VECU: TCP congestion algorithm for high speed ad hoc wireless networks

Abstract

In all practical implementations of TCP, it is assumed that the packet loss is caused by congestion while channel errors are neglected. However, the wireless communication links are very unreliable and have high Bit Error Ratio (BER). So TCP reduces the data transmission rate whenever it detects packet loss, even though they may have occurred due to the link error. We propose a new end to-end congestion control algorithm named VECU that is effective and efficient for dealing with random bit error. VECU monitors the network congestion level and from this detects whether packet loss is due to congestion or link error (losses due to the characteristics of the wireless environment). We use a function of degree three as window growth function. Due to this, when the current size of the window is far from the available capacity of the path, the window size grows fast and increases slowly otherwise.VECU is fair and allocates bandwidth fairly among flows with different RTTs. VECU can be very scalable and stable and fair with standard TCP flows. Also flows fully utilize the link. VECU is end to end and only need to change the sender side without any change in the receiver or in the network.

Network-coded internet-friendly transport protocol

“…Several other researchers are interested in improving the performance of TCP on wireless and mobile networks. [6][7][8][9][10] Network coding is a very simple idea. Instead of sending separate packets as in traditional networks, a linear combination of packets is sent.…”