In wireless networks, data packets are lost due to channel interference and fading rather than network congestion. Thus, TCP designed for wired networks, cannot achieve a satisfying performance in wireless networks. Utilizing a cross-layer mechanism to identify the course of packet loss, we have proved that a mobile-host-centric transport protocol (MCP) can achieve higher throughput than TCP Reno and New Reno in static wireless environment. In this paper, we extend the cross-layer feedback mechanism and congestion control algorithm based on previous work. Furthermore, we implement the extended MCP+ in NS-2 simulator and evaluate its performance in the mobile multi-hop WLAN scenarios. The simulation results show that the proposed protocol improves the end-to-end throughput more effectively than TCP Reno and New Reno.
In this paper, the average packet delay on IEEE 802.11 DCF under finite load traffic in multi-hop ad hoc networks is analyzed. We employ a Markov chain model to analyze the probability of transmission at each node in an arbitrary slot and derive the channel access delay. We model each node using an M/G/1 queue and derive the queueing delay. The model is extended from analyzing the single-hop average packet delay to evaluating the end-to-end packet delay in multi-hop ad hoc net-works without assuming the traffic to be in a saturation state. To validate our ana-lytic results, we have done extensive simulation. The analytic and the simulation results match very well.
