Detect-and-Forward Relaying Aided Cooperative Spatial Modulation for Wireless Networks

Abstract

A novel detect-and-forward (DeF) relaying aided cooperative SM scheme is proposed, which is capable of striking a flexible tradeoff in terms of the achievable bit error ratio (BER), complexity and unequal error protection (UEP). More specifically, SM is invoked at the source node (SN) and the information bit stream is divided into two different sets: the antenna index-bits (AI-bits) as well as the amplitude and phase modulation-bits (APM-bits). By exploiting the different importance of the AI-bits and the APMbits in SM detection, we propose three low-complexity, yet powerful relay protocols, namely the partial, the hybrid and the hierarchical modulation (HM) based DeF relaying schemes. These schemes determine the most appropriate number of bits to be re-modulated by carefully considering their potential benefits and then assigning a specific modulation scheme for relaying the message. As a further benefit, the employment of multiple radio frequency (RF) chains and the requirement of tight inter-relay synchronization (IRS) can be avoided. Moreover, by exploiting the benefits of our low-complexity relaying protocols and our inter-element interference (IEI) model, a lowcomplexity maximum-likelihood (ML) detector is proposed for jointly detecting the signal received both via the source-destination (SD) and relay-destination (RD) links. Additionally, an upper bound of the BER is derived for our DeF-SM scheme. Our numerical results show that the bound is asymptotically tight in the high-SNR region and the proposed schemes provide beneficial system performance improvements compared to the conventional MIMO schemes in an identical cooperative scenario.

An adaptive transmission protocol for exploiting diversity and multiplexing gains in wireless relaying networks

“…Spatial modulation (SM) was developed to improve the throughput of MIMO systems and was initially extended for WRNs in [23][24][25]. The intention was to add the spatial dimension to the modulated signal constellation; this allowed information to be transmitted not only using amplitude/phase modulation (APM) but also using the relay index.…”

“…The intention was to add the spatial dimension to the modulated signal constellation; this allowed information to be transmitted not only using amplitude/phase modulation (APM) but also using the relay index. This offers higher throughput due to data multiplexing via different relays [24,26]. However, the overall achieved diversity gain was limited to the number of receive antennas, as only one relay was active for any given transmission.…”

Spatial Modulation Exploited in Non-Reciprocal Two-Way Relay Channels: Efficient Protocols and Capacity Analysis

“…This approach aims to increase the data rate of a system without increasing the bandwidth requirements. It requires only a single radiofrequency chain while achieving higher energy efficiency than other multi-antenna approaches and, moreover, it has been proven full of promise not only in point-to-point systems [22]- [26], but also in cooperative networks [27]- [30]. A general survey on spatial modulation for its design framework and intrinsic limits is provided in [31].…”

Relay selection methods in cooperative spatial modulation for wireless networks

“…[3]'de önerilen yöntemde direk iletim ve iki röle kullanılarak işbirlikli ag modeli oluşturulmuştur. Literatürde bilinen çalışmalardaki yöntemler incelenerek eksikliklerinin giderildigi bir Çöz ve Aktar (Detect and forward, DF) röle tabanlı işbirlikli uzaysal modülasyon mimarisi [15]'deki çalışmada sunulmuştur. Bu çalışma incelendiginde uzaysal modülasyonun kaynak noktası ve iletilen bilgi bitlerinden oluşan iki farklı kümeye ayrıldıgı görülmektedir.…”

“…Bu kümeler: anten indisleri olarak iletilen bitler ve genlik-faz modülasyonu birleşimidir. Bu da röle bitlerinde esneklik saglamaktadır [15]. Bununla birlikte bu çalışmada sadece iki röle baz alınarak 2-PSK/QAM (Phase Shift Keying/Quadrature Amplitude Modulation) işbirlikli iletişim modeli oluşturuldugu görülmüştür.…”