An analytical solution to the problem of modeling bandpass nonlinear channels and evaluating the performance of digital communication systems operating on them is presented. A method based on a Volterra series representation of the overall channel is first proposed, which allows one to extend to nonlinearities with memory the well-known concepts of complex envelope of bandpass signals and low-pass equivalent of bandpass linear systems. The general results previously mentioned are then applied to digital satellite communication systems operating over nonlinear channels. The effect of a nonlinear amplifier located in the satellite is considered, in combination with that of transmitting and receiving filters located in the Earth stations. In addition, both uplink and downlink noise are taken into account. Basic advantages of this approach are the generality it offers to the analysis and the fact that it allows accurate evaluation of the error probability in a short computer time.

Modeling and Performance Evaluation of Nonlinear Satellite Links-A Volterra Series Approach

https://www.dtc.umn.edu/s/resources/gg-se.pdf

A bibliography on nonlinear system identification

Digital communication systems are frequently operated over nonlinear channels with memory. The analysis of the performance of these systems is difficult and no complete analytical treatment of the problem has been obtained before. Several recent efforts have been directed toward the computation of error probabilities via Monte-Carlo simulation using a complete system model. These simulations require excessively large sample sizes and are not practical for estimating very low values of error probabilities. This paper presents a modified Monte-Carlo simulation technique for estimating error probabilities in digital communication systems operating over nonlinear channels. An importance-sampling technique is used to modify the probability density function of the noise process in a way to make simulation possible. Theoretical results as well as realistic examples are presented, showing that the number of samples needed for simulation is reduced considerably.

A Modified Monte-Carlo Simulation Technique for the Evaluation of Error Rate in Digital Communication Systems

This paper summarizes the important aspects of digital modem (modulator-demodulator) design for linear and nonlinear satellite channels using time-division multiple access (TDMA). The modem performance degradations caused by transmission anomalies, such as amplitude and delay distortions, effects of single and cascaded nonlinearities, and band-limiting effects in nonlinear channels, have been examined using the test data gathered from various field test programs using INTELSAT IV satellites and laboratory simulations using both INTELSAT IV and INTELSAT V parameters. A systematic methodology has been prescribed to reduce the effect of transmission anomalies on the performance of the modems. This paper consists of three main sections; essential features of TDMA modem design, transmission anomalies and their effects on modem performance, and optimization of modem performance in the presence of transmission deviations. The latter includes a brief description of an advanced maximum-likelihood sequence detection (MLSD) technique for application to the nonlinear channel.

A Survey of Modem Design and Performance in Digital Satellite Communications

Bandwidth- and power-efficient modulation has been one of the most important research subjects for modern satellite communications. The modulation system design can be particularly complicated when the channels are severely bandwidth limited, power limited (nonlinear amplification), and subject to impairments caused by co-channel interference, adjacent channel interference and signal fades. This paper presents a bandwidth- and power-efficient modulation system which combines convolutional encoding and phase modulation. Signal waveforms are selected to achieve controlled intersymbol interference and to satisfy a given out-of-band emission constraint. Convolutional codes are selected to maximize the minimum free Euclidean distance between the modulator output signals. Maximum likelihood demodulators are employed to recover the messages. System performance in terms of BER vs E b /N o and RF spectral properties is presented, and results are compared with those of the conventional QPSK system for additive white Gaussian noise and INTELSAT V TDMA channels.

A bandwidth- and power-efficient modulation system

The design of 60 Mbit/s/180 Mbit/s time-division multiple-access (TDMA) channels for the European Communication Satellite (ECS) system is analyzed and a possible configuration is suggested [1]. The effects of adjacent-channel interference, nonlinear power amplifiers both on the ground and in space, uplink and downlink noise are investigated and results are shown. Methods for carrier recovery are investigated and comparisons made. The complete channel design includes pulse-shaping filters, satellite filters, limiters before each TWT, and a filter after the earth-station TWT to limit the radiated spectrum.

M. Lopriore

Papers

Transmission of 4Ø-Phase-Shift Keyed Time-Division Multiple Access over Satellite Channels

M. Lopriore

Papers

Transmission of 4&#216;-Phase-Shift Keyed Time-Division Multiple Access over Satellite Channels

Transmission of 4Ø-Phase-Shift Keyed Time-Division Multiple Access over Satellite Channels