Spatial Modulation in Zero-Padded Single Carrier Communication

TL;DR

This paper introduces a zero-padded single carrier spatial modulation system that achieves full multipath diversity with lower decoding complexity, extending existing methods to frequency selective channels and improving performance over cyclic prefix approaches.

Contribution

It proposes zero-padding instead of cyclic prefix in SC SM systems, achieving full multipath diversity and reduced ML decoding complexity, and extends PIC-R decoding to enhance diversity gains.

Findings

Zero-padding provides full multipath diversity in SC SM systems.

Decoding complexity depends only on the number of multipath links, not frame length.

Extended PIC-R enables full diversity with flat-fading like decoding complexity.

Abstract

In this paper, we consider the Spatial Modulation (SM) system in a frequency selective channel under single carrier (SC) communication scenario and propose zero-padding instead of cyclic prefix considered in the existing literature. We show that the zero-padded single carrier (ZP-SC) SM system offers full multipath diversity under maximum-likelihood (ML) detection, unlike the cyclic prefixed SM system. Further, we show that the order of ML decoding complexity in the proposed ZP-SC SM system is independent of the frame length and depends only on the number of multipath links between the transmitter and the receiver. Thus, we show that the zero-padding in the SC SM system has two fold advantage over cyclic prefixing: 1) gives full multipath diversity, and 2) offers relatively low ML decoding complexity. Furthermore, we extend the partial interference cancellation receiver (PIC-R) proposed by Guo and Xia for the decoding of STBCs in order to convert the ZP-SC system into a set of flat-fading subsystems. We show that the transmission of any full rank STBC over these subsystems achieves full transmit, receive as well as multipath diversity under PIC-R. With the aid of this extended PIC-R, we show that the ZP-SC SM system achieves receive and multipath diversity with a decoding complexity same as that of the SM system in flat-fading scenario.