Performance evaluation of dual backhaul links RF/FSO for small cells of 5G cellular system

Radio frequency (RF) backhaul links between the wireless stations especially between small cells stations such as relay stations (RSs) are insufficient with high capacities and huge number of users for 5G cellular networks. An alternative solution is using free space optics (FSO) communications, however, there are limitations in this system. In this paper we proposed a mixed of RF link together with FSO link. Using hard- selector between them and programmatically controlled according of quality of links to overcome the obstacles faced the transfer of high data. Based on the outage probability of each links an algorithm is proposed to select the optimal link and provide the power consumption with guaranteed high quality of the link. The analytical expressions for the outage probability and ergodic capacity are derived. The numerical results show the effectiveness of proposed model in terms of connectivity and capacity compared to other links