On the Capacity and Performance of Generalized Spatial Modulation

TL;DR

This paper analyzes the capacity of generalized spatial modulation (GSM) systems, deriving bounds, and proposes efficient encoding and detection algorithms for large-scale GSM-MIMO systems.

Contribution

It introduces capacity bounds for GSM, along with a novel bits-to-signal encoding method and a low-complexity detection algorithm for large-scale systems.

Findings

Derived capacity bounds for GSM systems.

Proposed an efficient bits-to-signal encoding scheme.

Developed a message passing detection algorithm.

Abstract

Generalized spatial modulation (GSM) uses $N$ antenna elements but fewer radio frequency (RF) chains ($R$) at the transmitter. Spatial modulation and spatial multiplexing are special cases of GSM with $R=1$ and $R=N$, respectively. In GSM, apart from conveying information bits through $R$ modulation symbols, information bits are also conveyed through the indices of the $R$ active transmit antennas. In this paper, we derive lower and upper bounds on the the capacity of a ($N,M,R$)-GSM MIMO system, where $M$ is the number of receive antennas. Further, we propose a computationally efficient GSM encoding (i.e., bits-to-signal mapping) method and a message passing based low-complexity detection algorithm suited for large-scale GSM-MIMO systems.