Questions tagged [coding]

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Minimum distance question

I´m reading a paper on Miller codes and I´m having trouble calculating the minimum distance out of a state diagram. The paper states in Fig. 3. that "it is easy to verify that dmin for these ...
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Other Examples of Complete Orthonormal Systems

I am interested in other examples of finite and complete orthogonal basis. I am not confident in my use of the term “complete”, so what I mean specifically is a set of basis vectors that can be used ...
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BER Too High in BCJR Error Correction Scheme (Compared with Viterbi)

I am having issues with my BCJR error correction scheme which I created for simulation of convolutional codes being sent over a binary symmetric channel (BSC) using Matlab. The issue is that my ...
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1 vote
1 answer
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Why is Line coding called "Line coding"?

Guys do you now why line coding also called digital base band modulation named "line coding" where does it come? and how is the name related to modulation
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5 votes
1 answer
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Optimal idle or frame sync symbols for OQPSK

Okay, everyone here knows that my thing was audio and that I have never gotten paid to do anything regarding communications systems. So, while I know a thing or two about DSP and even a little about ...
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-1 votes
1 answer
51 views

Shortened linear codes

I've been working on my linear code assignment in my coding theory course and I have encountered a problem I would like to get help with. the question is described below. I will try to expalin what I ...
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1 vote
0 answers
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Adding FEC to sporadic burst of Huffman-encoded words

This question may be interpreted as a second part of this other question. Basically, if we encode our data using Huffman's encoding and we want to introduce some FEC afterwards, unless we use a ...
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0 votes
1 answer
139 views

Having trouble interpreting z-transform description of a predictor from a codec paper

I've been looking at the opus paper (https://arxiv.org/pdf/1602.04845.pdf); in particular, in section 4.1, they describe the predictor for the current band energy based on energy from both the current ...
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2 answers
164 views

Optimal FEC option for extremely low SNR situation

I am new to this site, which I joined with the aim of finding someone to help me with a little doubt. I am trying to design a system that must be able to work at extremely low (the lower, the better, ...
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0 answers
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understanding FIR SRRC filter with memory implementation in C

I translated the Matlab QPSK receiver/transmitter into real-time C code that I have running on a PlutoSDR platform. QPSK receiver/transmitter I wrote the square root raised cosine filter for the TX ...
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100 views

Understanding of Reed Solomon code

We send the data in bytes to the RS Encoder block. The RS Encoder block encodes the data with the Reed Solomon (225,223) code. It waits for 223 bytes and after this encode them to make a codeword of ...
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1 answer
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Multi-bit gold code

Is the multi-bit gold code resulted from a xor of two different multi-bit m-sequences will still maintain its statistical property (bounded correlation, distribution of 1 and 0) ?
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How to apply an offset to a complex exponential without chopping it off?

I am trying to encode a bitstream as offset in a complex exponential, but when I do, the sinusoids get chopped off. Do I need to apply a lowpass to the bitstream or is there a more elegant way? ...
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1 answer
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Transition table / matrix for convolutional encoder K=3 understandings

Im trying to understand convolutional encoder $K=3$ , and I almost understand it but still confused about what's called transition matrix which in other words it means what input value ($0$ or $1$) ...
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3 votes
1 answer
533 views

Finding preferred pair of $m$-sequence for Gold code

I would like to find a preferred pair of $m$-sequence of degree 34 (not a multiple of 4) for Gold code. However, I am lost when I am checking William Wesley Peterson's table in his Error-correcting ...
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1 vote
1 answer
396 views

Differential Encoding for M-PSK

Confused about a few topics w.r.t. differential encoding/decoding. First, consider the below BER curve taken from wikipedia ( https://en.wikipedia.org/wiki/Phase-shift_keying ) comparing BPSK/QPSK and ...
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1 vote
1 answer
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Most reliable way to decode PAM2 signal with unknown signal levels?

I assume this is pretty much a standard problem. I have a PAM2 signal that comes from a complex envelope (i.e., it is not zero-centered) and is heavily imposed by noise. This shows 20 different ...
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-1 votes
2 answers
70 views

Can we broadcast two messages using NOMA?

Is it possible for a transmitter to broadcast two messages to a set of receivers at the same time using superposition coding (Non-Orthogonal Multiple Access - NOMA)? A transmitter has two messages $...
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2 answers
206 views

Interleaving or randomisation?

I am trying to implement a digital communication system as a learning exercise. For error correction, I am using two concatenated codes (RS and convolutional). However, I read that, in order to reduce ...
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0 votes
1 answer
185 views

What's the difference between quantization and coding?

From what I understand quantization takes an analog signal and assigns numerical values to it as convert it to a discrete signal. However coding converts a signal into binary. It seems like coding is ...
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1 answer
173 views

Bandwidth and BER of FM0 encoding

What is the bandwidth (i.e., the lowest possible bandwidth) and BER for FM0 encoding? To be precise, this is my example of an FM0 encoded waveform: There is always a transition between each bit. For ...
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2 answers
479 views

Definition of Perfect Code (and example of Hamming Code)

Let's consider the following sentences about coding a message before transmitting it in a communication system (here you find the complete pdf) First question: can you explain me these two ...
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1 vote
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Capacity achieving codes for BPSK at low SNR

I don't know a lot about comm system design. I have an AWGN channel and low SNR (-3dB). Bandwidth is constrained to some maximum, B. I would like to know good choices of modulation and coding to ...
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0 votes
1 answer
32 views

How good is the Leech lattice for AWGN coding or MSE quantization of Gaussian sources?

Anyone know where to find graphs showing how well it works vs other schemes? thanks
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-1 votes
1 answer
63 views

STBC Rank Criteria Explanation

I am learning about space-time block coding and I am trying to understand why the rank criteria is a good measure of diversity gain. I know that we want to maximize the distance between codewords $X_i,...
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1 vote
1 answer
81 views

What is the Asymptotic Equipartition Property (AEP)?

I am currently studying about Polar Codes in 5G standard and while reading my paper I found something called AEP which is required for channel coding. I surfed the web but didn't found a satisfying ...
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0 votes
1 answer
88 views

Prefix code of symbol pairs

An input sequence consists of two symbols, each independently and randomly chosen from a set of symbols with known associated probabilities. Each symbol is independently encoded using a prefix code ...
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1 answer
35 views

Randomized prefix code

An input symbol is randomly chosen from a set of symbols with known associated probabilities and encoded using a prefix code that minimizes the expected codeword length. Is it possible to further ...
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11 votes
2 answers
2k views

FFT vs DFT Run Time Comparison (Complexity Analysis) in MATLAB

So we were given an assignment to plot the time taken by the FFT algorithm by MATLAB and a DFT algorithm written by me in MATLAB.G The expected output should have been the DFT algorithm following the ...
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