In this paper, the authors focused on simulation on Markov chains for the channel allocation of primary users in cognitive radio networks. There are many other research areas which can be extended from their paper. This requires a new estimation algorithm that can perform the updating quickly without putting a burden on the processing time. The transmission pattern does vary with time and the parameter estimate should be updated periodically by incorporating new observations into the current estimate. In this paper, they focused on channel allocation for primary user and the spectrum access problem is the future work.