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Comparison of channel information acquisition schemes in cognitive radio system

In this paper, we compare the performance of two major spectrum information acquisition schemes in cognitive radio system, which are geo-location database based scheme and spectrum sensing based scheme. Although these two schemes are the major spectrum information acquisition schemes which are mainly considered in current researches on cognitive radio system, the comparison of two schemes has not been considered in previous works. In the comparison, we propose a new channel model for the cognitive environment which has three states, because recent measurements show that two-state Markov Chain model which has been widely used is not appropriate to model the cognitive environment. And based on the new channel model, we propose a new spectrum sensing scheme to reduce sensing overhead. Through performance analysis and numerical results, we show that our analysis is accurate and that the number of spectrum sensing can be reduced by using our proposed scheme so that the throughput of a cognitive radio system can be improved. We also find that the throughput of a spectrum sensing based scheme is better than that of a geo-location database based scheme in general cognitive environment.