A novel adaptive chunks allocation scheme based-QoS-threshold in downlink OFDMA systems (IEEE 802.16 m)

Scheduling algorithms prove crucial to ensure simultaneous requested services satisfaction per a mobile user in packet access networks. In this paper, we propose a novel Adaptive Chunks Allocation scheme based-QoS-threshold named “ACA-QoSthresh”. Our ACA-QoSthresh scheme consists of three steps: (1) Distribute chunks to mobile users under class of services constraints. A threshold for rtPS-class is defined based on the overall system capacity to ensure adequate resources for the rtPS-class without disadvantaging the other classes performances. (2) Order connections based on a defined function priority that depends on the channel quality and QoS requirements. (3) Allocate chunks to mobile users in order to maximize the total system capacity. Simulation results demonstrate that our proposed scheme provides better performances in terms of total Spectral Efficiency, rtPS Packet Loss Ratio and nrtPS Packet Satisfaction Ratio compared to other existing methods.