Even symmetric parallel linear deterministic interference channels are inseparable

Pritam Mukherjee, Ravi Tandon, Sennur Ulukus

Abstract: It is well known that parallel interference channels (ICs) are in general inseparable. Existing results illustrate the benefit of joint encoding across sub-channels by exploiting the asymmetry within the individual sub-channels. In this paper, we show, perhaps surprisingly, that symmetric parallel ICs are also inseparable. To this end, a class of parallel ICs is considered in which each individual sub-channel is a symmetric linear deterministic IC (LDIC). The capacity region of this class of parallel ICs is characterized. As a consequence, we find the necessary and sufficient conditions for inseparability of this class of parallel ICs.