Towards a general theory of source networks

A unified approach to multiterminal source coding problems not involving rate-distortion theory is presented. It is shown that, for determining file achievable rate region, attention may be restricted to source networks of a relatively simple structure. A product space characterizafion of the achievable rate region pinpoints the mathematical problem to be solved for getting a single letter characterization. The complexity of this problem depends on a structural condition, viz., the number of encoders of a certain kind in the source network. This approach yields all the known single-letter characterizations of achievable rate regions and a number of new ones for more complex networks. As a digression, for a class of source networks including that of Slepian and Wolf, exponential error bounds are derived which are attainable by universal codes. These bounds are tight in a neighborhood of the boundary of the achievable rate region.