Pseudo-random Phase Precoded Spatial Modulation

TL;DR

This paper introduces a novel Pseudo-random Phase Precoded Spatial Modulation (PRPP-SM) scheme that combines SM and PRPP techniques, achieving significant performance improvements in wireless communication systems, especially with large precoding sizes.

Contribution

The paper proposes a new PRPP-SM system that integrates pseudo-random phase precoding with spatial modulation, along with a low complexity detection algorithm, demonstrating substantial performance gains.

Findings

PRPP-SM outperforms traditional SM without PRPP by about 9 dB at BER of 10^{-2}

Performance improves with larger precoding sizes

Low complexity detection is effective for large PRPP-SM systems

Abstract

Spatial modulation (SM) is a transmission scheme that uses multiple transmit antennas but only one transmit RF chain. At each time instant, only one among the transmit antennas will be active and the others remain silent. The index of the active transmit antenna will also convey information bits in addition to the information bits conveyed through modulation symbols (e.g.,QAM). Pseudo-random phase precoding (PRPP) is a technique that can achieve high diversity orders even in single antenna systems without the need for channel state information at the transmitter (CSIT) and transmit power control (TPC). In this paper, we exploit the advantages of both SM and PRPP simultaneously. We propose a pseudo-random phase precoded SM (PRPP-SM) scheme, where both the modulation bits and the antenna index bits are precoded by pseudo-random phases. The proposed PRPP-SM system gives significant performance gains over SM system without PRPP and PRPP system without SM. Since maximum likelihood (ML) detection becomes exponentially complex in large dimensions, we propose low complexity local search based detection (LSD) algorithm suited for PRPP-SM systems with large precoder sizes. Our simulation results show that with 4 transmit antennas, 1 receive antenna, $5\times 20$ pseudo-random phase precoder matrix and BPSK modulation, the performance of PRPP-SM using ML detection is better than SM without PRPP with ML detection by about 9 dB at $10^{-2}$ BER. This performance advantage gets even better for large precoding sizes.