Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What I learn from textbook, viterbi can handle bit sequence with some mistakes, and output correct bit sequence. How can it handle complex data inputs? Because the received signal are complex. Q2, Can you kindly introduce some papers with simple math derivations to me or any key I need to focus on?I would like to chew them first, thanks a lot! Thanks in advance! Frankie

# ask help on viterbi equalization

Started by ●April 23, 2009

Posted by ●April 24, 2009

On Apr 23, 10:02�pm, "Fan.Zhang" <zf...@sina.com> wrote:> Dear All, > > I am learning how to use viterbi in GSM Channel Equalization. As a newer, > I have some basic questions about this method. > > Q1, What I learn from textbook, viterbi can handle bit sequence with some > mistakes, and output correct bit sequence. How can it handle complex data > inputs? Because the received signal are complex. >The purpose of a viterbi equalizer is to equalize channel or "reverse" the channel effect rather than to correct error as a viterbi decoder. Once you have estimated the channel, you can always calculate the euclidean distance of receiving the channel output y given a certain input x based on the transition probability p(y|x). x and y could be real or complex.> Q2, Can you kindly introduce some papers with simple math derivations to > me or any key I need to focus on?I would like to chew them first, thanks a > lot! >The math derivation of a viterbi equalizer is the same as a viterbi decoder. You probably can find such topics in proakis.> Thanks in advance! > > Frankie

Posted by ●April 24, 2009

"Fan.Zhang" <zf624@sina.com> wrote in message news:g-qdnWDRE7MmgGzUnZ2dnUVZ_qidnZ2d@giganews.com...> Dear All, > > I am learning how to use viterbi in GSM Channel Equalization. As a newer, > I have some basic questions about this method. > > Q1, What I learn from textbook, viterbi can handle bit sequence with some > mistakes, and output correct bit sequence. How can it handle complex data > inputs? Because the received signal are complex. > > Q2, Can you kindly introduce some papers with simple math derivations to > me or any key I need to focus on?I would like to chew them first, thanks a > lot! > > > Thanks in advance! > > Frankie

Posted by ●April 24, 2009

On Apr 23, 10:02�pm, "Fan.Zhang" <zf...@sina.com> wrote:> Dear All, > > I am learning how to use viterbi in GSM Channel Equalization. As a newer, > I have some basic questions about this method. > > Q1, What I learn from textbook, viterbi can handle bit sequence with some > mistakes, and output correct bit sequence. How can it handle complex data > inputs? Because the received signal are complex. > > Q2, Can you kindly introduce some papers with simple math derivations to > me or any key I need to focus on?I would like to chew them first, thanks a > lot! > > Thanks in advance! > > FrankieAll you need for a Viterbi algorithm are: 1. Some notion of distance or cost 2. A description of the state-space So it is not that mysterious. The first one you get from computing Eucliean distance in the complex plane, and the second you get from your channel estimate. Equalization using Viterbi (or more precisely, maximum-likelihood sequence estimation) is standard treatment in most intermediate communication textbooks. I don't know what level of math you find simple or not. Julius

Posted by ●April 24, 2009

On Apr 23, 10:02�pm, "Fan.Zhang" <zf...@sina.com> wrote:> Dear All, > > I am learning how to use viterbi in GSM Channel Equalization. As a newer, > I have some basic questions about this method. > > Q1, What I learn from textbook, viterbi can handle bit sequence with some > mistakes, and output correct bit sequence. How can it handle complex data > inputs? Because the received signal are complex. > > Q2, Can you kindly introduce some papers with simple math derivations to > me or any key I need to focus on?I would like to chew them first, thanks a > lot! > > Thanks in advance! > > FrankieThere was a paper some years back in one of the IEEE magazines called "How I Learned to Love the Trellis" by Bernard Sklar. I recommend it. John

Posted by ●April 26, 2009

>On Apr 23, 10:02=A0pm, "Fan.Zhang" <zf...@sina.com> wrote: >> Dear All, >> >> I am learning how to use viterbi in GSM Channel Equalization. As anewer,>> I have some basic questions about this method. >> >> Q1, What I learn from textbook, viterbi can handle bit sequence withsome>> mistakes, and output correct bit sequence. How can it handle complexdata>> inputs? Because the received signal are complex. >> >> Q2, Can you kindly introduce some papers with simple math derivationsto>> me or any key I need to focus on?I would like to chew them first,thanks =>a >> lot! >> >> Thanks in advance! >> >> Frankie > >There was a paper some years back in one of the IEEE magazines called >"How I Learned to Love the Trellis" by Bernard Sklar. I recommend it. > >John >Thanks all your kindly help! I am on the road. Frankie

Posted by ●April 27, 2009

On Apr 24, 8:27�am, John <sampson...@gmail.com> wrote:> On Apr 23, 10:02�pm, "Fan.Zhang" <zf...@sina.com> wrote: > > > > > > > Dear All, > > > I am learning how to use viterbi in GSM Channel Equalization. As a newer, > > I have some basic questions about this method. > > > Q1, What I learn from textbook, viterbi can handle bit sequence with some > > mistakes, and output correct bit sequence. How can it handle complex data > > inputs? Because the received signal are complex. > > > Q2, Can you kindly introduce some papers with simple math derivations to > > me or any key I need to focus on?I would like to chew them first, thanks a > > lot! > > > Thanks in advance! > > > Frankie > > There was a paper some years back in one of the IEEE magazines called > "How I Learned to Love the Trellis" by Bernard Sklar. I recommend it. > > John- Hide quoted text - > > - Show quoted text -That was a good article! Clay