# Questions tagged [channel]

A channel for communication between transmitter and receiver. Sometimes a channel is multi-input/multi-output, allowing for multiple transmitters and multiple receivers.

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### Simple Pathloss Model Question

If I have the path loss model below, $$128+37\log_{10}(d)$$ Why it is equivalent to $$\frac{P_r}{P_t} = \frac{10^{-12.8}}{d^{3.7}}$$
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### What is meant by channel knowledge? Difference between partial and full?

Keep coming across the term channel knowledge (specifically in the transmitter) in a reading for class but can't really grasp the idea and don't see a clear cut definition. From what I understand it ...
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### Binary-Input AWGN Channel Capacity

I am trying to reproduce graph 1.7 from the book Channel Codes: Classical and Modern. The graph contains the capacity plots for both soft-decision and hard-decision decoding plus the Shannon limit. I ...
1 vote
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### Delta dirac function in the Channel model

I have a question about the channel model below. theta, phi denotes AoA(Angle of Arrival), AoD(Angle of Departure) from receiver and transmitter. I know that channel impulse response is the sum of ...
57 views

### Can a cosine modulated complex valued baseband signal be transmitted over physical channels?

I am reading Digital Communication by Lee and Messerschmitt. In Chapter 6 on modulation, the authors say: "Modulating a complex-valued baseband signal with a cosine wave yields complex-valued ...
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### Multiple Transmitter Localization - Channel Modelling

I read in this paper about to localize multiple transmitter in a wireless scenario. I know from other source that this hypothesis is completely false. What do you think? Is there in the literature ...
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### How to estimate optimal channel length for multichannel blind system identification?

Let P1 and P2 two distinct output signals that are generated by a common input signal S. If you want to estimate S using multichannel blind system identification algorithms, you have to specify the ...
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### Averaging two channels with Python

I am trying to convert a stereo audio into a mono one by averaging both channels with Python. My audio is stored in sound and I calculate the average using ...
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### How does higher received signal power enable higher data rates?

On page 30, of the book Fundamentals of LTE by Arunabha Ghosh et al. it is written: This allows broadcast signals from different cells to combine over the air to significantly enhance the received ...
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### Generating a 2D delay-Doppler channel matrix

I was wondering if anyone here has any idea on 2D delay-Doppler channel and how to generate the channel matrix? Even a hint or a resource would be helpful. I just want to understand and visualize the ...
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### Understanding MMSE equalizer equation

I have read many online materials and journal paper where the equation for MMSE equalizer is given as: $G_{MMSE}$ = $H^H(HH^H+\nu^2I )$ where $H$ is the channel, $H^H$ is its hermitian. $\nu^2$ is ...
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### Can Oversampling help to mitigate the effect of additive white gaussian noise?

Oversampling the signal at the receiver's ADC is a common technique to improve the ADC's resolution, dynamic range and to improve the signal to noise ratio (SNR) due to ADC quantizaiton noise, thermal ...
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### 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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### Centre channel derivation using correlation

I would like to know the algorithm for how centre channel is derived from rejecting left and right channel in audio upmixing process. Can someone explain intuitively rather than hard hitting ...
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### Unstable Phase in Channel Impulse Response

I'm using DW1000 UWB radio transceiver and extract its channel impulse response (CIR). The CIR output by the transceiver is the complex baseband CIR. In a static environment, the CIR is a LTI filter ...
1 vote
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### Channel estimation using bit reversed order of FFT matrix

Is it possible to use the bit-reverse order of FFT instead of FFT to estimate the channel? Based on my reading, I found that bit reversed order of FFT matrix can diagonalize the channel, but ...
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1 vote
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### OFDM use a pulse shaping filter or not?

I've heard in various literature that band limited channels use pulse shaping filters. By the way, In OFDM it use a cyclic prefix to overcome ISI, so I wonder if OFDM does not use pulse shaping filter....
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### How is the Tx/Rx Gain calculated in USRP?

I know that USRPs are uncalibrated devices. In many exampls you can set the so called Tx or Rx gain (as in the picture below). Now, I know that this does not correspond to the real power of the ...
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