Markov Capacity of Continuous Phase Modulations

We propose a novel iterative method, similar to the generalized Blahut-Arimoto algorithm recently proposed by Kavcic, to evaluate the Markov capacity of a continuous phase modulated signal over an additive white Gaussian noise channel. One of the novelty of our approach is that we maximize, with respect to the input distribution, the spectral efficiency in bps/Hz rather than the mutual information in bits per channel use. We address this problem by taking into account the bandwidth occupancy of the CPM signal by means of the Carson´s rule bandwidth definition, and solving a linearly constrained nonlinear optimization problem. The results show that Markov capacity obtained with the proposed input optimization algorithm strongly outperforms the capacity for independent and uniformly distributed input.