Interference Cancellation and Rate Maximization in a Cognitive networks

Cognitive networks is an emerging technology to alleviate the spectrum shortage problem faced by traditional wireless networks through efficient utilization of resources. signaling is the major issue in the cognitive networks. Multiple Input Multiple Output (MIMO) technique is used for the transmission of signals in Cognitive Network. MIMO in a fading environment is considered. In this paper, we consider uncoordinated Beamforming in a cognitive networks with single primary user and secondary user sharing the same spectrum and are equipped with multiple antennas. This is in contrary to prior work, which requires coordination between primary users and secondary users. In particular, the beamforming vectors are designed to maximize the sum rate. The beamforming vectors are designed such that the interference caused by the cognitive transmitter to the primary receiver and the interference caused by the primary transmitter to the cognitive receiver is completely nullified while maximizing the rate of both the primary and secondary links Finally, we present some simulation results to evaluate the sum rate performance of the proposed algorithms. Simulation results also show the effectiveness of the number of transmit and receive antennas on the proposed design. Index Terms—Beamforming, MIMO, cognitive network, fading channel, interference cancellation.