Providing Packet-Level Quality of Services in Multihop Wireless Networks

摘要

Providing packet-level quality of service (QoS) is critical to support both rate-sensitive and delay-sensitive applications in the bandwidth-constrained, shared-channel, mutlihop wireless networks. This problem is challenging due to the unique issues such as location-dependent contention, inherent conflict between ensuring fairness and maximizing channel utilization, and the distributed nature of packet scheduling in such networks. In order to address these issues, we have taken a new self-organizing approach to QoS solutions for such networks. In this approach, local decision makers self-organize themselves and coordinate among one another, and collectively achieve the desired global property. Some features of our approach include fully localized design, coordination among local decision makers, intentional and optimized information propagation, scaling property and achievable global property. Two key contributions of this work are: (a) a model-referenced self-organizing design methodology for multihop wireless networks; and (b) a table-driven approach and a backoff-based approach to distributed packet scheduling that provides QoS performance bounds in terms of fairness, throughput and delay, maximizes channel spatial reuse, and arbitrates the conflict between fairness and maximal channel utilization. Both proposed designs work within the CSMA/CA MAC framework. We also compare the performance of these two approaches through simulations. Our extensive simulation results have confirmed the effectiveness of the proposed design.