Robust streaming erasure codes based on deterministic channel approximations

We study near optimal error correction codes for real-time communication. In our setup the encoder must operate on an incoming source stream in a sequential manner, and the decoder must reconstruct each source packet within a fixed playback deadline of T packets. The underlying channel is a packet erasure channel that can introduce both burst and isolated losses. We first consider a class of channels that in any window of length T +1 introduce either a single erasure burst of a given maximum length B, or a certain maximum number N of isolated erasures. We demonstrate that for a fixed rate and delay, there exists a tradeoff between the achievable values of B and N, and propose a family of codes that is near optimal with respect to this tradeoff. We also consider another class of channels that introduce both a burst and an isolated loss in each window of interest and develop the associated streaming codes. All our constructions are based on a layered design and provide significant improvements over baseline codes in simulations over the Gilbert-Elliott channel.