Rate-Splitting Meets Cell-Free MIMO Communications

Abstract

Multiuser multiple-input multiple-output wireless communications systems have the potential to satisfy the performance requirements of fifth-generation and future wireless networks. In this context, cell-free (CF) systems, where the antennas are distributed over the area of interest, have attracted attention because of their potential to enhance the overall efficiency and throughput performance when compared to traditional networks based on cells. However, the performance of CF systems is degraded by imperfect channel state information (CSI). To mitigate the detrimental effects of imperfect CSI, we employ rate splitting (RS) -a multiple-access scheme. The RS approach divides the messages of the users into two separate common and private portions so that interference is managed robustly. Unlike prior works, where the impact of RS in CF systems remains unexamined, we propose a CF architecture that employs RS with linear precoders to address deteriorated CSI. We derive closed-form expressions to compute the sum-rate performance of the proposed RS-CF architecture. Our numerical experiments show that our RS-CF system outperforms existing systems in terms of sum-rate, obtaining up to 10% higher gain.

Resource Allocation in Heterogeneously-Distributed Joint Radar-Communications Under Asynchronous Bayesian Tracking Framework

“…We demonstrated that, compared to the trivial uniform and random allocations, the system performance is significantly improved by properly allocating the accessible heterogeneous resources of both radar and communications through ANCHOR algorithm. This study is helpful in meeting challenges of nextgeneration wireless systems where heterogeneous networks are envisaged such as different radio access technologies (RATs) and cell-free massive MIMO systems [59].…”