A radio system with multi-element antennas

A radio hardware concept for indoor WLAN applications is described in which both the transmitter and the receiver use multi-element antennas. The system exploits the increased capacity of the multiple-input multiple-output (MIMO) indoor radio channel and it is designed especially for high data rates. A technique to measure the MIMO channel matrix is described. A weak pseudo-noise sequence out of a set of Gold codes is added to each transmitted signal from which the amplitude and phase of the carrier corresponding to that antenna is identified at each receive antenna. The data signals are reconstructed at the receiver in a weighted-signal combining network where IQ modulators steer the complex weights. Fully transparent transmission at high data rates is possible in this way.