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Soft-decision Viterbi decoder branch metrics

I understand how the hard-decision Viterbi algorithm works, it uses the Hamming distance to calculate branch metrics. But what about soft-decision? Assuming an AWGN channel, QPSK modulation and 8-bit ...
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Decoding for punctured convolutional encoder

I have 1/2 rate convolutional encoder which punctured to rate 3/4. The puncture pattern used is [1; 1 ;1 ;0 ;0; 1] . How to decode these punctured sequence using hard decision viterbi decoding? Can ...
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How to decode the received sequence by using convolutional code with generator matrix and Viterbi algorithm?

Consider the discrete memoryless channel with input alphabet $𝐴_𝑋 = ${$0,1$}, output alphabet $𝐴_Y=${$0,𝛼,𝛽,1$}, and transition probabilities: \begin{array}{} & 0 & \...
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1answer
45 views

Viterbi Algorithm - Selecting survivor paths which both contain the same Hamming distance

To my (limited) knowledge, when determining which survivor path to choose to produce an error-corrected output of a binary Viterbi decoder, the path with the smallest Hamming distance is the most ...
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Convolutional FEC decoding - is it necessary to know where a decoding block begins and ends with convolutional codes?

I understand that the difference between convolutional and block-based FEC is that convolutional codes can be used in a continuous stream – however every implementation I saw still uses blocks. So I ...
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Wrap Around Viterbi Algorithm for tail biting decoding “WAVA”

Tail-biting where the initial and final states of the encoder are identical. Tail biting is done by initializing the shift register contents with the last m information bits in the input block to ...
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Viterbi equalization of Fibonacci coding

I'm working a Viterbi equalizer for a BPSK signal which uses Fibonacci coding. In the more theoretical descriptions of the Viterbi algorithm I've read, there's a term for the probability of a ...
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1answer
78 views

Determining pulse shape for Viterbi Equalization

I believe I understand well enough how the Viterbi algorithm can reverse the effects of ISI when the combined impulse response (transmit filter, multipath, receive filter) is known. I've read How I ...
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170 views

Applying Viterbi algorithm to compensate for ISI in PSK31

I am implementing a receiver for the amateur radio mode PSK31. It is effectively a BPSK modulation with a pulse shape of a raised cosine twice the width of one symbol. Here are four consecutive pulses,...
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1answer
93 views

Viterbi Decoder without traceback

How can I use Viterbi algorithm for a real time scenario where I cannot afford to have delay in the tracing back the best path to the initial state?
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1answer
172 views

Decoding final bits with viterbi

I'm writing a viterbi decoder and I'm rather confused about the correct process of decoding the final k bits for a kth order ...
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169 views

Checking a convolutional enocder/decoder implementation

I've created a convolutional encoder and Viterbi decoder implementation in Python, and I'm trying to confirm that everything works properly. I'm finding a discrepancy in my testing, and I'm not sure ...
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75 views

State definition in Viterbi Algorithm?

An ISI channel of length 'L+1' $\mathbf{h}=[h_0 \space h_1 \space … \space h_L]$can always be modeled as a finite state machine(FSM) of memory 'L'. For a binary input $x\in\{+1,-1\}$,a state can be ...
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1answer
87 views

Performance of Viterbi detector over non-minimum phase channels

For sequences that are transmitted over channels with memory $\mu=n$ and response H=$[h_0 h_1 \ldots h_n]$,Viterbi algorithm implements Maximum Likelihood (ML) detection and BCJR implements Maximum A-...
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297 views

Viterbi Decoder=1/2 k=4 [closed]

Woud anyone have a viterbi decoding tool or c-code or .m file for (R=1/2, K=4)? I am trying to decode a bitstream received in RFSTUDIO from a non-TI transceiver and it says that it uses this kind of ...
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2answers
958 views

Viterbi equalizer in a GSM system

I'm about to tackle implementing a Viterbi equalizer fo a GSM system in gnuradio. I went through the internet and ieeexplore and I think that this document explains it best: Application of Viterbi ...
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78 views

Does the input data have to be passed through the Baum-Welsh function to compute the Viterbi decoder?

I'm using a Hidden Markov Model in order to train an application for gesture recognition. Currently, I have gathered samples, and, using a library have trained these values (They have been passed ...
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1answer
2k views

QPSK soft decoding

I'm trying to decode a Hamming Block Code transmitted using a QPSK modulation. For the moment I can sucessfully decode it using hard decision but in order to improve performance I'd like to use soft ...
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233 views

Most efficient algorithm for comparing two paths

I'm working with a Continuous Hidden Markov Model, and using the Viterbi Decoder which finds the best possible path for a given sequence. Here is how my algorithm works: ...
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1answer
334 views

Viterbi Decoder - How does inverting the input bits affect the result?

Does converting zeros into ones and ones into zeros in the input stream affect the decoding result? Empirically I have seen that it does not affect, decoding $[0 1 0 1 \ldots]$ and $[1 0 1 0 \ldots]$ ...