Living in symbiosis: On achievable rates of an oblivious interference system and a cognitive system

We analyze achievable rates of a setup involving a primary two user interference channel and a secondary cognitive point-to-point-system. The primary nodes are oblivious in the sense that they are un-aware of the existence of the secondary system, and thus do not change their strategy. Given the messages of the primary nodes are available a-priori at the secondary transmitter, we show that the secondary user can communicate with non-zero rate while not deteriorating (at least) the rates of the primary nodes. Thus, they are able to live in symbiosis. For the noisy interference regime, the rates achievable for the cognitive user can even be expressed in analytical form.