Space-Domain Index Modulation for mmWave Cloud Radio Access Networks

Abstract

In this paper, we investigate the uplink transmission strategy of a cloud radio access network (C-RAN) based millimeter-wave (mmWave) communication system and propose to use a space-domain index modulation (SDIM) scheme to improve the system reliability. The key idea of the proposed SDIM scheme is to enable the user (UE) to use different beam directions to carry part of information. We first introduce the SDIM scheme into C-RAN based mmWave communication system and model the signal design as an optimization problem. Then, two detection methods, namely the centralized detection and distributed detection, are proposed to demodulate the received signal. Moreover, we propose a power allocation algorithm to minimize the system symbol error rate (SER). Following this, by ignoring the side lobe of the UE, the condition which ensures the superiority performance of mmWave SDIM against the conventional communication scheme is derived. Finally, we model the position of the remote radio heads (RHHs) of the network as a homogeneous Poisson point process (PPP) and derive the probability that the proposed SDIM scheme outperforms the conventional communication scheme to evaluate its performance. Analytical and numerical results show that the proposed SDIM scheme can effectively enhance the system reliability.