A communication device is provided that includes a baseband circuit and a transmitter configured to transmit a first signal and a projected signal. The baseband circuit is configured to determine the projected signal based on an estimated signal state information such that an energy of a shaped projected signal is smaller than an energy of a shaped signal. The estimated signal state information is an estimate of a signal state information based on the first signal and a received signal that is received by a receiver of the second communication device. The shaped projected signal is the projected signal received by the receiver of the second communication device and filtered by a filter of the second communication device. The shaped signal is the received signal filtered by the filter of the second communication device.

Disclosed is 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 method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

Methods, systems, and devices for wireless communications are described. A base station may associate a first and second port with a set of antenna elements based on a first and second linear precoding vector. The base station may generate coefficients indicating a first combination and a second combination of a first data set for a first user equipment (UE) and a second data set for a second UE. The base station may apply the first and second linear precoding vectors to the first and second combinations, respectively, transmit a first demodulation reference signal (DMRS) and a second DMRS using a first comb corresponding to the first and second ports, and transmit at least a third DMRS indicating the coefficients using a second comb. The UEs may extract data from the precoded combinations by applying the coefficients and estimating channels associated with the first and second DMRS.

Embodiments herein include a method in a user equipment (UE) for transmitting uplink control information in time slots of a subframe over a radio channel to a radio base station. The uplink control information is comprised in a block of bits. The UE maps the block of bits to a sequence of complex valued modulation symbols. The UE block spreads the sequence across Discrete Fourier Transform Spread-Orthogonal Frequency Division Multiplexing (DFTS-OFDM) symbols. This is performed by applying a spreading sequence to the sequence of complex valued modulation symbols, to achieve a block spread sequence of complex valued modulation symbols. The UE further transforms the block-spread sequence, per DFTS-OFDM symbol. This is performed by applying a matrix that depends on a DFTS-OFDM symbol index and/or slot index to the block-spread sequence. The UE also transmits the block spread sequence, as transformed, over the radio channel to the radio base station.

The present disclosure discloses a method and a system for transmitting DFT-s-OFDM symbols. A data sequence for transmitting as an OFDM symbol is received as input from a data source. A reference sequence for transmitting along with the data sequence as the OFDM symbol is generated and time-multiplexed with the data sequence, to generate a multiplexed sequence. Thereafter, a Discrete Fourier Transform (DFT) operation is performed on the multiplexed sequence to generate a DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol that is further processed for transmitting over a channel. The transmission of the reference sequence and the data sequence in a single OFDM symbol provides better bandwidth utilization and flexibility in modulation of the reference sequence and the data sequence.

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

A signal processing device includes: a first subarray that includes power amplifiers and phase shifters and that forms a first beam facing in a first direction; a second subarray that includes power amplifiers and phase shifters and that forms a second beam facing in a second direction; a feedback unit that feeds back at least signals that are output from the power amplifiers included in the first subarray; and a processor that is connected to the first subarray and the second subarray. The processor executes a process including: generating, based on a first feedback signal and a transmission signal output to the first subarray, a cancellation signal corresponding to an interference component applied to the second beam by the first beam; and adding the generated cancellation signal to a transmission signal output to the second subarray.

Disclosed is 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.

The present disclosure discloses a method and a system for transmitting DFT-s-OFDM symbols. A data sequence for transmitting as an OFDM symbol is received as input from a data source. A reference sequence for transmitting along with the data sequence as the OFDM symbol is generated and time-multiplexed with the data sequence, to generate a multiplexed sequence. Thereafter, a Discrete Fourier Transform (DFT) operation is performed on the multiplexed sequence to generate a DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol that is further processed for transmitting over a channel. The transmission of the reference sequence and the data sequence in a single OFDM symbol provides better bandwidth utilization and flexibility in modulation of the reference sequence and the data sequence.