A MIMO system with reciprocal transceivers for the time-division duplex mode

For the application of advanced smart antenna and MIMO techniques as joint transmission, channel inversion and Tomlinson-Harashima pre-coding in future radio systems, channel side information is required at the transmitter. In the time-division duplex mode, the reciprocal channel coefficients estimated in the uplink may in principle be reused in the downlink. In practice, the reciprocity must not be limited to the radio frequency channel between the antennas but it should be available also at the transceiver interfaces to the baseband signal processing. Here we propose a new transceiver design suitable for the application of these advanced techniques.