A method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output are provided. The method includes: sending, by an access point (AP), indication information to at least two stations (STAs), wherein the indication information is used for indicating that the at least two STAs perform an uplink multiuser data transmission; receiving, by the AP, uplink data sent by the at least two STAs through channels from the at least two STAs to the AP, respectively; and demodulating, by the AP, the uplink data sent by the at least two STAs using receiving beams corresponding to pre-estimated channels from the at least two STAs to the AP, respectively.

The application provides a short training sequence design method and apparatus. The method includes: determining a short training sequence, where the short training sequence may be obtained based on an existing sequence, and the short training sequence with comparatively good performance may be obtained through simulation calculation, for example, by adjusting a parameter; and sending a short training field on a target channel, where the short training field is obtained by performing inverse fast Fourier transformation IFFT on the short training sequence, and a bandwidth of the target channel is greater than 160 MHz.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and a relevant device, characterized in that the method comprises: generating a cyclic prefix according to a partial time-domain main body signal truncated from a time-domain main body signal; generating a modulation signal based on a portion or the entirety of the partial time-domain main body signal; and generating time-domain symbols based on at least one of the cyclic prefix, the time-domain main body signal and the modulation signal, wherein the preamble symbol contains at least one of the time-domain symbols. Therefore, using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to implement coherent detection, which solves the issues of performance degradation with non-coherent detection and differential decoding failure under complex frequency selective fading channels; and generating a modulation signal as a postfix based on the entirety or a portion of the above truncated time-domain main body signal enables the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

Provided is a technology capable of securing communication quality without providing an additional function such as phase correction. A base station device and a communication terminal device when operating as a transmitting device rotate inverse fast Fourier transform (IFFT) output, and copy a last portion of the rotated IFFT output to a head of the rotated IFFT output as a cyclic prefix (CP) to thereby generate a transmission signal so that there is no phase rotation at a head of a demodulation reception window set in a receiving device.

A radio transmission apparatus determines information indicative of an estimated communications channel condition and generates a single modulation signal or a plurality of modulation signals based on the estimated communications channel condition information. The single modulation signal is transmitted from a first antenna of a plurality of antenna or the plurality of modulation signals are transmitted from the first antenna and at least a second antenna of the plurality of antenna. The plurality of modulation signals include different information from each other and are transmitted over an identical frequency band and at an identical temporal point. The single modulation signal and the plurality of modulation signals contain parameter information indicating a number of modulation signals transmitted at the same time.

A method of compensating for IQ mismatch (IQMM) in a transceiver may include sending first and second signals from a transmit path through a loopback path, using a phase shifter to introduce a phase shift in at least one of the first and second signals, to obtain first and second signals received by a receive path, using the first and second signals received by the receive path to obtain joint estimates of transmit and receive IQMM, at least in part, by estimating the phase shift, and compensating for IQMM using the estimates of IQMM. Using the first and second signals received by the receive path to obtain estimates of the IQMM may include processing the first and second signals received by the receive path as a function of one or more frequency-dependent IQMM parameters.

The present disclosure is directed to timestamp detection using a cable modem and to a control apparatus, control device and control method for detecting time stamps in various signals such as orthogonal frequency division multiplexing (OFDM) signals. The control apparatus comprising processing circuitry being configured to obtain information a channel frequency response of the multi-path channel, the channel frequency response being based on a signal comprising a sequence of symbols. The processing circuitry is configured to transform the channel frequency response into a channel impulse response. The processing circuitry is configured to identify a peak in the channel impulse response. The processing circuitry is configured to determine a timestamp offset time between the peak in the channel impulse response and a trigger time indicative of a beginning of a symbol in the signal. The processing circuitry is configured to synchronize the device clock based on the timestamp offset time.

This application provides an uplink multi-station channel estimation method, a station (STA), and an access point (AP), which can be applied to an uplink multi-user multiple-input multiple-output scenario. The uplink multi-station channel estimation method includes: a STA generating a frame including a first group of training sequences and a second group of training sequences, and sending the frame to the AP. The AP calculates a frequency offset value between the STA and the AP based on the received first group of training sequences and the received second group of training sequences. The AP performs channel estimation based on the calculated frequency offset value. According to the technical solutions provided in this application, the AP can more accurately learn of frequency offset values between a plurality of STAs and the AP. This improves channel estimation precision.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, in a slot, a preamble provided based at least in part on an orthogonal frequency division multiplexing (OFDM) waveform. The UE may perform an estimation operation based at least in part on the preamble. The UE may receive, in the slot, a data transmission via a single carrier time-domain waveform based at least in part on the estimation operation. Numerous other aspects are provided.

A first wireless device may generate a first pseudo-random data based on a seed known to a second wireless device, and may transmit a first training signal including first pseudo-random data to the second wireless device for a MI estimation at the second wireless device, the first pseudo-random data being modulated with a first modulation order. The second wireless device may estimate, based on the received first training signal and through the MI estimation, a reception quality associated with at least one modulation order lower than or equal to the first modulation order, and determine a second modulation order of the at least one modulation order lower than or equal to the first modulation order based on the MI estimation, the second modulation order being estimated to provide a reception quality greater than or equal to a reception quality threshold. The MI estimation may be periodic or aperiodic.