Method for bit error rate measurements in a cell-based telecommunication system

Abstract

A method for bit error rate measurements in a cell-based telecommunication system is presented, comprising the following steps of generating a first bit pattern at a first location of said telecommunication system, transmitting said first bit pattern from said first location to a second location of said telecommunication system, thereby obtaining a transmitted bit pattern, generating a second bit pattern at said second location, said second bit pattern being identical with the first bit pattern and comparing said transmitted bit pattern with said second bit pattern. The first bit pattern is transmitted in at least one unused cell (U, I), said unused cell (U, I) being generated during normal operation of said telecommunication system in the case of a lack of used cells to be transmitted.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a method for bit error rate measurements in a cell-based telecommunication system.[0002]In cell-based telecommunication systems, the information is transferred by means of cells of fixed or variable byte-length. These cells typically have an overhead section wherein control, management and routing information is embedded and a payload section, carrying user information.[0003]Cell-based telecommunication systems comprise for example ATM (Asynchronous Transfer Mode) communication networks. ATM cells for instance have a fixed length of 53 bytes, 8 bytes of which constitute the overhead section or the so called ATM cell header, reserved for overhead information.[0004]The whole transmitted cell-stream in a cell-based network is generally composed of two different types of cells: on the one hand used cells carrying in their payload section the proper user information and on the other hand unused cells with no user informati...

AI Technical Summary

Benefits of technology

The present invention provides a method for measuring bit error rates in a cell-based telecommunication system during normal operation of the system. This is done by generating a first bit pattern and transmitting it in an unused cell, which is generated during normal operation of the system in case of lack of used cells. The method uses a comparator to compare the transmitted bit pattern with a second bit pattern generated at the receiving end. The number of discrepancies between the two bit patterns serves as a measure for the bit error rate. The invention has the advantage of being able to measure bit error rates without interrupting the system and without falsifying measurement results. The method can be repeated at each generation of an unused cell to increase accuracy. The invention also includes a device for bit error rate measurement and a synchronizer for activating the second bit pattern generator at each arrival of an unused cell.

Problems solved by technology

Bit errors which occur during transmission of these cells, have a negative impact onto the quality of the connection.

A bit error which occurs in the payload section of the cell implies a falsification of the transmitted information; wherein a bit error which occurs in the overhead section of the cell potentially implies a falsification of the destination address, and thus a loss of the cell.

Traditional bit error rate measurement methods have the disadvantage, that normal operation of the system has to be interrupted and the system has to be brought in a test phase.

During this test phase, no transmission of proper user information is possible.

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