Cross-layer Optimization of Reliable Transmissions over IEEE 802.11 Multi-hop Networks

The transmission control protocol (TCP) suffers from a relevant performance degradation in multi-hop wireless networks (MWN) since it identifies any problem in the wireless network (disconnections, route changes, etc.) as congestion. Several solutions have been proposed in order to improve the performance of TCP in MWNs. Some of these approaches are based on the utilization of end-to-end mechanisms to differentiate the nature of the problems occurred in the network. In this paper, we analyze the behaviour of one of these proposals: ADTCP (ad-hoc TCP). We have observed, through simulation, that the usage of these mechanisms is insufficient in some cases. Thus, we propose modifications to ADTCP, based on the cross- layer optimization of transport and routing protocols. The results obtained show that our proposal considerably improves the performance of ADTCP and TCP resulting in a higher throughput and a greater efficiency of the network.