A flow control framework for improving throughput and energy efficiency in CSMA/CA based wireless multihop networks

In a CSMA/CA based multihop wireless network, excessive interference at a receiver or a potential forwarding node causes severe blocking and reduction in throughput. The unbalanced interference forces the node to consume more time receiving packets rather than sending them, resulting in dropped packets due to buffer overflow. We discuss a novel flow control framework at the MAC layer for regulating the transmission and improving the overall throughput of multihop wireless networks based on CSMA/CA protocol. The framework prevents congestion, reduces packet loss and is attractive because per-flow information at each node is kept to a minimum. The techniques used to improve throughput include a hop-by-hop, hybrid rate and window based flow control scheme that paces the transmission of frames such that competition between frames originating from the same flow is reduced. Simulations show more than five fold improvement in throughput and energy cost over the existing scheme without flow control in some cases