IEEE 802.11 wireless mesh network. (c2008)

Abstract

The IEEE 802.11 Medium Access Control (MAC) gained widespread popularity as a layer-2 protocol for Wireless Local Area Networks (WLANs). While the continuous lack of accurate analytical 802.11 MAC models as well as the nonexisting state of the art IEEE 802.11-based Wireless Mesh Networks (WMNs) simulation and analysis tools attract our attention, the adaptation of the existing Mobile Ad-Hoc Networks (MANETs) routing metrics and protocols to 802.1 Is-based WMNs remains a major source of performance degradation of those latter. This work addresses these three voids by first providing two distinct mathematical models for evaluating the queuing delays in an IEEE 802.1 I-based WMN. In the first model each node is modeled as a discrete time G/GIl queue characterized by general arrival patterns and service time distribution, whereas in the second model the service time is represented by a combination of Erlang-k and Coxian-2 distributions, thus nodes are modeled as either G/E-kll or G/C2/1 queues. Both models account for arbitrary packet size distributions, number of nodes in the network, channel access time resulting from the random access mechanism, collision avoidance and exponential back-off mechanism of 802.11, delays in channel access due to other nodes transmitting and delays caused by collisions. Second, this manuscript presents two novel MAC-AWARE and BUFFER-AWARE routing protocols based on a new IEEE 802.1 I-specific routing metrics used to provide Quality of Service (QoS) routing for both delay-sensitive and packet-loss sensitive traffic generated simultaneously in an 802.lI-based network in DCF mode. A new IEEE 802.II-MAC based networkspecific simulator that we developed allowed us to verify our models and assert the correctness and accuracy through extensive simulations.