Date Added: Jun 2009
Korner and Marton established the capacity region for the 2-receiver broadcast channel with degraded message sets. Recent results and conjectures suggest that a straightforward extension of the Korner-Marton region to more than 2 receivers is optimal. This paper shows that this is not the case. The authors establish the capacity region for a class of 3-receiver broadcast channels with 2-degraded message sets and show that it can be strictly larger than the straightforward extension of the Korner-Marton region. The idea is to split the private message into two parts, superimpose one part onto the "Cloud center" representing the common message, and superimpose the second part onto the resulting "Satellite codeword".