On the Performance of Consumer IoT Networks Based on Asynchronous Cell-Free Massive MIMO

Abstract

The proliferation of consumer electronics in the Internet of Things (IoT) has led to the expanding applications in various fields with increasing demand for large-scale connections. Spectrum scarcity has become a crucial challenge. Cell-free (CF) massive multiple-input multiple-output (mMIMO) is a promising technology to support the future consumer IoT networks due to its ability to assure seamless mobility support. However, a perfect synchronization has been commonly assumed in the CF mMIMO system which is infeasible in the consumer IoT networks where the intelligent devices and access points (APs) can be geographically distributed. This paper considers an asynchronous CF mMIMO system for the consumer IoT networks and investigates its performance. A rate-splitting (RS) strategy is proposed and the phase shift is considered in the line of sight (LoS) path of Rician fading channel with mobility and phase noise. The phase-aware minimum mean square error (MMSE) and non-perceptual linear MMSE (LMMSE) estimators are derived. The closed-form expressions of downlink spectral efficiency (SE) for coherent and non-coherent data transmission are derived for the system with and without RS strategy. Simulation results demonstrate that the proposed RS strategy can improve the downlink SE of the consumer IoT networks based on asynchronous CF mMIMO.