Summary: Park, Sangtae, Optimal Access Point Selection and Channel Assignment in IEEE 802.11
Networks. Master of Science (Computer Science and Engineering), December 2004, 45 pp.,
9 tables, 17 figures, 29 titles.
Designing 802.11 wireless networks includes two major components: selection of access
points (APs) in the demand areas and assignment of radio frequencies to each AP. Coverage
and capacity are some key issues when placing APs in a demand area. APs need to cover
all users. A user is considered covered if the power received from its corresponding AP is
greater than a given threshold. Moreover, from a capacity standpoint, APs need to provide
certain minimum bandwidth to users located in the coverage area.
A major challenge in designing wireless networks is the frequency assignment problem.
The 802.11 wireless LANs operate in the unlicensed ISM frequency, and all APs share the
same frequency. As a result, as 802.11 APs become widely deployed, they start to interfere
with each other and degrade network throughput. In consequence, efficient assignment of
channels becomes necessary to avoid and minimize interference.
In this work, we develop an optimal AP selection by balancing traffic load. We formulate
an optimization problem that minimizes heavy congestion. As a result, APs in wireless LANs
will have well distributed traffic loads, which maximize the throughput of the network. We
design our channel assignment algorithm by minimizing channel interference between APs.
Our optimization algorithm assigns channels in such a way that minimizes co-channel and
adjacent channel interference resulting in higher throughput.