10
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Confusion in Channel Encoding and Convolutional Encoding
Like other comments, I don't really understand your question. What I am trying to do is to list basic things so that other ones can suggest edit because I find it is much easier to write in answer ...
- 6,080
8
votes
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Why does FEC seem to make BER worse at low Eb/N0?
This is a behaviour that is commonly outlined in some textbooks and tutorials on FEC, but usually in the form of an observation. For instance, Turbo Codes are sometimes characterised by their ...
- 378
6
votes
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Capacity of cascade binary symmetric channels
A binary symmetric channel (BSC) can be characterized by its complemented probability $p$. Its well-known capacity is
$$C = 1 - H(p) = 1 - (-p\log(p) - (1-p)\log(1-p))$$
where $H(p)$ is binary ...
- 6,080
6
votes
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Interleaving or randomisation?
So, the technical difference between a scrambler and an interleaver:
The interleaver is just a permutation of input symbols; a resorting.
The scrambler is an operation designed to modify the ...
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5
votes
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Relationship between information retrieval and source separation in signal processing
There are, a few discrepancies that might be making a difference here. My suggestion would be to edit the question for clarity. There are quite a few assumptions that lead to non-straightforward ...
- 10.6k
5
votes
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Relationship between $E_b/N_0$ and $\rm SNR$ with channel coding
The relationship between SNR and $E_b/N_0$ is independent of the code rate. Note that $E_b$ is the energy per data bit (not the coded bits), and $R_b$ is the (uncoded) data bit rate. As long as you ...
- 88.9k
5
votes
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Unambiguously detecting (not correcting) between $t+1$ and $2t$ errors in a Reed-Solomon message
The Berlekamp-Massey algorithm and the extended Euclidean algorithm (both further extended with the Chien search and the Forney calculation of error values) for decoding BCH and RS codes (hereinafter ...
- 20.2k
5
votes
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Nyquist noiseless channel capacity; how can bit-rate be two times the bandwidth?
I think you're confusing two different (but related) terms.
Nyquist says that in a channel of bandwidth $B$ you can transmit up to $2B$ orthogonal pulses per second. So, $R_p \leq 2B$, where $R_p$ is ...
- 14.9k
4
votes
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What is the theoretical probability of error for OOK transmission?
It is not clear whether you want a derivation of the formula for the error probability of a wireless OOK system, or ideas about how the formula might apply to an optical communication system.
For a ...
- 20.2k
4
votes
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Finding $E_b/N_0$ when coding rate is $R_c$
The energy per bit, $E_b$, is independent of the coding rate. Note that $E_b$ measures the energy per transmitted information bit, not per transmitted symbol.
Let's say you're willing to spend one ...
- 14.9k
4
votes
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Shannon capacity limit & FEC comparisons
I start with BPSK achieving 1 bits/sec/Hz over passband AWGN. Factoring in 1/3 rate coding this becomes 0.333 bits/sec/Hz.
This is not correct.
The Shannon noisy channel coding theorem states that ...
- 6,080
3
votes
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Does Hamming encoding preserve orthogonality?
I don't think you cannot state generally that $y_1$ and $y_2$ will be orthogonal. I'll try to sketch out my thinking:
Since the Hamming code is a linear code, each parity bit can be represented as a ...
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3
votes
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How does a Huffman encoded message gets unified before channel encoding?
They don't get unified.
Think of the transmitter pipeline (data source, source encoder, channel coder, modulator, etc) as a sequence of independent blocks. Blocks don't assign any particular meaning ...
- 14.9k
3
votes
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Bose Chaudhuri Hocquenghem (BCH) vs Reed Solomon (RS) Error correcting codes and sound transmission channel modeling
What channel model fits data transmission over air best, I guess distortion generated by speakers should also be take under account?
Disclaimer: I'm really not an Audio person. There's a lot of audio ...
- 29.6k
3
votes
Adding AWGN noise with certain power
This is solved slightly differently if you're simulating a continuous-time or discrete-time AWGN channel. I'll assume you're simulating a discrete-time channel; that is, you're simulating the output ...
- 14.9k
3
votes
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Why $H(A)=H(C)$ where $C$ is $A$ with an additional parity bit?
Because the entropy represents information quantity, or if being measured in bit, the smallest number of bits per symbol we need to represent a source.
The source $A$ contains $4$ equiprobable ...
- 6,080
3
votes
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Getting the bitstream of an unknown RF signal
First I found the sine wave extrema (black markers at the bottom) and stretched and superimposed a sine wave graph (red) on top of the signal graph with the extrema in the same locations. The signal ...
- 13.5k
3
votes
Getting the bitstream of an unknown RF signal
The IQ data looks like a sinusoidal modulated pulse train with binary phase shift keying (BPSK) superimposed. The BPSK symbol rate appears to be at the same rate as the pulse repetition frequency (PRF)...
- 156
3
votes
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Setting Parity Check Matrix for LDPC channel coding
As specified in documentation, using 'ParityCheckMatrix' you can configure the Parity Check Matrix (PCM) during the constructions of the encoder/decoder objects.
...
- 6,080
3
votes
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Conventional channel coding/decoding
Yes, it is possible to determine the path that the Viterbi algorithm found through the trellis. Just apply the encoding algorithm to what you are calling Y_dec and ...
- 20.2k
3
votes
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Chosing the right type of convolution code for a M-QAM transmitter
So work off what you've got:
convolutional code: Important design constraint. (The rest of the application description really doesn't say this is necessarily a good use case for a convolutional ...
- 29.6k
2
votes
Relationship between $E_b/N_0$ and $\rm SNR$ with channel coding
The answer to the question depends on the fact if the code rate implies a change in the bit rate f the system. The bit rate would be the rate of bits that come out of the system per second, and the ...
2
votes
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Maximum Throughput of QAM system
When $\log_2(M)$ is even, the relationship betweeen BER and QAM if an AWGN channel is given as below (Assuming Gray coding so that a symbol error in most cases is one bit error):
\begin{align}
k&=...
- 48.9k
2
votes
Accepted
Question about symbol detection in ISI channels (use of APP decoder in Matlab)
As you mentioned, applying linear equalization (e.g. filtering with the inverse of the channel) will not yield the optimal performance. Though, what you are searching is not the ...
- 6,208
2
votes
Bose Chaudhuri Hocquenghem (BCH) vs Reed Solomon (RS) Error correcting codes and sound transmission channel modeling
"The best channel code" is really vague.
We can compare channel codes under power, bandwidth, encoder or decoder computational complexity criteria. We can compare minimum hamming distance, correction ...
- 4,225
2
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Bose Chaudhuri Hocquenghem (BCH) vs Reed Solomon (RS) Error correcting codes and sound transmission channel modeling
A few ideas to complement Marcus' answer:
It is relatively easy to find an approximation to the channel's impulse response: send audio consisting of a single positive sample surrounded by zeros, and ...
- 14.9k
2
votes
Accepted
Why are some LDPC codes more immune to noise than others?
As you mention, the LDPC code is completely determined by its generator matrix H. Hence, the properties of H define the (theoretic) performance of the code.
Since the LDPC code is a linear code, the ...
- 6,208
2
votes
Capacity of cascade binary symmetric channels
A cascade of $L$ binary symmetric channels (BSCs) with cross-over probability $p$ is the same as a single BSC with cross-over probability
$$p_L = \left.\left.\frac 12 \right(1 - (1-2p)^L\right).\tag{...
- 20.2k
2
votes
Accepted
why did convolution coding achieve BER less than Reed-Solomon?
Reed-Solomon codes are good for correcting bursts of errors (such as those that often occur in computer memory systems such as RAM, or on less volatile media such as CDs and DVDs) or at the output of ...
- 20.2k
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