February 1976 | NTIA Technical Report OT 76-82

Performance of Digital Modems with Cochannel Interference and Gaussian Noise

John R. Juroshek

Abstract: An approximate method for estimating the performance of digital systems operating with cochannel interference and Gaussian additive noise is described. The method uses Monte-Carlo techniques and an approximation, based on the geometrical characterization of signals, to estimate the error rate of a variety of digital systems as a function of signal-to-noise ratio and signal-to-interference ratio. Curves are presented that show excellent agreement between the estimates and theoretical predictions at symbol and bit error rates as low as 10-9 . Computer programs are included that estimate error rate for multiphase coherent phase-shift keyed (CPSK), noncoherent frequency-shift keyed (NCFSK), differentially coherent phase-shift keyed (DCPSK), and coherent amplitude-phase-shift keyed (CAPK) systems. The programs can handle single as well as multiple cochannel interference, and examples are given that show error rate in both environments.

Keywords: interference; digital systems; error rate; modems; Monte Carlo techniques; digital performance

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

Back to Search Results