Embodiments of the present disclosure relate to a data transmission method and a communications device. The method includes: performing an interpolation operation on a first signal sequence to obtain a second signal sequence, where a length of the second signal sequence is greater than a length of the first signal sequence; mapping the second signal sequence onto a subcarrier to obtain a second signal sequence that is on the subcarrier; performing an inverse fast Fourier transform (IFFT) on the second signal sequence that is on the subcarrier, to obtain a time-domain signal; and transmitting the time-domain signal. According to the embodiments of the present disclosure, a delay deviation can be better resisted.

In accordance with an embodiment of the present invention, a method for receiving a signal, comprising the estimation step for estimating time and frequency shifts that are embedded in the received signal, to cancel-out shifts, wherein the method refers to the non-commutative shift parameter space of co-dimension 2.

Processing of a data packet within a received wireless signal includes determining a frequency modulation (FM) domain carrier frequency offset (CFO) estimate component from a plurality of samples of the received wireless signal, determining a phase domain CFO estimate component from the plurality of samples of the received wireless signal, and determining a CFO estimation as a function of the FM domain CFO estimate component and the phase domain CFO estimate component. The data packet may be a Bluetooth Low Energy data packet. The FM domain CFO estimate component and the phase domain CFO estimate component may be determined from samples of a preamble field of the data packet.

The embodiments disclose a method in a base station for extracting a resource block at a frequency band from a signal received from a terminal device in a radio communication system employing OFDM. The method comprising: removing a CP portion corresponding to the resource block from the signal; for each of a predetermined number of successive symbols in the signal after the CP portion corresponding to the resource block has been removed, performing a FFT of the symbol, extracting a frequency domain signal corresponding to the frequency band from the FFT of the symbol, performing an IFFT on the extracted frequency domain signal to yield a time domain signal, and storing the time domain signal to form a time sequence by concatenation; performing a FFT of the stored time sequence; and extracting subcarriers corresponding to the resource block from the FFT of the stored time sequence.

A method and an apparatus for determining a time offset are disclosed. The method includes: obtaining, by a device at a head end, a time-domain signal based on a received signal; and then determining a time offset based on values of peak-to-average ratios of a preset quantity of symbols starting from a q.sup.th symbol in the time-domain signal, where a peak-to-average ratio of the q.sup.th symbol is greater than a preset threshold. A new method for determining a time offset is provided, and takes advantages that the time-domain signal obtained by the device at the head end has stronger capabilities of resisting interference such as frequency offset and phase noise. The method for determining a time offset can be applied both to initial ranging and periodic ranging.

Embodiments of the present invention relate to methods and systems for simultaneous communication with multiple wireless communication devices. In some embodiments, a method for simultaneous communication with multiple wireless communication devices includes receiving, using a plurality of antennas at a first wireless station, a plurality of packets, comprised of orthogonal frequency division multiplexing (OFDM) wireless signals, transmitted simultaneously from a plurality of other wireless stations wherein each of the simultaneously transmitted packets includes a plurality of frequency tones, frequency domain transform the received packets, grouping frequency domain transform outputs for each subcarrier, determining a difference between subcarrier groups formed over different sample sets, and determining a set of weights for each subcarrier, wherein the weights are selected such that the first wireless station can at least one of detect or demodulate the received plurality of packets.

Embodiments of the present invention relate to methods and systems for simultaneous communication with multiple wireless communication devices. In some embodiments, a method for simultaneous communication with multiple wireless communication devices includes receiving, using a plurality of antennas at a first wireless station, a plurality of packets, comprised of orthogonal frequency division multiplexing (OFDM) wireless signals, transmitted simultaneously from a plurality of other wireless stations wherein each of the simultaneously transmitted packets includes a plurality of frequency tones, frequency domain transform the received packets, grouping frequency domain transform outputs for each subcarrier, determining a difference between subcarrier groups formed over different sample sets, and determining a set of weights for each subcarrier, wherein the weights are selected such that the first wireless station can at least one of detect or demodulate the received plurality of packets.

A communication frame for an OTFS transmission system includes first-type and second-type blocks. The first-type block includes pilot signals, guard signals, and data signals, the second-type block exclusively includes data signals. The pilot symbols, guard signals, and data symbols of the first-type block, and the data symbols of the second-type block, are arranged along the points of a grid in the delay-Doppler domain. In the communication frame, a first-type block is followed by a second-type block, and a second-type block is followed by a first-type block. In the first-type block at least one pilot symbol is surrounded on at least three sides by one or more guard symbols. Points of the grid of the first-type blocks in the delay-Doppler domain that are not occupied by pilot symbols or guard symbols are used for data symbols. The communication frame permits determining oscillator frequency offset and channel coefficients in a receiver.

A communication frame for an OTFS transmission system includes first-type and second-type blocks. The first-type block includes pilot signals, guard signals, and data signals, the second-type block exclusively includes data signals. The pilot symbols, guard signals, and data symbols of the first-type block, and the data symbols of the second-type block, are arranged along the points of a grid in the delay-Doppler domain. In the communication frame, a first-type block is followed by a second-type block, and a second-type block is followed by a first-type block. In the first-type block at least one pilot symbol is surrounded on at least three sides by one or more guard symbols. Points of the grid of the first-type blocks in the delay-Doppler domain that are not occupied by pilot symbols or guard symbols are used for data symbols. The communication frame permits determining oscillator frequency offset and channel coefficients in a receiver.

A communication frame for an OTFS transmission system includes first-type and second-type blocks. The first-type block includes pilot signals, guard signals, and data signals, the second-type block exclusively includes data signals. The pilot symbols, guard signals, and data symbols of the first-type block, and the data symbols of the second-type block, are arranged along the points of a grid in the delay-Doppler domain. In the communication frame, a first-type block is followed by a second-type block, and a second-type block is followed by a first-type block. In the first-type block at least one pilot symbol is surrounded on at least three sides by one or more guard symbols. Points of the grid of the first-type blocks in the delay-Doppler domain that are not occupied by pilot symbols or guard symbols are used for data symbols. The communication frame permits determining oscillator frequency offset and channel coefficients in a receiver.