Full-Duplex Enabled Cloud Radio Access Network

Abstract

Abstract-Full-duplex (FD) has emerged as a disruptive solution for improving the achievable spectral efficiency (SE), thanks to the recent major breakthroughs in self-interference (SI) mitigation. The FD versus half-duplex (HD) SE gain, in the context of cellular networks, is however largely limited by the mutual interference (MI) between the downlink (DL) and uplink (UL). A potential remedy for tackling the MI bottleneck is through cooperative communications. This paper provides a stochastic analysis of FD enabled cloud radio access network (C-RAN) with finite user-centric cooperative clusters. Contrary to the most existing theoretical studies of C-RAN, we explicitly take into consideration non-isotropic fading channel conditions, and finite-capacity fronthaul links. Accordingly, we develop analytical expressions for the FD C-RAN DL and UL SEs. The results indicate that significant FD versus HD C-RAN SE gains can be achieved, particularly in the presence of sufficient-capacity fronthaul links and advanced interference cancellation capabilities.I. INTRODUCTION Cloud radio access network (C-RAN) is a novel cellular system architecture, intended to tackle the various underlying challenges posed by network densification [1], [2]. C-RAN facilitates cooperative communications on a large-scale basis [3], with central processors (CPs) handling the baseband processing and, via fronthaul links, exchanging information with distributed radio units (RUs), which in turn, provide (mostly) radio-frequency functionalities. C-RAN, thanks to its ability to address the inter-cell interference phenomenon, can provide significantly higher spectral efficiency (SE) and energy efficiency (EE) versus the legacy cellular systems [4], [5].Another emerging disruptive solution for improving the data rates is full-duplex (FD) communications, that is transceiving of information at the same time and frequency [6]. This trend follows from the recent major breakthroughs in signal processing techniques which combat self-interference (SI) directly in FD mode [7], [8]. On the other hand, the FD versus halfduplex (HD) SE gain, in cellular networks, is largely limited by the mutual interference (MI) between the downlink (DL) and uplink (UL) [9]-[11]. A potential remedy for tackling the MI bottleneck is through cooperative communications, also referred to as network multiple-input multiple-output (MIMO).In [12], the performance of C-RAN with FD enabled RUs was studied using the classical Wyner cellular model. In particular, the authors derived analytical expressions for the C-RAN DL and UL SEs in both FD and HD modes of communications. In [13], a FD multi-cell network MIMO scenario was considered. By utilizing spatial interference-alignment (IA),

A comprehensive survey on resource allocation for CRAN in 5G and beyond networks

“…Thus formulated non-convex problem is solved by utilizing second-order coneprogramming based alternating optimization. In addition, authors in [116] carried out the stochastic analysis of FD-enabled CRAN while considering user-centric cooperative clusters, non-isotropic channel fading conditions and fronthaul capacity limitations. The analytical expressions for the uplink and downlink spectral efficiencies of an FD-enabled CRAN are derived and significant performance gain of FD CRAN is shown over the half-duplex CRAN through numerical results.…”