Soft Decision Viterbi Decoding?

Started by ssohaib in comp.dsp10 years ago 14 replies

Hi, I have done convolutional codeing (length =3, rate=1/2) and viterbi hard decoding. The steps I have followed are: Data --> Convolutional...

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 anyone plz tell me how is the Soft Viterbi Decoding differ from the above mentioned hard viterbi decoding? w


Viterbi Equilizer?

Started by ssohaib in comp.dsp10 years ago 2 replies

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...

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,


Overflow problem in Viterbi algorithm implementation in DSP

Started by fl in comp.dsp4 years ago 6 replies

Hi, I once simulated Viterbi decoder (I programmed the code, not Matlab function or block) with Matlab without any problem. Now I implement...

Hi, I once simulated Viterbi decoder (I programmed the code, not Matlab function or block) with Matlab without any problem. Now I implement Viterbi decoder in TI DSP with fixed point short date type. I have puzzled with the integer wrapped problem. I think I have some incorrect understanding on the implementation. TI has a DSP pdf application note talking about Viterbi decoder (


Cycle Slip in Viterbi and Viterbi Non-linear Phase Estimator

Started by Aitezaz in comp.dsp8 years ago 3 replies

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...

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 to correct the phase offset in the section before cycle slip. I have tried to find out the cycle sl...


qpsk viterbi decoding

Started by khurram712 in comp.dsp11 years ago 1 reply

hello everybody what the customer have specified us for making viterbi decoding includes some units that i want to know about "SOFT...

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 insight on "Node Synchronizer" used for viterbi decoder...please provide some web links(one that dont...


Viterbi's contribution

Started by kbc in comp.dsp13 years ago 49 replies

What is Viterbi's claim to fame - only the Viterbi algorithm ? Has he invented any other theorem or circuit or algorithm ? He is a life...

What is Viterbi's claim to fame - only the Viterbi algorithm ? Has he invented any other theorem or circuit or algorithm ? He is a life fellow of ieee, right ? What criteria is there to promote from fellow to life fellow ? shankar


viterbi metric

Started by Anonymous in comp.dsp12 years ago 7 replies

How do you compute a soft Viterbi metric? I have gone through this excellent tutorial on the Viterbi...

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, then the metric compared to [0,0] is 2. Suppose I received [0.9,1.1] in the soft decsion case. Is...


viterbi

Started by shereen.ahmed in comp.dsp11 years ago 5 replies

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

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


MAP Vs Viterbi decoding

Started by Anonymous in comp.dsp12 years ago 9 replies

Hello, Can any one point me to paper/book which tabulates the performance of MAP decoder when compared to Viterbi. I see most sites only...

Hello, Can any one point me to paper/book which tabulates the performance of MAP decoder when compared to Viterbi. I see most sites only mentioning that the MAP algorithm outperforms Viterbi at low SNR and high BER condition. Can any one tell me how much is the performance gain by using MAP at low SNR conditions. Thanks Sudhi


ask help on viterbi equalization

Started by Fan.Zhang in comp.dsp8 years ago 6 replies

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...

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 deriv...


forward error correction capabilities?

Started by owpex in comp.dsp7 years ago 12 replies

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...

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 a BER before Viterbi of 9-6 that with a BER before Viterbi of 2-2? Said otherwise: Do I obtain...


viterbi on ADSP-blackfin

Started by inag...@gmail.com in comp.dsp11 years ago 2 replies

hi, i have implemnet soft decision viterbi decoder of constraintlength 7 on adsp black fin processor. can anybody...

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 register excahneg algorithm is good or trace-back is good for DSP implementation. I wnat to know so...


viterbi decoder

Started by bharathi in comp.dsp14 years ago 1 reply

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...

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

Started by JAlbertoDJ in comp.dsp10 years ago 9 replies

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...

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?


Power consumption models for Viterbi decoder

Started by Ramesh in comp.dsp14 years ago 1 reply

Hi Group, Is there a power dissipation model for the Viterbi decoder as a function of the constraint length, the code rate and the...

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 looking out for an emperical equation which relates the power consumption as a function of the code pa...


viterbi decoding

Started by sameer2009 in comp.dsp4 years ago 1 reply

I want to implement viterbi decoding for frequency selective fading channel in matlab, could any one help me please.

I want to implement viterbi decoding for frequency selective fading channel in matlab, could any one help me please.


The C source of Viterbi decoder for DVB-T

Started by simonyoyo in comp.dsp12 years ago

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,...

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


Viterbi Input, Branch Metrics, and the TI VCU

Started by Randy Yates in comp.dsp6 years ago 5 replies

Viterbi Input, Branch Metrics, and the TI VCU What is the input to the (hard-output) Viterbi decoder, and how is a branch metric...

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]), depending on the Viterbi implementation. Branch Metrics: If the inputs are hard bits, then...


GMSK Demodulation

Started by ls00722 in comp.dsp9 years ago

Hi All: while looking at GSM literature, i found it quite interesting in how GMSK is demodulated. In simulink library, the baseband GMSK...

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 one GSM simulink model i was looking at, after demodulator(which included viterbi decoder), the data ...


BER performance of Viterbi decoder

Started by lanbaba in comp.dsp12 years ago 10 replies

Hi all, does anyone know what BER should I expect after the Viterbi decoding if the channel BER is 7.0e-3? Constraint length 7, Generator (177,...

Hi all, does anyone know what BER should I expect after the Viterbi decoding if the channel BER is 7.0e-3? Constraint length 7, Generator (177, 133), punturing to code rate 5/6. Thanks! Cheers, Lanbaba