Characterization of echo in the Saudi telephone network for full-duplex data transmission

Abstract EN

This paper deals with the problem of measuring several aspects of echo arising in the dial lines of telephone networks and, in particular, the Saudi network.

When combined with the measurement of other impairments (such as noise, cross talks, hits, distortion, etc.), this echo measurement will lead to a statistical characterization of the dial-up lines of the network.

An in-house item of measuring equipment has been developed to perform the echo measurement.

This device is a microcomputer equipped with a digital signal processing (DSP) board, where most of the fonctions are performed with software.

In this paper, we present the results of using the developed system in field testing the echo in the Saudi network.

This being the concern of the testing, full-duplex data transmission at high rates (9600 bits per second) has also been examined in a side test using the new modem.

Although similar testing is recommended on a larger scale, the results of current testing show that the dial lines of the Saudi network suffer from relatively low volumes of echo that a reasonably powerful echo canceller could nullify.

The only exception to this occurs in nodes in the Eastern Province, where the level of echo is found to be well above the network average.