Advanced tutorial

Besides the manual, gui-based control for test bed related programs and devices, script controlled measurements are also possible. This approach developed at the Vodafone chair is called TestMan. The basic idea is to provide a common interface to exchange data, commands and status messages between different application, running on the same or distributed systems and written in different languages.

TestMan is based on the Microsofts .NET framework, which similar to java, is platform independent. So even a Linux computer can make use of .NET programs if the Mono project is used. In three important languages Matlab, Labview and Python it is possible to use dynamic link libraries (DLL). Therefore TestMan is a DLL which can be loaded into the specific application or script and it makes sure that data is transferred over the network from one Application to another, respectively to a group of applications.

TestMan uses two different network techniques to exchange information’s: For SNMP like status messages and commands UDP multicast is used whereas TCP peer to peer connection comes into place for transferring bigger data.

To distinguish between different applications a type and an ID are introduced for every application. So it is possible to group similar applications together and the TestMan DLL filters out messages which are intended for other applications.

UDP packets can be thrown away by network elements like routers and switches. For a status messages this is not always a problem, but definitely when a command is send. To mitigate this problem TestMan uses 4-way handshaking for commands as stated in the following figure.

The following picture shows an example how an OFDM-Transmitter can be implemented using TestMan.

Are more detailed example code will be published soon.