Joint Uplink and Downlink Scheduling in HetNets with Wireless Self-backhaul.

Wireless self-backhaul is an efficient solution to release the backhaul bottleneck of 5G Heterogeneous Networks (HetNets). This paper aims at jointly optimizing uplink and downlink scheduling to improve system throughput of time division duplex (TDD) HetNets. The problem that considers the uplink-downlink requirements and access-backhaul link coordination constraints is formulated, which has coupled variables and non-polynomial calculation complexity. Based on the structure property of the constructed problem, a joint uplink and downlink scheduling (JUDS) scheme is proposed to manage the complex interference and fully obtain the flexibility of wireless self-backhaul. In JUDS scheme, the original problem is decomposed into a transmission time slot (TTI) orchestration sub-problem and a sub-band scheduling sub-problem, both of which owns high efficient solutions. Simulation results address the effectiveness of JUDS scheme. On the one hand, the total system downlink throughput is significantly improved by JUDS scheme comparing with other existing scheduling schemes. On the other hand, The data rates of access links and backhaul links are well matched.