Although many problems for transmission control protocol (TCP) in multi-hop wireless networks have been studied with many proposals in the literature, they are not solved completely yet. Different from the existing proposals to mitigate the limitation of TCP in multi-hop wireless networks, we propose a framework of semi-TCP which decouples two functionalities of traditional TCP, i.e., congestion control and reliability control, in order to get rid of the constraint of TCP’s congestion window on performance enhancement. Specifically, we employ hop-by-hop congestion control which is more efficient than its end-to-end counterpart since the control efficiency of the later relies on the availability of end-to-end connectivity which is difficult to sustain in wireless networks. We implement hop-by-hop congestion control via intra-node and inter-node congestion control, and propose a distributed hop-by-hop congestion control algorithm based on the widely used request-to-send/clear-to-send protocol. Such a semi-TCP retains the reliability control in original TCP. Extensive simulations based on network simulator-2 show the promising performance of semi-TCP over traditional schemes.
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