Improved Delayed ACK for TCP over Multi-Hop Wireless Networks

TCP performance in contention-based multi-hop wireless networks is shaped by two main factors, which are unlike the wired network case. First, the maximum throughput for a given topology and flow pattern is reached for a specific congestion window. This window is very difficult to detect under dynamically changing network traffic. Second, the excessive control traffic consumes channel bandwidth more severely than in the wired case. Our analysis and simulations show that the smaller TCP ACK packets consume channel resource comparable to the much longer TCP DATA packets, over high-speed connections. Motivated by this observation, we propose a new approach to improve TCP performance by further lowering the number of control packets compared with the known methods. Extensive simulations show that our strategy improves the TCP throughput up to 205% compared with the regular TCP. Although our simulation is based on 802.11, the same idea works in other networks using a contention-based MAC design.