementations of the present disclosure. 
         FIG.  4    is a schematic block diagram of a terminal device in accordance with one or more implementations of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    illustrates a wireless communications system  100  for implementing the present technology. As shown in  FIG.  1   , the wireless communications system  100  can include a network device (or base station)  101 . Examples of the network device  101  include a base transceiver station (Base Transceiver Station, BTS), a NodeB 
     (NodeB, NB), an evolved Node B (eNB or eNodeB), a Next Generation NodeB (gNB or gNode B), a Wireless Fidelity (Wi-Fi) access point (AP), etc. In some embodiments, the network device  101  can include a relay station, an access point, an in-vehicle device, a wearable device, and the like. The network device  100  can include wireless connection devices for communication networks such as: a Global System for Mobile Communications (GSM) network, a Code Division Multiple Access (CDMA) network, a Wideband CDMA (WCDMA) network, an LTE network, a cloud radio access network (Cloud Radio Access Network, CRAN), an Institute of Electrical and Electronics Engineers (IEEE) 802.11-based network (e.g., a Wi-Fi network), an Internet of Things (IoT) network, a device-to-device (D2D) network, a next-generation network (e.g., a 5G network), a future evolved public land mobile network (Public Land Mobile Network, PLMN), or the like. A 5G system or network can be referred to as a new radio (New Radio, NR) system or network. 
     In  FIG.  1   , the wireless communications system  100  also includes a terminal device  103 . The terminal device  103  can be an end-user device configured to facilitate wireless communication. The terminal device  103  can be configured to wirelessly connect to the network device  101  (via, e.g., via a wireless channel  105 ) according to one or more corresponding communication protocols/standards. The terminal device  103  may be mobile or fixed. The terminal device  103  can be a user equipment (UE), an access terminal, a user unit, a user station, a mobile site, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communications device, a user agent, or a user apparatus. Examples of the terminal device  103  include a modem, a cellular phone, a smartphone, a cordless phone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having a wireless communication function, a computing device or another processing device connected to a wireless modem, an in-vehicle device, a wearable device, an Internet-of-Things (IoT) device, a device used in a 5G network, a device used in a public land mobile network, or the like. For illustrative purposes,  FIG.  1    illustrates only one network device  101  and one terminal device  103  in the wireless communications system  100 . However, in some instances, the wireless communications system  100  can include additional network device  101  and/or terminal device  103 . 
     The terminal device  103  is configured to start a contention-based RACH upon detecting beam failure of a serving cell. The terminal device  103  is further configured to transmit a MAC CE, which signals the beam failure of the serving cell in a message of the contention-based RACH. The terminal device  103  then determines completion of the contention-based RACH based on receipt of a PDCCH. After receiving one or more of the last symbols of the PDCCH, The terminal device  103  then determines a default transmission (Tx) beam for each resource of a PUCCH that includes a PUCCH spatial relation information parameter. 
     In some embodiments, the contention-based RACH can be a “4-step” process or a “2-step” process. In some embodiments, the beam failure can be detected by a “beam failure recovery” or “link recovery” process. In some embodiments, the serving cell can be either a primary cell (PCell) or a secondary cell (SpCell or PSCell). In some embodiments, the message of the contention-based RACH ca be a scheduled PUSCH Tx (e.g., “Msg3”). In some embodiments, the message of the contention-based RACH is a single message (e.g., “MsgA”). The single message “MsgA” includes a preamble (e.g., “Msg1”) and a scheduled PUSCH Tx (e.g., “Msg3”). 
     For example, in a contention-based RACH-based PCell/PSCell beam failure recovery process, if “Msg3” or “MsgA” of the contention-based RACH contains an MAC CE for beam failure recovery, the terminal device  103  can transmit a PUCCH in the PCell/PSCell with a same spatial domain filter used for the latest PRACH transmission. By this arrangement, the terminal device  103  can determine the default transmission beam for each resource of the PUCCH. 
     In some embodiments, the terminal device  103  is further configured to determine, after receiving one or more of the last symbols of the PDCCH, one or more power control parameters. For example, after receiving “K” (e.g., 28) symbols from the last symbol of the PDCCH, the terminal device  103  can determine that the contention-based RACH based beam failure recovery is complete. Details of the contention-based RACH based beam failure recovery are described in 3GPP TS 38.321, Clause 5.1.5, which is incorporated by reference herein in its entirety. 
     In some embodiments, the terminal device  103  is further configured to determine, after receiving one or more of the last symbols of the PDCCH, one or more power control parameters. In some embodiments, the power control parameters include a RS resource index for uplink, q u , an RS resource index for downlink, q d , and/or a PUCCH power control adjustment state, “I.” 
     In some embodiments, the RS resource index for uplink “q u ” can be set as “0,” the RS resource index for downlink “q d ” can be set as “q new ,” which is the RS (e.g., CSI-RS resource or SS/PBCH block) selected for the preamble “Msg1” transmission in the PRACH, and the PUCCH power control adjustment state “I ” can be set as “0.” 
     In some embodiments, the terminal device  103  is further configured to receive, from a gNB, one or more PUCCH resources. One or more of the PUCCH resources includes the PUCCH spatial relation information parameter. 
       FIG.  2    is a flowchart of a method  200  in accordance with one or more implementations of the present disclosure. The method  200  can be implemented by a terminal device or UE (e.g., the terminal device  103 ). The method  200  is for beam determination for a PUCCH transmission, in response to detecting a beam failure event. 
     At block  201 , the method  200  includes upon detecting beam failure of a serving cell, starting a contention-based RACH. At block  203 , the method  200  includes transmitting an MAC CE. At block  205 , the method  200  continuers by determining completion of the contention-based RACH based on receipt of a PDCCH. At block  207 , the method  200  continuers by determining, after receiving one or more of the last symbols of the PDCCH, a default transmission beam for each resource of a PUCCH that includes a PUCCH spatial relation information parameter. 
     In some embodiments, the MAC CE signals the beam failure of the serving cell in a message of the contention-based RACH. In some embodiments, the default transmission beam matches a spatial-domain filter used in the latest PRACH transmission. 
     The method  200  can include determining, after receiving one or more of the last symbols of the PDCCH, one or more power control parameters. The power control parameters comprise an RS resource index for uplink, “q u ,” an RS resource index for downlink, “q d ,” and/or a PUCCH power control adjustment state, “I.” In some embodiments, the RS resource index for uplink “q u ” can be set to “0.” The RS resource index for downlink “q d ” can be set to a RS selected for a preamble (“Msg1”) transmission in the PRACH “q new .” The PUCCH power control adjustment state “I ” can be set to “0.” 
     The methods can further include receiving, from a next-generation node B base station (gNB), one or more PUCCH resources. One or more of the PUCCH resources can include the PUCCH spatial relation information parameter. 
     In some embodiments, the serving cell can be either a primary cell or a primary secondary cell. In some embodiments, the message of the contention-based RACH can be a scheduled PUSCH transmission (e.g., “Msg3”). In some embodiments, the message of the contention-based RACH is a single message (e.g., “MsgA”). The “MsgA” can include a preamble (e.g., “Msg1”) and a scheduled PUSCH transmission (e.g., “Msg3”). 
       FIG.  3    is a flowchart of a method in accordance with one or more implementations of the present disclosure. The method  300  can be implemented by a base station (e.g., a gNB, the network device  101 , etc.), a terminal device or UE (e.g., the terminal device  103 ), etc. The method  300  is for beam determination for a PUCCH transmission, in response to detecting a beam failure event. 
     At block  301 , the method  300  includes a gNB configures “K” PUCCH resources to a UE. Each PUCCH resource is provided with a parameter “PUCCH-SpatialRelationInfo.” The parameter “PUCCH-SpatialRelationInfo” is for the UE to determine how to determine beams for PUCCH transmissions. 
     At block  303 , the method  300  includes configuring the UE operate a beam failure recovery process on a PCell or PScell. At block  305 , the UE detects beam failure on the PCell or PScell and then initiates a contention-based RACH to transmit a MAC CE for beam failure. The MAC CE for beam failure is in “Msg3” or “MsgA” of the contention-based RACH. 
     At block  305 , the UE uses a first PDCCH reception to determine the completion of the contention-based RACH based beam failure recovery process. At decision block  309 , the UE determines if the PUCCH is configured with the parameter “PUCCH-SpatialRelationInfo.” If negative, the method  300  goes back to previous step block  307 . If positive, the method  300  moves to block  311 . At block  311 , after “K” symbols from the last symbols of the first PDCCH reception, the UE determines a “default” transmission beam and power control parameters for that PUCCH resource. 
     In some embodiments, the “default” transmission beam can be the same as the spatial domain filter used for the latest PRACH transmission. The power control parameters can be “q u =0,” “q d =q new ,” and “I=0.” The parameter “q new ” can be the SS/PBCH block or CSI-RS resource index that was selected for the last PRACH transmission. 
     In other embodiments, the UE can transmit a first PUSCH MAC CE providing an index for the PCell or the PSCell with a radio link quality (which can be lower than a threshold “Q out , LR”). The first PUSCH can be scheduled by a Random Access Response (RAR) UL grant. After “K” (e.g.,  28 ) symbols from the last symbol of the PDCCH reception addressed to Cell Radio Network Temporary Identifier (C-RNTI) that is used to consider successful contention resolution as described in Clause 5.1.5 and Clause 5.1.4a of 3GPP TS 38.321. If a PUCCH resource is provided with the parameter “PUCCH-SpatialRelationInfo,” the UE can transmit the PUCCH on the same cell as used by the PRACH transmission. 
     In such embodiments, the power control parameters can be “q u =0,” “q d =q new ,” and “I=0.” The parameter “q new ” can be the SS/PBCH block or CSI-RS resource index that was selected for the last PRACH transmission. 
       FIG.  4    is a schematic block diagram of a terminal device  400  (e.g., an example of the terminal device  103  of  FIG.  1   ) in accordance with one or more implementations of the present disclosure. As shown in  FIG.  4   , the terminal device  400  includes a processing unit  410  (e.g., a DSP, a CPU, a GPU, etc.) and a memory  420 . The processing unit  410  can be configured to implement instructions that correspond to the method  200  of  FIG.  2    and the method  300  of  FIG.  3    and/or other aspects of the implementations described above. 
     It should be understood that the processor in the implementations of this technology may be an integrated circuit chip and has a signal processing capability. During implementation, the steps in the foregoing method may be implemented by using an integrated logic circuit of hardware in the processor or an instruction in the form of software. The processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or transistor logic device, and a discrete hardware component. The methods, steps, and logic block diagrams disclosed in the implementations of this technology may be implemented or performed. The general-purpose processor may be a microprocessor, or the processor may be alternatively any conventional processor or the like. The steps in the methods disclosed with reference to the implementations of this technology may be directly performed or completed by a decoding processor implemented as hardware or performed or completed by using a combination of hardware and software modules in a decoding processor. The software module may be located at a random-access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, or another mature storage medium in this field. The storage medium is located at a memory, and the processor reads information in the memory and completes the steps in the foregoing methods in combination with the hardware thereof. 
     It may be understood that the memory in the implementations of this technology may be a volatile memory or a non-volatile memory, or may include both a volatile memory and a non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory may be a random-access memory (RAM) and is used as an external cache. For exemplary rather than limitative description, many forms of RAMs can be used, and are, for example, a static random-access memory (SRAM), a dynamic random-access memory (DRAM), a synchronous dynamic random-access memory (SDRAM), a double data rate synchronous dynamic random-access memory (DDR SDRAM), an enhanced synchronous dynamic random-access memory (ESDRAM), a synchronous link dynamic random-access memory (SLDRAM), and a direct Rambus random-access memory (DR RAM). It should be noted that the memories in the systems and methods described herein are intended to include, but are not limited to, these memories and memories of any other suitable type. 
     The above Detailed Description of examples of the disclosed technology is not intended to be exhaustive or to limit the disclosed technology to the precise form disclosed above. While specific examples for the disclosed technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the described technology, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative implementations may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative implementations or sub-combinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed or implemented in parallel, or may be performed at different times. Further, any specific numbers noted herein are only examples; alternative implementations may employ differing values or ranges. 
     In the Detailed Description, numerous specific details are set forth to provide a thorough understanding of the presently described technology. In other implementations, the techniques introduced here can be practiced without these specific details. In other instances, well-known features, such as specific functions or routines, are not described in detail in order to avoid unnecessarily obscuring the present disclosure. References in this description to “an implementation/embodiment,” “one implementation/embodiment,” or the like mean that a particular feature, structure, material, or characteristic being described is included in at least one implementation of the described technology. Thus, the appearances of such phrases in this specification do not necessarily all refer to the same implementation/embodiment. On the other hand, such references are not necessarily mutually exclusive either. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more implementations/embodiments. It is to be understood that the various implementations shown in the figures are merely illustrative representations and are not necessarily drawn to scale. 
     Several details describing structures or processes that are well-known and often associated with communications systems and subsystems, but that can unnecessarily obscure some significant aspects of the disclosed techniques, are not set forth herein for purposes of clarity. Moreover, although the following disclosure sets forth several implementations of different aspects of the present disclosure, several other implementations can have different configurations or different components than those described in this section. Accordingly, the disclosed techniques can have other implementations with additional elements or without several of the elements described below. 
     Many implementations or aspects of the technology described herein can take the form of computer- or processor-executable instructions, including routines executed by a programmable computer or processor. Those skilled in the relevant art will appreciate that the described techniques can be practiced on computer or processor systems other than those shown and described below. The techniques described herein can be implemented in a special-purpose computer or data processor that is specifically programmed, configured, or constructed to execute one or more of the computer-executable instructions described below. Accordingly, the terms “computer” and “processor” as generally used herein refer to any data processor. Information handled by these computers and processors can be presented at any suitable display medium. Instructions for executing computer- or processor-executable tasks can be stored in or on any suitable computer-readable medium, including hardware, firmware, or a combination of hardware and firmware. Instructions can be contained in any suitable memory device, including, for example, a flash drive and/or other suitable medium. 
     The term “and/or” in this specification is only an association relationship for describing the associated objects, and indicates that three relationships may exist, for example, A and/or B may indicate the following three cases: A exists separately, both A and B exist, and B exists separately. 
     These and other changes can be made to the disclosed technology in light of the above Detailed Description. While the Detailed Description describes certain examples of the disclosed technology, as well as the best mode contemplated, the disclosed technology can be practiced in many ways, no matter how detailed the above description appears in text. Details of the system may vary considerably in its specific implementation, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosed technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosed technology with which that terminology is associated. Accordingly, the invention is not limited, except as by the appended claims. In general, the terms used in the following claims should not be construed to limit the disclosed technology to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. 
     A person of ordinary skill in the art may be aware that, in combination with the examples described in the implementations disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application. 
     Although certain aspects of the invention are presented below in certain claim forms, the applicant contemplates the various aspects of the invention in any number of claim forms. Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms, in either this application or in a continuing application.