Abstract:
The IEEE 802.11 Standard, serves as an access mechanism for multiple stations to exchange data over the wireless medium. This standard made it possible to provide Internet-
based services to untethered stations. With the undisputed success of IEEE 802.11 Standard over the contemporary short-range wireless networks, this technology is being quickly
adopted by the cellphone manufacturers, for their hand-held devices. In future, this will
mean, a large number of devices will be capable of transmitting over IEEE 802.11 protocol.
This access method however, results in collisions when two or more stations try to transmit simultaneously. Furthermore, the probability of collision, increases with the number
of stations sharing the medium. The Binary Exponential Back off (BEB) mechanism, in
Carrier-Sense Multiple Access/Collision Avoidance (CSMA/CA), reduces this probability
of collision to some extent. However, under saturation conditions, the behavior of BEB
is somewhat unfair, which leads to degradation of average channel utilization. Also, this
degradation increases linearly with the number of stations contending for the channel. A
new scheme, Enhanced Binary Exponential Back off (EBEB) is proposed, which enhances
the average channel utilization by improving degree of fairness for BEB at the Medium
Access Control sub-layer. EBEB scheme can blend with all flavors of the IEEE 802.11
Standard. Also, EBEB stations can coexist with the existing BEB stations. In this thesis,
analytical and simulation models for both schemes are developed, followed by comparison
of analytical and simulation results for both schemes.
