Neighbor-Aware Adaptive Retry Limit for IEEE 802.11-Based Mobile Ad Hoc Networks

In a mobile ad hoc network (MANET), it has been addressed that packet losses due to collision are often misinterpreted as routing failures, and cause unnecessary overhead for routing maintenance. There have been several attempts to avoid the unnecessary overhead through reducing collision losses. They are effective in a static topology where most losses are due to collision. In a dynamic topology, however, packets are lost due to actual routing failures (induced by mobility) as well as due to collision, and efforts for reducing collision are not enough. In this paper, we propose a new scheme for adjusting the limit of RTS retransmissions. In the proposed scheme, we treat packet losses differently as follows: (a) upon collisions, we increase the limit to reduce collision losses; and (b) upon routing failures, we decrease the limit to avoid unnecessary retransmissions. Through extensive simulations, it is shown that the proposed scheme effectively improves throughput in various scenarios and outperforms other comparable schemes.