Comments on "Analysis of cognitive radio spectrum access with optimal channel reservation

For original paper see X. Zhu et. al., IEEE Commun. Lett., vol.11, pp.304-6, (2007).This paper discusses a number of errors in the Markov model and analysis of the blocking and forced termination probabilities in a cognitive radio network, given in [4]. The correct expressions of forced termination and blocking probabilities are provided. Under the same conditions as in [4], the probabilities and call completion rate are re-evaluated. The results show that there are significant differences both in terms of magnitude and behavior. Furthermore, an expression of aggregate throughput in bits per unit time is also given and evaluated. All the numerical plots are supported by simulation results.