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.
