Avaliação dos Efeitos de Interferencias no Desempenho de Sistemas de Comunicações Digitais<br />DOI: 10.14209/jcis.1997.9

Abstract

This work examines analytical techniques to assess the effects of interferences on the performance of digital transmission systems. To evaluate the effect of interference in the symbol error probability the upper bound proposed by Glave & Rosembaum is used. The use of this upper bound, originally proposed for PSK modulation systems is extended to include QAM systems. The key parameter for the evaluation of the Glave & Rosembaum upper bound is the interfering signal peak value after filtering by the receiver detection filter. An original analytical algorithm to determine this parameter in the case of QAM-16 interfering signals is presented. In order to obtain estimates of the system bit error rate performance in the presence of interfering signals, a new concept of equivalent noise is proposed. This concept is used to generate estimates of the BER from the knowledge ofthe system theoretical symbol error probability in the presence of interferences and the system modem performance curves in the presence of background noise only. The application of the described techniques is illustrated by examples.