Backhaul metro cell-based guard channel in femto/macro cellular heterogeneous networks

The heterogeneous network (HetNet) deployed small cells technology in order to overcome the problems of holes “blind spots” coverage in 3G and 4G mobile networks. In this work, we propose a hierarchical HetNet layout comprises of three layers, macro, metro and femto cells. The metro cell is deployed as a backhaul layer in-between macro cell and femto cell layers and operates in a complementary fashion to fulfill handover (HO) traffic interplay between successive layers. Accordingly, the femto cell serves indoor traffic activity of femto users, while metro cell serves the outdoor traffic activities as well as the overflow traffic from femto cells. In addition, in order to reduce the failure probability of femto users handed over to metro cell, a guard channel scheme is employed to prioritize the HO call over new call requests. The highest layer in HetNet, macro cell only serves macro users and the overflowed traffic from the lower layer. Then, we develop a realistic teletraffic model in order to measure the QoS metrics of the proposed HetNet. The numerical results show the capability of HetNet with coexisting small cells to offload traffic from traditional macro cellular network in terms of reducing the blocking probability.