Multiple Beamforming with Perfect Coding

TL;DR

This paper introduces two novel multiple beamforming techniques using perfect space-time codes and SVD, significantly reducing decoding complexity while maintaining near-optimal performance in MIMO systems.

Contribution

The paper proposes Perfect Coded Multiple Beamforming and BICMB-PC, novel methods that lower decoding complexity in MIMO systems with perfect coding and channel state information.

Findings

Decoding complexity is substantially reduced with the new techniques.

Performance loss is negligible or modest compared to existing methods.

Complexity gains are especially significant in dimensions 2 and 4.

Abstract

Perfect Space-Time Block Codes (PSTBCs) achieve full diversity, full rate, nonvanishing constant minimum determinant, uniform average transmitted energy per antenna, and good shaping. However, the high decoding complexity is a critical issue for practice. When the Channel State Information (CSI) is available at both the transmitter and the receiver, Singular Value Decomposition (SVD) is commonly applied for a Multiple-Input Multiple-Output (MIMO) system to enhance the throughput or the performance. In this paper, two novel techniques, Perfect Coded Multiple Beamforming (PCMB) and Bit-Interleaved Coded Multiple Beamforming with Perfect Coding (BICMB-PC), are proposed, employing both PSTBCs and SVD with and without channel coding, respectively. With CSI at the transmitter (CSIT), the decoding complexity of PCMB is substantially reduced compared to a MIMO system employing PSTBC, providing a new prospect of CSIT. Especially, because of the special property of the generation matrices, PCMB provides much lower decoding complexity than the state-of-the-art SVD-based uncoded technique in dimensions 2 and 4. Similarly, the decoding complexity of BICMB-PC is much lower than the state-of-the-art SVD-based coded technique in these two dimensions, and the complexity gain is greater than the uncoded case. Moreover, these aforementioned complexity reductions are achieved with only negligible or modest loss in performance.