Wireless
networking is one of the fastest growing technologies in today's
communications scenario. More and more people are becoming active
subscribers of wireless based Internet Service Providers that
are mushrooming all over. As is well known, the wireless channel
is a highly unreliable medium for transmission of information.
Deep channel nulls, time varying impulse response of the channel,
hidden and exposed nodes in Wireless Local Area Networks (W-LANs),
channel access strategies, power control - these are some of the
issues and problems related with this type of communication.
One
of the major areas of research taking place at the LIST lab deals
with the solutions to some of these issues. In particular, the
Medium Access Control (MAC) Layer and the related protocols, as
applied primarily to Wireless Local Area Networks (W-LANs), are
being investigated. Extensive programs to simulate detailed wireless
scenarios have been written to study the impact of various network
parameters on the system throughput performance. These simulations
are being used to fine-tune the already existing recommendations
of the 802.11 family of protocols (e.g. the exponential back-off
schemes for CSMA/CA). Mathematical analyses to supplement the
results of these simulations are being worked out. Recently, a
few novel ideas for extracting better throughputs in W-LANs have
been suggested for deeper investigation. They include a sectorized
access methodology applied to situations with small coverage area
and high traffic intensity, and an efficient power control methodology
for extending battery life of mobile stations. Current research
involves detailed analytical and computer based simulations, and
possibly a neural network based optimization, of these. Figure
1 below shows a schematic layout of the sectorized scheme in 802.11
based networks (showing 4 sectors on the access point).