Joint virtual edge-clustering and spectrum allocation scheme for uplink interference mitigation in C-RAN

Fractional Frequency Reuse (FFR) and Coordinated MultiPoint (CoMP) processing are two of the conventional methods to mitigate the Inter-Cell Interference (ICI) and to improve the average Signal-to-Interference-plus-Noise Ratio (SINR). However, FFR is associated with low system spectral efficiency and CoMP does not take any action to mitigate the inter-cluster interference. In this article, we study the challenges and problems of the current interference management techniques and explain why the clustering and spectrum allocation must be studied jointly. Then, in the context of Cloud Radio Access Network (C-RAN), we propose a joint virtual clustering and spectrum allocation scheme, called Cloud-CFFR, to address such problems. With respect to both FFR and CoMP, Cloud-CFFR decreases the complexity, delay, and ICI while increasing the system spectral efficiency. Since the system performance in cell-edge regions relies on the cooperation of different Virtual Base Stations (VBSs), there is no service interruption in handling handovers; moreover, in order to address the unanticipated change in capacity demand, a flexible spectrum management technique is proposed which dynamically changes the subband boundaries based on the number of active users in the clusters. Simulation results confirm the validity of our analysis and show the benefits of this novel uplink solution compared to the traditional schemes.