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.

Embodiments of this application disclose example data processing methods and example apparatuses. One example method includes determining, by a first terminal device based on a parameter group, a first sequence including N elements, where the parameter group includes a first parameter, a second parameter, and a cyclic shift value, the first sequence is obtained by performing cyclic shift on a second sequence based on the cyclic shift value, and the second sequence is determined based on the first parameter and the second parameter. The first terminal device can then send a signal to a network device based on the first sequence.

In one aspect, an apparatus includes: a fast Fourier transform (FFT) engine to receive orthogonal frequency division multiplexing (OFDM) samples of one or more OFDM symbols and convert the one or more OFDM samples into a plurality of frequency domain carriers; and a tone cancellation circuit coupled to the FFT engine to receive the one or more OFDM samples and generate a plurality of frequency carriers for the one or more OFDM samples, identify a highest magnitude frequency carrier of the plurality of frequency carriers, and remove tone interference from the OFDM samples based at least in part on the highest magnitude frequency carrier.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N≥2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.

A receiving device includes a reception unit 10 that samples a signal to be measured a transmitted from a DUT 2 and acquires a sample signal d; an FFT processing unit 21 that performs an FFT process by multiplying the sample signal; a signal length calculation unit 31 that calculates a signal length of the signal to be measured from the sample signal; a comparing unit 33 that compares the calculated signal length of the signal to be measured with a first FFT length conforming to a communication standard; and an FFT length setting unit 34 that, when as a result of the comparison by the comparing unit, the signal length is shorter than the first FFT length, sets a second FFT length shorter than the signal length of the signal to be measured, as the FFT length of the FFT process by the FFT processing unit.

A method is provided for use in a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission using a direct-sequence spread-spectrum (DSSS) waveform. DSSS signals are received from other nodes on different channels. ASSW is performed to detect and remove interference signals received on the different channels. MDFT analysis banks each receive a beam in the spectral domain that can be channelized to generate a channelized beam that comprises multiple spectral channels. An adaptive interference mitigation space-frequency whitener module can then be applied to remove interference and generate interference-mitigated spatial-spectral domain channels. MDFT synthesis banks can each perform a MDFT synthesis operation on one of the spatial-spectral domain channels. A multi-user RAKE receiver can then combine the interference mitigated time-domain channelized signals to generate a subset (1 . . . F) of fingers that combine components of transmissions directly received from the other nodes and multipath components of those transmissions.

In some embodiments, a communication apparatus can transmit OFDM signals that include at least a first period and a second period. The communication apparatus can include a transmitting section and a signal processing section. The transmitting section can transmit the OFDM signals to an additional communication apparatus by using multiple subcarriers allocated a set of two or more contiguous frequency channels. The contiguous frequency channels can be used simultaneously by the additional communication apparatus. The signal processing section is configured to not use at least all subcarriers positioned in the respective centers of these frequency channels when allocating data to the subcarriers in the frequency channels used to transmit the OFDM signals for a first period.

A communication method, including: receiving a reference signal, where the reference signal is used for channel measurement; sending CSI, where the CSI is used to indicate one or more measured values, and the measured values are used to determine a precoding matrix, or the measured values are a precoding matrix. The measured value is related to a first group of base vectors and a second group of base vectors, or the measured value is related to a Kronecker product of the first group of base vectors and the second group of base vectors; the first group of base vectors includes an inverse discrete Fourier transform OFT vector or a Kronecker product of two IDFT vectors, and the second group of base vectors include a discrete Fourier transform DFT vector.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.