Abstract— This paper presents a methodology for determining the capacity of coherently detected continuousphase frequency shift keying (CPFSK) modulation under the constraints of binary coding and an ergodic channel. Building upon the capacity results, the coded CPFSK parameters of code rate, alphabet size, and modulation index are jointly optimized by using capacity as a cost function. From this optimization, it is possible to determine the minimum Eb/N0 required for bit-interleaved coded CPFSK to achieve an arbitrarily low error rate as a function of spectral efficiency. Results showing this minimum Eb/N0 are presented for a range of spectral efficiencies and several alphabet sizes in an AWGN channel.
Rohit Iyer Seshadri, Shi Cheng, Matthew C. Valenti