FPGA Central

Hi,
I am implementing a SC/MMSE equalizer for ISI channels . I am
doing this iteratively in channel coded system. But, it seems my
program is not correct as the iterations passes, my BER becomes worse.

I am using a static ISI channel with 3 taps and at the receiver I am
using a MMSE filter with 31 taps. I tested the code in different cases,
1. If the channel taps are [ 1 0 0], then the performance should be
exactly equal to AWGN, - My codes satisfies this condition.
2. With channel response say, [ 0.4 0.8 0.4], and no noise for each
iteartion the BER should be zero. But my code is gives BER equal to 0
at only 1st iteration. From the 2nd iteration onwards, I am not getting
0 BER . This means I am unable to proper equalization with the new
extrinsin ionformation, which I got from the channel decoder. In teh
1st ietation it is set to zero. I am not sure where I am doing mistake.

Does anybody faced this kind of problem,

Any help in tis regard is highly appreciated.

Best Regards,
-SaiRamesh.