High-performance Power Allocation Strategies for Secure Spatial Modulation

TL;DR

This paper introduces two high-performance power allocation strategies for secure spatial modulation, significantly improving secrecy rate with low complexity, and compares their effectiveness to exhaustive search and fixed methods.

Contribution

It proposes a gradient descent and a closed-form Max-P-SINR-ANSNR power allocation strategies for secure spatial modulation, addressing the lack of closed-form SR expressions.

Findings

Max-P-SINR-ANSNR achieves near-optimal SR with low complexity.

Both proposed methods outperform fixed PA strategies.

Max-P-SINR-ANSNR performs slightly better at low/medium SNR, GD at high SNR.

Abstract

Optimal power allocation (PA) strategies can make a significant rate improvement in secure spatial modulation (SM). Due to the lack of secrecy rate (SR) closed-form expression in secure SM networks, it is hard to optimize the PA factor. In this paper, two PA strategies are proposed: gradient descent, and maximum product of signal-to-interference-plus-noise ratio (SINR) and artificial-noise-to-signal-plus-noise ratio (ANSNR)(Max-P-SINR-ANSNR). The former is an iterative method and the latter is a closed-form solution. Compared to the former, the latter is of low-complexity. Simulation results show that the proposed two PA methods can approximately achieve the same SR performance as exhaustive search method and perform far better than three fixed PA ones. With extremely low complexity, the SR performance of the proposed Max-P-SINR-ANSNR performs slightly better and worse than that of the proposed GD in the low to medium, and high signal-to-noise ratio regions, respectively.