S.Bharathy, T.Perarasi, Dr.G.Nagarajan
Cognitive Radios emerged as a means of improving the efficiency of current spectrum allocation policy by utilizing the available unused spectrum. There are many challenges in the systematization of Cognitive Radio Network, and the most obvious is to fulfil the awareness requirement. The nodes must be able to share the spectral information which requires inter node communication, hence that shared channel is needed that can be operated under various mode activities from the primary users. MAC layer (IEEE 802.22) protocol is suitable for channel sharing and proved that the resulting controlled channel sharing performs better than the traditional sensing based MAC algorithms, the proposed algorithm for solving this problem has provably tight bounds in terms of the max-min throughput. In order to make less number of reconfigurations in the network, localized version share algorithm is preferred in CR network. Thus helps to combine the centralized algorithm and its localized version and hence the complete protocol is able to achieve high fairness and high network throughput with few channel reconfigurations.