Patent ID: 7366520

Claim:
An adaptive signal processing method for a bidirectional wireless transmission of digital data streams in uplink and downlink transmission directions over a MIMO channel with n antennas at one at one side of the channel and m antennae at the other side of the channel and with transmission-side signal preprocessing of the transmission signals x and receiving-side signal postprocessing of the received signals y, both being based upon an estimation of the complex-valued channel matrix, whereby the transmission-side signal preprocessing comprises a multiplication of the data signals to be transmitted by a transmission matrix and the receiving-side postprocessing comprises a multiplication of the received signals with a receiving matrix, the signal postprocessing taking place in the uplink transmission direction exclusively and the transmission and receiving matrix being derived from a linear dissection of the estimated channel matrix H; at least one antenna being used in the uplink transmission direction (n→m) at the receiving side than at the transmission side and in the downlink transmission direction (m→n) on the transmission side at least one antenna more being used than at the receiving side (n<m), and the estimation of the channel matrix H being determined at a symbol rate of at least 100 ksymbols/s selected in dependence of the channel properties, whereby by making use of the reciprocity of the MIMO-channel at the same transmission frequency in the uplink and downlink transmission and in the absence of common-channel interferences the channel matrix in the downlink transmission direction being derived by transposing the channel matrix from the estimation in the uplink transmission direction, and vice versa.