An interference and QOS aware distributed scheduling approach for hybrid IEEE 802.16E mesh networks

A distributed scheduling approach for fast deployable tactical IEEE 802.16e networks is presented where distributed base stations with dual radios form a mesh backhaul and mobile battle units communicate through these base-stations. The mesh backhaul is formed via an IEEE 802.16e mesh mode radio on each base station, while mobile units communicate with base stations via PMP mode radios. The scheduling approach consists of two phases. In the first phase where base stations are deployed, a centralized mesh scheduling algorithm is applied with collected information on network topology, radio parameters, and initial QoS provision requirements. At the same time, each base station utilizes the initial mesh schedule to derive a PMP schedule for actual demands from associated mobile units. In the second phase, each base station monitors its carried PMP traffic load statistics; to accommodate traffic load changes in a distributed fashion, each base station lends or borrows time slots from nearby base stations to adjust its mesh and PMP radio schedules. The distributed schedule adaptation method not only allows individual base stations to accommodate short-term increases in bandwidth demands, it also provides the means for optimizing the mesh and PMP schedules with respect to actual bandwidth demands. Integrated with a previously proposed routing scheme, the method is evaluated with simulations in network simulator ns-2. In various mobile scenarios, increased overall network throughput and per-mobile throughput across handoffs are achieved with the proposed scheduling methods.