Scalable Wireless Mesh Network Architectures with QoS Provisioning

The wireless mesh network (WMN) is an economical solution to enable ubiquitous broadband services due to the advantages of robustness, low infrastructure costs, and enhancing coverage by low power. The wireless mesh network also has a great potential for realizing green communications since it can save energy and resources during network operation and deployment. With short-range communications, the transmission power in the wireless mesh networks is lower than that in the single-hop networks. Nevertheless, wireless mesh network should face scalability issue since throughput enhancement, coverage extension, and QoS guarantee are usually contradictory goals. Specifically, the multi-hop communications can indeed extend the coverage area to lower the infrastructure cost. However, with too many hops to extend coverage, the repeatedly relayed traffic will exhaust the radio resource and degrade the quality of service (QoS). Furthermore, as the number of users increases, throughput and QoS (delay) degrade sharply due to the increasing contention collisions. In this chapter, from a network architecture perspective we investigate how to overcome the scalability issue in WMNs, so that the tradeoff between coverage and throughput can be improved and the goal of QoS provisioning can be achieved. We discuss main QoS-related research directions in WMNs. Then, we introduce two available scalable mesh network architectures that can relieve the scalability issue and support QoS in WMNs for the wide-coverage and dense-urban coverage. We also investigate the optimal tradeoff among throughput, coverage, and delay for the proposed WMNs by an optimization approach to design the optimal system parameters.