backhaul-aware decoupled uplink and downlink user association, and power control in fi-wi hetnets

Decoupling the uplink and downlink user association improves the throughput of heterogeneous networks (hetnets) and balances the traffic load of macro- and small- base stations. recently, fiber-wireless hetnets (fiwi-hetnets) have been considered as viable solutions for access networks. to improve the accuracy of user association and resource allocation algorithms in fiwi-hetnets, the capacity limitation of various backhaul technologies must be considered. in this paper, we investigate the backhaul-aware decoupled uplink/downlink (ul/dl) user association, subcarrier allocation, and power control optimization problem in fiwi-hetnets. in our system model, fiber and millimeter wave (mmwave) links are used as backhaul of base stations, and the backhaul capacity limitation and minimum required transmission rate (r_min) are modeled in the optimization problem. as the formulated optimization problem is non-convex, we present a heuristic algorithm to divide the main problem into two sub-problems that are solved iteratively. the proposed algorithms are evaluated through exhaustive simulations. the results indicate that decoupling ul/dl user association improves the sum rate of fiwi-hetnets. besides, we evaluate the effect of backhaul capacity limitation and r_min on the sum rate of fiwi-hetnets. the effect of upgrading fiber backhaul technology is also investigated to evaluate the role of fiber backhaul on the sum rate of the radio access network.