Optimized delay threshold scheduler for multimedia traffic over LTE downlink network

Abstract

Allocation of radio resources is very critical to Long Term Evolution (LTE) mobile network. Therefore, it is essential to design and implement optimum scheduling schemes to satisfy the required Quality of Service (QoS) that is vital for Real Time (RT) applications. In this paper, a new scheduling strategy for supporting both RT and Non-RT (NRT) applications is presented. The proposed scheduling scheme performs the allocation process of the available radio resources at two levels. At the first level of the scheduler, an optimized delay threshold is proposed to efficiently control Resource Blocks (RBs) allocation for video traffic. At this level, all video packets are investigated, and only users with Head of Line (HoL) packets delay greater than the optimized delay threshold will be considered for the allocation process in the next level. However, at the introduced scheduler’s second level, RBs are assigned to RT packets according to HoL delays, based on an enhanced algorithm that depends on Earliest Due Date (EDD) mechanism. The behaviour of the introduced scheduling strategy is investigated and compared to the behaviour of other schedulers considered in this research. Simulation results demonstrate that the introduced two-level scheduling strategy provides the best level of quality for the supported services, especially for RT applications. It provides the lowest Packet Loss Rate (PLR) and packet delay, while achieving the highest throughput when compared to other schedulers considered in this research. In addition, the proposed two-level scheduler achieves the highest efficiency of the spectral and system capacity.