Enhancing the performance in cognitive network

In the next generation of wireless networks, the entire network operating on different radio frequencies under wireless mode will be available for communication. Cognitive Networks are an emerging new type of networking technology that can utilize both Radio Spectrum and Wireless Station. Based on the Knowledge of the availability of such resources gathered from past experience the resources can be utilized efficiently. Signaling is the major issue in Cognitive Network. Multiple Input Multiple Output (MIMO) technique is used for the transmission of signals in Cognitive Network. In this paper, the performance of MIMO in a scattered environment is analyzed and water filling algorithm is used to maximize the capacity of MIMO channels. We also propose an optimum beamforming algorithm to design beamforming vectors such that, interference caused by the primary transmitter to the cognitive receiver and the interference caused by the cognitive transmitter to the primary receiver is completely nullified while maximizing the rate of both primary and secondary links. The proposed technique does not require any changes in the existing environment between the primary and secondary user. The secondary user will be allowed to transmit concurrently to the primary user. Since the primary user is a licensed one it need not to have any knowledge about the resources utilized and performance of the secondary user and it transmits independently. Further it is also proved that the rate of Cognitive Multiple Input Multiple Output (MIMO) link implemented by the proposed beamforming algorithms is equal to interference free Multiple Input Single Output (MISO) link.