The antenna-part of the software-radio has the structure as shown in fig. @Antenna-blowup: Common/Driver/HW/Server@ Their respective functions are as follows:
The interface of the antenna offers the following parameters to the signal-processing part:
This is the implementation of a certain way to transmit and receive samples. It has to take care about all initialisations and correct handling of all exceptions. The following drivers are functional:
The final part of the software-radio defines the channel. The Emul driver, for example, implements a flat single-tap channel with no noise. The Simul drivers need a channel-server that takes multiple radios together, mixes their signal, and sends back the calculated signal.
The most interesting parts are the RF and ICS hardware, because they offer a real channel to test the transmission with.
In the following table you can find a comparison of the two hardware-systems available.
|Max. number of antennas||1||4|
In simulation-mode, a channel-server accepts connections from different radios, as can be seen in fig. @channel-server with two radios@. The channel-server can simulate multi-tap channels and add gaussian noise to the transmitted signals. This allows for easy simulation of real-world signals, before taking the modules on the air.
Linus Gasser 2004-04-14