Virtual Spatial Channel Number and Index Modulation

Zahid Iqbal,Fei Ji,Yun Liu,Xiaojie Wang

doi:10.1155/2021/2982226

Abstract

This paper proposes a novel precoding-aided and efficient data transmission scheme called virtual spatial channel number and index modulation (VS-CNIM), which conveys extra data by changing both the number and index of active virtual parallel channels of multiple-input multiple-output (MIMO) channels, obtained through the singular value decomposition (SVD) in each time slot. Unlike the conventional virtual spatial modulation (VSM), where extra data bits are transmitted only using index of active virtual parallel channels, the VS-CNIM scheme, depending on incoming information bits, transmits extra bits utilizing both the number and indices of active parallel channels along the bits carried by M -ary constellation symbols. Therefore, VS-CNIM provides significantly superior spectral efficiency (SE) compared to VSM. Considering the influence of imperfect channel estimation, a closed-form upper bound is derived on average bit error probability (ABEP). The asymptotic performance is also analyzed, which gives the coding gain and diversity order and describes error floor under the consideration of perfect and imperfect channel estimation, respectively. Monte Carlo simulations exhibit that the VS-CNIM scheme achieves considerably better error performance and high SE than precoding-aided SM (PSM) and VSM schemes.

Highlights

Introduction of a multiple transmit and receive antennabased scheme in wireless communication systems referred to as multiple-input-multiple-output (MIMO) substantially improves the channel capacity [1,2,3]
We investigate the performance of VSCNIM considering ideal and realistic channel conditions
A novel better error performance and spectral efficient Spatial modulation (SM) scheme, namely, virtual spatial channel number and index modulation (VS-CNIM), has been proposed, which conveys extra spatial bits by utilizing both the number and indices of active parallel channels obtained from the decomposition of MIMO channels

Summary

Introduction

Introduction of a multiple transmit and receive antennabased scheme in wireless communication systems referred to as multiple-input-multiple-output (MIMO) substantially improves the channel capacity [1,2,3]. In [27], Multistream Receive-Spatial Modulation (MSR-SM) which extends the GPSM scheme to multistream is introduced, achieving better performance in terms of coding gain and diversity as compared to state-of-the art MIMO schemes. Incorporating both in-phase and quadrature parts of the received signal, generalized precoding-aided quadrature SM (GPQSM) [28] can transmit additional information as compared with GPSM. In order to mitigate the limitations, such as elimination of ICI, number of transmit antennas, and high correlation between the parallel channels, of above-mentioned precoding schemes, a new precoding scheme called virtual spatial modulation (VSM) and its variants are proposed in [31,32,33] which exploits the “virtual parallel channels” to convey information. This work was supported in parts by the National Natural Science Foundation of China under Grants 61431005 and 62071504 and by the Guangdong provincial research project under Grant 2016A030308006

General System Model and VSM Overview

Proposed VS-CNIM

Performance Analysis

Simulation Results and Comparison

Conclusions and Future Work