Embodiments of the invention provide a decoder (10) for decoding a signal received through a transmission channel in a communication system, the signal carrying information symbols selected from a given set of values and being associated with a signal vector, the transmission channel being represented by a channel matrix. The decoder comprises: a sub-block division unit (12) configured to divide the received signal vector into a set of sub-vectors in correspondence with a division of a matrix related to said channel matrix; at least one weighting coefficient calculation unit (14) configured to calculate a sub-block weighting coefficient for each sub-vector, at least one symbol estimation unit (11) for recursively determining estimated symbols representative of the transmitted symbols carried by the data signal from information stored in a stack. The at least one symbol estimation unit is configured to apply at least one iteration of a sequential decoding algorithm, the sequential decoding algorithm comprising iteratively filling a stack by expanding child nodes of a selected node of a decoding tree comprising a plurality of nodes, each node of the decoding tree corresponding to a candidate component of a symbol of at least a part of the received signal and each node being assigned an initial metric. The symbol estimation unit is further configured to calculate a modified metric for at least one node of the expanded child nodes from the metric associated with the at least one node and from the sub-block weighting coefficient calculated for the sub-vector to which the at least one node belongs, symbol estimation unit being configured to assign the modified metric to the at least one node.

A method that may include receiving, by multiple antennas of a receiver, received signals that are received with diversity and represent transmitted signals; and processing, by at least one processor of the receiver, the received signals to provide processed signals that are indicative of the transmitted signals; wherein the processing comprises applying a dimension-reducing process. The dimension-reducing process may be channel independent.

Disclosed herein is a method of receiving a broadcast signal. The method comprises receiving the broadcast signal; an Orthogonal Frequency Division Multiplexing (OFDM) demodulating on the received broadcast signal; parsing at least one signal frame from the demodulated broadcast signal to extract service data or service component data; converting the service data or service component data into bits; decoding the converted bits; and outputting a data stream comprising the decoded bits.

Provided is a wireless communication device, which is configured to: execute, for each of a plurality of counterpart wireless communication devices to be targets, first processing for determining a maximum number of assignable transmission streams based on transmission line quality information with respect to each of the plurality of counterpart wireless communication devices; execute, for each of the plurality of counterpart wireless communication devices, second processing for calculating a diversity order value of a single stream or each of a plurality of streams through use of the maximum number of transmission streams obtained by the first processing, and compare the calculated diversity order value of the single stream or each of the plurality of streams and a diversity order lower limit value set in advance to each other, to thereby determine a number of transmission streams; and determine the number of transmission streams obtained by the second processing as a finally-determined number of transmission streams for each of the plurality of counterpart wireless communication devices, and notify the finally-determined number of transmission streams that has been determined.

The object of the present invention can be achieved by providing a method of transmitting broadcast signals including encoding Data Pipe, DP, data, wherein the encoding further includes Forward Error Correction, FEC, encoding the DP data, Bit interleaving the FEC encoded DP data and mapping the bit interleaved DP data onto constellations; building at least one signal frame by mapping the encoded DP data; and modulating data in the at least one built signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, method and transmitting the broadcast signals having the modulated data, wherein each of the at least one signal frame includes at least one preamble having repeated at least one signaling information.

An optical transmission system includes an optical transmission apparatus and an optical reception apparatus. The optical transmission apparatus includes a conversion unit that converts multiple binary data sequences into data in a predetermined signal format; a coding unit that generates multiple pieces of coded data by performing predetermined coding on each of the multiple pieces of converted data; an optical signal generation unit that generates multiple optical signals by converting the multiple pieces of coded data into optical signals; and a mode multiplexer that converts the multiple optical signals into different modes, generates a mode-division multiplexed optical signal by mode-division multiplexing the optical signals, and transmits the generated mode-division multiplexed optical signal to the optical reception apparatus. The optical reception apparatus includes a mode demultiplexer that demultiplexes the mode-division multiplexed optical signal transmitted from the optical transmission apparatus into light in different modes; a photoelectric conversion unit that converts the light in the multiple different modes into electrical signals; an analog/digital conversion unit that converts the multiple electrical signals into coded data; and an MIMO equalization processing unit that performs MIMO equalization processing on the converted coded data.

A system includes: a unit configured to communicate a modulated signal via a signal interface; and at least one additional unit configured to receive the modulated signal from the unit. The at least one additional unit includes circuitry configured to remove jitter from a recovered clock signal to generate a jitter reduced clock signal that tracks long-term drift in the modulated signal, wherein the at least one additional unit is configured to generate the recovered clock signal from the modulated signal.

An STBC/SFBC-based signal transmission method and apparatus is provided for use in a multi-carrier system. A method for a transmitter to transmit a signal to a receiver in a diversity transmission mode according to the present invention includes transmitting a filter index indicating a filter allocated to the receiver and transmitting Space Time Block Code (STBC) symbols to the receiver at symbol positions selected based on the filter index.

Disclosed herein is a method of transmitting a broadcasting signal. The method comprises formatting input streams into at least one data transmission channel, encoding data corresponding to each of data transmission channel carrying service data or service component data, building at least one signal frame comprising the encoded data, modulating the at least one signal frame by an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and transmitting a broadcasting signal comprising the at least one modulated signal frame.

An apparatus for deriving a submatrix {tilde over (G)}.sup.1 is described. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to select an N-elements-column and an N-elements-row of an NN-Matrix G or G.sup.1. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to rearrange the selected column to the rightest column and the selected row to the lowest row of G or G.sup.1 so as to generate a NN-matrix G.sub.p or G.sub.p.sup.1. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to calculate a submatrix {tilde over (G)}.sup.1 by

[00001]${\tilde{G}}^{-1}=A-\frac{\mathrm{AbcA}}{d^{-1}+c^T.Math.\mathrm{Ab}},$

wherein the parameters (N1)(N1)-submatrix A, b, d, c are obtained from the G.sub.p or the G.sub.p.sup.1; wherein

[00002]$G_p=\left[\begin{array}{cc}\tilde{G}& b\\ c^T& d\end{array}\right],.Math.G_p^{-1}=\left[\begin{array}{cc}A& \tilde{b}\\ {\tilde{c}}^T& \tilde{d}\end{array}\right].$