Cross-layer flow control in lightly-loaded multi-hop ad hoc networks

The throughput in multi-hop ad hoc networks (MANETs) is highly dependent on the sending rate and the route length from the source node to the destination. Sending packets at the optimal rate for a given route length maximizes throughput in the network, whereas slightly increasing the sending rate over the optimal value may decrease throughput by up to 55%. This paper presents a novel cross-layer technique for flow control in lightly-loaded MANETs. The technique allows applications to send packets at the rate that maximizes throughput for a given route length. To achieve this, the routing layer notifies interested applications about routing changes, and the applications adaptively modify their sending rates based on the new route length to the destination. In static and mobile networks, this technique outperforms UDP-based flows with a fixed sending rate and doubles the throughput of TCP for networks with up to 2 concurrent flows.