## Forums Search for: Viterbi

## Systolic Viterbi Decoder ?

Hi, Sorry for the cross-post, but I think this is a relevant topic in both newsgroups. Has anyone come across this paper ? T.K. Troung,...

Hi, Sorry for the cross-post, but I think this is a relevant topic in both newsgroups. Has anyone come across this paper ? T.K. Troung, Ming-Tang Shih, I.S. Reed, E.H. Satorius, "A VLSI design for a trace-back viterbi decoder", IEEE Tranactions on Communications, Vol. 40, No. 3, March 1992. They describe a register-based systolic approach to implement the traceback that they claim ...

## TCM metric computation

inHi, I am writing a Matlab simulation of "Pragmatic-TCM" (see "A pragmatic approach to trellis coded modulation", Viterbi et al, IEEE...

Hi, I am writing a Matlab simulation of "Pragmatic-TCM" (see "A pragmatic approach to trellis coded modulation", Viterbi et al, IEEE Comms magazine, July, 1989, p.11). One point I am unsure of is how to compute the metrics for the Viterbi algorithm which decodes the least-significant bits of the received signal point. I understand that when you receive a point for decoding, you first ...

## Locating Frame Boundaries when De - Puncturing (Viterbi Decoder)

Hello, I am trying to add the ability to de-puncture to my viterbi decoder, but I am unsure of how to determine where to insert my "don't care"...

Hello, I am trying to add the ability to de-puncture to my viterbi decoder, but I am unsure of how to determine where to insert my "don't care" bits. If I have received a stream of bits that are encoded, how is it possible to find the proper location to place the bits that were punctured out at the encoder? I have thought of using an initial block of data and testing different offsets, usin...

## Viterbi Soft Decision

inI have implemented a Viterbi soft decision (1/2 k=7) for a BFSK modulation. I need to know the minimum level deeper into the trellis to get...

I have implemented a Viterbi soft decision (1/2 k=7) for a BFSK modulation. I need to know the minimum level deeper into the trellis to get symbol. In a book, i read something about a good value is 4 or 5 times the constraint lenght. Now, for example, after 32 levels (or states) i get the first symbol, but then o have a delay of 32 bits. Can i get a good measure of metric after 8 o...

## qpsk and viterbi decoding

inQPSK has four constellation points representing a the following data bits (00, 01, 10 and 11). If this was transmitted using, say 1/3 rate...

QPSK has four constellation points representing a the following data bits (00, 01, 10 and 11). If this was transmitted using, say 1/3 rate convolutional encoder, and soft decision viterbi decoding was applied at the receiver, then of the 3 bits received, 2 of the 3 bits can be used to decode a QPSK symbol. from which the euclidean distance can be calculated. This now leaves one bit remaini...

## One dimensional modulation - advantage!!

inHi All, I have collected few classic papers on channel coding,MLSE and Viterbi Algorithm written by the pioneers during 1966-1972 - Including...

Hi All, I have collected few classic papers on channel coding,MLSE and Viterbi Algorithm written by the pioneers during 1966-1972 - Including works of Hancock,Gallager,Viterbi,G.D.Froney,Omura,Lucky etc. I have found a later paper written by Ungerboeck at IEEE trans on info theory,Jan,1982 where he introduced the idea of set partitioning later popularized by S U H Quereshi et al as RSSE - ...

## puncturing clock in viterbi

inRespected sir, with ur valuable information i have implemented a viterbi decoder with k=7,1/2 decoder with ...

Respected sir, with ur valuable information i have implemented a viterbi decoder with k=7,1/2 decoder with puncturing capability satidfactorily.... . i have also implemented a puncturing unit which punctures the 1/2 code to rate 2/3 and 3/4 rate... using fifo ram and state machine.. and it is working... but i have a problem with the output data r...

## Viterbi Decoder Codes

inHi ! I am looking for Viterbi decoder codes in C and fixed point. Please point me to the source code for the same. Thanks &...

Hi ! I am looking for Viterbi decoder codes in C and fixed point. Please point me to the source code for the same. Thanks & Regards, Poorva

## Soft Decision for Viterbi Decoding..

Hello all, This is my first post here. :) I am currently working on a 802.16d receiver where I have to combine signals from 4 antennas and...

Hello all, This is my first post here. :) I am currently working on a 802.16d receiver where I have to combine signals from 4 antennas and then pass on soft decisions values to the Viterbi decoder for the final output. I have managed to figure out how to combine the 4 signals and figure out which point was transmitted. I used a method described by a user on this very forum named James Sungj...

## Viterbi Decoder (Does the complexity depend on the Code Rate)

inHi, Does the complexity of the viterbi decoder of a 1/N-rate convolutional code increase with N? The constraint length L is kept...

Hi, Does the complexity of the viterbi decoder of a 1/N-rate convolutional code increase with N? The constraint length L is kept constant? My point of view: to decode 1 information bit, one has to process N channel bits. Hence, when N increases, the number of necessary operations increases too. Is that true? Thanks!

## Rate 2/3 convolutional encoder + viterbi decoder

Hi, thanx for answers to previous mails. I did simulation of viterbi (hard decision) of rate 1/2 ..soft decision still stuck on that...

Hi, thanx for answers to previous mails. I did simulation of viterbi (hard decision) of rate 1/2 ..soft decision still stuck on that LLR- Soft decision understanding part :-(. now my current question is, lets say i use 2 rate 1/2 decoders and do puncture pattern as {1,1,0,1} assuming this is the trellis poly2trellis( 4, [17 15]) (matlab notation..its in octal format) in decimal it is ...

## best state traceback in Viterbi

inHi All, I am using traceback approach for viterbi decoding. After acquisition of a block of D data,I choose the minimum state as best...

Hi All, I am using traceback approach for viterbi decoding. After acquisition of a block of D data,I choose the minimum state as best state to start traceback. I am implementing normalisation on path metrics to constrain the bit width. Now my question is while finding the minimum state as best state,is there any chance of occuring more than two or three states having minimum value.If...

## Viterbi algoritms for STTC

Hi all, Can anybody please tell me if there is any different between the viterbi algorithm for Convoluntional code and that for Space time...

Hi all, Can anybody please tell me if there is any different between the viterbi algorithm for Convoluntional code and that for Space time trellis codes. I have tried using the decoding approach for convoluntional and trellis coded modulation (TCM) to decode my 2 states BPSK space time trellis code but the ber that is producing is quite embarasing. Can anybody please help me out. I am writin...

## Viterbi algoritms for STTC

inHi all, Can anybody please tell me if there is any different between the viterbi algorithm for Convoluntional code and that for Space time...

Hi all, Can anybody please tell me if there is any different between the viterbi algorithm for Convoluntional code and that for Space time trellis codes. I have tried using the decoding approach for convoluntional and trellis coded modulation (TCM) to decode my 2 states BPSK space time trellis code but the ber that is producing is quite embarasing. Can anybody please help me out. I am writin...

## the traceback depth of viterbi decoder in simulink

Dear All, Now I face a problem about the traceback depth of viterbi decoder. For an example, the convolutional code with coding...

Dear All, Now I face a problem about the traceback depth of viterbi decoder. For an example, the convolutional code with coding rate 5/8(the mother rate is 1/3, puncture vector is [1 0 1 1 0 0 1 0 1 0 0 1 1 0 1]), constraint length K=7. I use the Bernoulli Binary Generator as the signal source to generate a column vector with the size 125*1(frame_based), after the 5/8 encoder, the ...

## looking for help on sofe demodulate and soft-input Viterbi decode

inis there any article or paper that describe the detail algorithm of soft demodulate and soft-input viterbi decode? Thank you!

is there any article or paper that describe the detail algorithm of soft demodulate and soft-input viterbi decode? Thank you!

## Sliding window Viterbi

inI am using a homemade Viterbi decoder to remove ISI. Originally, my decoder maintained path history (states vs time) for the entire duration of...

I am using a homemade Viterbi decoder to remove ISI. Originally, my decoder maintained path history (states vs time) for the entire duration of the message (1e5 bits) and it traced all the way back from end to finish. Then I modified it to use a sliding window. I created a circular buffer equal to the desired traceback length (about 5 times the ISI duration) and kept the path history in that ...

## Viterbi decoder - full traceback or K x Y?

inHi, Can someone explain fact that for longer messages a traceback depth of K x Y, where K is constraint length of convolutional encoder, and if...

Hi, Can someone explain fact that for longer messages a traceback depth of K x Y, where K is constraint length of convolutional encoder, and if Y increases, then ok we could say that decoding delay and decoder memory requirements increases, while not significantly improving the performance of the decoder. But, if we use full-traceback (i.e. best performance) Viterbi decoder, we need to built la...

## Viterbi decoder's error correction/noise tolerance capability

Hi: Can someone explain to me the meaning of the statement "The noise tolerance of a Viterbi decoder is x dB"? Is noise tolerance the same...

Hi: Can someone explain to me the meaning of the statement "The noise tolerance of a Viterbi decoder is x dB"? Is noise tolerance the same as BER (as measured in the form 10^(-y))? How are these 2 quants related? I am using a soft demapper that takes in 16 bit input to generate 4 single-byte "soft" inputs per iteration, which are then passed pair wise through a soft input/hard output ...

## Viterbi Soft Decision for 16FSK

inHi, I need to build a Viterbi for 16FSK. 1/2 with K=7. In the case of BFSK, Soft Decision is not a problem for me, I compare...

Hi, I need to build a Viterbi for 16FSK. 1/2 with K=7. In the case of BFSK, Soft Decision is not a problem for me, I compare the correlation for a symbol '0' and for a symbol '1' and i know the confidence for '0' o for '1'. In the case of 16FSK, i am lost, because a symbol has 4 bits that belong to a same frecuency. For example: "0000" belong to a tone of 1000 Hz For example: "0001...