Differential space-frequency trellis codes

A new differential space-frequency trellis coding (DSFTC) scheme is proposed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. The transmitter differentially encodes the message drawn from a set of unitary matrices following a trellis encoding rule. At the receiver, where no channel state information (CSI) is available, differential decoding and soft-input Viterbi algorithms are employed in the decoding process. The proposed codes can achieve full rate, 1 symbol/subcarrier, and full spatial diversity. Simulation results show that the proposed codes provide significant improvements over differential space-frequency block codes (DSFBC) due to increased coding gains