Method and apparatus for event-based uplink transmit beam switch

1 . A user equipment (UE) comprising:

a transceiver configured to:

receive a configuration including information about a beam indication indicating N uplink (UL) transmit beams, where N≥M>1, and

receive the beam indication; and

a processor operably coupled to the transceiver, the processor configured to, when N>M, identify M beams (B 1 , . . . , B M ) from the N UL transmit beams,

wherein the transceiver is further configured to transmit an UL transmission using the M beams (B 1 , . . . , B M ) simultaneously,

wherein a beam of the N UL transmit beams corresponds to a spatial property used to receive or transmit a source reference signal (RS), and

wherein:

the beam indication is via a two-stage downlink control information (DCI) comprising (DCI 1 , DCI 2 ),

DCI 1 includes B 1 and an indication on whether B 2 , . . . , B N is indicated, and

when the DCI 1 includes the indication that B 2 , . . . , B N is indicated, the DCI 2 includes B 2 , . . . , B N .

2 . The UE of claim 1 , wherein:

M=2 and the M beams correspond to (B 1 , B 2 ),

the processor is further configured to determine whether an event is detected with a beam B i , and

in response to the event being detected, the transceiver is further configured to transmit another UL transmission using a beam B j , where j≠i and i,j∈{1,2}.

3 . The UE of claim 2 , wherein the event detection is based on whether a maximum permissible exposure (MPE) limit is met for the beam B i .

4 . The UE of claim 1 , wherein the transceiver is further configured to transmit capability information regarding the UL transmission using the M beams (B 1 , . . . , B M ) simultaneously.

5 . The UE of claim 1 , further comprising:

at least N antenna panels,

wherein each of the identified M beams is associated with one of the at least N antenna panels.

6 . The UE of claim 1 , wherein the transceiver is further configured to receive a downlink (DL) transmission using a DL beam, where the DL beam is one of the N UL transmit beams.

7 . The UE of claim 1 , wherein the beam indication indicating N beams (B 1 , . . . , B N ) is common for both downlink (DL) reception and UL transmission.

8 . A base station (BS) comprising:

a processor configured to identify a configuration including information about a beam indication indicating N uplink (UL) transmit beams, where N≥M>1; and

a transceiver operably coupled to the processor, the transceiver configured to:

transmit the configuration,

transmit the beam indication, and

receive an UL reception associated with M beams (B 1 , . . . , B M ) simultaneously,

wherein, when N>M, the M beams (B 1 , . . . , B M ) are from the N UL transmit beams,

wherein a beam of the N UL transmit beams corresponds to a spatial property used to receive or transmit a source reference signal (RS), and

wherein:

the beam indication is via a two-stage downlink control information (DCI) comprising (DCI 1 , DCI 2 ),

DCI 1 includes B 1 and an indication on whether B 2 , . . . , B N is indicated, and

when the DCI 1 includes the indication that B 2 , . . . , B N is indicated, the DCI 2 includes B 2 , . . . , B N .

9 . The BS of claim 8 , wherein:

M=2 and the M beams correspond to (B 1 , B 2 ), and

when an event is detected with a beam B i , the transceiver is further configured to receive another UL reception associated with a beam B j , where j≠i and i,j∈{1,2}.

10 . The BS of claim 9 , wherein the event detection is based on whether a maximum permissible exposure (MPE) limit is met for the beam B i .

11 . The BS of claim 8 , wherein the transceiver is further configured to receive capability information regarding the UL reception associated with the M beams (B 1 , . . . , B M ) simultaneously.

12 . The BS of claim 8 , wherein each of the identified M beams is associated with one of at least N antenna panels of a user equipment.

13 . The BS of claim 8 , wherein the transceiver is further configured to transmit a downlink (DL) transmission for reception via a DL beam, where the DL beam corresponds to one of the N UL transmit beams.

14 . The BS of claim 8 , wherein the beam indication indicating N beams (B 1 , . . . , B N ) is common for both downlink (DL) transmission and UL reception.

15 . A method performed by a user equipment (UE), the method comprising:

receiving a configuration including information about a beam indication indicating N uplink (UL) transmit beams, where N≥M>1;

receiving the beam indication;

when N>M, identifying M beams (B 1 , . . . , B M ) from the N UL transmit beams; and

transmitting an UL transmission using the M beams (B 1 , . . . , B M ) simultaneously,

wherein a beam of the N UL transmit beams corresponds to a spatial property used to receive or transmit a source reference signal (RS), and

wherein:

the beam indication is via a two-stage downlink control information (DCI) comprising (DCI 1 , DCI 2 ),

DCI 1 includes B 1 and an indication on whether B 2 , . . . , B N is indicated, and when the DCI 1 includes the indication that B 2 , . . . , B N is indicated, the DCI 2 includes B 2 . . . , B N .

16 . The method of claim 15 , wherein M=2 and the M beams correspond to (B 1 , B 2 ), the method further comprising:

determining whether an event is detected with a beam B i , and

in response to the event being detected, transmitting another UL transmission using a beam B j , where j≠i and i,j∈{1,2}.

17 . The method of claim 16 , wherein the event detection is based on whether a maximum permissible exposure (MPE) limit is met for the beam B i .

18 . The method of claim 15 , further comprising transmitting capability information regarding the UL transmission using the M beams (B 1 , . . . , B M ) simultaneously.