Cross-layer Scheduling Algorithms for IEEE 802.16 Based Wireless Mesh Networks

Wireless mesh network (WMN) is emerging as an important networking architecture for future wireless communications. The mesh mode supported in IEEE 802.16 protocol provides a TDMA solution for WMN, in which scheduling is an important issue. In this paper, we discuss the issues on how to satisfy a set of bandwidth requests in IEEE 802.16 WMNs using minimal radio resources (or solving minimal schedule length problem). In consideration of transmission overhead and adaptive modulation and coding (AMC), two cross-layer scheduling algorithms are proposed, namely max-transmission and priority-based algorithms. In particular, they are proposed based on a physical interference model, instead of a protocol interference model as suggested in the literature. For the priority-based algorithm, we study several priority criteria based on different cross-layer information. An iterative scheme for QoS traffic is introduced to guarantee fairness when traffic load exceeds the network capacity. Simulation results show that our algorithms outperform the existing schemes based on protocol model, and they also ensure better fairness among different nodes.