AMACA-a new multiple access collision avoidance scheme for wireless LANS

It\´s well known that "hidden-and exposed-terminal" is among the main problems in ad-hoc WLAN networks. In addition, there are scenarios where the desired destination is located in the range of other transmitters, so that the efforts on setting up communication with this terminal will fail due to collisions occurred between desired control packets and unwanted received data packets at destination. In such scenarios, conventional protocols can not address the problem efficiently, resulting in throughput and channel utilization degradation. In this paper, by using the same PHY of IEEE 802.11 and making slight changes in its MAC layer, a new MAC protocol is presented to address such problems. Our simulations show that the performance of the new method is better than IEEE 802.11 and DBTMA; besides, in addition to solving the above problems, it improves channel utilization and reduces the total overhead due to its prior channel reservation feature.