Improving the Performance of Medium Access Control Protocols for Mobile Adhoc Network with Smart Antennas

Requirements for high quality links and great demand for high throughput in Wireless
LAN especially Mobile Ad-hoc Network has motivated new enhancements and work in
Wireless communications such as Smart Antenna Systems. Smart (adaptive) Antennas
enable spatial reuse, increase throughput and they increase the communication range
because of the increase directivity of the antenna array. These enhancements quantified
for the physical layer may not be efficiently utilized, unless the Media Access Control
(MAC) layer is designed accordingly.
This thesis implements the behaviours of two MAC protocols, ANMAC and MMAC
protocols in OPNET simulator. This method is known as the Physical-MAC layer
simulation model. The entire physical layer is written in MATLAB, and MATLAB is
integrated into OPNET to perform the necessary stochastic physical layer simulations.
The aim is to investigate the performance improvement in throughput and delay of the
selected MAC Protocols when using Smart Antennas in a mobile environment. Analytical
methods were used to analyze the average throughput and delay performance of the
selected MAC Protocols with Adaptive Antenna Arrays in MANET when using spatial
diversity. Comparison study has been done between the MAC protocols when using
Switched beam antenna and when using the proposed scheme.
It has been concluded that the throughput and delay performance of the selected protocols
have been improved by the use of Adaptive Antenna Arrays. The throughput and delay
performance of ANMAC-SW and ANMAC-AA protocols was evaluated in details
against regular Omni 802.11 stations. Our results promise significantly enhancement over
Omni 802.11, with a throughput of 25% for ANMAC-SW and 90% for ANMC-AA.
ANMAC-AA outperforms ANMAC-SW protocol by 60%. Simulation experiments
indicate that by using the proposed scheme with 4 Adaptive Antenna Array per a node,
the average throughput in the network can be improved up to 2 to 2.5 times over that
obtained by using Switched beam Antennas. The proposed scheme improves the
performances of both ANMAC and MMAC protocols but ANMAC outperforms MMAC
by 30%.