Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, said transmission channel being represented by an upper triangular matrix, wherein the decoder comprises: a processing unit (309) configured to determine a set of division parameters depending on at least one division metric derived from components of said upper triangular matrix; a decoding unit (311) configured to divide said upper triangular matrix into two or more sub-matrices using said set of division parameters in accordance with a division of said vector of information symbols into two or more sub-vectors, and to determine at least one estimate of each sub-vector of information symbols by applying a symbol estimation algorithm,
wherein the decoder is configured to determine at least one estimate of said vector of information symbols from the estimates of said sub-vectors of information symbols.

What is disclosed is a method for wireless communication comprising receiving a wireless communication via a receiver of the mobile communication device, deriving a demodulation reference signal from a first plurality of symbols of the wireless communication; creating a channel estimation matrix using the demodulation reference signal; inverting the channel estimation matrix to obtain a channel pseudo-inverse matrix; deriving a tracking reference signal from a second plurality of symbols of the wireless communication; calculating a phase shift for one or more additional symbols based on the tracking reference signal; determining a corrected channel pseudo-inverse matrix for the one or more additional symbols by adjusting the channel pseudo-inverse matrix according to the calculated phase shift; and controlling the receiver to accomplish data detection using the corrected channel pseudo-inverse matrix on one or more orthogonal frequency division multiplexing subcarriers.

A communication device is provided that includes a baseband circuit and a transmitter configured to transmit a first signal and a projected signal. The baseband circuit is configured to determine the projected signal based on an estimated signal state information such that an energy of a shaped projected signal is smaller than an energy of a shaped signal. The estimated signal state information is an estimate of a signal state information based on the first signal and a received signal that is received by a receiver of the second communication device. The shaped projected signal is the projected signal received by the receiver of the second communication device and filtered by a filter of the second communication device. The shaped signal is the received signal filtered by the filter of the second communication device.

Systems and methods related to improved coherent demodulation and, in particular, improved channel equalization that accounts for variation in an effective channel estimation error with transmitted symbols are disclosed. In one embodiment, a wireless node includes a receiver front-end, a channel estimator, and an equalizer. The receiver front-end is adapted to output samples of a received signal. The channel estimator is adapted to estimate a channel between a transmitter of the received signal and the wireless node based on the samples of the received signal. The equalizer is adapted to process the samples of the received signal according to a modified equalization scheme that compensates for variation in an effective channel estimation error with transmitted symbols to thereby provide corresponding bit or symbol decisions. In this manner, channel equalization is improved, particularly for a wireless system that utilizes a modulation scheme with varying amplitude.

A wireless system, and particularly, a multiple-input multiple-output (MIMO) wireless communication system is disclosed. The wireless system includes a plurality of (re)configurable antennas and a rate-two space coding design for a MIMO system. The MIMO wireless communication system generally includes M (re)configurable antennas configured to independently transmit or broadcast wireless electromagnetic signals having a frequency in the microwave and/or optical ranges, a controller configured to control the (re)configurable antennas, and an encoder configured to encode information onto the wireless electromagnetic signals. The information comprises codewords having N symbols, and the codewords are expressed in an NM matrix having a non-zero determinant and in which at least one symbol is associated with a coefficient configured to maximize diversity, maximize coding gain and/or reduce channel fading in the MIMO wireless communication system. M and N are each independently an integer of at least 2.

A method for transmitting a signal in a communication system includes transmitting a signal using pre-generated matrix, wherein the pre-generated matrix is generated by repeating one matrix including zero elements by a predetermined number of times and a particular sequence is allocated to non-zero elements included in the pre-generated matrix. An apparatus for receiving a signal in a communication system includes at least one processor configured to make a control to receive a transmitted signal based on a pre-generated matrix and to receive the signal, wherein the pre-generated matrix is generated by repeating one matrix including zero elements by a predetermined number of times and a particular sequence is allocated to non-zero elements included in the pre-generated matrix.

A receiver estimates a vector of emitted symbols over a MIMO transmission channel which is emitted by emitting antennas. The receiver receives a vector of received symbols on receiving antennas. Estimation of the vector of emitted symbols is made by calculating a metric associated with a criterion for each vector of a subset of all possible vectors of emitted symbols and selecting an estimation for said vector of emitted symbols as the vector of emitted symbols among said subset which minimizes said metric.

A device includes delay units connected in a chain, each delaying the equalized symbol signals by a unit time and outputting the delayed signals, a determiner configured such that the symbol level for the current symbol signal inputted from a final stage delay unit of the delay units is determined as one of the predetermined symbol levels at which a minimum error sum is obtained from possible error sums of a current error calculated for the current symbol signal and a predicted error calculated for next discrete symbol signals following the current symbol signal, wherein the current error is a difference value between the current symbol signal and the specified symbol level of the compensated first signal, and the predicted error is a difference value between the predetermined symbol level of the compensated second signal and each of the next discrete symbol signals.