Customer Solutions

Testing BTS Modules with LabWindows/CVI at Alcatel Télécom

Author(s):

Stéphane Lamarre, Alcatel Télécom

Industry:

Telecommunications

Product:

LabWindows/CVI, PXI/CompactPCI

The Challenge:

Calibrating and testing the Transceiver Receiver Entity (TRE) modules in Base Transceiver Stations (BTS) before shipment to customers.

The Solution:

Setting up a post-production test bed using a PXI platform, measurement instruments, and National Instruments LabWindows/CVI.

Introduction
The Alcatel Télécom plant in Eu, Normandy, France produces telephone switching systems and mobile communications BTSs used by telephone operators in France and abroad. One BTS can hold as many as twelve TRE electronic modules. Each module manages the radio communication with mobile phones. The TRE modules require a test bed for calibration and testing before shipment to customers.
Faced with increased production and limitations on space, we wanted to develop a new generation of test beds that was compact, upgradeable, fast, which we could use in an environment that is well-suited for test and measurement.

The PXI rack-mountable chassis, on board controller, and 3U-format modules met all of these criteria. The resulting test system fulfilled our needs for an open test bed that we could easily expand for future development.

Implementation
The test system consists of a master PC which controls four slave stations via TCP/IP. Each station includes a PXI chassis, an on-board PXI 333 MHz controller, a GPIB interface, and two additional serial ports. The GPIB interface of each station controls an HF signal generator, a GSM tester, and a wattmeter.
The serial link communicates with the TRE modules for testing. Each test station controls three TRE modules. Therefore, with the complete system, you can parallel test twelve TRE modules.

The master PC also controls an RF switching matrix via GPIB. The matrix routes the signals between the TRE modules and the measurement instruments. The aim of the design is to optimize resource sharing. When testing of a TRE with one instrument is complete, the master PC signals that you can connect the next TRE module to the instrument, and so on. The operator then inserts the next module into the test bed, makes the proper connections, then signals the master PC to start the tests.

With LabWindows/CVI, you can import ANSI C and reuse a large portion of the test code already written with a Borland compiler. Using the multithreading capabilities of LabWindows/CVI, each test system can manage nine threads in parallel. For each module tested, one thread manages IHM and the TCP/IP dialogue, a second thread is used for testing, and the third thread produces the result files during the test. The result files are returned to the master PC and then downloaded to a factory server, where they are stored. Storage of results ensures that all tests are completely traceable.

Results
We began using the new test bed in September 1999 and met our expectations - proving that parallel testing reduces test time and improves productivity. Most importantly, with the test bed we can manage several test stations and functions from a single PC. We plan to use this concept again in testing different BTS modules.

For more information, contact:

Mr. Stéphane Lamarre

Alcatel Télécom

Service SMI/BTS

ZI rue de Lavoisier,

76260 Eu

France

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