A transmitter for transmitting data to communications devices via a wireless access. The transmitter including modulator circuitry configured to receive modulation symbols of a segment and to rotate each modulation symbol by an angle dependent on a choice of modulation scheme, and receive each of the segments of rotated modulation symbols and for each segment to separate real and imaginary components of the rotated modulation symbols for the segment and to interleave the real components of the rotated modulation symbols of the segment differently to the imaginary components of the rotated modulation symbols of the segment. The circuitry also is configured to recombine the real and imaginary interleaved components of the rotated modulation symbols of each segment and to form from the real and imaginary components modulation cells.

A method of performing carrier frequency offset (CFO) estimation and/or time offset (TO) estimation at a radio equipment in a mobile communications system. The method allows, for each of a plurality of synchronization signal (SS) blocks (SSBs) in a SS Burst detected at said radio equipment, determining a CFO estimation and/or a TO estimation based on network information signal prediction. The method includes selecting at least some of said detected SSBs in said SSB Burst and combining the CFO estimations and/or the TO estimations to obtain improved CFO compensation and/or TO compensation for signal processing at said radio equipment.

Disclosed are a method for multi-user transmission and reception in a wireless communication system and a device for same. More particularly, a method for performing multi-user (MU) transmission by a station (STA) device in a wireless communication system comprises the steps of: generating a high efficiency-long training field (HE-LTF) sequence in a frequency domain in accordance with an MU transmission bandwidth; and transmitting a physical protocol data unit (PPDU) which comprises one or more symbols to which the HE-LTF sequence is mapped, wherein the HE-LTF sequence can be generated by multiplying one row of a P matrix to a length unit of a row of the P matrix in a predetermined sequence.

Provided are a multipath separation method and device, and a storage medium. The multipath separation method includes: extracting frequency domain response characteristics of received reference signals in at least two different frequency bands; for each of the at least two different frequency bands, constructing a Toeplitz matrix; combining Toeplitz matrixes corresponding to the at least two different frequency bands; performing singular value decomposition on the synthesized Toeplitz matrix; determining a signal space matrix and a noise space matrix according to the decomposed matrix; constructing a plurality of frequency domain response vectors according to frequency domain response characteristics of local signals having different delays and are the same as the received reference signals; and comparing a first preset threshold with inner products between each of the plurality of frequency domain response vectors and the noise space matrix respectively, and determining a delay corresponding to each of a plurality of frequency domain response vectors in which inner products satisfy the first preset threshold to be a delay of one path in the multipath.

Disclosed are a robust method and device for estimating frequency offset in orthogonal frequency division multiplexing communication. The method includes: performing frequency-domain cyclic shift cross-correlation on preprocessed signal sequences with a short training field sequence in multiple symbol periods respectively in an initial signal receiving stage to obtain a cross-correlation result set; detecting a short training field signal according to the cross-correlation result set; when the short training field signal is detected, performing rough frequency offset estimation to obtain a rough frequency offset estimation value; performing rough frequency offset compensation according to the rough frequency offset estimation value; fixing the rough frequency offset estimation value, performing fine frequency offset estimation, and compensating residual frequency estimation; detecting a long training field signal to obtain a frame boundary; and performing channel estimation to obtain a final signal.

A method is performed by a wireless node in a wireless communication network for receiving a reference signal. The method includes collecting a first set of samples of the received signal in time domain, transforming the first set of samples into frequency domain, forming a plurality of hypotheses including a set of hypotheses for time offset of the received signal and/or a set of hypotheses for frequency offset of the received signal, correlating the frequency domain samples of the received signal with at least a subset of the plurality of hypotheses, and selecting a hypothesis based on the correlation, wherein the selected hypothesis corresponds to a synchronisation of the received signal such that the synchronisation is achieved. A wireless communication device, a network node, and computer programs for implementing the method are also described.

Some demonstrative embodiments include apparatuses, devices, systems and methods of communicating a PPDU including a training field. For example, an Enhanced Directional Multi-Gigabit (DMG) (EDMG) wireless communication station may be configured to determine one or more Orthogonal Frequency Division Multiplexing (OFDM) Training (TRN) sequences in a frequency domain based on a count of one or more 2.16 Gigahertz (GHz) channels in a channel bandwidth for transmission of an EDMG PPDU including a TRN field; generate one or more OFDM TRN waveforms in a time domain based on the one or more OFDM TRN sequences, respectively, and based on an OFDM TRN mapping matrix, which is based on a count of the one or more transmit chains; and transmit an OFDM mode transmission of the EDMG PPDU over the channel bandwidth, the OFDM mode transmission comprising transmission of the TRN field based on the one or more OFDM TRN waveforms.

Systems, methods and computer software are disclosed for providing high resolution timing advance estimation based on Physical Random Access Channel (PRACH). An example method includes receiving a preamble signal r(n) having a predetermined sampling frequency and a predetermined length; correlating a down sampled version of the received preamble with a reference preamble sequence c(n) using an FFT method to provide correlation output Ryc; using a peak value P of the correlation output Ryc to detect a preamble ID and a timing advance at a resolution of 24 Ts; zero padding sequences Y(k) and C(k) so that they have a predetermined length resulting in sequences Y_hat(k) and C_hat(k), which are 1024-point FFT of y(n) and c(n); performing a maximum likelihood estimation (MLE) to estimate a timing offset; and detecting a peak value out of the R_hat(m) and using a corresponding index Q to provide a timing advance with an accuracy of 2 Ts.

A base station for transmitting a synchronization signal from N transmission antennas (N>=2) in orthogonal frequency division multiple access includes a signal sequence generation unit configured to generate a synchronization signal sequence to be used for the synchronization signal in a frequency domain; a subcarrier mapping unit configured to divide a transmission band of the synchronization signal into K frequency blocks (K>=2) and map the synchronization signal sequence into one or more subcarriers in the K frequency blocks; a precoding unit configured to generate N precoding vectors to be multiplied by the synchronization signal sequence in the frequency domain and multiply the synchronization signal sequence to be transmitted from an n-th antenna (1<=n<=N) by at least an n-th precoding vector; and a transmission unit configured to transmit the synchronization signal from the N transmission antennas.

Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.