A cross-layer design for improving TCP performance in opportunistic networks

Opportunistic networks have attracted attention from researchers because of their inherent characteristics, including long latency, low data rate, and intermittent connectivity. Extensive research has been conducted on opportunistic networks, including the architecture and routing. However, few researchers have investigated the performance of TCP in opportunistic networks, especially when Epidemic Routing is used. In this paper, we first evaluate the performance of TCP in opportunistic networks with Epidemic Routing. Our results show that the Epidemic Routing in opportunistic networks degrades the performance of TCP due to too many multicopy data packets and in turn consume limited resource. Then a cross-layer design based on TCP and Epidemic Routing, named ACK-EPI is proposed to solve the above problem. ACK-EPI can avoid the packets that have already been delivered being forwarded again in the network. The simulation results show that ACK-EPI outperforms the Epidemic Routing in opportunistic networks.