## Forums Search for: Viterbi

## Soft-decision viterbi implementation

inHi all, I want to implement soft decision viterbi decoder in FPGA. I have already implemented hard-decision decoding and the design works fine...

Hi all, I want to implement soft decision viterbi decoder in FPGA. I have already implemented hard-decision decoding and the design works fine in xilinx FPGA. We have implemented "high bit clear circuit" for path metrics normalization to reduce the area. Now, i want to implement soft-decision decoding an I need to change the BMU and ACS modules in my code. One thing that worries me is the ...

## ACS block in soft decision viterbi

Hi all, I want to implement soft decision viterbi decoder in FPGA. I have already implemented hard-decision decoding and the design works fine...

Hi all, I want to implement soft decision viterbi decoder in FPGA. I have already implemented hard-decision decoding and the design works fine in xilinx FPGA. We have implemented "high bit clear circuit" for path metrics normalization to reduce the area. Now, i want to implement soft-decision decoding an I need to change the BMU and ACS modules in my code. One thing that worries me is the ...

## data aided phase estimation

ini m currently on a project that requires me to do symbol to symbol phase estimation. was using the non data aided viterbi&viterbi...

i m currently on a project that requires me to do symbol to symbol phase estimation. was using the non data aided viterbi&viterbi algorithm unfortunately i wasnt able to meet the specs of the project. was wondering if there is any data aided algorithm via pilots that is able to achieve enhanced performance? cheers This message was sent using the Comp.DSP web interface on www.DSPRelated.co...

## soft output viterbi

inHi, I very well understand the advantages of soft input being used for viterbi decoding but, i fail to understand what is the use of soft...

Hi, I very well understand the advantages of soft input being used for viterbi decoding but, i fail to understand what is the use of soft output? How is this soft output generated and how is it useful.If its iterative decoding then we can use this output softbits for further decoding. please let me know how to generate the soft-output and the use of it. Rgds, S.Diwakar. _____...

## Decode QPSK convolutional encoded symbols using viterbi soft decoding

Hi, Can anyone plz tell me how to decode QPSK convolutional encoded symbols using viterbi soft decoding? I know we have to find the Eucledian...

Hi, Can anyone plz tell me how to decode QPSK convolutional encoded symbols using viterbi soft decoding? I know we have to find the Eucledian distance but plz tell me all the steps i should follow to decode it. Regards, Sarmad

## Regarding Viterbi decoder of continuous transmission?

inI am reading Viterbi decoding technique, and confused with the trace back. Assume rate 1/2 K=3 convolutional encoding. When the trace back...

I am reading Viterbi decoding technique, and confused with the trace back. Assume rate 1/2 K=3 convolutional encoding. When the trace back depth is 5K. Is the trace back operation performed in blocks of 5K bits and decode 5K bits at a time, or trace back operation is performed on a 5K FIFO which stores the state history, and decode the single bit in the beginning of the state history FIF...

## Convolutional coding - block lenght

inHi, Does anyone knows does block length of info data, which then goes through convolutional encoder(convolutional encoding), has impact of...

Hi, Does anyone knows does block length of info data, which then goes through convolutional encoder(convolutional encoding), has impact of performance on convolutional coding and Viterbi decoding(FEC system). For example if info message length is 256 bits, or 1024 bits, or 8912 bits does performance of FEC system(convolutional encoding and Viterbi decoding) changes with different input block l...

## Re:Block viterbi decoding

Hi, I referred xilinx application note. But there is no such information given

Hi, I referred xilinx application note. But there is no such information given

## New algorithms in MLSE?

inHi, Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? Thanks

Hi, Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? Thanks

## When does ML (Viterbi) gives MAP performance?

inGreetings, I always assumed that MAP and ML performances differ, with former being superior. However, under certain conditions ML approaches...

Greetings, I always assumed that MAP and ML performances differ, with former being superior. However, under certain conditions ML approaches MAP performance. I know of trivial case when the variables to be decoded are uncorrelated, ML is MAP. I am interested in knowing about other cases when this is true. Could anyone throw some light on this issue? Regards, KK

## OFDM BER Measure

inHello, Does anyone know how to estimate the BER of a Viterbi decoder when p = |H|^2 * |r-x|^2 is used as the decision metric ? Thanks...

Hello, Does anyone know how to estimate the BER of a Viterbi decoder when p = |H|^2 * |r-x|^2 is used as the decision metric ? Thanks for your cooperation. Engin |H|^2 = Channel's kth coefficient in frequency domain r = received symbol x = transmitted symbol This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## Theoretical BER

inHi guys, I need to fing plots (or equations) for the theoretical BER for some error correction codes: Reed-Solomon, Turbo Codes, Viterbi,...

Hi guys, I need to fing plots (or equations) for the theoretical BER for some error correction codes: Reed-Solomon, Turbo Codes, Viterbi, CRC-8. Could someone please point me out where can I find this. Michael B.

## Serial List Viterbi Algorithm

Hello, I was wondering if anyone knows a link to an article and/or paper which graphically describes the SLVA, preferably through an example. I...

Hello, I was wondering if anyone knows a link to an article and/or paper which graphically describes the SLVA, preferably through an example. I have read through the IEEE papers on it, but wanted to see step by step diagrams of how the N-best paths are selected (not just the analytical analysis). _____________________________ Posted through www.DSPRelated.com

## CPFSK receiver architecture

inI'm evaluating receiver structures for the ETSI DMR spec, but not having much luck finding any work in this area. They use continuous...

I'm evaluating receiver structures for the ETSI DMR spec, but not having much luck finding any work in this area. They use continuous phase modulation, so I anticipate I'll have to use a viterbi demodulator to get it done. Unfortunately they choose h=.27, so I have at least 200 states, times whatever number of symbol cycles their pulse shape is over (not clear on this, three maybe?). So I'm loo...

## non - binary sova

Hi, I have this kind of a problem. I don't know how to implement soft output viterbi algorithm for non-binary (over ring) codes. What should...

Hi, I have this kind of a problem. I don't know how to implement soft output viterbi algorithm for non-binary (over ring) codes. What should the the extrinsic information contain and how to compute and process it??. I went through many papers relating sova and non binary case, but still I?m stuck. Thank You Filip

## Viterbi distance measure

inHi, Can someone help in proving/disproving the following? if (a^2 > b^2) then |a| > |b|. can it be extended to say that if (a^2 +...

Hi, Can someone help in proving/disproving the following? if (a^2 > b^2) then |a| > |b|. can it be extended to say that if (a^2 + b^2) > (c^2 + d^2) then ( |a| + |b| ) > ( |c| + |d| ) This is to check if an euclidean distance measure can be replaced by an absolute distance measure? Thanks, Raju

## ML equalizer

Hi, I am working on equalization schemes without using Viterbi type of algorithms. Assume that complexity is not an issue. I am trying...

Hi, I am working on equalization schemes without using Viterbi type of algorithms. Assume that complexity is not an issue. I am trying to detect the received samples using ML equation. Mathematically , if a1, a2, a3 .. aN are the input symbols, say h1, h2, h3 are the channel tap gains. Then the received signal is represented in vector fom as R= A*h+n, where R is the received vector...

## BER estimation for a modem

inHi everybody, Someone explains to me that to estimate the SNR of the channel (and then the BER of a modem), i have to use the output bits of...

Hi everybody, Someone explains to me that to estimate the SNR of the channel (and then the BER of a modem), i have to use the output bits of the viterbi decoder. These bits are convolutionnally encoded and the output is compared with the signal received. Someone can tell me about the precision of this method ? I've tried to search informations with google but i didn't find anything. ...

## Viterbi decoding

inI am using "vitdec" in Matlab with 'trunc' and 'unquant' propoerties for decoding real-valued data in between almost -2.5 and 2.5 (i.e. binary...

I am using "vitdec" in Matlab with 'trunc' and 'unquant' propoerties for decoding real-valued data in between almost -2.5 and 2.5 (i.e. binary values with interference and noise). The interesting problem is that I'm having intervals of %100 correct detections and %100 wrong decisions (bits are flipped) in my decoded stream. It's like the detector changes sign and switches between two interval...

## CPFSK synchronization.

inHello, I am trying to demodulate a binary CPFSK with modulation index of 0.6 With correlation receiver & viterbi decoder I am able to...

Hello, I am trying to demodulate a binary CPFSK with modulation index of 0.6 With correlation receiver & viterbi decoder I am able to demodulate a synchronized signal, but i am stuck with synchronization techniques. Can anyone please let me know any ideas for synchronization. Thanks & Regards, Ajith