Quasi-orthogonal Space Time Block Codes (STBC) with full transmit rate Concatenated LDPC codes

Abstract

In MIMO system of wireless communications, Space time block coding (STBC) is the attractive technique for high bit-rate and high capacity transmission. Methods for providing transmit diversity in communication over fading channels also been concerned. Although STBC has full diversity gain but not coding gain. The concatenation scheme of STBC codes and LDPC (STBC-LDPC) was proposed and it has been shown that the STBC-LDPC can achieve the good error rate performance and coding gain. 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. In this paper, a concatenation scheme of LDPC codes and Quasi orthogonal STBC which should apply full transmit rate with multiple transmit antennas is proposed. Refering to it as the QOSTBC-LDPC. We evaluate the bit error rate (BER) of the QOSTBC-LDPC with multiple transmit antennas in a quasi-static Rayleigh fading channel by the computer simulation. We show that the BER of the QOSTBC-LDPC is better than that of the STBC with same antennas in a quasi-static Rayleigh fading channel. When receive antennas increasing, the diversity gain will be increasing too.