A scheduling algorithm for IEEE 802.16 and IEEE 802.11 hybrid networks

Hybrid networks can be conceived by combining suitably interfaced 802.11 access points (APs) and WiMAX (802.16) backhaul. One of the major problems associated with such networks is the increased communication delay experienced by 802.16 users. For instance, containing such delay is important in maintaining quality of service for VoIP applications. This delay can be substantially decreased by a strategic reduction in the number of active 802.16 subscribers in the network. This paper deals with realizing such reduction by rerouting traffic through lightly loaded 802.11 APs. For doing so, a schedule has to be generated. A scheduling algorithm was designed and its effect on the overall network performance, using end to end packet delay as a metric, was analyzed. For this purpose CBR traffic was used over UDP connections. NS-2 simulations using CBR traffic show significant improvement in end-to-end packet delay.