Network Utility Aware Traffic Loading Balancing in Backhaul-constrained Cache-enabled Small Cell Networks with Hybrid Power Supplies

摘要

Explosive data traffic growth leads to a continuous surge in capacity demandsacross mobile networks. In order to provision high network capacity, small cellbase stations (SCBSs) are widely deployed. Owing to the close proximity tomobile users, SCBSs can effectively enhance the network capacity and offloadingtraffic load from macro BSs (MBSs). However, the cost-effective backhaul maynot be readily available for SCBSs, thus leading to backhaul constraints insmall cell networks (SCNs). Enabling cache in BSs may mitigate the backhaulconstraints in SCNs. Moreover, the dense deployment of SCBSs may incurexcessive energy consumption. To alleviate brown power consumption, renewableenergy will be explored to power BSs. In such a network, it is challenging todynamically balance traffic load among BSs to optimize the network utilities.In this paper, we investigate the traffic load balancing inbackhaul-constrained cache-enabled small cell networks powered by hybrid energysources. We have proposed a network utility aware (NUA) traffic load balancingscheme that optimizes user association to strike a tradeoff between the greenpower utilization and the traffic delivery latency. On balancing the trafficload, the proposed NUA traffic load balancing scheme considers the green powerutilization, the traffic delivery latency in both BSs and their backhaul, andthe cache hit ratio. The NUA traffic load balancing scheme allows dynamicallyadjusting the tradeoff between the green power utilization and the trafficdelivery latency. We have proved the convergence and the optimality of theproposed NUA traffic load balancing scheme. Through extensive simulations, wehave compared performance of the NUA traffic load balancing scheme with otherschemes and showed its advantages in backhaul-constrained cache-enabled smallcell networks with hybrid power supplies.