Distortion exponent for multiple description coding
Distortion exponent has been proposed as performance measure to characterize how fast the average distortion decays to zero when the SNR increases to infinity. The distortion exponent for Multiple Description Coding (MDC) has only been investigated for two descriptions and symmetric SNR. In this paper, we consider the case of any number of descriptions and asymmetric SNR. We derive an achievable distortion exponent for MDC with N ≥3 description and an upper bound for the distortion exponent for N =3. Our results are based on an high-SNR approximation which we named noise cancellation method. We also consider a special case of our noise cancellation approximation method which we refer to as equal correlation. For each method, the distortion exponent is obtained as the solution of a linear program. Numerical results verify the validity of our approximation method.