# 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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### Why does altering path length in radio transmission alter the phase of the received signal?

I do have a very naive yet bothering question: Assume I send a sinusoid signal \begin{equation} A*cos(2\pi ft+ \phi_0) \end{equation} over a radio channel. Assume there is only a LOS-path for each ...
134 views

### Why multi-path channel has linear phase within the coherence bandwidth?

I read some sentence that said "It is usually assumed that the multi-path channel has a constant gain and linear phase within the coherence bandwidth". I can't understand what it mean " linear phase "....
55 views

### What is the physical meaning of coherence bandwidth in mmWave massive MIMO channel?

I am doing some research about millimeter wave massive MIMO channel now. We first take account about static MIMO channel, cause we only have SISO measurement system now. We use scanner to move our ...
26 views

### awgn function in MATLAB

I'm using 'awgn(input_signal,snr_db,'measured')' function in MATLAB to add white noise to the input signal. Here is the simplified script. Does zero padding the input signal affect the behavior of ...
27 views

### Why SRS signalling is used in 5g?

Since DMRS is also being used as a reference signal in PUCCH and PUSCH channel, so why an extra SRS signalling is required.
38 views

### Degrees of freedom in coding (for a communication channel)

I was reading on my lecture slides about how to achieve diversity (i.e. transmit more copies of the same message in order to avoid its corruption; this technique may be realized by repeating the ...
34 views

### how to determine a length of a channel? ( given path, delay)

Given a channel matrices for each subcarrier of a frequency selective channel (OFDM): i.i.d.. channel =(randn(ntx,nrx, N)+1i*randn(ntx,nrx, N))/sqrt(2); simulated ...
22 views

### Interference Distribution Assumption in NOMA IoT Scenario

I am assuming a NOMA IoT Uplink scenario, which is interference marred. I have to ascertain the SINR at the Access Point (AP) for the NOMA users. A sub-channel is allocated to various users and ...
46 views

### 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 ...
56 views

### How does subcarrier correlation affect the BER of OFDM?

I am studying the OFDM system and would like to examine it under different subcarrier correlation scenarios. I have calculated BER for the uncorrelated scenario and now I have rewritten it for the ...
12 views

### In a communications system does the order of channels is in a cascaded channel affect the overall capacity?

I'm currently looking at capacity for cascaded channels as part of my Communications Systems module and we're looking at a question in which we have four identical channels represented by the ...
75 views

### Why the relationship between Es/N0 and SNR under complex signal is different from the relationship between Es/N0 and SNR under real signal?

I try to use the AWGN Channel model of MATLAB to build my simulation model, but the explanation of the relationship between Es/N0 and SNR in the official manual of MATLAB makes me confused. It says ...
12 views

### 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 ...
35 views

### Gain and average gain of two-path channel

For two-path channel with no loss or phase shift in the reflection, Why the gain of the channel at radio frequency less than average gain of the channel?
I want to implement Least Square (LS) channel estimation method in the presense of AWGN noise in MATLAB. $y(n) = x(n) * h(n)$ $Y(k) = X(k)H(K)$ Y(k) is the received signal in frequency ...
I am trying to create a non-i.i.d channel: correlated Rayleigh fading channel. $$H= R_H \cdot H_o,$$ where $H_o$ is i.i.d. channel ( uncorrelated) and $R_H$ is a channel correlation matrix, is ...