Two-Phase-Joint Access-Backhaul Scheduling for Two Cell Sum Rate Maximization in LTE Systems

Backhauling is a constraint for the large-scale deployment of ultra-dense networks in 5G systems. In order to research on the influence of such constraints on scheduling., this paper considers a simple time-division duplex two-transceiver joint access-backhaul scheduling in LTE systems, and analyzes the causality constraints of backhaul link on scheduling, time-division duplex constraints and minimum data rate requirement, then formulates the scheduling problem under those constraints. Realizing the great computational complexity produced by solving it directly, two-phase access-backhaul scheduling scheme (TPABS) is introduced. In the first phase, the scheduling problem is reconstructed to reduce the number of variables and some integer constraints are removed to obtain the upper bound of scheduling performance by linear programming. In the second phase, we continue to process the results obtained in the first phase to make the final scheduling solution under integer constraint. By analyzing the total computational complexity of two phases, it is found that the two-phase access-backhaul scheduling scheme has a polynomial computational complexity. At last, a simulation of it is done to get the CDFs of throughput, data rate of each link and the backhaul to access data rate ratio and the result shows our scheme approaches performance upper bound.