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In reality, how does channel estimation for multi-user work?

At BS, for antenna $m$, I see some papers and some code that presents the received signal $Y_{nm}$ from user $n$ as a $K \times N_{\text{symbol}}$ matrix ($K$ is the number of subcarriers, $N_{\text{...
Hiếu Hoàng's user avatar
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ML bound for Massive MIMO

How can one estimate the ML bound for Massive Mimo detection with 128 transmitting antenna and 128 receiving antennas using 4 QAM modulation? I have seen for a 8 by 8 system it is possible to use K-...
albusSimba's user avatar
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A question of channel capacity in precoding case

I’ve a general question about precoding. The channel capacity after precoding is $\log_2(\det(I+F’H’HF))$ where $\det$ is the determinant, $I$ the identity matrix, $F$ the precoding matrix, $H$ the ...
c1119's user avatar
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outage capacity of K user fading channel

Suppose you have $K$ users, each seeing a point to point fading channel with $n$ receive diversity. So the rate of the kth user is at most $\log(1+ SNR|h_k|^2)$. Now suppose, each user transmits at ...
RTS's user avatar
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SIMO systems diversity and matched filter response

Let's assume we have a SIMO system with multiple transmitter antennas (e.g. qty 4), and a single receiver or 4x1. Let's suppose we're talking about the SSR steady-state response, Gaussian noise, and ...
irrationalpie31415's user avatar
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121 views

Eigen Beamforming: Explanation [closed]

It's been a few days that I have been searching the term eigen beamforming, but still haven't get any satisfactory literature reference. It would be great if you could give any details or point to any ...
Aragorn's user avatar
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MIMO usage in ENDC

For a 5G NSA UE supports 4x4 DL MIMO, in theory, is there any restriction for the device to get maximum throughput with 4x4 DL MIMO in both LTE and NR in ENDC mode?
Patrick's user avatar
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MMSE is approximately zero-forcing at high SNR

In https://stanford.edu/~dntse/Chapters_PDF/Fundamentals_Wireless_Communication_chapter8.pdf page 360, it is stated that for a flat fading MIMO channel with receiver CSI only: at high SNR, the $\...
RTS's user avatar
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1 answer
207 views

MIMO reading clarification

On page 301 of https://stanford.edu/~dntse/Chapters_PDF/Fundamentals_Wireless_Communication_chapter7.pdf, equation (7.33) says that the magnitude of the dot product of two unit complex vectors is ...
Ray's user avatar
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Coordinates of cluster in CDL channel model

I was reading the 3gpp specification to understand the CDL channel models. (See section 7.7.1 and tables within). It says that for a cluster $C$,it has angles of arrival/departure along the azimuth $(\...
wanderer's user avatar
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What wavelength do we use when calculating the array manifold vector when transmitting LFM waveforms?

We know that the array manifold vector, also called the steering vector, for an M element array is given by: $$ \mathbf{a}(\theta, \phi) = [e^{-j \omega \tau_{1}(\theta, \phi)}, e^{-j \omega \tau_{2}(\...
The Dude's user avatar
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Calculation of the LMMSE Channel Estimator

Consider a MIMO system equipped with $N_t$ transmit antennas and $N_r$ receive antennas. The received signal over $L$ snapshots are given by $$Y = H X + Z,$$ where $X$ is the $N_t \times L$ transmited ...
maphado fan's user avatar
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169 views

How to implement maximum likelihood (ML) detector in MATLAB?

Consider the MIMO system which has $N_t$ antennas at transmitter and $N_r$ antennas at receiver and uses Generalized space shift keying (GSSK) modulation. The received signal is given by: $$Y = H X + ...
Heretolearn's user avatar
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How to do MIMO precoding for OFDM?

I studied OFDM, MIMO, and MU-MIMO, but I'm not sure how it works when MIMO and OFDM are combined. I can't find good literature that talks about MIMO-OFDM. I want to understand how to use eigenmode ...
Ryo Onishi's user avatar
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How to express random signal in MATLAB which is transmitted from transmitter to receiver

I am trying to model a random transmitted signal between transmitter (source) to receiver. Specifically, the transmitter has $N_s = 1$ antenna and receiver has $N_r = 2$ antennas. My query is that I ...
Heretolearn's user avatar
1 vote
2 answers
92 views

Can the number of subcarriers/user be greater than 12 in 5G?

In 5G, I think 1 resource block (RB) carrier is 12 subcarriers. So one user uses 12 subcarriers. But in some research, 612 subcarriers are used for channel estimation research. Is it okay to use more ...
Ryo Onishi's user avatar
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1 answer
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Delayed waves existing MIMO eigenmode transmission

Assume that the numbers of transmitting antennas, receiving antennas, and delayed waves are $N_t$, $N_r$, and $N_p$, respectively. The channel matrix is three-dimensional ($N_r$, $N_t$, $N_p$). In ...
Ryo Onishi's user avatar
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About generating MIMO FMCW IF Signal and angle detection

I want to detect some targets where their range, velocity and angle information can be given before creating the radar cube. Then using IF signal for MIMO FMCW radar I want to construct the radar cube....
esi's user avatar
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compute EVM for MIMO channel including additive Gaussian white noise

Good time. I would like to compute EVM for a Rayleigh channel including additive Gaussian white noise. The accepted EVM for BPSK issued by IEEE is -5dB. Since the variance of white noise depends on ...
Shadi's user avatar
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What is the difference between array gain and diversity gain?

In a multi-antenna system, we often mention diversity gain in fading channels. I am doing simulations with multiple antenna settings at the receiver considering TDLC channel, for example, 1rx, 2rx, ...
Aragorn's user avatar
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MIMO LMMSE detector: why 8x8's BER is better than 4x4?

I am simulating the MIMO linear detector algorithms including Matched Filter, Zero Forcing and Linear MMSE. I simulated three configures: 4x4 ( 4 tx antennas 4 rx antennas ), 8x8 and 16x16. For ...
LeBa's user avatar
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4 votes
1 answer
147 views

Understanding Maximum likelihood detector expression?

Consider the MIMO system which has $N_t$ antennas at transmitter and $N_r$ antennas at receiver and uses Generalized space shift keying (GSSK) modulation. The received signal is given by: $$Y = H X + ...
Heretolearn's user avatar
2 votes
1 answer
65 views

Is it possible to generate SAR like pictures with a non moving MIMO radar and static scene?

Recently I study radar alot and was wondering if there is a possibility to generate SAR like pictures with MIMO radar. Under the condition that the MIMO radar is not moving and the scene does not ...
jang's user avatar
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Diversity gain in MIMO-OFDM system

What is the diversity gain in $4\times2$ vs $2 \times 2$ MIMO system. Is it $10 \log \left( N_{t} - N_{r} \right)$?
user64996's user avatar
-1 votes
1 answer
50 views

MIMO antennas and Resource Block

Assuming there are 4 transmit antennas, do these four antennas share the bandwidth? In other words, I wonder if these four antennas use one resource grid.
Kitae Kim's user avatar
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224 views

What does QCL quasi-colocation actually mean?

Quasi-colocation is a concept stated in 5G NR specifications. But I'm not quite sure about what it actually means. Is one of its meanings that the propagation channel of the physical channel has the ...
c1119's user avatar
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611 views

How to estimate Range, Doppler and Angle with FMCW MIMO Radar?

I am trying to obtain the range, Doppler and angle of arrival estimation with an TDM MIMO FMCW radar. Actually, I have completed this process. In doing so, however, a few things remained unclear. ...
abdullah A's user avatar
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1 answer
111 views

How to decode a MIMO stream using V-BLAST?

I am attempting to implement the V-BLAST algorithm for MIMO streams as described by Wolniansky et al. in the following paper: https://ieeexplore.ieee.org/document/738086 (I am not commenting on its ...
Sander Zuckerman's user avatar
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1 answer
33 views

Why the transpose of wireless channel vector is taken in SIMO system?

I am getting confused about the received signal expression in case of SIMO wireless channel. SIMO system=> Here we will have one antenna at Tx and multiple ($N$) antenna at Rx. Therefore received ...
paru's user avatar
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Pdf of product of two i.i.d random variable distributed as circular symmetric gaussian

What is a distribution of the product of two circular symmetric Gaussian random variables? i.e $X ~ CN(0,1)$ and $Y ~ CN(0,1)$ then distribution of $XY.$?
Jaimin Shah's user avatar
1 vote
1 answer
853 views

MIMO detection using ZF and MMSE

I have a problem related to my uni assignment. The task seems rather simple - plot SER as a function of Es/N0 for 2x2 MIMO and 16-QAM modulation assuming AWGN noise and Rayleigh flat-fading channel. ...
Pawel's user avatar
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2 answers
72 views

High frequency and received signal power? Why using massive MiMo?

The power received by an isotrapic antenna is calculated by: $P_0=\frac{P_T}{4 \pi d^2}\cdot \frac{\lambda^2}{4 \pi} = \frac{P_T}{4 \pi d^2}\cdot A_e$ or, by Friis transmission formula: $\frac{P_r}{...
user674907's user avatar
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1 answer
67 views

Complexity of ZF precoding at the transmitter

If we have a modulated signal $s$ and ($m\times n$) MIMO channel $H$ where $m$ and $n$ are number of receive and transmit antenna, respectively. The ZF pre-coded signal is \begin{equation} x=Fs \end{...
Riva11's user avatar
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0 answers
113 views

How to build a model for $2 \times 2$ MIMO using GNU Radio?

I have been trying to set up a GNU Radio flowgraph where I can implement a $2 \times 2$ MIMO system. don't know how to make spatial diversity using the blocks, also I am not sure which block ...
Abidur Rahman's user avatar
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1 answer
145 views

Square Root MMSE

Could anyone please explain how to perform the derivation of the square-root MMSE equation using an extended channel matrix H (as it is said in the "A LOW COMPLEXITY SQUARE ROOT MMSE MIMO DECODER&...
dcs's user avatar
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1 vote
1 answer
688 views

Radar MIMO Virtual Antenna Array Formation

Referring to the figure attached above, is the ordering of the virtual antenna arrays (shown on the right) to measure azimuth and elevation angles of arrival correct? In my understanding, the ordering ...
Learner's user avatar
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0 answers
133 views

How to calculate received signal power for a Multi-User MIMO OFDM system?

I have a Multi-User MIMO system where there are 2 users served by a base station. The base station consists of 64 transmit elements and the users are equipped with linear antenna array consisting of 3 ...
GS_123's user avatar
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-1 votes
2 answers
61 views

Can beamforming be created by transmitting same signal with different phase

As known, the basic idea of beamforming is to transmit the same signal using more transmit antennas, let's say we have $4$ transmit; leading to increase the power of the transmitted signal as well as ...
Gze's user avatar
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0 answers
74 views

Alamouti scheme and MIMO OFDM model, theoretical or practical concept?

I am not an expert in signal processing but last week I attended a class of signal processing. We discussed MIMO, OFDM and Alamouti scheme. On this lecture it was represented a lot of math equations, ...
LeeLeeYa's user avatar
1 vote
0 answers
64 views

Matlab: Could anyone suggest why Iam getting a different geometry for QPSK constellation diagram

I'm developing a Multi-user MIMO communication model in MATLAB where a base station communicates with 2 users. The model uses OFDM (QPSK) modulation. Channel model, precoding and covolutional encoder ...
GS_123's user avatar
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1 vote
1 answer
84 views

Does same data inserted to all antenna at beamforming?

I wonder do I understand beamforming right. Question 1 Does same data inserted to all antenna at beamforming? Like figure below? The only different is through different phase shift? If it is right how ...
S OT's user avatar
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Property of the trace and expectation

I'm reading the paper Model-Driven Deep Learning for Joint MIMO Channel Estimation and Signal Detection by Hengtao He, Chao-Kai Wen, Shi Jin, and Geoffrey Ye Li on Orthogonal Approximate Message ...
Cobretti's user avatar
1 vote
0 answers
94 views

Blind STBC question

I am working on blind identification of the physical layer parameters of a particular protocol. Everything was going well until I got to the MIMO part. The system contains two transmitter antennas and ...
christopher richer's user avatar
-1 votes
1 answer
198 views

What is the Co-channel interference in MIMO communication

I try to understand the co-channel interference occurred in MIMO systems with rich multi-path channels, but I couldn't find clear explanation about how it happens and what's its effects to the ...
New_student's user avatar
-1 votes
1 answer
231 views

Inter Channels interference in MIMO system

If we have MIMO system with $2$ transmit antennas, ($T_1$ and $T_2$) and $2$ receive antennas ($R_1$ and $R_2$). The received signal of the first received antennas can be explained: $r_1$ = $h_{11}$$...
New_student's user avatar
3 votes
1 answer
3k views

FMCW Radar - Range-Doppler Plot

The FMCW radar with the following parameters was implemented: ...
SenSen's user avatar
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3 votes
2 answers
526 views

Radar for Vital Signs – Matlab Simulation

Interested to design and simulate FMCW radar for Vital Signs sensing. The initial signal parameters are(1): When using the following Matlab code to generate the waveform: ...
SenSen's user avatar
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2 votes
1 answer
258 views

Spatial multiplexing MIMO, antenna critical spacing, antenna isolation

How does antenna isolation affect single user spatial multiplexing MIMO performance in an antenna array? Text books talk about a critical antenna spacing of 1/2 of the wavelength provided that the ...
ali khalil's user avatar
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2 answers
197 views

Multi-input Single-output communication system

In case of communication in MISO system, if we have a system of 4 x 1, which means 4 transmitter with 1 receiver. Will the received signal be a vector of dimension 4 x 1 ? Or it will be 1 x 1 since ...
New_student's user avatar
1 vote
1 answer
115 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 ...
user36610's user avatar