Fundamentals of wireless communication
Fundamentals of wireless communication
Cognitive radio: an information-theoretic perspective
IEEE Transactions on Information Theory
Diversity and multiplexing: a fundamental tradeoff in multiple-antenna channels
IEEE Transactions on Information Theory
On the achievable diversity-multiplexing tradeoff in half-duplex cooperative channels
IEEE Transactions on Information Theory
Capacity bounds for Cooperative diversity
IEEE Transactions on Information Theory
Achievable rates in cognitive radio channels
IEEE Transactions on Information Theory
Capacity of a Class of Cognitive Radio Channels: Interference Channels With Degraded Message Sets
IEEE Transactions on Information Theory
Degrees of freedom of the MIMO interference channel with cooperation and cognition
IEEE Transactions on Information Theory
Hi-index | 0.07 |
This paper considers the generalized cognitive radio channel where the secondary user is allowed to reuse the frequency during both the idle and active periods of the primary user, as long as the primary rate remains the same. In this setting, the optimal power allocation policy with single-input single-output (SISO) primary and secondary channels is explored. Interestingly, the offered gain resulting from the frequency reuse during the active periods of the spectrum is shown to disappear in both the low and high signal-to-noise ratio (SNR) regimes. We then argue that this drawback in the high SNR region can be avoided by equipping both the primary and secondary transmitters with multiple antennas. Finally, the scenario consisting of SISO primary and multi-input multi-output (MIMO) secondary channels is investigated. Here, a simple Zero-Forcing approach is shown to significantly outperform the celebrated Decoding-Forwarding-Dirty Paper Coding strategy (especially in the high SNR regime).