Angelo Luvison

Error Probability in the Presence of Intersymbol Interference and Additive Noise for Multilevel Digital Signals

A new method is presented to compute the average probability of error in the presence of intersymbol interference and additive noise for multilevel pulse-amplitude-modulation (PAM) and partial-response-coded (PRC) signaling schemes. The method is based upon nonclassical Gauss quadrature rules (GQR) and suffers no limitation on noise statistics, so that it applies also for non-Gaussian noise. Moreover it yields some remarkable advantages as compared with other methods, in particular, with the series expansion method that has recently received considerable attention. Expressions for the truncation error are also given and their derivation is reported in the Appendix. Finally, examples of applications are presented and comparisons with other methods are carried out.

Error probability in optical fiber transmission systems

A method for evaluating the average error probability in digital fiber optic transmission systems is described. It takes into account the statistical properties of the main impairments that affect the information signal, i.e., shot noise (dark current included), thermal noise, and intersymbol interference. Unlike other methods, the analysis of shot-noise statistics does not entail the second-moment characterization alone, but uses a number of moments sufficient to evaluate the error probability with a high degree of accuracy. For this purpose it is shown how the cumulants of shot noise and intersymbol interference of any order can be computed. The baseband pulse response and the statistical distribution of the avalanche-photodetector gain are assumed to be available. Moreover, techniques for exploiting the cumulants are given; knowledge of the cumulants allows one to compute the probability of error by means of Gaussian numerical integration rules. Finally, some results and comparisons are reported.

Design and Performance of an Adaptive Kalman Receiver for Synchronous Data Transmission

A class of multilevel linear-modulation data-transmission systems, over unknown, slowly time-varying, and bandlimited channels is considered. It is shown how sequence estimation in the presence of Gaussian noise and intersymbol interference can be carried out by means of a discrete Kalman estimator. Moreover, the receiver can be provided with data-aided adaptive loops for performing channel identification, carrier recovery, and timing extraction. A computational method is presented to evaluate the average probability of error of the overall system in the presence of inter-symbol interference, additive noise, and phase-and sampling-synchronization errors. The method is based upon nonclassical one-and two-dimensional quadrature rules, which are outlined in the Appendix. As an example, numerical performance results related to a phase-shift-keying (PSK) system are given. The results are obtained by means of general-purpose and system-oriented computers.

Application of Gauss Quadrature Rules to Digital Communication Problems

In multilevel bandpass data transmission there is usually a difference between the phase of the carrier signal and the phase of the receiver oscillator, thereby causing imperfect demodulation. The use of nonclassical Gauss quadrature rules (GQRs) allows: 1) a theoretical study of the joint effects of phase jitter, thermal noise, and intersymbol interference on average error probability; and 2) a maximum-precision sampling technique in the simulation of digital communication systems. On this basis, the mean-square-error and zero-forcing equalizers are considered, and their performances evaluated in terms of the average error probability for multilevel pulse-amplitude-modulation (PAM) and partial-response-coded (PRC) signaling schemes.

Baseband equalization in fibre optic digital transmission

The problem of baseband equalization in optical p.c.m. fibre systems is considered. Zero-forcing, minimum-mean-square error, and Kaiman equalizers are briefly reviewed and their relative merits discussed. The performance of the overall communication system is the average probability of error, which can be computed by means of the proposed method with high accuracy. A final section presents some diagrams that may be useful in designing the equalizer and in evaluating the degradation affecting the error probability with respect to ideal conditions. A presentation ofadaptive equalization results concludes the paper.

The architecture of full services access network

Summary form only given. An international idea the full services access network (FSAN)-to create the conditions for the development and the introduction of access systems supporting a full range of narrow-band and broadband services is presented. Although it is recognized that the needs of each network operator differ because of the differing regulatory, business, and structural environments in each country, sufficient similarities exist in the needs for future access networks to suggest that significant benefits can be achieved through adopting a common set of requirements specification.

The Max Project Approach to Multiservice Business Communications

Project 2100 “Metropolitan Area Communication System (MAX)” aims at an effective solution to meet the communication requirements of heterogeneous business user over large (e.g. metropolitan) areas with a high concentration of information-based organizations. Major objectives of the project regard the definition, design, prototype development and testing of an integrated communication system for the flexible provision of data, video services and applications. The paper highlights these issues, outlines the basic technical choices and emphasizes the project rationale and scope, i.e. market opportunities for viable products and services, policy towards standards and compatibility with related developments, in particular the broadband integrated services digital network (B-ISDN).

Signal processing in digital fiber communications

Transmission ofpcmsignals over optical fibers is limited in transmission rate by the inherent imperfections of the carrier medium. The paper discusses the model for an optical telecommunications system (signal and noise models), simulation in base-band (stressing the rational approximation made for the fiber’s transfer function) pulse equalization, encoding and synchronization. Equalizers, whether linear or not, recursive or not, adjustable or not, reduce intersymbol interference, by compensation of distortion in compliance with certain criteria with a view to improving the error rate. The encoding used is a trade-off between bandwidth, tolerance to intersymbol interference and acquisition and tracking of the signal.AnalyseLa transmission de signauxmicsur fibres optiques est limitée en débit par les caractéristiques imparfaites de la voie. L’article discute la modélisation d’un système de télécommunication optique (modèles de signal et de bruit), la simulation en bande de base (en insistant sur l’approximation rationnelle de la fonction de transfert de la fibre), l’égalisation des impulsions, le codage et la synchronisation. Des égaliseurs linéaires ou non, récursifs ou non, réglables ou non, réduisent le brouillage mutuel des symboles, en compensant la distorsion selon certains critères de façon à améliorer le taux d’erreurs. Le codage réalise un compromis entre la largeur de bande, la tolérance au brouillage entre symboles, et l’acquisition et la poursuite du signal.

A simple timing circuit for optical PCM repeaters

A simple synchronization system is proposed for timing recovery in optical PCM repeaters. The basic idea is to exploit the spectral line at the transmission rate, which is already present in the unipolar symbol stream travelling along the fibre. Since a nonlinear circuit is no longer needed, the amplified signal at the photodetector output is directly filtered by a resonant circuit to give the clock recovery by means of a zero-crossing detector. The limits of effectiveness of this synchronization system are then discussed, especially with regard to the accumulation of timing jitter as well as of alignment error.

Timing error tolerant waveforms in optical fibre systems

The problem of pulse shaping and sensitivity to timing errors in optical fibre data communication is considered. The performance of the overall transmission system is the average probability of error, which is computed for intersymbol interference, thermal noise, and shot noise in avalanche photodiodes. An analysis of the immunity to small sampling errors of various Nyquist pulses indicates useful design criteria.