On the Capacity of a Class of MIMO Cognitive Radios

TL;DR

This paper investigates the fundamental capacity limits of MIMO cognitive radio networks with one licensed and one cognitive user, deriving bounds and conditions for optimality in the interference channel setting.

Contribution

It introduces new capacity bounds and conditions for optimality in MIMO cognitive radio channels with degraded message sets, advancing understanding of their fundamental limits.

Findings

Achievable region and outer bound derived for the MIMO cognitive radio setting.

Under certain conditions, the achievable region is shown to be optimal.

The results include insights into sum capacity and capacity region characterization.

Abstract

Cognitive radios have been studied recently as a means to utilize spectrum in a more efficient manner. This paper focuses on the fundamental limits of operation of a MIMO cognitive radio network with a single licensed user and a single cognitive user. The channel setting is equivalent to an interference channel with degraded message sets (with the cognitive user having access to the licensed user's message). An achievable region and an outer bound is derived for such a network setting. It is shown that under certain conditions, the achievable region is optimal for a portion of the capacity region that includes sum capacity.