'Three-User Cognitive Interference Channel: Capacity Region with Strong Interference'
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Cognitive interference channel, three-user interference channel, strong interference, capacity region.

Introduction
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Interference avoidance techniques have traditionally been used in wireless networks wherein multiple source-destination pairs share the same medium. However, the broadcasting nature of wireless networks may enable cooperation among entities, which ensures higher rates with more reliable communication. On the other hand, due to the increasing number of wireless systems, spectrum resources have become scarce and expensive. The exponentially growing demand for wireless services along with the rapid advancements in wireless technology have lead to cognitive radio technology which aims to overcome the spectrum inefficiency problem by developing communication systems that have the capability to sense the environment and adapt to it [@GolJafMarSri09; @Mit91].

In overlay cognitive networks, the cognitive user can transmit simultaneously with the non-cognitive users and compensate for the interference by cooperation in sending, i.e., relaying, the non-cognitive users’ messages [@GolJafMarSri09]. In order to obtain the fundamental limits of these networks by information theoretical techniques, researchers have to consider the models with idealized assumptions. The assumption of *full non-causal* knowledge of the primary messages (as side information) at the cognitive users is a standard one, 