Improving TCP Performance Over Multi-Hop Wireless Networks

In multi-hop wireless networks, unlike the wired ones, two main factors affect the TCP performance. First, the maximum throughput is reached for a specific congestion window that 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, over high-speed connections, the much shorter ACK_tcp packets consume the channel capacity comparable to the much longer data packets. Motivated by this insight, we first propose using different routes for data and ACK flows in a grid sensor network which achieves 60~100% performance gain. After that, we reformulate and improve an existing idea for TCP performance improvement by further lowering the number of control packets compared to the known methods. Extensive simulations show that this improves the TCP throughput up to 200% compared to the regular TCP, in long-hop wireless networks.