a topology-independent scheduling scheme for wireless mesh networks
To meet the needs of wireless broadband access, the IEEE 802.16 protocol for wireless metropolitan networks had been recently standardized. The medium access control (MAC) layer of the IEEE 802.16 has point-to-multipoint (PMP) mode and mesh mode. Previous works on the IEEE 802.16 have focused on the PMP mode. In the mesh mode, all nodes are organized in an ad hoc fashion and use a pseudo-random function to calculate their transmission time. In this paper, we implemented the Coordinated Distributed Scheme (CDS) of the mesh mode of the IEEE Std. 802.16 in a well-known simulation tool, ns2. Through extensive simulations we tracked some characteristics of the CDS and after that we developed a different scheduling scheme, the Randomized-MAC (R-MAC). R-MAC is a totally distributed scheduling scheme and it tries to overcome some intrinsic "limit" of the CDS. We compared CDS and R-MAC and through extensive simulations, we observed that our R-MAC protocol works very well to cope with variations in the network. Our protocol outperforms CDS mechanism both in throughput and average end-to-end data packet delay. These results are related with the different mechanism to compute the next transmission time implemented in R-MAC.
wireless mesh networks 802.16 mac scheduling sheme tdma