SPACK: rapid recovery of the TCP performance using SPlit-ACK in mobile communication environments

The TCP protocol has been designed assuming a relatively reliable wired network with fixed hosts. However, in wireless networks, it suffers from significant packet losses due to high bit error rates. Therefore, the TCP protocol frequently invokes congestion control procedure responding to all packet losses, resulting in degrading end-to-end TCP performance severely. In this paper, in order to improve the performance of the TCP in lossy wireless networks, we present a new acknowledgement scheme namely SPACK. When the base station detects packet losses, SPACK splits the newly arrived acknowledgement packet into several ones and transfers them to the fixed host. The fixed host, receiving several acknowledgement packets, increases the window size rapidly, thus the performance of TCP quickly recovers. We measure the performance of our algorithm using computer simulation. As a result, the TCP applied SPACK shows better performance than the TCP without it.