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Soft Decision Viterbi Decoding?

Hi, I have done convolutional codeing (length =3, rate=1/2) and viterbi hard decoding. The steps I have followed are: Data --> Convolutional Encoder --> QPSK Modulation --> Channel --> Demodulation --> Viterbi Hard Decoding The above steps give me good result for AWGN channel. Can any...

Viterbi Equilizer?

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, ...

GMSK Demodulation

Hi All: while looking at GSM literature, i found it quite interesting in how GMSK is demodulated. In simulink library, the baseband GMSK demodulator included a hard decision viterbi decoder. In my mind viterbi decoder is used for error correction of convolutional encoded channel data. In o...

forward error correction capabilities?

Hello I wanted to know the difference that can exist between(among) a flow of bits that goes out of a decodificador viterbi + Reed solomon and the flow of bits originally in a transmission of tdt cofdm That is to say: do I obtain the same result to the exit of the corrector Reed Solomon with ...

qpsk viterbi decoding

hello everybody what the customer have specified us for making viterbi decoding includes some units that i want to know about "SOFT SLICER" what it is doing is converting 10 bits I and Q inputs to two 3-bits output pair....any idea what it is.... and can someone provide some i...

viterbi

Dear all Any one have a resource explain in detail the Viterbi algorithm for linear block codes ...

Channel order and matrix state of viterbi equalization

Hi All, I am learning viterbi equalization to deal with ISI caused by multichannel effect. Let us denote L as the channel memory, that means we have L+1 channel taps. like this figure below. i.g. L=4 In --D--D--D--D-- | | | | | | | | | | h0 h1 h2 h3 h4 | |...

viterbi metric

How do you compute a soft Viterbi metric? I have gone through this excellent tutorial on the Viterbi decoder: http://home.netcom.com/~chip.f/viterbi/tutorial.html It is for a hard decision decoder, which makes it easy to compute the metrics. In the hard decsion case, if I receive [1,1] say,...

Viterbi decoding of Repetition codes. Is it possible?

Hello, now my question is that can we do viterbi decoding of a repetition code; for eg, I have an input '1' so I repeat it 20 times (I know this not good as an error correction code and also as far as efficient use of channel capacity is concerned, but I want to know this for knowledge) and vice...

viterbi decoder

hello, i'm doing my project in FPGA IMPLEMENTATION OF VITERBI DECODER .is there any groups to clarify my doubts and if there any links to get the ideas ...

Interleaver for Viterbi

I want to insert a interleaver-deinterlaver in my software for Viterbi. If i have select r=1/2 and k=7, How many bits of interleaving is a good option? ...

ask help on viterbi equalization

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...

Cycle Slip in Viterbi and Viterbi Non-linear Phase Estimator

Hi all, I am using Viterbi and Viterbi algorithm for estimating phase of the carrier in a 8psk demodulator. I am facing problem relating to cycle slips and observing that half of my burst is demodulated correctly and the rest of the burst has a constant phase offset. My training symbol is able ...

The C source of Viterbi decoder for DVB-T

Hi everyone, I am working on a project of DVB-T now. I try to use the C6416 to implement the Viterbi decoder. As my known, the co-processor, VCP, includes in the C6416. Does anyone can give me the C source of Viterbi decoder using VCP or compatible in C6416? Thanks in advanced. yoyo ...

Power consumption models for Viterbi decoder

Hi Group, Is there a power dissipation model for the Viterbi decoder as a function of the constraint length, the code rate and the operating data rate?? I know that the answer depends on many other factors such as the fabrication process, implemention of the Viterbi algo etc. But, I am loo...

Re: problem with matlab function "vitdec"

If you are doing a lot of Viterbi decoding and would like a faster decoder, check out my library of Viterbi decoders that use the vector instructions on both x86 and PPC CPUs. It's all LGPLed. http://www.ka9q.net/code/fec --Phil ...

Zero flushing in viterbi decoder

Hi all, In zero termination method of convolution encoder, we pad zeros in the end of each packet. Should we remove the padded zeros in the viterbi decoder. ...

viterbi on ADSP-blackfin

hi, i have implemnet soft decision viterbi decoder of constraintlength 7 on adsp black fin processor. can anybody sugegst some document regarding implementation on ADSP. i know the theory of viterbi decoder. I already implemenetd hard decision decoder on FPGA. Whether r...

Viterbi soft-decoding

how does Viterbi soft-decoding work? Also suppose rate R=1/2, constraint length is 3, convolutional code(2,1,3). Thank you very much. ...

Viterbi Input, Branch Metrics, and the TI VCU

Viterbi Input, Branch Metrics, and the TI VCU What is the input to the (hard-output) Viterbi decoder, and how is a branch metric computed? Here are what I think are the correct answers: Inputs: The inputs are either hard bits (i.e., x_n \in {-1, +1}) or soft bits (i.e., x_n \in [-1, +1...

Complexity of Viterbi decoding algorithm?

Hi I was wondering how to express the complexity of the Viterbi algorithm... Is it O(N2) or O(Nlog N) or is it exponential ? Thanks. Pratap ...

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 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-...

Viterbi decoding

Hi all I want to implement viterbi decoding for frequency selective fading channel in matlab could u tell me how i should start writing program ? thanks Mohd Israil Saifi Researcher AMU Aligarh (india) _____________________________________ Do you know a company who employs DSP enginee...

Soft-decision viterbi implementation

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 d...

Re: MAP Vs Viterbi decoding

Viterbi decoding is Maximum-Likelihood, so it gets lower W( word )ER. But in very low SNR, MAP gets lower BER, because it is optimal for each bit. ...

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 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 d...

Block Viterbi decoding

Hi all, I need to use block viterbi decoder in my project. What should be the minimum delay required between two blocks of data. Can I input next few blocks of data while the present block is being decoded. I tend to use xilinx/lattice IP core. ...

Viterbi Decoder

I want to know that for a particular viterbi decoder e.g for 1/2,7 type ,with traceback depth of 48, if input data frame contains 2000 bits ,IS it possible to correct only upto 4 errors in this data stream and is there any relation between error correcting capability and location of these erro...

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 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 sig...

Re: Viterbi Decoder: Bit Rate > Clock Rate

What I am trying to do is increase the throughput of a viterbi decoder that is currently contrained by the FPGA clock rate. What you say is right. The decoder would have to operate on symbols rathter than on bits. I may have been incorrect to assume that this was tied to the use of radix 2 b...

Viterbi Decoder Codes

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 ...

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" 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 ...

cdma2000 viterbi decoder using TMSC67 DSP (fixed point)

Hi Does anyone know where I can find the code for implementing the subject decoder? Ideally, I am looking for a TI application note or some similar document. I searched the TI website but couldn't find a lot there. Note that my DSP would not have a viterbi coprocessor(VCP) so the implementations ...

hardware Viterbi

Hi all, I implemented an OFDM receiver in C++ and it turs out that some parts are bottle necks for the speed, like e.g. Viterbi decoding and RS decoding. Does anyone know if there is a hardware based decoding solution on the market? Ideally it would be a PCI card for PC and configurable for dif...

speaker verification with HMM

Hi. I am trying to write a program to verify the speaker. I'm confusing with the viterbi algorithm in Hidden Markov Model(HMM). As I know, the viterbi algorithm is used to find the best path of the sequence. I would like to know how this algorithm can help when I want to verify whether t...

Viterbi Soft Decision

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 t...

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

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

Trace-back clock in viterbi

Hi all, I have this doubt in implementation of viterbi decoder in FPGA While the trace-back unit decodes the single bit after tracing back the path of length 5*L, next input to the viterbi decoder should not be given. But if the input data is continuous, trace-back operation should be comp...

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 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 co...

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 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 co...