1Low-Latency Video Streaming with Congestion Control in Mobile Ad-Hoc Networks

Abstract — In this paper, we address the challenge of delivering a video stream, encoded with multiple descriptions, in a mobile ad-hoc environment with low-latency constraints. This kind of application is meant to provide an efficient and reliable video communication tool in scenarios where the deployment of an infrastructure is not feasible, such as military and disaster relief applications. First, we present a recently proposed protocol that employs a reliable form of one-hop broadcast to build an efficient overlay network according to a multi-objective function that minimises the number of packets injected in the network and to maximises the path diversity among descriptions. Then, we introduce the main contribution of this article: a cross-layer congestion control strategy where the MAC layer is video-coding aware and adjusts its transmission parameters (namely, the RTS retry limit) via congestion/distortion optimisation. The main challenge in this approach is providing a reliable estimation of congestion and distortion, given the limited information available at each node. Our simulations show that, if a stringent constraint of low delay is imposed, our technique grants a consistent gain in terms both of both PSNR and delay reduction, for bitrates up to a few megabits per second