CO-PHASING FACTOR INDICATION IN DOWNLINK CONTROL INFORMATION

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive downlink control information that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels. The UE may determine precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. The UE may communicate by joint transmission using the multiple antenna panels according to the determined precoders. Numerous other aspects are provided.

INTRODUCTION

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for co-phasing factor indication.

SUMMARY

In some aspects, a method of wireless communication, performed by a user equipment (UE), may include receiving downlink control information (DCI) that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels. The method may include determining precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. The method may include communicating by joint transmission using the multiple antenna panels according to the determined precoders.

In some aspects, a method of wireless communication, performed by a base station (BS), may include determining multiple precoder indicators and at least one co-phasing factor indicator for a UE. The method may include transmitting DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator.

In some aspects, a UE for wireless communication may include memory and one or more processors coupled to the memory. The memory and the one or more processors may be configured to receive DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels. The memory and the one or more processors may be configured to determine precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. The memory and the one or more processors may be configured to communicate by joint transmission using the multiple antenna panels according to the determined precoders.

In some aspects, a BS for wireless communication may include memory and one or more processors coupled to the memory. The memory and the one or more processors may be configured to determine multiple precoder indicators and at least one co-phasing factor indicator for a UE. The memory and the one or more processors may be configured to transmit DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to receive DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels. The one or more instructions may cause the one or more processors to determine precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. The one or more instructions may cause the one or more processors to communicate by joint transmission using the multiple antenna panels according to the determined precoders.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a BS, may cause the one or more processors to determine multiple precoder indicators and at least one co-phasing factor indicator for a UE. The one or more instructions may cause the one or more processors to transmit DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator.

In some aspects, an apparatus for wireless communication may include means for receiving DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels. The apparatus may include means for determining precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. The apparatus may include means for communicating by joint transmission using the multiple antenna panels according to the determined precoders.

In some aspects, an apparatus for wireless communication may include means for determining multiple precoder indicators and at least one co-phasing factor indicator for a UE. The apparatus may include means for transmitting DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described with reference to and as illustrated by the drawings and specification.

DETAILED DESCRIPTION

A base station (BS) may schedule or configure uplink transmissions for a user equipment (UE) (e.g., in a physical uplink shared channel (PUSCH)). For example, the BS may transmit downlink control information (DCI) that schedules an uplink transmission of the UE. In some cases, the uplink transmission may be a multi-panel transmission. For a multi-panel transmission, the UE may use multiple antenna panels to transmit an uplink communication, such as in a spatial division multiplexing, frequency division multiplexing, or time division multiplexing manner.

In some wireless communication systems, a joint transmission may not be enabled for a multi-panel transmission of a UE. In a joint transmission, a UE may transmit the same information on multiple antenna panels using coordinated beamforming. For example, the UE may concurrently transmit multiple layers of an uplink communication on two antenna panels. Moreover, when phases of the transmissions are aligned, the joint transmission may provide a stronger signal. Accordingly, joint transmission may improve uplink performance of a UE.

Some techniques and apparatuses described herein provide for joint transmission using multiple antenna panels of a UE. In some aspects, DCI scheduling a multi-panel transmission may identify a co-phasing factor indicator that enables a UE to generate a co-phased joint transmission using multiple antenna panels. In this way, uplink performance of the UE may be improved by the joint transmission.

As shown inFIG.1, the UE120may include a communication manager140. As described in more detail elsewhere herein, the communication manager140may receive DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels, determine precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator, and communicate by joint transmission using the multiple antenna panels according to the determined precoders. Additionally, or alternatively, the communication manager140may perform one or more other operations described herein.

Similarly, the base station110may include a communication manager150. As described in more detail elsewhere herein, the communication manager150may determine multiple precoder indicators and at least one co-phasing factor indicator for a UE, and transmit DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator. Additionally, or alternatively, the communication manager150may perform one or more other operations described herein.

As indicated above,FIG.1is provided merely as an example. Other examples may differ from what is described with regard toFIG.1.

FIG.2shows a block diagram of a design200of base station110and UE120, which may be one of the base stations and one of the UEs inFIG.1. Base station110may be equipped with T antennas234athrough234t, and UE120may be equipped with R antennas252athrough252r, where in general T>1 and R>1.

Controller/processor240of base station110, controller/processor280of UE120, and/or any other component(s) ofFIG.2may perform one or more techniques associated with co-phasing factor indication in DCI, as described in more detail elsewhere herein. For example, controller/processor240of base station110, controller/processor280of UE120, and/or any other component(s) ofFIG.2may perform or direct operations of, for example, process400ofFIG.4, process500ofFIG.5, and/or other processes as described herein. Memories242and282may store data and program codes for base station110and UE120, respectively. A scheduler246may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, the UE120may include means for receiving DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels, means for determining precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator, means for communicating by joint transmission using the multiple antenna panels according to the determined precoders, and/or the like. Additionally, or alternatively, the UE120may include means for performing one or more other operations described herein. In some aspects, such means may include the communication manager140. Additionally, or alternatively, such means may include one or more components of the UE120described in connection withFIG.2.

In some aspects, the base station110may include means for determining multiple precoder indicators and at least one co-phasing factor indicator for a UE, means for transmitting DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator, and/or the like. Additionally, or alternatively, the base station110may include means for performing one or more other operations described herein. In some aspects, such means may include the communication manager150. In some aspects, such means may include one or more components of the base station110described in connection withFIG.2.

As indicated above,FIG.2is provided merely as an example. Other examples may differ from what is described with regard toFIG.2.

As described above, in some wireless communication systems, joint transmission may not be enabled for a multi-panel transmission of a UE. A joint transmission may provide a stronger signal when phases of the transmissions are aligned (i.e., a co-phased joint transmission). Accordingly, joint transmission may improve uplink performance of a UE. Some techniques and apparatuses described herein provide for joint transmission of a multi-panel transmission of a UE. In some aspects, DCI scheduling a multi-panel transmission may identify a co-phasing factor indicator that enables a UE to generate a co-phased joint transmission using multiple antenna panels. In this way, uplink performance of the UE may be improved by the joint transmission.

FIG.3is a diagram illustrating an example300of co-phasing factor indication in DCI, in accordance with various aspects of the present disclosure. As shown inFIG.3, a UE120and a BS110may communicate in connection with an uplink multi-panel transmission of the UE120. In some aspects, the UE120may employ multiple transmit antenna panels.

As shown by reference number305, the BS110may determine multiple precoder indicators, and at least one co-phasing factor indicator, that are to be used by the UE120for an uplink multi-panel transmission. A precoder indicator may identify a transmit precoder matrix indicator (TPMI) (e.g., for a codebook-based multi-panel transmission) or a sounding reference signal (SRS) resource indicator (SRI) (e.g., for a non-codebook-based multi-panel transmission). A co-phasing factor indicator may identify a co-phasing factor that defines a phase offset between precoders. Thus, when a co-phasing factor is applied to a first precoder, the first precoder may be phase-aligned with a second precoder.

In some aspects, a precoder indicator may be an index (e.g., an SRI index) of a mapping of indices to SRI combinations (e.g., combinations of 1, 2, 3, or 4 SRIs, where the quantity of SRIs in an SRI combination indicates a transmission rank (e.g., a quantity of layers)). As an example, an index of [7] may map to an SRI combination of [1, 2] (where precoders used to transmit SRS resources identified by 1 and 2 are to be used for a two-layer (i.e., a transmission rank of two) uplink transmission), an index of [12] may map to an SRI combination of [0, 2, 3] (where precoders used to transmit SRS resources identified by 0, 2, and 3 are to be used for a three-layer (i.e., a transmission rank of three) uplink transmission), and the like (additional examples are provided in 3GPP Technical Specification (TS) 38.212, such as in Table 7.3.1.1.2-31). A particular mapping of indices to SRI combinations that is to be used may be based at least in part on a quantity of SRSs configured for the UE120.

In some aspects, a precoder indicator may be an index (e.g., a TPMI index) of a mapping of indices to transmission rank and TPMI combinations. As an example, an index of [9] may map to a transmission rank and TPMI combination of [2 layers, TPMI=5] (where a codeword mapped (in another mapping) to an index of 5 is associated with a two-layer (i.e., a transmission rank of two) uplink transmission), an index of [29] may map to a transmission rank and TPMI combination of [3 layers, TPMI=2] (where a codeword mapped (in another mapping) to an index of 2 is associated with a three-layer (i.e., a transmission rank of three) uplink transmission), and the like (additional examples are provided in 3GPP TS 38.211, such as in Table 6.3.1.5-3, or TS 38.212, such as in Table 7.3.1.1.2-2). A particular mapping of indices to transmission rank and TPMI combinations that is to be used may be based at least in part on whether the UE120is capable of full coherence transmission (e.g., transmission using 4 antenna ports), partial coherence transmission (e.g., transmission using 2 antenna ports out of 4 antenna ports), or non-coherence transmission (e.g., transmission using 1 antenna port of 4 antenna ports).

In some aspects, the BS110may select the multiple precoder indicators from a set of precoder indicators. In some aspects, the BS110may select a first precoder indicator from the set of precoder indicators, and may select a second precoder indicator from a subset of the set of precoder indicators. For example, the set of precoder indicators may include all indices of a mapping (e.g., the mapping for SRI combinations or the mapping for transmission rank and TPMI combinations), and the subset of the set may include a subset of the indices of the mapping. In some aspects, the precoder indicators that are included in the subset from which the second precoder indicator is selected may be based at least in part on the first precoder indicator that is selected by the BS110.

The first precoder indicator selected by the BS110may be associated with a particular transmission rank and/or a particular coherence type (e.g., full coherence, partial coherence, or non-coherence). In the case of the mapping for SRI combinations, the transmission rank may correspond to a quantity of SRIs included in an SRI combination. In the case of the mapping for transmission rank and TPMI combinations, the transmission rank is explicitly indicated. Moreover, a TPMI, of a transmission rank and TPMI combination, may be associated with a coherence type (e.g., a quantity of antenna ports).

Accordingly, the precoder indicators that are included in the subset from which the second precoder indicator is selected may be based at least in part on the particular transmission rank and/or the particular coherence type associated with the first precoder indicator selected by the BS110. In other words, the second precoder indicator may be selected from a restricted group of precoder indicators that is dependent upon the selected first precoder indicator. In this way, the second precoder indicator may be identified using less bits (relative to the first precoder indicator) because the subset is a restricted group of precoder indicators (relative to the set of precoder indicators).

In some aspects, the subset includes only the precoder indicators of the set that are associated with the particular transmission rank of the selected first precoder indicator. For example, the set may include precoder indicators associated with a transmission rank of 1, 2, 3, or 4, and the selected first precoder indicator may be associated with a transmission rank of 3. Accordingly, the subset may include only precoder indicators of the set that are associated with a transmission rank of 3.

In some aspects, the subset includes only the precoder indicators of the set that are associated with the particular transmission rank of the selected first precoder indicator, as described above, and the particular coherence type of the selected first precoder indicator. For example, the set may include precoder indicators associated with full coherence, partial coherence, or non-coherence, and the selected first precoder indicator may be associated with full coherence in a joint transmission scenario. Accordingly, the subset may include only precoder indicators of the set that are associated with full coherence.

In some aspects, the BS110may determine co-phasing factors to enable the UE120to generate a co-phased joint transmission using multiple antenna panels. The co-phasing factors may be for precoders of multiple layers that are to be transmitted by the UE120on an antenna panel of the multiple antenna panels. That is, a co-phasing factor may align a phase of a precoder for a layer on a first antenna panel with a phase of a precoder for the layer on a second antenna panel. In this way, the layer may be transmitted on the first antenna panel and the second antenna panel in a phase-aligned manner.

The co-phasing factors determined by the BS110may be associated with at least one co-phasing factor indicator. In some aspects, a co-phasing factor indicator may identify a single co-phasing factor. In some aspects, a co-phasing factor indicator may be an index value that identifies a plurality of co-phasing factors.

As shown by reference number310, the BS110may transmit, and the UE120may receive, DCI that schedules uplink transmissions of the UE120. For example, the DCI may schedule a joint transmission of the UE120using multiple antenna panels, such as a PUSCH communication in one or more layers on a first antenna panel of the UE120and a second antenna panel of the UE120. In some aspects, the UE120may receive the DCI from a first TRP (e.g., associated with the BS110), and the DCI may schedule an uplink multi-panel transmission to the first TRP and a second TRP (e.g., associated with the BS110or another BS). In some aspects, the UE120may receive the DCI from the BS110, and the DCI may schedule an uplink multi-panel transmission to the BS110(e.g., in a coordinated manner).

In some aspects, the BS110may indicate that the DCI is scheduling a joint transmission for the UE120based at least in part on a configuration (e.g., a radio resource control (RRC) configuration) for the DCI. Similarly, the UE120may determine that the DCI is scheduling a joint transmission based at least in part on the configuration for the DCI. The configuration for the DCI may indicate a quantity of transmission configuration indicators (TCIs) configured for the DCI, a quantity of precoder indicators configured for the DCI, whether a co-phasing factor is configured for the DCI, and whether a frequency division multiplexing (FDM) indicator or a quantity of reserved bits is configured for the DCI.

In some aspects, the DCI may schedule a joint transmission when two TCIs are configured for the DCI, two precoder indicators are configured for the DCI, a co-phasing factor is configured for the DCI, and an FDM indicator is not configured for the DCI. In some aspects, the DCI may schedule a non-coherent joint transmission when two TCIs are configured for the DCI, two precoder indicators are configured for the DCI, a co-phasing factor is not configured for the DCI, and an FDM indicator is not configured for the DCI. In some aspects, the DCI may schedule a dynamic panel selection transmission when one TCI is configured for the DCI, one precoder indicator is configured for the DCI, a co-phasing factor is not configured for the DCI, and an FDM indicator is not configured for the DCI. In some aspects, the DCI may schedule a frequency division multiplexed joint transmission when two TCIs are configured for the DCI, two precoder indicators are configured for the DCI, a co-phasing factor is not configured for the DCI, and an FDM indicator is configured for the DCI.

The DCI may identify (e.g., in the same field of the DCI) the multiple precoder indicators (e.g., the first precoder indicator and the second precoder indicator) selected by the BS110. The second quantity of bits may be a quantity of bits needed to identify a particular precoder indicator of the subset from which the second precoder indicator is selected. For example, the DCI may identify a first TPMI index and a second TPMI index selected by the BS110in a TPMI field of the DCI. As another example, the DCI may identify a first SRI index and a second SRI index selected by the BS110in an SRI field of the DCI.

3GPP TS 38.211 specifies that, when transforming precoding is disabled for CP-OFDM in a single panel uplink transmission, a TPMI index, of TPMI indices associated with 4 antenna ports with different transmission ranks and/or different coherence types, may be indicated. Table 1 shows a quantity of bits needed to indicate a TPMI index for a single antenna panel:

The DCI may identify the first precoder indicator selected by the BS110using a first quantity of bits and the second precoder indicator selected by the BS110using a second quantity of bits that is less than (or in some cases equal to) the first quantity of bits. That is, in cases in which the second precoder indicator is selected from a restricted group of precoder indicators (relative to a group of precoder indicators from which the first precoder indicator is selected), a reduced quantity of bits of the DCI may be allocated to identify the second precoder indicator.

In some aspects, the DCI may identify the at least one co-phasing factor indicator selected by the BS110. For example, the DCI may identify the at least one co-phasing factor indicator in the same field of the DCI that identifies the multiple precoder indicators selected by the BS110. In some aspects, bits of the DCI that are not used (e.g., by reducing a quantity of bits needed to indicate the second precoder indicator, as described above) may be allocated or shared for indicating the at least one co-phasing factor indicator. In some aspects, the DCI may allocate a quantity of bits for the co-phasing factor indicator that corresponds to a transmission rank (e.g., a quantity of layers) associated with the second precoder indicator, as shown below in Tables 2-5.

In some aspects, the DCI may identify a single co-phasing factor indicator that identifies a single co-phasing factor. In this case, the UE120may use the single co-phasing factor indicator to determine multiple co-phasing factors, as described below. In some aspects, the DCI may identify multiple co-phasing factor indicators that identify multiple co-phasing factors. In some aspects, a single co-phasing factor indicator identified by the DCI may be an index value that identifies multiple co-phasing factors.

In some aspects, the first precoder indicator is a first TPMI index associated with any of full coherence, partial coherence, or non-coherence, and the second precoder indicator is a second TPMI index associated with full coherence (e.g., when the first precoder indicator is associated with full coherence) for joint transmission. In this case, the DCI may allocate a quantity of bits for identifying the first TPMI index, the second TPMI index, and the at least one co-phasing factor indicator as shown in Table 2 (DCI alignment is used to align a length of DCI under different transmission ranks to be the same):

In some aspects, the first precoder indicator is a first TPMI index associated with full coherence, partial coherence, or non-coherence, and the second precoder indicator is a second TPMI index associated with full coherence or partial coherence. In this case, the DCI may allocate a quantity of bits for identifying the first TPMI index, the second TPMI index, and the at least one co-phasing factor indicator as shown in Table 3:

In some aspects, the first precoder indicator is a first TPMI index associated with partial coherence or non-coherence, and the second precoder indicator is a second TPMI index associated with partial coherence. In this case, the DCI may allocate a quantity of bits for identifying the first TPMI index, the second TPMI index, and the at least one co-phasing factor indicator as shown in Table 4:

In some aspects, the first precoder indicator is a first SRI index and the second precoder indicator is a second SRI index. In this case, the DCI may allocate a quantity of bits for identifying the first SRI index, the second SRI index, and the at least one co-phasing factor indicator as shown in Table 5:

As shown by reference number315, the UE120may determine precoders for multiple antenna panels based at least in part on the DCI. That is, the UE120may determine the precoders for the multiple antenna panels based at least in part on the multiple precoder indicators (e.g., the first precoder indicator and the second precoder indicator) and the at least one co-phasing factor indicator identified by the DCI. In some aspects, the UE120may determine co-phasing factors for precoders of one or more layers that are to be transmitted on an antenna panel based at least in part on the at least one co-phasing factor indicator identified by the DCI.

For example, if the DCI identifies a single co-phasing factor indicator that identifies a single co-phasing factor, the UE120may determine one or more additional co-phasing factors based at least in part on the single co-phasing factor. In this case, the UE120may use a co-phasing shifting function to determine additional co-phasing factors based at least in part on the single co-phasing factor. For example, the UE120may determine one or more additional co-phasing factors according to Equation 1:

where cl,nrepresents a co-phasing factor for a layer l,f(l) represents a co-phasing shifting function for layer l, g(n) represents the single co-phasing factor identified by the DCI, and e (2.71828) and j(√{square root over (−1)}) are constant values.

As another example, if the DCI identifies multiple co-phasing factor indicators that identify multiple co-phasing factors, the UE120may identify co-phasing factors for multiple layers based at least in part on the multiple co-phasing factor indicators. In this case, the co-phasing factors for the multiple layers may be represented by Equation 2:

where cl,nrepresents a co-phasing factor for a layer l, g(l, n) represents a co-phasing factor identified by the DCI for layer l, and e and j are constant values, as described above. For example, g(l, n) may be {0, pi} or cl,nmay be {1, −1}.

As a further example, the DCI may identify a single co-phasing factor indicator that is an index value. In this case, the UE120may determine one or more co-phasing factors based at least in part on the index value. For example, the UE120may be configured with a mapping of index values to arrays of co-phasing factors, and the UE120may identify an array of co-phasing factors from the mapping according to the index value identified by the DCI. An array of co-phasing factors may be represented by Equation 3:

where cnrepresents an index value identified by the DCI, cl,nrepresents a co-phasing factor for layer 1, c2,nrepresents a co-phasing factor for layer 2, and cL,nrepresents a co-phasing factor for a layer L.

In some aspects, the UE120may determine precoders for layers that are to be transmitted on a first antenna panel based at least in part on the first precoder indicator. In some aspects, the UE120may determine precoders for layers that are to be transmitted on a second antenna panel based at least in part on the second precoder indicator and the at least one co-phasing factor indicator. In other words, the UE120may determine precoders, that are not phase aligned, for multiple antenna panels based at least in part on the first precoder indicator and the second precoder indicator, as represented by Equation 4:

where P represents a matrix of precoders, ν1Arepresents a precoder for layer 1 on antenna panel A, ν2Arepresents a precoder for layer 2 on antenna panel A, νLArepresents a precoder for layer L on antenna panel A, ν1Brepresents a precoder for layer 1 on antenna panel B, ν2Brepresents a precoder for layer 2 on antenna panel B, and νLBrepresents a precoder for layer L on antenna panel B. In this example, the first precoder indicator may identify precoders for antenna panel A and the second precoder indicator may identify precoders for antenna panel B.

Based at least in part on the precoders that are not phase aligned (e.g., according to Equation 4), the UE120may determine precoders, that are phase aligned, for the multiple antenna panels based at least in part on the determined co-phasing factors, as represented by Equation 5:

where P, ν1A, ν2A, νLA, ν1B, ν2B, and νLBare as described above, cl,nrepresents a co-phasing factor for layer 1, c2,nrepresents a co-phasing factor for layer 2, and cL,nrepresents a co-phasing factor for layer L. Thus, in this example, the precoders for antenna panel B may be combined with the determined co-phasing factors to derive new precoders that are phase-aligned with the precoders for antenna panel A.

As shown by reference number320, the UE120may communicate by joint transmission with the BS110using multiple antenna panels based at least in part on the determined precoders. For example, the UE120may concurrently transmit the same communication (e.g., multiple layers) on a first antenna panel (e.g., a first PUSCH transmission using a first beam that is formed based at least in part on the precoders for the first antenna panel) and a second antenna panel (e.g., a second PUSCH transmission using a second beam that is formed based at least in part on the precoders for the second antenna panel) based at least in part on the determined precoders. In some aspects, the UE120may transmit to a first TRP (e.g., associated with the BS110) using the first antenna panel and to a second TRP (e.g., associated with the BS110or another BS) using the second antenna panel. In some aspects, the UE120may transmit the communication to the BS110using the first antenna panel and the second panel in a phase aligned manner. In this way, the communication may be transmitted with greater signal strength.

FIG.4is a diagram illustrating an example process400performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process400is an example where the UE (e.g., UE120, and/or the like) performs operations associated with co-phasing factor indication in DCI.

As shown inFIG.4, in some aspects, process400may include receiving DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels (block410). For example, the UE (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or the like) may receive DCI that identifies multiple precoder indicators and at least one co-phasing factor indicator for generating a co-phased joint transmission using multiple antenna panels, as described above.

As further shown inFIG.4, in some aspects, process400may include determining precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator (block420). For example, the UE (e.g., using controller/processor280, and/or the like) may determine precoders for the multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator, as described above.

As further shown inFIG.4, in some aspects, process400may include communicating by joint transmission using the multiple antenna panels according to the determined precoders (block430). For example, the UE (e.g., using controller/processor280, transmit processor264, TX MIMO processor266, MOD254, antenna252, and/or the like) may communicate by joint transmission using the multiple antenna panels according to the determined precoders, as described above.

In a first aspect, process400includes determining co-phasing factors for precoders of multiple layers that are to be transmitted on an antenna panel based at least in part on a single co-phasing factor indicator identified by the DCI. In a second aspect, alone or in combination with the first aspect, the DCI identifies respective co-phasing factor indicators that identify co-phasing factors for precoders of multiple layers that are to be transmitted on an antenna panel. In a third aspect, alone or in combination with one or more of the first and second aspects, the at least one co-phasing factor indicator is an index value that identifies respective co-phasing factors for precoders of multiple layers that are to be transmitted on an antenna panel.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the DCI identifies the at least one co-phasing factor indicator in a same field of the DCI that identifies the multiple precoder indicators. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the multiple precoder indicators identify transmission rank and TPMI combinations or SRI combinations.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the multiple precoder indicators include a first precoder indicator selected from a set of precoder indicators and a second precoder indicator selected from a subset of the set of precoder indicators. In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the set includes precoder indicators associated with full coherence, partial coherence, and non-coherence, and the subset includes only the precoder indicators of the set associated with full coherence.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process400includes determining that communication is by joint transmission based at least in part on a quantity of TCIs configured for the DCI, a quantity of precoder indicators configured for the DCI, whether a co-phasing factor is configured for the DCI, and whether an FDM indicator is configured for the DCI.

AlthoughFIG.4shows example blocks of process400, in some aspects, process400may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG.4. Additionally, or alternatively, two or more of the blocks of process400may be performed in parallel.

FIG.5is a diagram illustrating an example process500performed, for example, by a BS, in accordance with various aspects of the present disclosure. Example process500is an example where the BS (e.g., BS110, and/or the like) performs operations associated with co-phasing factor indication in DCI.

As shown inFIG.5, in some aspects, process500may include determining multiple precoder indicators and at least one co-phasing factor indicator for a UE (block510). For example, the BS (e.g., using controller/processor240, and/or the like) may determine multiple precoder indicators and at least one co-phasing factor indicator for a UE, as described above.

As further shown inFIG.5, in some aspects, process500may include transmitting DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator (block520). For example, the BS (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or the like) may transmit DCI that identifies the multiple precoder indicators and the at least one co-phasing factor indicator to enable the UE to generate a co-phased joint transmission using multiple antenna panels based at least in part on the multiple precoder indicators and the at least one co-phasing factor indicator, as described above.

In a first aspect, the DCI identifies a single co-phasing factor indicator that enables the UE to determine co-phasing factors for precoders of multiple layers that are to be transmitted by the UE on an antenna panel. In a second aspect, alone or in combination with the first aspect, the DCI identifies respective co-phasing factor indicators that identify co-phasing factors for precoders of multiple layers that are to be transmitted by the UE on an antenna panel. In a third aspect, alone or in combination with one or more of the first and second aspects, the at least one co-phasing factor indicator is an index value that identifies respective co-phasing factors for precoders of multiple layers that are to be transmitted by the UE on an antenna panel.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the DCI identifies the at least one co-phasing factor indicator in a same field of the DCI that identifies the multiple precoder indicators. In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the multiple precoder indicators identify transmission rank and TPMI combinations or SRI combinations.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the multiple precoder indicators include a first precoder indicator selected from a set of precoder indicators and a second precoder indicator selected from a subset of the set of precoder indicators. In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the set includes precoder indicators associated with full coherence, partial coherence, and non-coherence, and the subset includes only the precoder indicators of the set associated with full coherence.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process500includes indicating that communication of the UE is by joint transmission based at least in part on configuring a particular quantity of transmission configuration indicators for the DCI, configuring a particular quantity of precoder indicators for the DCI, selectively configuring a co-phasing factor for the DCI, and selectively configuring an FDM indicator for the DCI.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software.