Partial Linear and SQRD-based DF Detections for DSTTD-OFDM Systems in Severely Time-Varying Multipath Channels

This paper proposed partial linear and sorted QR decomposition (SQRD)-based decision feedback detection (DFD) schemes for double space time transmit diversity (DSTTD)-orthogonal frequency division multiplexing (OFDM) systems to overcome severely time-varying multipath channels. The rapid channel variation deteriorates BER performance due to the introduction of intra-STTD-unit interference and intercarrier interference (ICI). The partial linear approaches mitigate the ICI effects with banded submatrices, instead of full channel frequency response (CFR) matrix. For further improvement of BER performance, the partial SQRD-based DFD with a modified ordering criterion is developed, which effectively removes above two types of interferences including inter-STTD-unit interference simultaneously. Computer simulation results show that the performance of the partial SQRD-based DFD is superior to those of the other linear approaches, with comparable complexity.