Cooperation between Channel Access Control and TCP Rate Adaptation in Multi-Hop Ad Hoc Networks

In this paper, we propose a new cross-layer scheme Cooperation between channel Access control and TCP Rate Adaptation (CATRA) aiming to manage TCP flow contention in multi-hop ad hoc network. In CATRA scheme, we collect useful information from MAC and physical layers to estimate channel utilization of the station. Based on this information, we adjust Contention Window (CW ) size to control the contention between stations. Then, we can achieve the fair channel access of each station and the efficient spatial channel usage. Moreover, the fair value of bandwidth allocation for each flow is calculated and sent to the Transport layer. Then, we adjust the sending rate of TCP flow to solve the contention between flows and the throughput of each flow becomes fairer. The performance of CATRA scheme is examined on various multi-hop network topologies by using Network Simulator (NS-2). key words: Cross-layer method, per-flow/per-station fairness, flow/station contention, throughput, TCP rate control, channel access control, IEEE 802.11 back-off algorithm, multi-hop ad hoc.