Streaming Codes with Unequal Error Protection against Burst Losses

Error control codes for real-time interactive applications such as audio and video streaming must operate under strict delay constraints and be resilient to burst losses. Previous works have characterized optimal codes that guarantee perfect recovery of all source packets when the burst loss is below a certain maximum threshold. In this work we introduce two notions of unequal error protection (UEP) in streaming codes. The first is symbol-level UEP where each source packet consists of two sub-packets, one of which has higher level of importance than the other. While the important sub-packet has the same deadline it must recover from a longer burst loss. Perfect recovery of the entire source packet is required if the burst loss is below a certain nominal threshold. The second notion is packetlevel UEP. Here we assume that the source packets arriving at odd and even times have different levels of importance. When the burst length is below a certain threshold, all the source packets must be recovered. On the other hand, in the period of the longer burst, we only require the recovery of the source packets at even time slots. We discuss practical motivations for both settings and develop coding schemes that use previously proposed streaming codes as constituent codes. We establish optimality or near optimality guarantees through information theoretic converse. Simulation over Gilbert channels show that these codes outperform baseline schemes over a wide range of channel parameters.