Reply by January 23, 20082008-01-23
On Jan 23, 3:45 pm, "ssohaib" <ssoh...@gmail.com> wrote:
> Hi, > Can anyone please forward me some literature on Viterbi Equilizer. Also I > would be grateful if some one give me SNR vs BER curve for any MPSK system > when Viterbi Equilizer is employed. > > Regards,
The idea behind it is pretty simple. Multipath propagation causes intersymbol interference in your received symbol stream. The received symbols can be modeled as the "correct" symbols convolved with the channel's multipath response (with noise thrown in, of course). Therefore, you can treat the channel's effect as if it was a convolutional code and use the Viterbi algorithm to optimally decode it. Caveat: you need to have a model for the channel's impulse response (sampled at the symbol rate). In systems where you can't predict that ahead of time (like a wireless receiver in an urban environment), you might use a linear equalizer in tandem with the Viterbi decoder. The equalizer is responsible for providing an estimate of the inverse of the channel impulse response. From that inverse, you can estimate what the impulse response actually is, and generate the trellis that you use for decoding the symbol stream. The estimate can be updated periodically as needed. Jason
Reply by John January 23, 20082008-01-23
On Jan 23, 3:45&#2013266080;pm, "ssohaib" <ssoh...@gmail.com> wrote:
> Hi, > Can anyone please forward me some literature on Viterbi Equilizer. Also I > would be grateful if some one give me SNR vs BER curve for any MPSK system > when Viterbi Equilizer is employed. > > Regards,
Look for an article by B. Sklar in IEEE Comms Mag (I think). It's called "How I Learned to Love the Trellis". John
Reply by ssohaib January 23, 20082008-01-23
Hi,
Can anyone please forward me some literature on Viterbi Equilizer. Also I
would be grateful if some one give me SNR vs BER curve for any MPSK system
when Viterbi Equilizer is employed.

Regards,