An analytical model to describe the performance of digital radio links

The author describes an analytical tool capable of predicting the average bit error rate (BER), the percent error-free seconds (PEFS), and the availability for an end-to-end digital connection. Availability is defined with respect to the hypothetical reference link (HRX). A connection is considered to be in an unavailable state if the BER is worse than 10^-3 10 consecutive 1-s intervals or longer. It leaves the unavailable state if the BER in each of 10 consecutive 1-s intervals is better than 10^-3. A four-state Markov chain is used to model the error performance of a 4 GHz digital radio route at DS-0, DS-1, and DS-3 rates. The parameters for this model are derived from experimental data collected between a pair of cities. The end-to-end performance is calculated by concatenating two such links. The results verify that the Markov chain model can predict the long-term error performance of digital connections