This invention presents methods for signal detection and transmission in MU-MIMO wireless communication systems, for inverse matrix approximation error calculation, for adaptively selecting the number of multiplexed UEs in a MU-MIMO group, for adaptively choosing a modulation and channel coding scheme appropriate for the quality of MU-MIMO channels with the approximation error of matrix inverse being incorporated.

Interference is processed in a waveform received at a device in a wireless network, the received interference comprising non-linear products of at least a first signal (C.sub.1) at a first carrier frequency and a second signal (C.sub.2) at a second carrier frequency. A complex composite baseband signal is generated comprising at least the first and second signal at baseband, occupying a respective first and second frequency range within a composite baseband frequency range and not overlapping in frequency. The complex composite baseband signal is processed by applying at least a first non-linear function (74a) to generate simulated interference comprising at least one simulated non-linear product. The received interference is then processed in dependence on the simulated interference.

A method for performing virtualization of a radio access technology (RAT) over Orthogonal Frequency-Division Multiple Access (OFDMA) wireless networks is provided. The method includes splitting OFDMA time-frequency resources into non-overlapping regions including a virtualization region including a part of a spectrum and the OFDMA symbols that are reserved for virtualization of the RAT; reserving resource elements of the OFDMA time-frequency resources in the virtualization region, for insertion of downlink reference signals including complex sequences known by a receiver to perform downlink channel estimation with a specified separation between signals in time and frequency domains; inserting training or pilot signals along the OFDMA time-frequency resources of the virtualization region; and mapping complex baseband symbols corresponding to information from the RAT into the OFDMA time-frequency resources of the virtualization region.

Methods, systems, and devices for spectral sharing wireless systems, wherein multiple user devices share time and frequency resources for uplink and/or downlink transmissions, are described. One example method includes transmitting transmission symbols from the network station to at least one user device by processing through a first precoder and a pre-compensation stage, wherein the pre-compensation stage is selected to have the transmission symbols receivable at the at least one user device to appear as if the transmission symbols are processed by a second precoder different from the first precoder.

There is provided a method for processing a set of input symbols. The method is performed by a transmitter. The method comprises acquiring a set of input symbols. The method comprises generating a set of precoded symbols from the set of input symbols by subjecting the set of input symbols to a coding vector. The method comprises generating a transmission signal comprising a sequence of pulse forms from the set of precoded symbols by pulse shaping the set of precoded symbols. The coding vector is based on a model vector modelling intersymbol interference experienced by the pulse forms.

The present disclosure provides a method for estimating timing and/or frequency of a wireless signal; the method including the steps: receiving a digitally modulated signal; extracting a plurality of signal samples associated with a short training field (STF) of a PHY protocol data unit (PPDU) of an 802.11 frame; performing correlation operations on the plurality of signal samples to generate a predetermined number of correlation peaks; comparing the generated correlation peaks with a variable dynamic threshold; and calculating timing and/or frequency of the digitally modulated signal using the outcome of the comparing step.

An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.

Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can synchronize, with less error, the data transmitted by the transmitter and the data it received. To further improve the framer index estimation, a lock indicator signal can be generated to signal to other receiver components that the estimated framer indices are reliable. The receiver can determine frequency offset and additional framer index estimations with increased reliability when performed after the lock indicator signal is generated.

This disclosure describes systems, methods, and devices related to EHT training fields. A device may send a trigger frame having a type of HE null data packet (NDP) feedback, wherein the trigger frame requests feedback from a station device (STA) of one or more station device (STA). The device may receive a frame from the STA, wherein the frame comprises an HE long training field (HE-LTF) portion and an HE short training field (HE-STF), wherein the HE-STF is generated in a frequency domain over a first bandwidth. The device may identify that the HE-LTF comprises energy on a set of tones, wherein the set of tones are selected based on feedback status values associated with a resource unit (RU) tone set index. The device may identify that the HE-STF comprises a second set of tones that are energized based on a sequence that is selected based on the first bandwidth used for the frame

A method performed by a communication device includes generating an initial channel estimate of a channel for a current time step with a Kalman filter based on a first signal received at the communication device. The method also includes inferring, with a neural network, a residual of the initial channel estimate of the current time step. The method further includes updating the initial channel estimate of the current time step based on the residual.