A Novel Coding Scheme For Symmetric Multiple Description Coding

We propose a novel coding scheme for multiple description coding with $K$ descriptions, with symmetric rate and symmetric distortion constraints. In this new coding scheme, channel codes are introduced on top of some carefully chosen source coding component. The channel coding component for $K=3$ is akin to the network coding idea. We first show that for the quadratic Gaussian source, adding a simple channel coding component is able to achieve rate-distortion point outside the achievable region based on $(n, k)$ source-channel erasure codes (SCEC), previously proposed by Puri et al., when Gaussian codebook is assumed to be optimal for that scheme. The channel coding component and $(n, k)$ SCEC can be strategically combined, and for the special case of quadratic Gaussian three description case where any two of them are rate-distortion optimal jointly, the resulting scheme can achieve performance better than a direct time sharing between the new operating point and the $(n, k)$ SCEC-based scheme. Moreover, this combination can be generalized naturally, which leads to a new coding scheme for the general $K$-description problem.