Techniques for indicating sounding reference signal resources

An apparatus for wireless communications at a base station, comprising:

• a processor,
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• receive, from a user equipment (UE), a capability message indicating a first number of one or more transmit antennas supported by the UE for antenna switching and a second number of ports supported for uplink transmission that exceeds the first number of one or more transmit antennas;
• transmit, based at least in part on the capability message, a sounding reference signal configuration indicating a mapping between each sounding reference signal resource group for at least a subset of a plurality of sounding reference signal resource groups and a respective bit sequence of a plurality of bit sequences;
• transmit a control message comprising a first bit sequence of the plurality of bit sequences indicating a first sounding reference signal resource group of the subset of the plurality of sounding reference signal resource groups based at least in part on the mapping;
• receive a first sounding reference signal in a first sounding reference signal resource of the first sounding reference signal resource group based at least in part on the control message;
• and
• receive a second sounding reference signal in a second sounding reference signal resource of the first sounding reference signal resource group based at least in part on the control message.

A method for wireless communications at a user equipment (UE), comprising:

• transmitting a capability message indicating a first number of one or more transmit antennas supported by the UE for antenna switching and a second number of ports supported for uplink transmission that exceeds the first number of one or more transmit antennas;
• receiving, based at least in part on the capability message, a sounding reference signal configuration indicating a mapping between each sounding reference signal resource group for at least a subset of a plurality of sounding reference signal resource groups and a respective bit sequence of a plurality of bit sequences;
• receiving a control message comprising a first bit sequence of the plurality of bit sequences indicating a first sounding reference signal resource group of the subset of the plurality of sounding reference signal resource groups based at least in part on the mapping;
• transmitting a first sounding reference signal in a first sounding reference signal resource of the first sounding reference signal resource group based at least in part on the control message;
• and
• transmitting a second sounding reference signal in a second sounding reference signal resource of the first sounding reference signal resource group based at least in part on the control message.