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18 views

Doubts about Huffman and Shannon - Fano Coding

I was reading these slides about Source Coding and I have the following questions: 1) Let's consider this part: Can you explain me step by step the reasons of a, b, c? Which is the general rule to ...
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0answers
8 views

How to recover 2*Zc systematic bits punctured in LDPC?

In 5G NR LDPC encoder 2Zc systematic bits are punctured at the transmitter end. At the receiver end, it is able to recover all bits excluding the punctured bits at the transmitter end. As the ...
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0answers
30 views

How to detect missing bit position in a bit-stream?

I'm trying to establish a one-way communication and facing problem in the receiver end because of some missing bits. For example, if the sender sends 100 bits the receiver received 95/96 bit. Now the ...
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0answers
19 views

Convolutional Code: choosing a trellis and puncture pattern for code 2/3

I'm working on convolutional coding in which I'm using generator polynomials as {13, 15} with puncture pattern of {1 1 0 1} for code rate 2/3. I don't get expected BER trend. If I use puncture ...
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0answers
13 views

Convolutional coding that payload length does not change

This is the question about Sigfox radio specification. The stack: Specifically, in Section 3.10 of the specification, we have a convolutional coding (after CRC) with three possible polynominals. I ...
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0answers
22 views

Parity Check matrix from degree and check nodes polynoms, LDPC codes

I'm trying to simulate LDPC codes which were optimized for the BEC channel. I generated the degree and check nodes polynomials according to chapter 3.15 in "Modern Coding Theory" by Richardson and ...
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0answers
54 views

5G NR base matrix

The 5G NR specs for channel code are found here: https://www.etsi.org/deliver/etsi_ts/138200_138299/138212/15.02.00_60/ts_138212v150200p.pdf Starting on page 21 there is base matrix for the LDPC code ...
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1answer
17 views

operations valid for predicting new codewords for a Linear block code having linear encoder mapping

I want to know which operations are valid for predicting/finding a new codeword from a set of known codewords for a linear block code having linear encoder mapping, for eg.: Consider a linear ...
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2answers
37 views

Sampling vs repetition code

I'm working on a multiuser wireless system simulation and have run into something regarding sampling rates. From everything I've known for a matched filter receiver, the correlation step is performed ...
0
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1answer
64 views

Error detection and correction algorithms for Wireless Body Area Networks

I am working on transmitting ECG signals over wireless body area network based on IEEE 802.15.4 standard. To reduce the BER and increase the signal reconstruction quality, I think that I need to ...
0
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1answer
103 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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2answers
106 views

Alamouti Scheme. MISO. STBC for real constellation

I have a real orthogonal design for codeword... $$ \begin{bmatrix} s1 & s2 \\ -s2 & s1 \end{bmatrix} $$ $$ s=\begin{bmatrix} s1\\ s2 \end{bmatrix} $$ $$ Y^T=\sqrt{\frac{P}{Mt}} h^T ...
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1answer
25 views

Computing overall bitrate of a transmitter with a two chunks package

I'm programming a digital communication system in MATLAB and I have a two chunk package, let's say a header and a body, and I'm using a different channel code for each chunk, i. e. BHC1 and BCH2. But ...
3
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3answers
2k views

Capacity of cascade binary symmetric channels

Let's imagine that we have interconnected in cascade $L$ binary symmetric channels each with the same transition probability $p(y|x) \in \{p, q=1-p\}$, where the output of each BSC is connected to the ...
-1
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1answer
33 views

Why GCD(1+D, 1+D^2) = 1+D?

I'm reading Digital Communications, Proakis, and in order to classify an encoder as catastrophic or noncatastrophic I need the GCD of the elements in the generator G(D). I don't really know what kind ...
3
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2answers
686 views

Confusion in Channel Encoding and Convolutional Encoding

If I'm making NRZ signal by first encoding 1 input bit into 10 bits multiplied by -V/+V before sending it into a channel, is it called channel encoding? If I then modulated it using GMSK technique, ...
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1answer
95 views

How does a Huffman encoded message gets unified before channel encoding?

I aim to understand the signal entire transmission pipeline. Currenlty, I am facing a problem regarding the handling of a Huffman encoded message. Example: Message $X$ contains symbols $a(50\%)$, $...
2
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3answers
1k views

Bose Chaudhuri Hocquenghem (BCH) vs Reed Solomon (RS) Error correcting codes and sound transmission channel modeling

I've implemented an acoustic based information transmission system using a bandwidth of 2 kHz and the band between 18.5 and 20.5 kHz. I'm trying to find the best error correcting code for it, in the ...
1
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1answer
214 views

Finding $E_b/N_0$ when coding rate is $R_c$

I would like to calculate $E_b/N_0$ when the code rate is $R_c$ for BPSK signal. What I got this $$ E_b/N_0= \frac{1}{2R_mR_c \sigma^2} $$ and that is the case also according to this page. $R_m=1$ ...
1
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2answers
563 views

Relationship between $E_b/N_0$ and $\rm SNR$ with channel coding

I would like to know what would be the relationship between $E_b/N_0$ and $\rm SNR$ when there is a coding rate of $R_c=K/N$. Normally when there is no channel coding according to this link. $$\...
0
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1answer
124 views

Adding AWGN noise with certain power

Assume I have a signal(BPSK) and it has a certain amplitude. I would like to add a noise with a certain power to it. Assume I am using coding rate Rc as well. One method I am thinking would be to ...
0
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1answer
60 views

Difference between sticky channel Poisson-repeat channel

I don't quite understand the difference between a sticky channel and Poisson-repeat channel. A sticky channel allows duplications of symbols sent over the channel, then the block structure at the ...
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1answer
48 views

Do convolution encoders exist with two separate (independent) inputs?

Do convolution encoders exist with two separate (independent) inputs? I got the question in my mind when I saw the question attached here.
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0answers
621 views

Generating LDPC codes of arbitrary sizes in MATLAB

I am having problems generating LDPC codes of arbitrary sizes in MATLAB primarily because MATLAB insists on the parity check matrix that is input into its ldpcenc ...
5
votes
1answer
362 views

What is the cost of Hamming coding?

We know that (7,4) hamming code has 4 message bits and 7 code bits and can detect any single bit error. The (12,4) repetition code has 4 message bits and 12 code bits and can detect any single bit ...
-1
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1answer
136 views

How to write cyclic codes?

I am studying cyclic codes. From what I understood of it, a cyclic code is a special kind of linear code with the property that any codeword cyclic shift is also a codeword. Generally, we start with ...
2
votes
2answers
664 views

Why does FEC seem to make BER worse at low Eb/N0?

I've been plotting BER curves and am wondering why FEC seems to make a BER curve worse at low Eb/N0 than the un-coded theoretical BER curve? My example plot below is for Differential BPSK using a ...
1
vote
1answer
739 views

Transmission capacity in “duobinary coding”

In "duo-binary signalling" how exactly is the transmission capacity increased? Because , when we encode the binary bits, the bit duration remains the same, but the amplitude will change. Then how can ...
0
votes
1answer
341 views

Important differences between BCJR and SOVA algorithms?

BCJR algorithm needs noise variance for Gamma (branch metrices) calculation. So I am wondering does SOVA (soft output Viterbi algorithm) needs noise variance?
5
votes
1answer
144 views

Does any error correction code still work in such situation?

I'm looking for a kind of error correction code or solution that can correct my codeword in this case: My message holds $k$ bits, and $2k$ bits codeword (rate is $1/2$) is produced by the generator ...
4
votes
3answers
3k views

Why is an interleaver often placed between an outer block code and an inner convolution code?

It seems that when doing FEC with a concatenated-code, an interleaver is often placed between the outer block code and the inner convolution code. The explanations I've seen say that this is because ...
4
votes
3answers
828 views

Optimal DC-free line encoding

I have a block of n bits that I'd like to encode into m bits that have an equal number of zeros and ones. I looked at protocols like 8b/10b but it wastes 25% of the data to achieve balance. As an ...
2
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1answer
2k views

increase of encoding rate increases bandwidth?

I came across this paragraph in an article about signal processing. Addition of redundant bits for improving the error probability leads to bandwidth expansion of the transmitted signal by an amount ...
4
votes
1answer
358 views

Why is privacy scrambling a standalone block in a communications transmitter?

In some telecommunication systems, scrambling of transmitted data is applied to provide some level of security. For example, the communication system might look like: Data -> Scrambling -> ...