Questions tagged [channel-coding]
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14 questions
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Number of inputs of states in Viterbi Algorithm
In the Viterbi algorithm (trellis state diagram,) I wonder why the number of inputs to each state is the same and equals the input alphabet size.
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Why standard LDPC codes, such 5G NR, have 4 cycles in its parity check matrix? Isn't short cycles detrimental in error performance?
We know that short cycles in Tanner Graph are detrimental in error performance. So, Why standardized 5G NR LDPC codes have 4-cycles? 3rd generation Partnership Project (3GPP) had announced Base Matrix ...
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Is BPSK better than QPSK in any way?
I wonder why there are still some modems using BPSK as their modulation.
Is there any benefit over QPSK (power, bandwidth, synchronization techniques, etc.)?
I have been searching and found these:
...
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Unable to get ADC voltage reading from Infineon MCU
Processor is an Infineon CY8C6245LQI-S3D42. We're basing our code on the examples in the documentation but seem to be unable to get an actual reading off the ADC. Debugging has traced the problem to ...
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How to measure channel capacity performance for enhanced speech samples in GSM speech coders?
I've been conducting some research lately on Speech Enhancement of the ITU-T Recommended G.729 Voice Activity Detection (VAD) algorithm for GSM Speech coders.
It has been suggested in the literature ...
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Real-world CQI-to-MCS and SNR-to-CQI tables?
How can I get real-world CQI-to-MCS and SNR-to-CQI tables? I am particularly looking for 5G-NR or LTE-A related tables.
Can someone share any references?
Edit: I had found one table for CQI-MCS ...
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Difference between 2b1q and 2b1q with paired disparity
I have a question about 2b1q line code. Is there a modified 2b1q code with paired disparity option available? And if yes, which is the coding rule for a simple 2b1q and modified 2b1q code, plus the ...
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In discrete memoryless channels what is meant by output probabilities?
In my book it is mentioned that P[Y]= P(X)* P(Y/X) Where P[Y] is the output probability matrix, P(X)=input probability matrix, P(Y/X)= channel matrix. I understand the physical significance of input ...
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How does bipolar line coding such as AMI work with medium like fiber optics
We know that in bipolar encoding (sometimes called multilevel binary), there are three voltage levels: positive, negative, and zero. The voltage level for one data element is at zero, while the ...
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Shift Registers for generating codes
can you explain me in simple words how does a linear feedback shift register work for generating a code?
Consider for instance this scheme:
If I have understood it correctly, each block is a D Flip ...
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difference between error control coding and channel coding
Is there a difference between error control coding (like forward error correction) and channel coding(like convolution coding)? Both of them help in correcting the errors because of the channel.Why is ...
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Calculating number of errors that is undetected by a CRC using a particular polynomial
My goal is to determine optimal generator polynomial and size of the Frame Check Sequence (CRC field) for protocol that I am developing. Reading the paper, "Cyclic Redundacy Code (CRC) Polynomial ...
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A query on (7,4) Hamming Code
I have a query on (7,4) Hamming code.
The generator polynomial for this is \$g(x) = x^3 + x + 1\$. The non-systematic code for the message signal \$m(x)\$ is \$c(x) = m(x)g(x)\$
The above procedure ...
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Genie-aided decoder
I am reading about different type of decoders and I am often coming across the term "genie-aided." However, I am having trouble understanding what this is. Can someone clarify? Genie-aided decoders ...
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