Master Thesis - Past Projects - Abstract
QoS-aware MAC layer protocol for wireless ad hoc networks
Due to infrastructure-less deployment, wireless ad hoc networks are
drawing a lot of interest. The users expect to run various types of
applications over wireless ad hoc networks, like email, internet browsing,
voice over IP networks and video streaming. Each of these applications has
unique needs, characteristics and importance. As of today there is little
support for Quality of Service (QoS) in wireless ad hoc networks. The aim
of the thesis is to test and evaluate a prioritized MAC layer, where we
allocate the wireless channel to the packets with higher priorities. Our
strategy is to classify packets according to their criticality for the
users, and to achieve an absolute priority-based bandwidth allocation by
transmitting higher prioritized packets on the wireless channel first.
Moreover, all nodes in the network should treat packets of a particular
priority class in same manner. We modified the CSMA/CA protocol
implementation in the Network Simulator (NS2) in order to introduce
support for priority-based packet forwarding. Experiments indicate that
our modifications enforce prioritized channel allocation. Due to our
modifications, highly prioritized packets always occupy the channel first,
as they have to wait for a shorter time interval before transmission.
However, channel utilization is effected negatively when there are only
low-prioritized packets to transmit, since these packets have to wait for
a longer time before transmission.
Keywords: MAC layer, QoS, CSMA/CA, DIFS, Contention window
Author(s): Muhammad Azam Akram
Contact: Calin Curescu
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