A cross layer rate based transport solution to control intra flow contention in multi hop MANET

Transmission Control Protocol (TCP) is a predominant transport layer protocol for data transmission over internet. TCP being touted as the “protocol that saved the internet” due to its widely acclaimed congestion control algorithm, has started choking with the advent of challenges faced in the decentralized Multi-hop Ad Hoc Networks. Most notably, the burstiness of this congestion control mechanism has often lead to heavy link layer contentions over ad hoc networks. Such intense contentions pave way to misinterpreted route failures, frequent timeouts and unnecessary retransmissions which dramatically reduces the throughput. In this paper, we propose a cross layer transport protocol (CLTSP) to minimize the intra flow contention and also to improve the spatial reuse. CLTSP performs rate controlled transmission to prevent self-contention among data packets by spacing them out at an appropriate interval. The time interval between the deliveries of successive data packets is dynamically measured based on four hop propagation delay and an appropriate correction factor that are collected from intermediate nodes. We evaluate the performance of our protocol with TCP New Reno and show significant improvement in terms of throughput, end to end delay, Link layer collisions and control overheads.