Abstract: A channel estimating method is provided for a signal transmitted in an orthogonal frequency division multiplexing (OFDM) system, wherein an OFDM symbol of the signal has at least one null subcarrier set in its defined bandwidth. The method includes: obtaining at least one initial channel estimate over at least one OFDM symbol of a received signal; processing the at least one initial channel estimate for delivering at least one soft information in a form of a complete matrix; and updating the at least one initial channel estimate by performing a truncated singular value decomposition of a partial FFT matrix. The partial FFT matrix includes only the first LDP columns and the rows NDP of an FFT matrix of the complete matrix, the NDP rows corresponding to modulated subcarriers of received signal, including data and pilot symbols and excluding the at least one null subcarrier, delivering an improved channel estimate.

Abstract: An embodiment of a method for transmitting a sequence of symbols through at least a channel in a wireless communication system includes: forming a coding matrix with the sequence of symbols, each component of the coding matrix being a linear combination of two symbols among a first, a second, a third, and a fourth symbol (s1, s2, s3 , s4), transmitting a first component and a second component of a first column and of a second column of the coding matrix through a first transmit antenna and a second transmit antenna at a first and a second time slot wherein the coding matrix is defined as ( as 1 + bs 3 - cs 2 * - ds 4 * as 2 + bs 4 cs 1 * + ds 3 * ) , a, b, c, d being complex numbers of modulus 1.

Abstract: A channel estimation treatment method and device for obtaining binary data conveyed in a signal. The method includes: obtaining a current vector of channel estimates, each element of the current vector corresponding to an estimate of a subchannel; detecting, inside the current vector, at least one pilot symbol; splitting the current vector in at least two subvectors, at least one first subvector including channel estimates related to data symbols and/or pilots symbols and at least one second subvector including channel estimates related to null symbols; decoding the at least one first subvector, delivering at least one first treated subvector; modifying the at least one second subvector by assuming presence of pilot symbols in the at least one second subvector, delivering at least one second treated subvector; and calculating a new vector of channel estimates with the at least one first treated subvector and the at least one second treated subvector.

Abstract: A method of canceling co-channel interference of a signal received by a mobile station having at least two receiving antennas, in a cellular OFDMA-TDD communication network having a serving base station and at least one interfering base station. The signal is a result of a serving signal transmitted by the serving base station which is distorted by at least one interfering signal transmitted by the interfering base station. The serving signal is transmitted with a first modulation scheme and the interfering signal is transmitted with a second modulation scheme. The method includes: a channel estimation phase delivering channel estimations of the serving signal and the interfering signal; and a MIMO detecting phase, detecting symbols by using the channel estimations of the serving signal and the interfering signal. The MIMO detection phase is realized using a non-linear method which uses the first modulation scheme and the second modulation scheme.

Abstract: A channel estimating method is provided for a signal transmitted in an orthogonal frequency division multiplexing (OFDM) system, wherein an OFDM symbol of the signal has at least one null subcarrier set in its defined bandwidth. The method includes: obtaining at least one initial channel estimate over at least one OFDM symbol of a received signal; processing the at least one initial channel estimate for delivering at least one soft information in a form of a complete matrix; and updating the at least one initial channel estimate by performing a truncated singular value decomposition of a partial FFT matrix. The partial FFT matrix includes only the first LDP columns and the rows NDP of an FFT matrix of the complete matrix, the NDP rows corresponding to modulated subcarriers of received signal, including data and pilot symbols and excluding the at least one null subcarrier, delivering an improved channel estimate.

Abstract: A method and apparatus for estimating a transmission channel in a receiver of an OFDMA signal formed by a plurality of carriers modulated by data elements and distributed in the time-frequency domain in successive symbols, the plurality of carriers including pilot carriers, modulated by reference data elements known by receivers. The method includes: receiving a signal comprising a series of n symbols covering at least one resource block; making an initial channel estimation by identifying the pilot carriers included in the series of n symbols; determining diagonal entries of p frequency domain channel matrices G(x) for estimating the channel for at least x symbols among the n symbols, the x symbols being pilot symbols; determining, in the frequency domain, at least some non diagonal entries for each frequency domain channel matrix G of the n symbols from the determined diagonal entries of the x frequency domain channel matrices G(x).

Abstract: An embodiment of a method for transmitting a sequence of symbols through at least a channel in a wireless communication system comprises at least the steps of: forming a coding matrix (MC) with said sequence of symbols, each component of the coding matrix (MC) being a linear combination of two symbols among a first, a second, a third, and a fourth symbol (s1, s2, s3, s4), transmitting a first and a second components of a first column and of a second column of the coding matrix through a first and a second transmit antennas (Tx1, Tx2), at a first and a second time slot (T1, T2). The coding matrix (MC) is defined as: ( as 1 + bs 3 - cs 2 * - ds 4 * as 2 + bs 4 cs 1 * + ds 3 * ) , a, b, c, d being complex numbers of modulus 1.

Abstract: An embodiment of a method for transmitting data through at least a channel in a wireless communication system, the method comprising at least the steps of: encoding the data by performing a forward-error-correction encoding, forming a sequence of symbols from the encoded data, forming an M-by-T coding matrix from said sequence of symbols, each column of the coding matrix comprising N different symbols of the sequence of symbols and M?N zeros, N being an integer equal at least to one, T representing the number of consecutive transmission intervals, M representing the total number of transmit antennas, and using the coding matrix for transmitting the sequence of symbols during the T consecutive transmission intervals, by transmitting one different column of the coding matrix at each transmission interval through the M transmit antennas, only N transmit antennas are enabled during a given transmission interval.