Performance analysis in cloud radio access networks: user-centralized coordination approach

The cloud radio access network (C-RAN) has recently been proposed as an important component of the next generation wireless networks providing opportunities for improving both spectral and energy efficiencies. The performance of this network structure is however constrained by severe inter-cell interference due to the limited capacity of fronthaul between the radio remote heads (RRH) and the base band unit (BBU) pool. To achieve performance improvement taking full advantage of centralized processing capabilities of C-RANs, a set of RRHs can jointly transmit data to the same UE for improved spectral efficiency. In this paper, a user centralized joint coordinated transmission (UC-JCT) scheme is put forth to investigate the downlink performance of C-RANs. The most important benefit the proposed strategy is the ability to translate what would have been the most dominant interfering sources to usable signal leading to a significantly improved performance. Stochastic geometry is utilized to model the randomness of RRH location and provides a reliable performance analysis. We derive an analytical expression for the closed integral form of the coverage probability of a typical UE. Simulation results confirm the accuracy of our analysis and demonstrate that significant performance gain can be achieved from the proposed coordination schemes.