As in any project , the first step is to get acquainted with the software. The software toolkit for the NI PXIe setup is LabVIEW 2010. To draw a rough comparison, LabVIEW is very much like the simulink blockset in MATLAB the only exception being LabVIEW has many more functional tools( Signal processing, Matrix operations, RF Communications etc.) . The front end of LabVIEW is pretty much like a CRO. It has controls, indicators, graphs on the front panel and the actual control logic flow is built at the rear panel. The following images will give you a clearer idea.
Front Panel Rear Panel
Before going into the actual implementation of the OFDM, I did a few simulation experiments on LabVIEW. I developed an M- ary communications system which employed M-PSK and M- ASK. The purpose behind doing these simulations was just to get a hang of the software. I also went ahead and simulated OFDM with a mask. To check whether the simulations make sense, I plotted a BER curve for the simulated communications system.
Before actually going towards the Real time Implementation, It was necessary to know how your waveforms look like. I did an NC- OFDM simulation assuming an AWGN channel with an SNR of 8 dB. LabVIEW has a very good simulation environment and it has any tools which emulate real environment specifications. The transmitted and received signal amplitude v/s subcarrier index graphs are as shown in the figure
