The emergence of portable terminals in work and living environments is accelerating the
progression of wireless networks. A wireless ad hoc network is a new network concept
where users establish peer-to-peer communication among themselves independently, in
their small area. Since the wireless medium is a shared resource, it becomes an
important design issue to efficiently allocate bandwidth among users. MAC (Medium
Access Control) layer arbitrates the channel access to the wireless medium and is also
responsible for bandwidth allocation to different users, therefore a large amount of
research has been conducted on various MAC protocols for ad hoc wireless networks.
This dissertation begins with a survey of existing wireless MAC protocols. The survey
includes protocols designed for different network generations and topologies, classifying
them based on architecture and mode of operation. Next, we concentrate on the MAC
protocols proposed for distributed wireless networks. We propose a new MAC protocol
based on a token-passing strategy; which not only incorporates the advantages of the
guaranteed access scheme into the distributed type of wireless networks, but also the
data rate and delay level QoS guarantees. Data rate QoS provides fairness into sharing of
the channel, while delay level QoS introduces a flexible prioritized access to channels by
adjusting transmission permission to the current network traffic activities. A simulation
model for the protocol is developed and delay and throughput performance results are
presented.
To examine the efficiency and performance of the proposed MAC scheme in an ad hoc
wireless environment, it is incorporated into the Bluetooth structured network. The
model is then simulated in the Bluetooth environment and performance results are
presented. Furthermore, an analytical model is proposed and an approximate delay
analysis conducted for the proposed MAC scheme. Analytical results are derived and
compared with results obtained from computer simulations. The dissertation concludes
with suggestions for improvements and future work. / Thesis (M.Sc.-Engineering)-University of Natal, 2003.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/4172 |
| Date | January 2003 |
| Creators | Liu, Yi-Sheng. |
| Contributors | Takawira, Fambirai. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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