TD(98)026

Abstract
Channel sounder measurements have expanded considerably. In the past,
mainly field strength measurements were performed. Today we face a great
variety of measurements, e.g. impulse responses, transfer functions.
They might contain diversity and direction-of-arrival information,
several types of stamps (e.g. location and time), and online processed
characteristics.

Currently used formats are often not capable of handling these new
demands. Furthermore it is difficult, if not impossible, to compare
existing data which has been gathered by different instruments and
stored in different formats. Because of the complex data structures and
the variety of different contents the data may consist of, commercial
databases are to be inadequate.

We developed a new dataformat, called CSM (Channel Sounder Measurement
Format), which offers flexibility and efficiency for storage. It is
adaptable to future needs and makes it possible to store different
stages of processed data, as generated by different devices. For
example, some equipment may put the raw impulse response samples of
different antenna-elements into the files, whereas others might operate
with high-gain directive antennas and store the directional impulse
response (i.e. impulse response for each considered angle).
In order to compare these different measurement results, one of them
(preferably the first) has to be converted to the other representation
by some algorithm. The result is again stored in the database.

No additional dataformat for the output-data of post-processing needs to
be handled out. All kinds and processing-stages of measurement data are
covered by our dataformat.

In order to free the engineer from such tasks as how to get the data he
wishes, a software-library for easy access of data stored in CSM has
been developed. It is called METABASE and will be usable on most
computing platforms since it is written in ANSI-C.