Assessment of contention-based wireless medium access using realistic smart antennas

We assess the performance of the slotted Aloha protocol with capture in a mobile communications environment with Rayleigh and log-normal fading when used with switched-beam smart antennas. We consider the configuration where one receiver is present at each base station and calculate the capture probability, its asymptotic value as the number of colliding packets tends to infinity. The results demonstrate that by using realistic smart antennas with non-zero sidelobes, we can achieve higher performance in terms of capture probability when compared to a conventional antenna system using the slotted Aloha protocol