I recently came across an article on the inventor of adaptative equalizer Robert Lucky, In this article : An Oral History by Robert Lucky (http://www.ieeeghn.org/wiki/index.php/Oral-History:Robert_Lucky).
And I have a couple of questions :
- Quoting Lucky speaking about DFE :"It was the idea that you could use your own decisions to improve correction ability. When you start transmitting data and the channel is very corrupted the bits you’re getting have a lot of mistakes in them. Nonetheless, you say, “Let’s assume these bits are correct and reconstruct what the perfect signal would have looked like with these bits. Compared to what the signal actually was, we’ll just try to make them look alike with our adaptive filter. ” You're basing this model on corrupted bits on the outside, so that the question is, “Is this ever going to converge ?” " ?
Can some one elaborate on this and expain how the DFE equalizer is assure to converge and provide better equalization than the simple forward filter system ?
My second question is about the design of the filter, I choose to use an MMSE criterion, is that the best alternative ?
My DFE equalizer is for HF ionopheric channels, how can I update the filters coefficients, i.e., based on the channel estimate, what is the exact algorithm ?
Any Hints, thoughts, or ideas will be very appreciated