Methods, systems, and devices for wireless communications are described in which different spreading sequences may be used to distinguish concurrent non-orthogonal multiple access (NOMA) transmissions. The spreading sequences may be selected based on one or more codebooks configured at a user equipment (UE) and a codebook for an uplink NOMA transmission determined based on a set of common resources allocated for the uplink NOMA transmission and a number of expected transmitters in a transmitter group. The UE may identify data to transmit in the uplink NOMA transmission, apply the spreading sequence to the data, and transmit the spread data in the uplink NOMA transmission. A base station may receive multiple concurrent uplink NOMA transmissions, perform receive signal processing to identify spreading signals and UE identity, de-spread the signals based on different spreading sequences, and demodulate and decode the de-spread signals of the NOMA UE.

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.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

All data symbols used in data transmission of a modulated signal are precoded by switching between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol along the frequency axis and the time axis all differ. A modulated signal with such data symbols arranged therein is transmitted.

Methods, systems, and devices for wireless communications are described. One method may inlcude a base station or other device estimating an intended coverage area of all possible communication devices that are to be serviced by the base station or other device. The base station or other device may dynamically optimize at least one transmission metric such as a codebook, in response to a change in the coverage area. Another method may include a base station estimating a dynamic coverage area of a set of all possible user equipments or devices to be serviced, and dynamically optimizing a codebook structure in response to a change in the coverage area. Another method may include the base station determining a use-case of the set of all possible user equipments to be serviced by the base station, and hard-coding a metric corresponding to the use case.

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.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

The present invention discloses an indication information transmission method and apparatus. The method includes: determining, in one or more codebooks, a first codebook used to send a first downlink data stream to a terminal device; determining one or more second codebooks used to send a second downlink data stream; determining codebook indication information used to indicate the first codebook and the one or more second codebooks; and sending the codebook indication information to the terminal device.

Disclosed is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals that are transmitted in the same frequency bandwidth at the same time. According to the precoding method, one matrix is selected from among matrices defining a precoding process that is performed on the plurality of baseband signals by hopping between the matrices. A first baseband signal and a second baseband signal relating to a first coded block and a second coded block generated by using a predetermined error correction block coding scheme satisfy a given condition.