Outage Probability of Multiuser Mixed RF/FSO Relay Schemes for Heterogeneous Cloud Radio Access Networks (H-CRANs)

The increase in deployment of various advanced wireless technologies, services, and applications have put significant pressure on the mobile network operators (MNOs) in terms of system requirements such as capacity, quality of service (QoS), and network coverage. In an effort to optimally meet the system requirements, the MNOs are confronted with high total cost of ownership (TCO), however, the associated income is relatively low. In order to address the challenges, MNOs as well as service providers (SPs) have given considerable interest to the small-cell schemes along with the associated advanced centralized and heterogeneous network architectures. This is due to their beneficial qualities regarding system performance optimization and cost-effectiveness. However, achieving the stringent requirements of the fronthaul for connecting the network elements is highly demanding. In this paper, taking into consideration the small-cell network architectures, we present multiuser mixed radio-frequency/free-space optical (RF/FSO) relay schemes as viable means of alleviating the stringent requirements. Furthermore, we study the end-to-end outage performance of the mixed RF/FSO schemes considering the effect of pointing errors in the FSO links. The simulation results portray the feasibility of deployment of the mixed RF/FSO schemes in real-life scenarios.