In [J12], a novel representation of Continuous Phase Modulated (CPM) signals as sum of PAM signals is presented for both integer and noninteger modulation index cases. Then, the Nth-order cyclostationarity properties of binary CPM signals are derived in terms of Nth-order temporal and spectral moment and cumulant functions. Moreover, the case of M-ary CPM signals is briefly addressed. The results are illustrated with simulations involving MSK, LREC, and GMSK signals.
In [J23], the cyclostationarity properties of a general class of Long-Code Direct-Sequence Spread-Spectrum (DS-SS) signals are analyzed and it is shown that these properties can be exploited in long-code direct-sequence code-division multiple access (DS-CDMA) systems.
In [J13], a blind algorithm for the estimation of amplitude, phase, and relative time delay of each user in multiple-access communication systems is presented. The proposed method can be used in frequency-division multiple-access (FDMA), code-division multiple-access (CDMA), and some variations of time-division multiple-access (TDMA) systems. It is based on the cyclostationarity features of the received signals and provides estimates of the unknown parameters that are intrinsically immune to the effects of noise and interference, provided that a cycle frequency of the user signals exists which is not shared with the disturbance terms.
In [J19], the algorithm presented in [J13] is extended to the case of channels introducing frequency shifts for noncircular transmissions. The second-order conjugate cyclostationarity of the transmitted signals is exploited to estimate the frequency shifts. The proposed estimators are, under mild assumptions, asymptotically unbiased and consistent. Moreover, the proposed algorithms are asymptotically near-far resistant and are not based on the usual assumption of white and/or Gaussian noise.
The case of circular transmissions is addressed in [J20] where the higher-order cyclostationarity of the transmitted signals is exploited to estimate the frequency shifts. Moreover, in [J20] a reduced complexity algorithm is proposed, whose computational cost is comparable with that of second-order-statistic based estimation algorithms.
The problem of blind signal parameter estimation for single-user communications is addressed in [J22], [C36].
The narrow-band signal model is treated in [J22] where amplitude, phase, time-delay, and frequency shift of the received signal are estimated by exploiting its cyclostationarity properties. In [C36], the wide-band signal model is considered, and also the time-scale factor is estimated. The paper [J29] deals with Doppler-stretched wide-band signals occurring in mobile communications and in radar/sonar problems in the presence of moving targets in the case of constant relative radial speeds. Loeve bifrequency spectrum and cross-spectrum are used to characterize in the spectral domain the received signal and to jointly characterize the transmitted and received signals. It is shown that, even if both the transmitted and received signals are singularly ACS, they are not jointly ACS but, rather, jointly spectrally correlated. The problem of uniformly sampling these nonstationary signals is addressed.