Resilient hybrid optical-RF backhauling for tiered networks

Abstract To meet the huge demand in 5G data services, it is expected to have an enormous number of small cells along the conventional base stations. Various backhaul links including Optical Fiber (OF), Free Space Optics (FSO) and Radio Frequency (RF) are used to support the backhaul demand of such tiered network. The objective of this paper is to improve the connectivity of tiered networks by obtaining the optimal combinations of backhauling technologies (OF, FSO, RF or hybrid FSO/RF). In this paper, optimization of two-tier networks connectivity and resilience is performed, under the constraints of minimum data rate, cost, and reliability of different links. Under realistic cost assumptions and linear relaxation, it was shown that the problem can be formulated as a convex optimization problem. In this paper, an iterative solution is proposed. The proposed solution iterates between two computationally efficient methods to successively maximize the algebraic connectivity and resilience. The simulation results show that the proposed algorithm can achieve gains of 240 % − 600 % in terms of the network algebraic connectivity, depending on the rate constraint range. Similarly, it can achieve gains of 60 % − 100 % enhancement in terms of the network resilience.