Hybrid frame structure method for IEEE 802.16 WiMAX mesh networks

Abstract

In addition to the Point-to-Multipoint mode, WiMAX standard defines the Mesh mode of operation, allowing Subscriber Stations (SS) to exchange data packets directly with each other besides the Internet traffic through the Base Station (BS). The Frame structure defined for the Mesh mode can either use Centralized Scheduling (CS), Distributed Scheduling (DS), or both CS/DS data subframes for resource allocations. CS is coordinated by the BS, thus designed for Internet traffic, whereas DS is more suitable for intranet traffic. The lack of spatial reuse in CS causes scalability issues and performance limitations. In this thesis, a Hybrid Frame Structure (HFS) method is proposed, which sets specific roles to the SSs according to their hop counts to the BS, taking advantage of both CS and DS schemes defined in the standard. Simulation results suggest that by exploiting the spatial reuse property of DS, HFS provides significant improvement in network throughput, while maintaining acceptable latency values.