A method to exploit channel estimation for a DS-CDMA mobile radio system with coherent reception in the Rake receiver is investigated by means of a software tool, named CDMASIM. Channel estimation is performed in the down link (base to mobile) by transmission of a pilot signal from the base station. Two different techniques for channel estimation are proposed and investigated in time and frequency selective channels. The first technique is based on correlation between the received signal and the pilot signal to perform channel identification, while the second is based on an adaptive stochastic gradient algorithm for channel equalization. The parameters that characterise the two techniques have been optimized in terms of BER and performance results are given in faded multipath environments with optimal parameters.>

The paper presents the performance of a simulcast digital radio paging system, computed and measured in the presence of both additive white Gaussian noise (AWGN) and Rayleigh fading plus AWGN. A number of combinations of time delay, frequency offset, amplitude imbalance among the signals are considered. The results presented have been utilized for contributing to the definition of ERMES, the new European radio message system.>

A number of continuous-phase modulation methods suitable for digital and mobile radio applications has been grouped in a common class, which has been named 12PM3 (12-state, phase modulation with correlation over three consecutive bits). This paper introduces the definition of this class of modulation schemes, and presents some of its features. With reference to the scheme that gives the best spectral compactness, some effects of typical implementation imperfections of the modulation circuits are discussed. The performance of some 12PM3 modulators associated with a frequency discrimination receiver is then computed with reference to both AWGN (additive white Gaussian noise) channels and the typical propagation conditions envisaged for SCPC/FDMA digital land mobile radio systems in urban environment. The adopted pre and postdiscrimination filters of the receiver are optimized for the best performance. Different decision techniques are considered, namely 2-TH (2-threshold), 4-TH, mixed 2-TH/4-TH and MLSE (maximum-likelihood sequence estimation) techniques.