| In this thesis we study the throughput performance and fairness in Wireless LANs in saturated and unsaturated traffic conditions. With extensive OPNET simulations we show that there is an intrinsic relationship between optimal throughput and packet collision rate. Through simulations, we observe that the optimal contention window at which throughput is maximized and the packet collision rate at the optimal operating point bear a relationship with each other, i.e., we find an optimal range of packet collision rates at which the network throughput is maximized. Thus we show that if contention window could be tuned by either increasing or decreasing the window size to maintain certain favorable range of packet collision rates, optimal or near-optimal throughput is realized in saturated and unsaturated networks irrespective of the numbers of users. We also propose a basic contention window adaptation algorithm and show that it outperforms the legacy access scheme employing exponential backoff. |
