Matlab is used in WiMAX base-station tests

Cambridge Consultants has used the Matlab technical computing environment from The MathWorks to develop a comprehensive simulation test bench for multi-antenna WiMAX base-stations.

Cambridge Consultants has used the Matlab technical computing environment from The MathWorks to develop a comprehensive simulation test bench for multi-antenna WiMAX base-stations.

The complete test environment was developed for Aspex Semiconductor to verify and demonstrate its WiMAX physical layer (PHY) platform.

Matlab was used to rapidly build a transmitter model, a graphical user interface (GUI) for test scripting and test result analysis, and a hardware interface for the PHY implementation.

As a result, the project was delivered ahead of schedule, in just seven weeks, and the unit testing was simplified.

Worldwide Interoperability for Microwave Access (WiMAX) has the potential to provide fast, inexpensive wireless Internet access across kilometres instead of metres.

Developers of WiMAX base-stations, however, face the challenge of meeting evolving standards.

Aspex Semiconductor built a scalable, software-based solution around its Linedancer processors that implements the WiMAX PHY for multi-antenna base-stations to accommodate emerging IEEE 802.16 standards.

It then contracted Cambridge Consultants to build a test bench so that it could demonstrate the platform.

"Matlab was the best tool for this project", said Robert Tan, Principal Engineer at Cambridge Consultants.

"It enabled us to rapidly build a prototype of a WiMAX transmitter, develop an accurate physical layer model, interface with hardware and work effectively in a multiplatform environment".

"Its testing and debugging facilities accelerated the development of the test bench and proved that it was what our customer needed".

As part of the test bench, Cambridge Consultants developed a prototype of a new standards-compliant WiMAX transmitter using Matlab.

It also used algorithms for fast Fourier transforms and a Read-Solomon encoder from The MathWorks product the Signal Processing Toolbox.

Elaborating on this prototype, the company developed a faster, bit-accurate model and verified its functionality using test vectors specified in the IEEE 802.16d standard.

In addition, it used the Matlab language as a built-in scripting mechanism to drive the model with MAC layer messages.

Cambridge Consultants used Matlab development tools to design a GUI to enable customers to run test scripts and analyse test results.

This GUI displays plots of the results, including bit-error rates, transmitter output, the power spectrum magnitude and the receiver's signal-to-noise ratio.

The company also wrote custom C-code that it compiled into a MEX-file (Matlab executable) to interface with the Aspex Accelera card on a Linux system.

The transmitter model running in Matlab on a Windows system called this code directly to send and receive data from the card.

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