LDPC-based space-time transmit diversity schemes with multiple transmit antennas

Abstract

Space-time transmit diversity (STTD) and space-time block coding (STBC) are the attractive techniques for high bit-rate and high capacity transmission. The concatenation scheme of turbo codes and STBC (turbo-STBC) was proposed and it has been shown that the turbo-STBC can achieve the good error rate performance. Recently, low-density parity-check (LDPC) codes have attracted much attention as the good error correcting codes achieving the near Shannon limit performance like turbo codes. The decoding algorithm of LDPC codes has less complexity than that of turbo codes. Furthermore, it has been shown that when the block length is relatively large, the error rate performance of the LDPC codes is better than that of the turbo codes with almost identical code rate and block length. In this paper, we propose a concatenation scheme of LDPC codes and STBC with multiple transmit antennas. We refer to it as the LDPC-STBC. We evaluate the frame error rate (FER) of the LDPC-STBC with multiple transmit antennas in a flat Rayleigh fading channel by the computer simulation. We show that the FER of the LDPC-STBC is worse than that of the turbo-STBC in a quasi-static Rayleigh fading channel, while that of the LDPC-STBC is better than that of the turbo-STBC in a flat Rayleigh fading channel. Furthermore, we show that the FER of the LDPC-STBC without channel interleaver (CI) is better than that of the turbo-STBC with CI in a fast fading channel.