# Questions tagged [channelcoding]

Questions related to channel coding, forward error correction, code performance calculations, and decoding algorithms. Typical code examples are Hamming codes, cyclic codes, BCH, Reed-Solomon, turbo codes, and LDPC.

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### What are different encoding schemes used in gigabit ethernet?

I was reading about digital transmission, there are many steps namely Analog to Digital conversion Source coding Channel coding Line coding Pulse shaping Modulation Multiple access techniques Out of ...
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### Comparing communication systems with different modulation orders and code rates

I propose an end-to-end communication method in my research. The key part of the method is not the channel coding and modulation but we use them anyway. I am using 1/3 rate Turbo codes with QPSK and ...
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### Raw BER or Uncoded BER in LTE/5G

Could you please tell me what would be the benefit of using Raw BER (or uncoded BER) in comparison to BER? Thanks
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1 vote
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### How to calculate the following mutual infomation between $X$ and $Y$ in matlab or python?

Recently I meet the following question: Let $X\in {\mu_1,\mu_2,\cdots,\mu_m}$, $Y \in {R_1,R_2,\cdots,R_n}$, where $\mu_i, i = 1,2,\cdots,m$ is means of $m$ gauss probablity density function, $Y$ is ...
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### How to accomodate feedback bits from Base Station to devices in LTE or 5g?

I am trying to think of a way in which the base station (BS) can send say 100 bits of feedback to devices in my cell. My confusion is what is a good way to send this feedback bits. This is during the ...
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### Generate 5G compliant parity check matrix and save it to .alist file

My aim is to try out the 5G LDPC codes by using the aff3ct library. This library needs the parity check matrix loaded from a .alist or a .gc file to create the LDPC encoder. I've been looking how to ...
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1 vote
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### Why can interleaving make the channel "memoryless"?

I'm trying to understand "interleaving" from a theoretical point of view. This paper claimed that by sufficient long interleaving, the channel can be treated as memoryless. Does this holds ...
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### recursive, systematic convolutional encoder with finite response

In an exercise, we had the following recursive encoder given: For which we should find an input sequence that generates an output with finite hamming weight (I see this question similar to a find ...
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### RS FEC correct more than t/2 errors sometimes... why is this happening?

According to the Reed-Solomon Wikipage, the RS code can correct up to $\lfloor\frac{t}{2}\rfloor$. While I was playing around with Reed-Solomon FEC (github repo), I noticed that sometimes the RS(544, ...
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### Reuse channel decoder for a smaller code dimension of linear block codes

I am working with the 5G NR polar code and have implemented the CRC-Aided Successive Cancellation List decoder based on this paper (Tal et al. 2012). As my decoder is only used to decode a limited ...
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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 ...
1 vote
103 views

### Increasing Spreading Factor vs reducing FEC rate

This time, I have been reading a lot about how LoRa works and how it is able to achieve such long ranges in non-LOS propagation channels. However, a simple doubt arises regarding the way they ...
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1 vote
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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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781 views

### Shannon capacity limit & FEC comparisons

In this figure from Fundamentals of Digital Communications by Madhow , pp 328 there is a comparison of a rate 1/3 turbo code with the shannon limit for rate 1/3 BPSK: Trying to understand the limit ...
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### Understanding Asymptotic Equipartition Property

I have some problems in understanding the precise meaning of the Asymptotic Equipartition Property, related to a large number n of independent and identically distributed random variables (X1, X2, ...,...
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### 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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### Notes or books to quickly get started on the basics of signal processing or wireless communication

I'll soon start working in signal processing, specially wireless communication systems. Hence I'd like to get a quick understanding of MIMO and related systems, for example, the topics like: 1) where ...
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I'm confused by the Nyquist channel capacity formula. How can channel maximum capacity approach double the bandwidth. $C = 2\times BW \times log_{2}(L)$ bits/sec The way it was explained to me ...