Three-User Cognitive Interference Channel: Capacity Region with Strong Interference

TL;DR

This paper characterizes the capacity region of a three-user cognitive interference channel with strong interference, providing inner bounds, conditions for capacity, and Gaussian case results, advancing understanding of cognitive radio networks.

Contribution

It introduces new capacity bounds and conditions for a three-user cognitive interference channel, including the Gaussian case, with comprehensive capacity region characterization.

Findings

Inner bounds on capacity region established

Capacity region characterized under strong interference conditions

Gaussian case capacity results derived

Abstract

This study investigates the capacity region of a three-user cognitive radio network with two primary users and one cognitive user. A three-user Cognitive Interference Channel (C-IFC) is proposed by considering a three-user Interference Channel (IFC) where one of the transmitters has cognitive capabilities and knows the messages of the other two transmitters in a non-causal manner. First, two inner bounds on the capacity region of the three-user C-IFC are obtained based on using the schemes which allow all receivers to decode all messages with two different orders. Next, two sets of conditions are derived, under which the capacity region of the proposed model coincides with the capacity region of a three-user C-IFC in which all three messages are required at all receivers. Under these conditions, referred to as strong interference conditions, the capacity regions for the proposed three-user C-IFC are characterized. Moreover, the Gaussian three-user C-IFC is considered and the capacity results are derived for the Gaussian case. Some numerical examples are also provided.