Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit a UE capability message, the UE capability message indicating a supported transmit antenna switching (TxAS) capability for each port of the UE. The UE may receive a configuration message indicating an uplink multiple-input/multiple-output (UL MIMO) configuration for the UE, the UL MIMO configuration being based at least in part on the UE capability message. The UE may identify, based at least in part on the configuration message, a sounding reference signal (SRS) configuration to use for transmitting SRSs in conjunction with the UL MIMO communications, the SRS configuration comprising a configuration for transmission by the UE of SRSs using at least one of the two or more ports of the UE, the SRSs transmitted on one or more antennas of the UE selected according to a TxAS configuration for the respective port.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine a plurality of virtual antenna panels, wherein the plurality of virtual antenna panels correspond to a plurality of groups of antenna ports and map to one or more portions of at least one physical antenna panel. The UE may map a plurality of reference signal resources to the plurality of virtual antenna panels. The UE may transmit, to a base station and based at least in part on the mapping, reference signals using the plurality of reference signal resources. Numerous other aspects are provided.

Certain aspects of the present disclosure provide techniques for network assisted selection of UE antenna ports for uplink transmissions. A method for wireless communication by a user equipment (UE) includes transmitting, to a network entity, a plurality of sounding reference signals over a plurality of UE antenna ports. The method further includes receiving, from the network entity, an indication of one or more antenna port indexes associated with one or more preferred antenna ports for uplink transmissions, and transmitting UE uplink transmissions to the network entity using one or more selected antenna ports of the one or more indicated preferred antenna ports.

In one embodiment, a system comprises a distributed unit (DU) and a plurality of remote units (RUs). All of the RUs are used to serve the same cell. The system can be configured to wirelessly transmit at least some user data to a first user device using a first subset of the RUs and a first beam, where the first subset of the RUs includes less than all of the RUs otherwise used to serve the same cell. In such an embodiment, the system can be configured to determine which RUs are included in the first subset of RUs used to transmit said at least some user data to the first user device based on measurement reports made by the first user device of reference signal transmissions transmitted using multiple beams, where at least some of the reference signal transmissions are transmitted from less than all of the RUs.

The technologies described herein are generally directed to preparing for a connection with a user equipment while the user equipment is in an idle state in a fifth generation (5G) network or other next generation networks. For example, a method described herein can include facilitating transmitting a signal directed by an antenna of base station equipment. The method can further include, facilitating receiving, from a user equipment, a message, wherein the message comprises feedback information describing receipt of the signal while the user equipment was in an idle mode at a location. Further, the method can comprise, based on the feedback information and the location, generating a model of signal propagation applicable to signals at the location.

A transmitting device includes a plurality of transmission antennas, and includes: a signal processor which generates a first baseband signal by modulating data of a first stream, and a second baseband signal by modulating data of a second stream; and a transmitter which generates, from the first baseband signal, first transmission signals having different directivities, generates, from the second baseband signal, second transmission signals having different directivities, and transmits the first transmission signals and the second transmission signals at a same time.

Methods and apparatus for sounding reference signal (SRS) power control for a wireless transmitter/receiver unit (WTRU) are disclosed. These methods and apparatus include methods and apparatus for carrier-specific and carrier-common SRS power control in WTRUs that utilize carrier aggregation techniques. These methods and apparatus also include methods and apparatus for SRS power control in WTRUs utilizing both carrier aggregation and time division multiplexing (TDM) techniques. Additionally, these methods and apparatus include methods and apparatus for SRS power control for WTRUs utilizing multiple input multiple output MIMO operation. Methods and apparatus for SRS overhead reduction and power management in a WTRU are also disclosed.

The technologies described herein are generally directed to preparing for a connection with a user equipment while the user equipment is in an idle state in a fifth generation (5G) network or other next generation networks. For example, a method described herein can include facilitating transmitting a signal directed by an antenna of base station equipment. The method can further include, facilitating receiving, from a user equipment, a message, wherein the message comprises feedback information describing receipt of the signal while the user equipment was in an idle mode at a location. Further, the method can comprise, based on the feedback information and the location, generating a model of signal propagation applicable to signals at the location.

A system comprising a plurality of nodes communicatively coupled to one another via at least one wireless link and a controller communicatively coupled to at least one of the nodes, wherein the controller (1) coordinates at least one scan that measures interference introduced into the wireless link, (2) identifies, based at least in part on the scan, one or more characteristics of the wireless link, (3) determines, based at least in part on the characteristics of the wireless link, that the node is eligible for a tapered codebook that, when implemented, modifies at least one feature of an antenna array that supports the wireless link in connection with the node, and then (4) directs the node to implement the tapered codebook. Various other apparatuses, systems, and methods are also disclosed.

Systems and methods are provided for determining, at a beamformee, to transmit data signals from transmitting spatial streams at one or more beamformers. Next, a gain resulting from an uplink transmit beamforming protocol may be determined to exceed an overhead of the transmit beamforming protocol. In response to the determination, the uplink transmit beamforming protocol may be conducted. This protocol includes, transmitting trigger frames to the beamformers to obtain channel data regarding channels between each of the transmitting antennae and the active receiving antennae, receiving responses to the trigger frames from each of the beamformers, generating the channel data based on the received responses, feeding back the channel data to each of the beamformers, scheduling the uplink transmit beamforming protocol based on the channel data, and receiving an integrated data signal from the beamformers based on a processing of the data signals via the uplink transmit beamforming protocol.