Energy and Delay Efficient Fountain-Coded File Transfer Assisted by Unreliable Feedback

We propose a unicast wireless file-transfer scheme based on fountain coding augmented by a feedback mechanism to help the source make near-optimal transmission decisions. By avoiding wasted transmissions that occur in conventional fountain coding due to the delayed reception of feedback messages, the proposed scheme provides large reductions in the energy expenditure, while keeping the delivery latency very close to its minimum achievable value and avoiding excessive computational overhead. The scheme is robust against feedback message losses and imperfect estimates of system parameters. We demonstrate up to 85% reduction in the energy expenditure compared to conventional fountain coding and similar reductions in the average delivery latency compared to a state-of-the-art method.