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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, ...

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 ...

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 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? ...

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 ...

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. ...

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...

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. ...

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 ...

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...

soft output viterbi

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 le...

4D - 8PSK Trellis modulation

Hi, I'm trying to simulate on Simulink a multidimensional TCM system, but I have some problems with RX subsystem. In the TX subsystem there are 8 input bits, of which only 3 come into the convolutional encoder (rate 3/4). The other 5 bits, together with the 4 encoder's output bits, come into a ...

Re: Soft Decision Viterbi Decoding?

On Mon, 24 Dec 2007 07:07:18 -0800 (PST), John wrote: > On Dec 24, 8:32 am, "ssohaib" wrote: > > Hi, > > Thanks for your kind reply. Could you please explain me if I quantize real > > and imaginary part of my received coded QPSK separately how can I use these > > 3 bits from real a...

data aided phase estimation

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 p...

Soft demapping for QPSK symbols for 1/3 convolutional code

Can someone help me how can I do the algorithm for softbits or soft demapping for QPSK symbols that will be used for rate 1/3 convolutional decoder? > Lakie, > > I think that a more clear way of representing it is as follows > > Encoding: > N-data bits, where N is an integer multiple of 2 ...

Re: inmarsat

Crusader Wrote via direct email > > Hello. Thank you very much for You answer, but I have got some > > questions. Sometimes I use a software of company WaveCOM and Hoka(Code > > 32). In the software of Hoka(Code 32, last version) I can use two > > universal demodulator: BPSK and 2DPSK. But f...

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 distance but plz tell me all the steps i should follow to decode it. Regards, Sarmad ...

BFSK with Viterbi vs 16FSK with Viterbi

** BER for a FSK noncoherent is PE=(M-1)/2 * exp(-Es/2No) => PE= (16-1)/2 * exp(-Es/2No) BER= PE*(M/2)/(M-1)=> BER= PE*8/15 BER= 4 * exp(-Es/2No) ** BER for a BFSK noncoherent is BER= 1/2 * exp(-Es/2No) So, BER for 16FSK is 8 times BER for BFSK. But, after Viterbi ...

best state traceback in Viterbi

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 a...

Re: 16-PAM Demodulation and Viterbi

> Hi, > If I have a 16-QAM demodulator I know I can use the I and Q values to > access a lookup table and output soft codes for a Viterbi uisng LLR > > What do I do if I'm using 16-PAM? If my information is right its just > amplitude modulation. So out of the demodulator I will get 1 of 16 val...

qpsk and viterbi decoding

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...

Regarding Viterbi decoder of continuous transmission?

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 w...

Re: BER after Viterbi or RS decoding

On Thu, 08 Dec 2005 20:04:20 GMT, Vladimir Vassilevsky wrote: > Eric Jacobsen wrote: > > > > > Does any one know a way to measure the BER after Viterbi or RS decoding at > > > the Rx side if the uncoded data at the Tx side is unknown? > > > > As mentioned already, re-encode and com...

OFDM + Convolutional code

I have finished a basic OFDM simulation with BPSK modulation on it. Now I want to use the convolutional code in transmitter and a multipath channel with AWGN. At receiver , a viterbi decoder would be used. But I have some question in it.First,when the data have done FFT at the receiver.There...

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, 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 19...

Viterbi Soft Decision for 16FSK

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 ...

Re: Viterbi 'synchronization'?

> You take the Viterbi decoded output and you re-encode it with R=1/2 K=7 > (identical to the source encoder). In parallel, you take the input stream of > the encoder and delay it by the transport delay of the decoder/encoder > cascade. Then you compare both streams (input stream and decoded/r...