Patent Publication Number: US-2023156626-A1

Title: Method and apparatus for power control of physical uplink control channel repetitions

Description:
TECHNICAL FIELD 
     Embodiments of the present disclosure are related to wireless communication technology, and more particularly, related to methods and apparatuses for power control of physical uplink control channel (PUCCH) repetitions of a PUCCH transmission with one or more beams or multiple transmit-receive points (TRPs). 
     BACKGROUND 
     In a wireless communication system, the term “beam” is introduced for wireless communications in high frequency bands, such as FR2 (from 24.25 GHz to 52.6 GHz) or other frequency bands higher than 6 GHz. A beam refers to a main lobe of the radiation pattern of an antenna array or a panel. Each beam is associated with a spatial transmitter or receiver. 
     Currently, in a 3rd Generation Partnership Project (3GPP) New Radio (NR) system or the like, details regarding how to improve the reliability and robustness of an uplink (UL) transmission by using one or more beams when there are multiple beam links between a user equipment (UE) and a base station (BS) have not been specifically discussed in 3GPP 5G NR technology yet. 
     SUMMARY 
     Some embodiments of the present application provide a method for wireless communications. The method may be performed by a UE. The method includes: receiving configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission, wherein the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions; determining power for each PUCCH repetition of the plurality of PUCCH repetitions according to the configuration information and a mapping relationship between the each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets; and transmitting, by using the determined power for the each PUCCH repetition, the each PUCCH repetition in a time interval of a plurality of time intervals. 
     Some embodiments of the present application also provide an apparatus for wireless communications. The apparatus includes: a non-transitory computer-readable medium having stored thereon computer-executable instructions; a receiving circuitry; a transmitting circuitry; and a processor coupled to the non-transitory computer-readable medium, the receiving circuitry and the transmitting circuitry, wherein the computer-executable instructions cause the processor to implement the above-mentioned method performed by a UE. 
     Some embodiments of the present application provide a method for wireless communications. The method may be performed by a BS. The method includes: transmitting configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission, and the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions; and receiving each PUCCH repetition of the plurality of PUCCH repetitions in a time interval of a plurality of time intervals, and power for the each PUCCH repetition is determined according to the configuration information and a mapping relationship between the each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets. 
     Some embodiments of the present application provide an apparatus for wireless communications. The apparatus includes: a non-transitory computer-readable medium having stored thereon computer-executable instructions, a receiving circuitry; a transmitting circuitry; and a processor coupled to the non-transitory computer-readable medium, the receiving circuitry and the transmitting circuitry, and the computer-executable instructions cause the processor to implement the above-mentioned method performed by a BS. 
     The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which advantages and features of the present disclosure can be obtained, a description of the present disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the present disclosure and are not therefore intended to limit the scope of the present disclosure. 
         FIG.  1    illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present application; 
         FIG.  2    illustrates a flow chart of a method for wireless communications in accordance with some embodiments of the present application; 
         FIG.  3    illustrates an exemplary scheme for determining power of PUCCH repetitions of a PUCCH transmission in accordance with some embodiments of the present disclosure; 
         FIG.  4    illustrates another exemplary scheme for determining power of PUCCH repetitions of a PUCCH transmission in accordance with some embodiments of the present disclosure; 
         FIG.  5    illustrates a flow chart of a method for wireless communications in accordance with some embodiments of the present application; 
         FIG.  6    illustrates an exemplary block diagram of an apparatus in accordance with some embodiments of the present application; and 
         FIG.  7    illustrates an exemplary block diagram of an apparatus in accordance with 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 disclosure and is not intended to represent the only form in which the present disclosure 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 disclosure. 
     Reference will now be made in detail to some embodiments of the present disclosure, 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 3GPP 5G, 3GPP LTE Release 8 and so on. Persons skilled in the art know very well that, with the development of network architecture and new service scenarios, the embodiments in the present disclosure are also applicable to similar technical problems. 
       FIG.  1    illustrates a schematic diagram of a wireless communication system  100  in accordance with some embodiments of the present application. 
     As shown in  FIG.  1   , the wireless communication system  100  includes a BS  102  and a UE  104 . 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 disclosure. 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 disclosure. 
     The BS  102  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  102  is generally part of a radio access network that may include a controller communicably coupled to the BS  102 . 
     The UE  104  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 disclosure, the UE  104  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  104  may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the UE  104  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. 
     The UE  104  may communicate with the BS  102  to receive data packets from the BS  102  on downlink (DL) and/or transmit data packets to the BS  102  on uplink (UL). The UE  104  may activate multiple panels for communications between the UE  104  and the BS  102 , and report the panel status to the BS  102  by higher layer signaling such as radio resource control (RRC) signaling or medium access control (MAC) control element (CE) signaling. 
     In 3GPP NR Release 15, a mechanism of PUCCH repetitions with inter-slot frequency hopping has already been supported for improving the robustness of PUCCH transmissions, and has been drafted in 3GPP standard document TS38.213. A UL beam is expressed as spatial relation information. 
     Multiple PUCCH power control parameter sets may be configured for a PUCCH transmission with PUCCH repetitions, and each PUCCH power control parameter set is associated with a piece of spatial relation information configured for the PUCCH transmission. 
     As drafted in 3GPP standard document TS38.331, each piece of PUCCH spatial relation information is mapped to a set of PUCCH power control parameters which includes PUCCH pathloss reference signal (RS), p0-PUCCH, and a closed loop index. Specifically, TS38.331 defines “PUCCH-SpatialRelationlnfo information element” as follows: 
     
       
         
           
               
             
               
                   
               
               
                 PUCCH-SpatialRelationInfo information element 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 -- ASN1START 
               
               
                 -- TAG-PUCCH-SPATIALRELATIONINFO-START 
               
            
           
           
               
               
            
               
                  PUCCH-SpatialRelationInfo ::= 
                  SEQUENCE { 
               
               
                   pucch-SpatialRelationInfoId 
                 PUCCH-SpatialRelationInfoId, 
               
               
                   servingCellId 
                   ServCellIndex 
               
               
                  OPTIONAL, -- Need S 
               
               
                   referenceSignal 
                   CHOICE { 
               
               
                    ssb-Index 
                    SSB-Index, 
               
               
                    csi-RS-Index 
                    NZP-CSI-RS-ResourceId, 
               
               
                    srs 
                    SEQUENCE { 
               
               
                   
                     resource   SRS-ResourceId, 
               
               
                   
                     uplinkBWP   BWP-Id 
               
               
                   
                     } 
               
               
                   }, 
               
               
                   pucch-PathlossReferenceRS-Id 
                   PUCCH-PathlossReferenceRS-Id, 
               
               
                   p0-PUCCH-Id 
                    P0-PUCCH-Id, 
               
               
                   closedLoopIndex 
                   ENUMERATED { i0, i1 } 
               
               
                  } 
               
               
                  PUCCH-SpatialRelationInfoId ::= 
                 INTEGER (1..maxNrofSpatialRelationInfos) 
               
               
                   
               
            
           
         
       
     
     In addition, 3GPP standard document TS38.213 defines that:
         If a UE is provided PUCCH-SpatialRelationlnfo, the UE obtains a mapping, by an index provided by p0-PUCCH-Id, between a set of pucch-SpatialRelationlnfold values and a set of p0-PUCCH-Value values;   If the UE is provided two or more values for pucch-SpatialRelationlnfold and the UE receives an activation command [11, TS38.321] indicating a value of pucch-SpatialRelationlnfold, the UE determines the p0-PUCCH-Value value through the link to a corresponding p0-PUCCH-Id index;   If the UE is not provided PUCCH-SpatialRelationlnfo, the UE obtains the p0-PUCCH-Value value from the P0-PUCCH with p0-PUCCH-Id value equal to the minimum p0-PUCCH-Id value in p0-Set;   If the UE is provided pathlossReferenceRSs and PUCCH-SpatialRelationlnfo, the UE obtains a mapping, by indexes provided by corresponding values of pucch-PathlossReferenceRS-Id, between a set of pucch-SpatialRelationlnfold values and a set of referenceSignal values provided by PUCCH-PathlossReferenceRS.   If the UE is provided more than one values for pucch-SpatialRelationlnfold and the UE receives an activation command [ 11 , TS38.321] indicating a value of pucch-SpatialRelationlnfold, the UE determines the referenceSignal value in PUCCH-PathlossReferenceRS through a link between the UE and a BS to a corresponding pucch-PathlossReferenceRS-Id index; and   If the UE is provided pathlossReferenceRSs and is not provided PUCCH-SpatialRelationlnfo, the UE obtains the referenceSignal value in PUCCH-PathlossReferenceRS from the pucch-PathlossReferenceRS-Id with index 0 in PUCCH-PathlossReferenceRS where the RS resource is either on a same serving cell or, if provided, on a serving cell indicated by a value of pathlossReferenceLinking.       

     During 3GPP NR Release 17 study item phase, PUCCH repetitions with one or more beams or multiple TRPs in multiple slots can utilize the spatial diversity of one or more beams or multiple TRPs of a PUCCH transmission to increase the reliability and robustness. Considering a PUCCH transmission with PUCCH repetitions by using one or more beams may be received by multiple TRPs, a power control of the PUCCH repetitions should be different according to different links between a UE and different TRPs. The power control of a PUCCH transmission with one or more beam corresponding to different TRP receptions should be separately controlled. Therefore, an issue on how to enhance a power control of PUCCH repetitions of a PUCCH transmission needs to be solved. 
     Based on this, one object of the embodiments of the present application targets to the future enhancement of PUCCH repetitions of a PUCCH transmission in 3GPP NR Release 17 on one or more beams or multiple TRPs, which involves issues on how to improve reliability and robustness of physical downlink control channel (PDCCH), physical uplink shared channel (PUSCH), and PUCCH transmissions by using multi-TRP and/or multi-panel, especially, when there are multiple beam links between a UE and a BS and etc. More details on the embodiments of the present disclosure will be illustrated in the following text in combination with the appended drawings. 
     3GPP NR Release 16 supports PDSCH repetition with one or more beams in a “single DCI based multiple TRPs” case, which implies that a backhaul of multiple TRPs is ideal or almost ideal. Some embodiments of the present application assume that one or more beams are configured or indicated for PUCCH repetition in the “single DCI based multiple TRPs” case. 
       FIG.  2    illustrates a flow chart of a method for wireless communications in accordance with some embodiments of the present application. The method may be implemented by a UE (e.g., UE  104  as illustrated and shown in  FIG.  1   ). 
     In the exemplary method  200  as illustrated and shown in  FIG.  2   , in step  202 , a UE may receive configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission. In some embodiments of the present disclosure, the configuration information is configured by RRC signaling. 
     In some embodiments of the present disclosure, the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions. Each power control parameter set of the plurality of the power control parameter sets may at least include a power offset identifier, a pathloss reference RS identifier, and a closed loop index. 
     The power offset identifier may be included in a power offset list, the pathloss reference RS identifier is included in a pathloss reference RS list, and the closed loop index is a value of a plurality of predefined values. For instance, the power offset list or the pathloss reference RS list may be configured by high layer signaling. 
     In an embodiment of the present disclosure, each power control parameter set may be associated with a transmit power control (TPC) command indicated by a downlink control information (DCI). The DCI is associated with the closed loop index included in the each power control parameter set in the configuration information. The DCI may be used for scheduling the PUCCH transmission. For example, the DCI includes a TPC command field, and the TPC command field indicates TPC commands of a plurality of closed loop indexes. 
     In an embodiment of the present disclosure, each power control parameter set of the plurality of power control parameter sets in the configuration information is associated with one piece of spatial relation information of a plurality of pieces of spatial relation information configured for the PUCCH transmission. 
     In some embodiments of the present disclosure, in response to the PUCCH transmission being not configured with spatial relation information; the closed loop index, the power offset identifier, and the pathloss reference RS included in a power control parameter set in the configuration information are predefined. A specific example is shown in  FIG.  4   . 
     In step  204 , the UE determines power for each PUCCH repetition. The power for each PUCCH repetition may be determined according to the configuration information and a mapping relationship between each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets included in the configuration information. 
     For instance, with reference to the embodiments of  FIG.  3   , the mapping relationship determined in step  204  indicates the beam parameter mapping pattern  0011 . With reference to the embodiments of  FIG.  4   , the mapping relationship determined in step  204  indicates the power control parameter mapping pattern  0101 . Details regarding the embodiments of  FIGS.  3  and  4    are described below. 
     In step  206 , the UE transmits, by using the determined power for each PUCCH repetition, each PUCCH repetition in the time domain, such as, in a time interval of a plurality of time intervals. 
     Details described in all other embodiments of the present application (for example, details of how to improve reliability and robustness of PUCCH repetitions of a PUCCH transmission by using multi-TRP and/or multi-panel) are applicable for the embodiments of  FIG.  2   . Moreover, details described in the embodiments of  FIG.  2    are applicable for all the embodiments of  FIGS.  1  and  3 - 7   . 
     Considering that a PUCCH repetition with one or more beams or multiple TRPs may be supported both in FR1 (low carrier frequency range) and FR2 (high carrier frequency range) and one PUCCH transmission will not be configured with spatial relation information especially in FR1, the present application discusses power control mechanisms of PUCCH repetitions in the following two cases:
         Case 1: a PUCCH transmission is configured with spatial relation information; and   Case 2: a PUCCH transmission is not configured with spatial relation information.       

     In Case 1, a PUCCH transmission may be configured with multiple pieces of spatial relation information. The multiple pieces of spatial relation information may be activated by a MAC control element (MAC CE). A specific example regarding Case 1 is shown in  FIG.  3   . 
     In Case 1, assuming that a PUCCH transmission with one or more beams are received by multiple TRPs, there will be one or more closed power control loops for the PUCCH transmission with one or more beams. Some embodiments of the present disclosure propose that the TPC command field in DCI format  1 _ 0 / 1 _ 1  is enhanced to separately control different closed power control loops for the PUCCH transmission. 
     For example, in some embodiments of the present disclosure, if a UE is configured by RRC to maintain M (M&gt;=1) closed power control loops for a PUCCH transmission with one or more beams, and if the UE is configured by RRC signaling to transmit a PUCCH transmission repeatedly in multiple slots, 2 M bits are included in the TPC command field for PUCCH transmission in DCI format  1 _ 0 / 1 _ 1 . In particular, the first 2 bits within the 2 M bits correspond to the closed power control loop index 0, the second 2 bits within the 2 M bits correspond to the closed power control loop index 1, and the third 2 bits (if any) within the 2 M bits correspond to the closed power control loop index 2 (if any), and so on. 
     According to the 3GPP standard document, the DCI format  2 _ 2  can indicate the TPC command of a closed loop index indicated in the DCI format  2 _ 2  for all PUCCH transmissions of a UE. According to some embodiments of the present disclosure, in which multiple closed loops are maintained for a PUCCH transmission, multiple DCI format  2 _ 2  may be used to indicate the TPC commands of multiple closed loops, or an enhanced DCI format  2 _ 2  may be used to indicate multiple TPC commands of multiple closed loops for a UE. 
     Mapping between configured spatial relation information (beam) and configured power control parameter set may be referred to as a beam mapping pattern. In some embodiments of the present disclosure, a beam mapping pattern is indicated for a PUCCH transmission to inform a UE to use which beam to transmit each PUCCH repetition of the PUCCH transmission. When there is one to one mapping between the configured spatial relation information (beam) and the configured power control parameter set and the corresponding TPC command, a power control mechanism of each PUCCH repetition of the PUCCH transmission may be calculated by using the method disclosed in 3GPP standard document TS38.213 7.2 according to the beam mapping pattern. 
       FIG.  3    illustrates an exemplary scheme for determining power of PUCCH repetitions of a PUCCH transmission in accordance with some embodiments of the present disclosure. 
     The embodiments of  FIG.  3    assume that a PUCCH transmission is configured to be transmitted repeatedly in 4 slots, and 2 beams are configured for the PUCCH transmission, respectively corresponding to spatial relation information  0  and spatial relation information  1 . As shown in  FIG.  3   , a PUCCH transmission is configured with 4 PUCCH repetitions, i.e., repetition  1 , repetition  2 , repetition  3 , and repetition  4  as shown in  FIG.  3   , while 2 beams are configured for the PUCCH transmission. Beam  1  corresponds to spatial relation information  0 , and beam  2  corresponds to spatial relation information  1 , respectively. 
     The spatial relation information  0  and the spatial relation information  1  are associated with two PUCCH power control parameter sets, respectively. Each PUCCH power control parameter set includes a p0-PUCCH identifier value, a PUCCH pathloss reference RS identifier value, and a closed loop index value. 
     As shown in  FIG.  3   , the spatial relation information  0  is configured to be associated with power control parameter set  0 . The power control parameter set  0  includes three parameters: p0-PUCCH Id  0 , PUCCH pathloss reference RS Id  0  and closed loop index 0. 
     As shown in  FIG.  3   , the spatial relation information  1  is configured to be associated with power control parameter set  1 . The power control parameter set  1  includes three parameters: p0-PUCCH Id  1 , PUCCH pathloss reference RS Id  1 , and closed loop index 1. 
     According to the embodiments of  FIG.  3   , assuming that a UE is configured to maintain 2 closed power control loops by RRC signalling and the PUCCH transmission is scheduled by DCI  1 _ 0 / 1 _ 1  to provide HARQ-ACK feedback corresponding to the scheduled PDSCH, there are 4 bits in the TPC command field of the corresponding DCI, as shown in  FIG.  3   . Within these 4 bits, the first 2 bits in the TPC command field of DCI format  1 _ 0 / 1 _ 1  is the TPC command of closed loop index 0, and the second 2 bits in the TPC command field of DCI format  1 _ 0 / 1 _ 1  is the TPC command of closed loop index 1. The first 2 bits of the TPC command are associated with power control parameter set  0 , because power control parameter set  0  includes closed loop index 0 as shown in  FIG.  3   . The second 2 bits of the TPC command are associated with power control parameter set  1 , because power control parameter set  1  includes closed loop index 1 as shown in  FIG.  3   . 
     The embodiments of  FIG.  3    assume that the beam mapping pattern is 0011, which means the spatial relation information  0  is used for transmitting the first and second PUCCH repetitions, and the spatial relation information  1  is used for transmitting the third and fourth PUCCH repetitions. In other words, the embodiments of  FIG.  3    assume that the spatial relation information  0  is used for the first and second repetitions, i.e., repetition  1  and repetition  2  as shown in  FIG.  3   . The embodiments of  FIG.  3    assume that the spatial relation information  1  is used for the third and fourth repetitions, i.e., repetition  3  and repetition  4  as shown in  FIG.  3   . 
     According to the embodiments of  FIG.  3   , since spatial relation information  0  is associated with power control parameter set  0  and the first 2 bits of the TPC command of DCI format  1 _ 0 / 1 _ 1 , the power of each of repetition  1  and repetition  2  may be determined by the power control parameter set  0  and its associated TPC command of DCI format  1 _ 0 / 1 _ 1  as shown in  FIG.  3   . Since spatial relation information  1  is associated with power control parameter set  1  and the second 2 bits of the TPC command of DCI format  1 _ 0 / 1 _ 1 , the power of each of repetition  3  and repetition  4  may be determined by the power control parameter set  1  and its associated TPC command of DCI format  1 _ 0 / 1 _ 1  as shown in  FIG.  3   . 
     In Case 2, a PUCCH transmission is not configured with spatial relation information, and PUCCH repetitions of the PUCCH transmission are transmitted to multiple TRPs, repeatedly. This case is different from PUCCH repetitions in 3GPP NR Release 15. Although a power control mechanism of each PUCCH repetition of a PUCCH transmission is the same as that in 3GPP NR Release 15, links between a UE and different TRPs are very different, and therefore, the power control mechanism of different links between the UE and TRPs are different from that for 3GPP NR Release 15. Some embodiments of the present disclosure assume that multiple power control parameter sets should be configured for a PUCCH transmission repeatedly transmitted by a UE but received by multiple TRPs. A specific example regarding Case 2 is shown in  FIG.  4   . 
     Some embodiments of the present disclosure assume that multiple p0-PUCCH values are configured for multiple PUCCH repetitions of a PUCCH transmission received by multiple TRPs, which means that a PUCCH transmission configured for multiple PUCCH repetitions is configured with multiple predefined indexes of p0-PUCCH-Id configured in p0-Set. For instance, if the embodiments of  FIG.  4    assume that multiple PUCCH repetitions of the PUCCH transmission are received by N TRPs (N&gt;=2), the PUCCH transmission without configuring spatial relation information is configured with N predefined indexes of p0-PUCCH-Id. The N predefined indexes of p0-PUCCH-Id are configured in p0-Set and correspond to N p0-PUCCH values in p0-PUCCH-Value. 
     Some embodiments of the present disclosure assume that only one p0-PUCCH value is configured for multiple PUCCH repetitions of a PUCCH transmission received by multiple TRPs. The only one p0-PUCCH represents the target receiving power at the TRPs after the pathloss being compensated. A UE can be configured one or multiple p0-PUCCH values with predefined p0-PUCCH indexes for multiple PUCCH repetitions of a PUCCH transmission in these embodiments. In these embodiments, the only one p0-PUCCH value may be with the minimum p0-PUCCH-Id in p0-Set. The only one p0-PUCCH value may be obtained by the same method as that in 3GPP NR Release 15. 
     In some embodiments of the present disclosure, multiple pathloss reference RSs are configured for multiple PUCCH repetitions of a PUCCH transmission received by multiple TRPs, which means that the PUCCH transmission configured for repetition is configured with multiple predefined indexes of pucch-PathlossReferenceRS-Id that are configured in PUCCH-PathlossReferenceRS. For example, in these embodiments, if the PUCCH transmission with repetition is received by N TRPs, the PUCCH transmission without configuring spatial relation information is configured with N pathloss reference RSs with predefined N indexes of pucch-PathlossReferenceRS-Id. 
     In some embodiments of the present disclosure of Case 2, if the PUCCH transmission is not configured with spatial relation information, the closed loop index, the power offset identifier, and the pathloss reference RS included in each power control parameter set may be predefined. 
     In some embodiments of the present disclosure, the closed loop index of a PUCCH transmission without configuring spatial relation information is fixed to 0. In these embodiments, multiple closed loop indexes may be maintained in a UE. For example, in these embodiments, if UE is configured to maintain M (M&gt;=1) closed loops, 2 M bits are included in the TPC command field for PUCCH transmission in DCI format  1 _ 0 / 1 _ 1 . The first 2 bits within the 2 M bits correspond to the closed power control loop index 0, the second 2 bits within the 2 M bits corresponds to the closed power control loop index 1, and the third 2 bits within the 2 M bits (if any) corresponds to the closed power control loop index 2 (if any), and so on. These embodiments assume that M equals to the number of TRPs receiving the PUCCH transmission with multiple PUCCH repetitions. 
     Some embodiments of the present disclosure refer to a case in which there are 2 TRPs receiving the PUCCH transmission with repetition. In these embodiments, two predefined PUCCH power control parameter sets are configured for a PUCCH transmission with repetition. A PUCCH power control parameter set includes a p0-PUCCH identifier, a pathloss reference RS identifier, and a closed loop index value, the closed loop index value is associated with a TPC command with 2 bit in a TPC command field of a DCI format  1 _ 0 / 1 _ 1  or a TPC command with 2 bit in a DCI format  2 _ 2 . 
     For instance, in these embodiments, PUCCH power control parameter set  0  includes the p0-PUCCH with the lower index of the predefined indexes of p0-PUCCH-Id configured in p0-Set, the pathloss reference RS with lower index of predefined indexes of pucch-PathlossReferenceRS-Id, and the closed loop index 0. PUCCH power control parameter set  1  includes the p0-PUCCH with the higher index among the predefined indexes of p0-PUCCH-Id configured in p0-Set, the pathloss reference RS with higher index among predefined indexes of pucch-PathlossReferenceRS-Id, and the closed loop index 1. 
     In these embodiments, the number of predefined p0-PUCCH indexes may be configured as 1 or 2. If there is only 1 predefined p0-PUCCH index configured for the PUCCH transmission, the p0-PUCCH in power control parameter set  0  is same as those in the p0-PUCCH in power control parameter set  1 . 
     In addition, although no spatial relation information is configured for the PUCCH transmission in these embodiments, multiple PUCCH control parameter sets are configured for the PUCCH transmission with multiple repetitions, and a power control parameter mapping pattern between the multiple PUCCH control parameter sets and multiple PUCCH repetitions of the PUCCH transmission may be configured, to indicate a UE to use which power control parameter set during determining transmitting power for each PUCCH repetition of the PUCCH transmission. 
       FIG.  4    illustrates another exemplary scheme for determining power of PUCCH repetitions of a PUCCH transmission in accordance with some embodiments of the present disclosure. 
     The embodiments of  FIG.  4    assume that a PUCCH transmission is configured to be transmitted repeatedly in 4 slots which are received by 2 TRPs. As shown in  FIG.  4   , a PUCCH transmission is configured with 4 PUCCH repetitions, i.e., repetition  1 , repetition  2 , repetition  3 , and repetition  4  as shown in  FIG.  4   . 
     The PUCCH transmission in the embodiments of  FIG.  4    is configured with 2 p0-PUCCH values with predefined indexes of p0-PUCCH-Id (p0-PUCCH  0  and p0-PUCCH  1 ),  2  pathloss reference RSs with predefined indexes of pucch-PathlossReferenceRS-Id (pucch-PathlossReferenceRS  0  and pucch-PathlossReferenceRS  1 ), and 2 closed loop indexex ( 0  and  1 ). PUCCH power control parameter set  0  includes p0-PUCCH Id  0 , pucch-PathlossReferenceRS Id  0  and closed loop index 0. PUCCH power control parameter set  1  includes p0-PUCCH Id  1 , pucch-PathlossReferenceRS Id  1  and closed loop index 1. 
     The embodiments of  FIG.  4    assume that the PUCCH transmission is scheduled by DCI format  1 _ 0 / 1 _ 1 , and there are 4 bits in the TPC command filed in the corresponding DCI. Specifically, as shown in  FIG.  4   , the first 2 bits within the 4 bits are the TPC command of the closed loop index 0, and the second 2 bits within the 4 bits are the TPC command of the closed index 1. The first 2 bits in the TPC command field of DCI format  1 _ 0 / 1 _ 1  is associated with PUCCH power control parameter set  0 , and the second 2 bits in the TPC command filed of DCI format  1 _ 0 / 1 _ 1  is associated with PUCCH power control parameter set  1 , respectively, as shown in  FIG.  4   . 
     The embodiments of  FIG.  4    assume that power control parameter mapping pattern is  0101 , which means the power of each of repetition  1  and repetition  3  is determined according to power control parameter set  0  and its associated TPC command, and the power of each of repetition  2  and repetition  4  is determined according to power control parameter set  1  and its associated TPC command as shown in  FIG.  4   . 
       FIG.  5    illustrates a flow chart of a method for wireless communications in accordance with some embodiments of the present application. The embodiments of  FIG.  5    may be performed by a BS (e.g., BS  102  as illustrated and shown in  FIG.  1   ). 
     In the exemplary method  500  as illustrated and shown in  FIG.  5   , in step  502 , a BS transmits configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission. In some embodiments of the present disclosure, the configuration information is configured by RRC signaling. 
     In some embodiments of the present disclosure, the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions. Each power control parameter set of the plurality of the power control parameter sets may at least include a power offset identifier, a pathloss reference RS identifier, and a closed loop index. 
     The power offset identifier may be included in a power offset list, the pathloss reference RS identifier is included in a pathloss reference RS list, and the closed loop index is a value of a plurality of predefined values. The power offset list or the pathloss reference RS list may be configured by high layer signaling. 
     In some embodiments of the present disclosure, if the PUCCH transmission is not configured with spatial relation information, the closed loop index, the power offset identifier, and the pathloss reference RS included in a power control parameter set in the configuration information may be predefined. 
     In step  504 , the BS receives each PUCCH repetition of the plurality of PUCCH repetitions in a time interval of a plurality of time intervals. The power for each PUCCH repetition may be determined according to the configuration information and a mapping relationship between the each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets. 
     For instance, with reference to the embodiments of  FIG.  3   , the mapping relationship in step  504  indicates the beam parameter mapping pattern  0011 . With reference to the embodiments of  FIG.  4   , the mapping relationship in step  504  indicates the power control parameter mapping pattern  0101 . 
     Details described in all other embodiments of the present application (for example, details of how to improve reliability and robustness of PUCCH repetitions of a PUCCH transmission by using multi-TRP and/or multi-panel) are applicable for the embodiments of  FIG.  5   . Moreover, details described in the embodiments of  FIG.  5    are applicable for all the embodiments of  FIGS.  1 - 4 ,  6 , and  7   . 
       FIG.  6    illustrates an exemplary block diagram of an apparatus in accordance with some embodiments of the present application. In some embodiments of the present disclosure, the apparatus  600  may be a UE, which can at least perform the method illustrated in  FIG.  2   . 
     As shown in  FIG.  6   , the apparatus  600  may include at least one receiver  602 , at least one transmitter  604 , at least one non-transitory computer-readable medium  606 , and at least one processor  608  coupled to the at least one receiver  602 , the at least one transmitter  604 , and the at least one non-transitory computer-readable medium  606 . 
     Although in  FIG.  6   , elements such as receiver  602 , transmitter  604 , non-transitory computer-readable medium  606 , and processor  608  are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiver  602  and the at least one transmitter  604  are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus  600  may further include an input device, a memory, and/or other components. 
     In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium  606  may have stored thereon computer-executable instructions which are programmed to implement the steps of the methods, for example as described in view of  FIG.  2   , with the at least one receiver  602 , the at least one transmitter  604 , and the at least one processor  608 . 
     For example, the at least one receiver  602  may receive configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission, and the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions. The at least one processor  608  may determine power for each PUCCH repetition of the plurality of PUCCH repetitions according to the configuration information and a mapping relationship between the each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets. The at least one transmitter  604  may transmit, by using the determined power for the each PUCCH repetition, the each PUCCH repetition in a time interval of a plurality of time intervals. 
       FIG.  7    illustrates an exemplary block diagram of an apparatus in accordance with some embodiments of the present application. In some embodiments of the present disclosure, the apparatus  700  may be a BS (e.g., gNB), which can at least perform the method illustrated in  FIG.  5   . 
     As shown in  FIG.  7   , the apparatus  700  may include at least one receiver  702 , at least one transmitter  704 , at least one non-transitory computer-readable medium  706 , and at least one processor  708  coupled to the at least one receiver  702 , the at least one transmitter  704 , and the at least one non-transitory computer-readable medium  706 . 
     Although in  FIG.  7   , elements such as receiver  702 , transmitter  704 , non-transitory computer-readable medium  706 , and processor  708  are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiver  702  and the at least one transmitter  704  are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus  700  may further include an input device, a memory, and/or other components. 
     In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium  706  may have stored thereon computer-executable instructions which are programmed to implement the steps of the methods, for example as described in view of  FIG.  5   , with the at least one receiver  702 , the at least one transmitter  704 , and the at least one processor  708 . 
     For example, the at least one transmitter  704  may transmit configuration information regarding a plurality of PUCCH repetitions of a PUCCH transmission, and the configuration information includes a plurality of power control parameter sets corresponding to the plurality of PUCCH repetitions. The at least one receiver  702  may receive each PUCCH repetition of the plurality of PUCCH repetitions in a time interval of a plurality of time intervals, and power for the each PUCCH repetition is determined according to the configuration information and a mapping relationship between the each PUCCH repetition and a power control parameter set of the plurality of power control parameter sets. 
     Those having ordinary skills in the art would understand that the steps of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the steps of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product. 
     While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, those having ordinary skills in the art would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. 
     In this document, 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 term “having” and the like, as used herein, are defined as “including.”