A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

A transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

Aspects described herein relate to wireless communications. According to some aspects, a first base station may coordinate with a second base station to select beamforming codewords. The first base station may receive an index indicating beamforming codewords used by a second base station. The first base station may select a beamforming codeword for use in transmitting signals to a wireless device based on the beamforming codeword indicated by the second base station.

Methods, apparatus, and systems for wireless communications are disclosed. A first base station may receive one or more message from a second base station. The messages may include downlink beamforming information elements for a downlink cell. Each downlink beamforming information element may be associated with a respective group of resource blocks of a plurality of groups of resource blocks in the downlink cell. The first base station may select a first beamforming codeword for at least one group of resource blocks of the plurality of groups of resource blocks based on the downlink beamforming information associated with the at least one group of resource blocks. The first base station may transmit, to a wireless device, signals on the at least one group of resource blocks employing the first beamforming codeword.

A channel measurement method includes: receiving a plurality of reference signals in a plurality of first frequency domain units in a same time domain unit, where the plurality of reference signals may be respectively precoded by using precoding matrices corresponding to the first frequency domain units in which the plurality of reference signals are located, and precoding matrices corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different; generating a precoding matrix indicator (PMI) based on the plurality of reference signals, where the PMI indicates a plurality of codewords corresponding to a plurality of second frequency domain units, the plurality of second frequency domain units and the plurality of first frequency domain units belong to a same frequency domain resource, and the plurality of codewords may be used for determining a downlink channel; and sending the PMI.

Methods, apparatus, and systems for wireless communications utilizing a precoding matrix indicator (PMI) based on first signals received from a first node and based on second signals received from a second node are described. A wireless device may receive measurement information that indicates resources of a first node and a second node for use in determining the PMI. After receiving the first signals and the second signals, the wireless device may use the first signals and the second signals to determine the PMI. The determined PMI may be sent to a base station, which may transmit one or more packets based on the determined PMI.

Methods, systems, and devices for wireless communications are described. In some cases, a network entity may estimate an uplink sampling time offset (STO) associated with a user equipment (UE) based on an uplink signal from the UE and may remove the uplink STO from a first estimated channel to generate a second estimated channel. Thus, the network entity may equalize a first downlink signal in accordance with the second estimated channel and may transmit the first downlink signal to the UE. The network entity may additionally receive an indication of a downlink STO associated with the UE based on transmission of the first downlink signal and may equalize a second downlink signal in accordance with a third estimated channel, where the third estimated channel is based on (e.g., free of) the uplink STO and the downlink STO.