Welcome

The riddle of OFDM and the construction of Rome

This site is dedicated to signal and system modelling and simulation. In time it may grow and, perhaps one day, become useful to others. And while Rome was not built in a day, this site was. This is why, for now, it contains just a handful of examples (such as a few simulations of OFDM; a simulation of an idea similar to OFDM, but with wavelets; a packet-queuing simulator for Wi-Fi; and that's more or less all).

It was way back in the spring of 2005, when a friend asked me a question about an OFDM communication system. What had puzzled my friend was why signal processing in such systems did not seem to follow the rules?! (Well, if you wish to learn what exactly it was about then you are welcome to visit this page A. OFDM and Other Schemes). I wanted to provide my friend with an explanation that would be simple to follow and yet not sound like reciting a mantra, something that would be visual but not static like a picture. This was what prompted me to think about creating a visual simulator for OFDM signal processing, which would allow its users to play with it by changing its configuration and entering different values for its parameters. Such a simulator would include a model of the channel with additive noise and Doppler shift, etc. This, I thought, could allow an interested user to study the performance of the OFDMA system (e.g. calculate BER for raw unprotected bits). And by playing with the simulator and creating "what-if" scenarios a user would, I hoped, acquire understanding of the OFDM principles rather than learn to recite mantras about them. As a result, the user would be able see that the OFDM systems were indeed following the rules. This is how the foundations of this website were laid, though they stayed that way (just laid and nothing built on them) for a while.

Unlike the results of my other work, these simulations were done privately in my free time and were not paid by my employer, which in a way was fortunate because now I am able to publish them entirely free for you to download and to play with, including to modify and to use them in whichever way you might wish.

Thanks for taking a look around and please feel free to download the Excel® workbooks and watch the simulations in action (they do use VBA code).

Yours faithfully,

Plamen Grozdanov

Hint: each of the simulations is presented on its own page, complete with some screenshots and files to download. Navigate to them using the links shown below or in the panel on the left side.