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Questions tagged [capacity]

Capacity refers to the capability of a channel to transport data, typically measured in bits per channel usage.

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"Best" energy efficiency via capacity of uncoded BPSK AWGN

I have numerically approximated the capacity of an uncoded, binary uniform input, real AWGN BPSK channel versus the SNR using mutual information and entropy, via Gauss-hermite quadrature. My task is ...
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What is the correct interpretation of the capacity formula with modulation?

Someone sent me the image below, and I think I'm confused as well. Is the second formula (modulation) correct? What does it mean? From the symbol, I think it represents capacity, but it doesn't make ...
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Applying Blahut-Arimoto Algorithm for AWGN Channels Capacity Calculation with Cost

I am exploring the Blahut-Arimoto algorithm (or any numerical method) for channel capacity calculations, particularly for continuous channels. I understand its application in discrete scenarios, but I ...
Alireza Ghazavi's user avatar
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Error in the visualizing Capacity bounds of FSO Links over Gamma-Gamma Atmospheric Turbulence Channels Using OOK Signaling?

I simply want to visualize 【Capacity bounds and mutual information】 versus 【SNR $\gamma$(dB) or probability $p$ (The input to the channel is a binomial distribution with parameter $p$)】 But I cannot ...
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OFDM system capacity if we double the subcarriers

Suppose we have two OFDM based systems A & B. System A has $N$ subcarriers and bandwidth $W$, and the number of samples in the CP is 10% of $N$. System B has $2N$ subcarriers, $2W$ bandwidth and ...
Ravindra's user avatar
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What is the intuition explaining the Shannon-Hartley theorem?

In the digital domain, the signal to noise ratio (SNR) may be interpreted loosely but usefully as the number of discrete or quantized levels one can transmit reliably. For instance, loosely speaking, ...
kbakshi314's user avatar
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Are there any techniques that can achieve higher transmission rate than Shannon capacity?

The maximum bit rate that can be transmitted over a channel with bandwidth B is determined by Shannon C=B log(1+S/N) Are there any techniques that could break this limit?
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Log-normal shadowing and mean power

Let's assume I'm receiving a signal with power measured in dBm shadowed according to the normal distribution, i.e. $P_{\text{dBm}} \sim N(0,1) $. If there is also a normally distributed noise power $...
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Rayleigh Fading

I am calculating the capacity of $K$ channels between a transmitter and $N$ receivers in a cellular scenario. I use the following equation: $$C_n^k = B\log_2\left(1 + \frac{Ph_n^k}{N_0B + I_n^k}\right)...
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Why are some Shannon's limit plots exponential rather than logarithmic?

This diagram again. This is clearly not the shape of $\log_2(1+SNR)$ but I very frequently see this instead of this: But this is also a stupid diagram because it doesn't cross at the origin. Also why ...
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Are capacity and spectral efficiency identical for a dicrete-time digital signal?

I saw this answer and saw on the wikipedia page that both spectral efficiency and capacity can be measured in bpcu i.e. 'bits/symbol'. I just want to confirm then that they are identical for a ...
Lewis Kelsey's user avatar
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Difference: Ergodic channel capacity and spectral efficiency

Can someone explain what is the difference between the capacity and ergodic capacity? Ergodic capacity and spectral efficiency?
Jang Lee's user avatar
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1 answer
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Capacity and channel estimation algorithms: explanation of results

I study a spectral efficiency of a system with a precoding scheme with different channel schemes. Algorithm A for channel estimation gives a smaller estimation error instead of Algorithm B. I have ...
Noel Miller's user avatar
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How to send two packets in a point-to-point transmission with NOMA? [duplicate]

If a transmitter T1 has two packets M1 and M2 to send to a receiver R1, can T1 send M1 and M2 at the same time and using the same frequency based on Non-orthogonal multiple access (NOMA)? If T1 sends ...
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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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Relationship between Nyquist and Shannon channel capacity

Nyquist channel capacity(Cn) used for theoretical noiseless channel $C_n=2B\log_2(M)$ Shannon channel capacity(Cs) for noisy channel $C_s=B\log_2(1+\text{SNR})$ So is there a relationship between ...
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Channel Capacity of OFDM with Index Modulation

I am trying to figure out the channel capacity of OFDM with index modulation (OFDM-IM). One of the article reports that the conditional channel capacity of OFDM-IM is $\mathcal{C}_{\mathrm{OFDM-IM}}(\...
Ali Waqar Azim's user avatar
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interpretation of simulation results : capacity with precoder

I am studying the concept of computation the capacity. I have early asked about the difference between CSI unknown/ known to transmitter here. In the book about Matlab implementation OFDM system, the ...
Jang Lee's user avatar
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Basic results of error correcting codes

Please can someone verify these basic results about error correcting codes. For this example I am using Reed-Solomon because there are functions to calculate the rate $r$ and distance $d$ of the code,...
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Example of Entropy and Channel Capacity Computation

Can you help me on verifying if this computation of entropy is correct and on understanding its meaning? I am not sure of the result especially because it is equal to 0: it means that we cannot ...
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When channels are in a cascade and are independent is the capacity the sum?

Just wondering if two channels are independent then is the overall capacity, the sum of the individual capacities? For example suppose I have two BEC where the probability of erasure is $\varepsilon$...
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Achievable rate for MIMO channel with estimated channel matrix

In a MIMO system, if the receiver has perfect CSI, i.e. knows that channel matrix $\boldsymbol{H}$, then the achievable rate is: $$ R = \log \left|\boldsymbol{I}+\frac{P}{N_RN_T}\boldsymbol{H}\...
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2 votes
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Nyquist noiseless channel capacity; how can bit-rate be two times the bandwidth?

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 ...
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Modulation with Maximum Likelihood decoder and capacity

My question comes from the high spectrum efficiency claim of OFDM. This seems not correct IMHO, at least theoretically. For me, we lose energy in using cyclic prefix, hence OFDM should be a waste of ...
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Assessing relative wireless channel quality using Capacity and Condition Number CDFs

I have Channel capacity analysis figures for two wireless channels show below: My question: While ergodic capacity in the first subplots are very clear in conveying the channel capacity, How to make ...
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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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Concatenated Deletion & Sticky Channel Capacity

Suppose you are sending information through a deletion channel with a deletion rate of .5 and then the output of this channel is sent through a sticky channel with a repeat rate of .5 also. No error ...
William Hird's user avatar