Two-dimensional diversity with serial concatenation of spectral precoding and DSTBC

Much attention has been paid to higher frequency (HF) radio communication providing large capacity. As well, maintaining its communication quality is one of the crucial issues, and diversity approaches should be effective ways in terms of physical layer. Differential Space-Time Block Coding (DSTBC), which is a spatial diversity strategy, has robustness against phase noise serious in a HF band. Employing less receiving antennas is required to establish reasonable systems although multiple receiving antennas can improve the quality. Therefore, we try to obtain a frequency diversity effect instead by applying spectral precoding which exploits abundant frequency resources of a HF band, in addition to DSTBC. In this paper, we propose two-dimensional diversity scheme which is concatenation of spectral precoding and corrected DSTBC to compensate an imbalance of equivalent noise variances between subcarriers. The performance evaluation using computer simulations reveals that the proposed solution yields the performance gain up to 4dB at BER=10
⁻⁴
compared to simple DSTBC. Afterwards, we also examine the performance when applying error correction code, and indicate that applicability of spectral precoding is dependent on the coding rate.