Towards TCP optimization in wireless networks by a frame based cross layer routing metric

With the rapid development of wireless networks, the solution for degradation of Transmission Control Protocol (TCP) over wireless networks becomes more and more significant because of the software reusability. In order to improve the performance of TCP protocol, several studies have been proposed in different directions. Some of them attempt to find a suitable path for TCP transmission. Expected Transmission Count (ETX) is one of the most famous routing metrics to select a path with the least expected transmissions. However, ETX does not consider the Automatic Repeat Request (ARQ) mechanism in TCP, which generates extra transmissions. By modifying the ETX, we proposed a Frame-based TCP-ETX (FTCP-ETX), which calculates the expected frame transmissions for a TCP segment transmission. To evaluate our proposal, we conducted simulations by comparing FTCP-ETX, ETX and DSDV. Simulation results reveal that our routing metric improves TCP performance by selecting a better path.