Science topic

# Communication Engineering - Science topic

Explore the latest questions and answers in Communication Engineering, and find Communication Engineering experts.

Questions related to Communication Engineering

Any body who wants to guide me???

In literature, there is no closed form for the information rate of visible light channel. Consider the visible light channel as

Y=ho*xo+ sum( hi *xi)+N,

Y: received signal, h the VLC channel , xi (xi >0) is the transmit signal with average transmit optical power constraint E{xi}=p, N is the Gaussian noise.

In some paper they evaluate the information rate of this channel using Shannon capacity formula R=log(1+SINR), where SINR= (r*h0*p)^2/(N+ sum (r*hi*p)^2). Is this still a valid and measure with the mean and positive signal constraints??.

Some papers discuss DC biasing for input signals then at receiver they removed the DC bias and find a relations with DC bias and optical transmit power. will the DC biasing make the the Shannon capacity formula valid for such channel?

While designing any general optical CDMA network these two terms are often used interchangeably. I want to know the analytical relation between these two. Kindly help

I am working in free space optics i need code source matlab please if anyone have help me...best regard

when i use interpolation sweep, the option of sweep is hidden from this box. why?

Also, I would appreciate it if you could give me some relevant references.

Thanks :)

Please let me know if any book or website is available for reference

Is there someone who has a research paper?

Preferably for frequencies around 700 Mhz, 868 Mhz, 900 Mhz.

Hi, How can we calculate the entropy of chaotic signals? Is there a simple method or formula for doing this?

Since i am not able to get proper VSWR as well as Return Loss.. at Freq 1.5 ghz.. you can take any number of turns and any radius of helix. please.. I have attached the paper if it can be implemented in CST.. I need it please..

what is the difference between nakagami-m and general fading, where they are applicable?

How should I determine threshold on received signal power(underwater acoustic signals) so that the signal can be decoded correctly. I understand that the threshold may vary device to device but I want the value for research purpose independent of any device.

Regards

**Kindly, suggest me some SCI/SCOPUS indexed journals paid/unpaid in RF and Microwave Engineering with 1-2 months of review time.**

I am recently studying "Spatially sparse precoding in millimeter wave mimo systems" at

So, the attached matlab codes is for the simulation of figure 3 in the paper.

It seems like that I have success in SVD(optimal) and spatially sparse precoding but not at "Beem Steering method".

This method seems based on the paper "The capacity optimality of beam steering in large millimeter wave MIMO systems"

I appreciate your comment about what's wrong in my implemenation.

PS.

laprnd.m is not my implementation. It is on the mathworks site

Hi I am confused about the concept of signal quality index. what is signal quality index? what is the relation between signal quality index and signal strength? can we determine signal strength from signal quality index?

I am a Master student in Communication and I am looking forward to plan my futur career.

In 0.1 - 10 THz regime, how to reduce the path loss?, what are issues associated with path loss?

I just came across a problem in power amplifier used in communication chain which exhibits nonlinearity due to memory effects.This can be nullified with a help of digital pre-distortion using signal processing algorithms.

Can anyone please tell how it is achieved and explain the math part behind the algorithm?

Suggestion of book or a research article is preferred.

Thanks

Rakesh

I am working on transmitting ECG signal over wireless body area networks. According to IEEE802.15.4 standards , I am using ZigBee transceiver at 2.4 GHZ . Complex baseband equivalent channel model is used.

The steps are as follows :

1. Signal Compression

2. Quantization

3. Coding

4. OQPSK modulation using the matlab function (

**oqpskmod**)5. Fading Channel plus AWGN

6. Equalization

7. OQPSK Demodulation using the matlab function (

**oqpskdemod**)8. Decoding and Dequantization

* According to the IEEE 802.15.4 standard, a pulse shaping step is performed in the transmitter after the OQPSK modulation step .

I didn`t perform this pulse shaping process, and I obtained reasonable results. Is it necessary to perform this step ?

If yes , How should the receiver be modified ?

I am analyzing the complexity of resource allocation problems in NOMA systems. The network model is shortly summarized as: a base station (BS) and multiple users (UES), singles for all UEs are superimposed at the BS, and the objective is to allocate at the BS so that optimize the resources. In addition, I am using the network sum-rate maximization is a baseline, which is NP-Hard according to my own finding. However, I am not sure about this (NP-Hardness of the sum-rate maximization problem).

Does anyone have any suggestions for me?

Many thanks in advance.

What is CQI standards for D2D commmunication, can any one describe for me CQI in D2D?

I can´t get data from simulator because of some license issue/error.

I am working on the implementation of a small Wireless Sensor Network using USRP devices to form a star network consisting of multiple sensors and one controller. I am looking for a simple mechanism to synchronize the nodes with the network controller. There will be no communication between sensor nodes.

Antenna design in one software varies with result in another software. Also which one is better for mesh analysis.

The main functional block of a microprocessors is the ALU (Arithmetic and Logic Unit) because of its involvement in all computing activities. The important tasks of ALU are arithmetic and logical operations. Speed of the microprocessor mainly depends on ALU’s performance. Most of the processors are included with stand alone design for arithmetic operations. In very large-scale integrated circuits (VLSI), ALUs with various bit-widths are required to perform operations efficiently.

Papers:

S.M. Swamynathan, V. Banumathi “Design and Analysis of FPGA Based 32 Bit ALU Using Reversible Gates,” International Conference on Electrical, Instrumentation and Communication Engineering (ICEICE2017), 2017.

Mohammed F. Tolba, Ahmed H. Madian and Ahmed G. Radwan “FPGA realization of ALU for mobile GPU,” 3rd International Conference on Advances in Computational Tools for Engineering Applications (ACTEA), 978-1-4673-8523-7/16/31.00, IEEE, 2016.

we come to generation that subcarriers are no longer orthogonal to each other. here the different parameters such as amplitude, frequency and phase will change for each subcarrier. by using cognitive radio the spread spectrum is reduced. GFDM plays a major role here. im looking for an MATLAB code or LABVIEW code to analyze this.

anyone related to this work, kindly reply

What is the main difference between dual band and dual radio?

Let

A system equipped with:

Dual Band= 2.4 GHz and 5 GHz

Dual Radio=802.11 and 802.14.5

where 802.11 with 5GHz is deploy between air to air link

and 802.11 with 2.4 GHz between air to ground.

similarly some nodes are also connected through 802.15.4 with 2.4 GHz between air to air.

The above system is dual band dual radio

or triple band dual radio

or triple band triple radio?

What is the practical operating frequency of FEMTOCELL. What kind of antenna (arrays) is used in the recent models and what is the range?

One of the threat to humanity is THE emergence intelligent machines. When AI gets full control and when sky-net comes to exist....might be already there, ....the plan is to enslave humanity rather than making things easy for him. I know, soon the robots replace many employees and do many complicated jobs including industry works, medical works (complicated surgery, scanning etc), cooking, nuclear and other energy sector operations, care works for child and elderly etc.

Machines are smart and fast; they don't get tired, they don't do random (ie they are error free). They are very adaptive, capable of evolving abruptly and are self aware. Machines spy on humans 24/7, on every little corner of the earth due to the emergence of 5G which gives them this ability, the ability to track and identify everyone for every space-time on the glob with their direct satellite connection...and this means the end of human privacy. I have no idea what the fate of human being will be in such times.

Making human half machine half human (cyborg), a bio-mechanical being is one application of this field to create superhuman soldiers. Many countries including Russia, US, china, UK are using such technology side by side with their genetic engineering research to strengthen their military. They are always up to humanity, to destroy the human race from the face of the earth in every way possible.

5G is a key together with AI for all these to succeed. 5G towers are already in place to begin work in US and UK (some are already in operation). 5G has a data speed of 100 times that of the 4G network system and the towers should be installed very near to the client residents as it work in very short distance point to point communication. It uses very short wavelength or very high frequency which obviously expected to cause caner and other serious side effects on any living cell due to its high frequency microwave radiation. I know many people are not aware of the downside of such technology and the potential damage it might cause. It is my belief that 5G radiation is responsibly the cause for the massive death of birds and other animals near to such towers in US. The towers look like this, you might find one of these on your building or neighborhood.

I would like to know what you think about 5G network and the technology related with it.

It is needed in wide band reflectarray. Please clear this multiple of 360 degree effect on the bandwidth.

To get ouput graphs I need to generate vector and scalar graphs but can't find any way to do it. Only an event log file is generated.

User1- power(p1)

User2- power(p2)

P1>p2, how to detect P1 in case of power division multiplexing in NOMA in terms of matlab at the receiver

Thanks

Brij Mohan Kumar

M-tech (Communication Engineering)

IIT Patna

In optiwave the eye diagram shows the q factor how is this calculated?

Current research focus on 5G is on which bands in the frequency spectrum.

In optimization problem often we use local optimum but is it global? Or are there any meta-heuristics algorithm to obtain global solution? If there any then what is the name of that algorithm and if possible how we can get that solution?

I try to implement FBMC in simulink. I have already matlab code for FBMC but when I implement in simulink, it creates problem as poly phase network block is not available in simulink library.

I want to design an Op-Amp using CMOS technology. For that I have been designing a differential amplifier as an input stage. I am stuck at transistor sizing. Recently I came across gm/id methodology for transistor sizing. I would like to know how this method can be used to decide the aspect ratio of transistor. Please share some material, if possible.

1) Zigbee.

2) Wi-Fi

3) Bluetooth

4)NRF24L

etc

What kind of projects are out there in neural system analysis?

What are the take aways?

I know it can be applied to many of the industries, commercials, and at home.

But I am bit vague or cannot grip on what the term stands for and what can be done within.

I honestly thought neural systems are somewhat related to bioengineerings.

Would you kindly give some explanations??

I want to implement power saving mechanism in ieee 802.11ac networks. I want guidelines how should i design in netsim software?? please help me through this.

For my PhD topic and research, I wish to work on intercell interference mitigation (ICI) in heterogeneous networks (HetNets) using cell range expansion (CRE) in combination with hybrid power control (HPC) techniques. How can I effectively implement this?

Actually, I intend exploiting the advantage of CRE in offloading some users from macrocell to small cells (picocells or femtocells). Thereafter, power control technique/algorithm would be used to mitigate co- and cross-tier interference to offloaded users. I will appreciate any guideline on how to implement this, coupled with any helpful codes, links, textbooks and softwares.

Hi

My question is related to underwater acoustic sensor networks.

I have written the attached matlab code to calculate required transmission power based on distance between the sender and receiver and SNR threshold at the receiver(My aim is to calculate energy consumption ultimately). However I get infinity for required Intensity(Req_I) and Required Transmission Power (Req_Pt). Please suggest what is the mistake that is resulting in my required transmission power to be infinity and how can I fix the problem.

Best Regards

I am designing a VLC system with DMT. For the channel response, I have chosen BPSK on all subcarriers and calculated the SNR of each subcarrier from BER-SNR relation.

For subcarriers with SNR greater than required SNR for BER of 10^-3, I have increased the number of bits over that subcarrier. (for example if subcarriers SNR is greater than 9.8, I have changed the bits assigned from 1 to 2).For this new bit-loading, I have found that SNR of both QPSK and BPSK loaded subcarriers getting degraded. How can I arrive at a decent bit-loading to maximize the transmission?

I am interested in understanding what problems are remaining for reducing or removing wind noise for outdoor noise detection source localisation or speech enhacement.

FYI have a resonable understanding of non-stationary noise characterisation and beamforming approaches.

Thankyou in advance

What could be the maximum distance that one can control a UAV from?

Dear and Respected Colleagues

I am requesting to all those respected mentors and researchers working on Optical Communications Please help me on PM to IM conversion to generate UWB pulses?????

Having a periodic pulse signal p(t) with

p(t) = 1 for (n-1)*P < t-phi <= (n-1)*P+d*P and

p(t) = 0 for (n-1)*P+d*P < t-phi <= n*P

where phi is the phase shift, P is the period and d is the duty cycle.

(phi in [0,P), d in [0,1])

Assume that we sample the pulse signal K times every ts, i.e., we have p(k*ts) for k=0...K-1.

**Is there a limit on the accuracy of estimating the pulse parameters phi, P, d solely due to sampling?**

To my understanding, since (depending on d) there exist even and odd harmonics up to infinity, one is not able to sample with the double of the highest frequency. Thus due to image frequencies errors are induced. But how can this be characterized?

Thanks in advance!

I am working on systematic polar codes. But the problem is, after decoding we need to encode the decoded bits again to have the original information.

However, belief propagation (BP) decoding provides soft output. There is a problem again: after one iteration, the output (which would be used as the input of next iteration) is changed. Therefore, if it is used as the input in the second iteration, it generates an error. In this case, what would be the possible solution?

Thanks in advance.

i want to buid a scrambler in matlab for 802.11 standard

Hi everyone,

Could anyone show me some approaches for detecting and extracting wideband radar signals in ELINT systems? The receiver bandwidth is about 500 MHz.

I am currently following the time-frequency (T-F) analysis approach. However, I don't know which T-F technique is the most efficient one for this application?

So, could anyone help me in narrowing down the research?

Many thanks.

I would like to play an audio file Meanwhile plotting and updating a diagram. However, my audio file is interrupted. I would like to play audio file smoothly in background and update the figure at the same time.

for i=1:10

player = audioplayer(audio, Fs);

play(player);

scatter(x(i),y(i),'r.')

end

ETSI bursty traffic model

Can any one suggest application of microwave absorbers in 5G communication systems?

If yes, how do you treat the weights for the two different variables? Do you launch different weight vector for position and another one for the velocity?

I am trying to simulate a Cognitive Radio Sensor Network using Matlab. Can anyone be of help with a code for doing this? NS-2 can also be ok.

Thank a lot and be blessed

Dear all

I am writing a paper in the field of LDPC codes. I have a problem for simulating my proposed parity check matrix and obtaining the chart of bit error vs SNR values. I need to an expertise co-author in this field for finishing my paper. can everyone help me as co-author for simulating my paper? please contact me and I will explain more details

.

When the number of receive antennas is larger than transmit antennas, we have the relay beamforming matrix is written as wt*wr^{H}, where w_r \in C(M+n), and w_t \in C(M)? Is it reasonable for practical communication systems?

Any suggestion/hint will be appreciated.

Dear friends

plz let me know the mathematical relation of bandwidth of optical bandpass filter(OBPF) with FWHM/Pulse width of optical gaussian regenerated pulse at OBPF output???

i will be very obliged for your help

I am working on WSN localization for the Indoor Environment. I want to know either the use of yagi antenna is suitable for localization. What my thoughts are: When transmitting, a Yagi antenna allows more transmitted power to be sent in the direction of the receiver, increasing the received signal strength. When receiving, a Yagi antenna captures more of the signal, increases signal strengths. This can also reduce interference that makes this antenna ideal for indoor localization. Plz do help me regarding this as I am new in antenna design and configuration.

Secondaly, do calculation of compass sensor from antenna angle helpful in this framework.

Why so many of wireless gadgets operate at 2.4 GHz or 5.8 GHz? What is the reasons for choosing this specific frequencies for ISM bands?

Your answers will be highly appreciated.Thanks

Now a days ,For multiple frequency for different application,we must require frequency reconfigurable antenna.But it is challenging to design .

Hi

I need to implement my own channel mapping based on a different scenario. For example, in the list of bad channels and good channels which use RSSI or PER, I want to increase the BER for good channels in a certain time period. Another example can be rescheduling the channel list based on different timing or clustering.

I was wondering if somebody can help with the reference or hardware and BLE stack suggestion.

Regards

Ali

Compressive Sensing is very popular technique to process sparse signal. most of the researchers applying CS technique for DVB-T/DAB or OFDM, GSM based passive radars whose bandwidth is small, whereas FM has huge bandwidth.

if CS is not suitable suggest me any other techniques.

Thank you

I use following code to simulate a QPSK signal through 3-path Rayleigh channel,

signal_r=2*(rand([Ls,1])>0.5)-1;

signal_i=2*(rand([Ls,1])>0.5)-1;

QPSK=signal_r+1i*signal_i;

Es=((QPSK)' *(QPSK) ) / Ls;

N0=Es/10^(SNR_dB/10);

h=sqrt(P/2)*(randn(1,3)+1i*randn(1,3));

fading=conv(QPSK , h);

noise=sqrt(N0/4)*( randn(length(fading),1)+1i*randn(length(fading),1) );

received = fading+noise;

Is it right?

Why do I need to multiply (randn(1,3)+1i*randn(1,3)) by sqrt(P/2)? The denominator is always 2? How do I define P ?

h is called impulse response of Rayleigh channel? 3 paths are also called 3 taps?

Thank you for your answer.

Can any one offer a qualitative solution as to why partial grounding helps in enhancing bandwidths in patch antenna?

I want to know how can the coherence times of a 3.5 GHz channel can be scaled to a 800 Mhz channel?

Can someone give me an idea?.

Hi, i would like to estimate my channel (Multipath Rayleigh channel) using preambule. I don't understand how to do this in Matlab and how to know the length of the frame( the period to insert the next preambule) and what will be the suitable function to model the channel in this case (in terme of matlab code)

trying to decide if demodulation is done in DSP itself ,instead of demodulation circuit

Hi everyone, I'm working on arithmetic compression. I am trying to compress the channel iut of the international standard. With my algorithm I have a compression ratio of 0.86 if I take the channel A iut with a modulation ofdm of 128 subcarriers.

NB: I send the exponential form of the complex numbers therefore of the angles comprised between 0 and 2pi.

Then my question is: would anyone have an idea to create an algorithm arithmetic enough powerful because mine gives results that do not bother me

I'm trying to understand the different modulation techniques for the satellite communication

I have implemented Sum-product algorithm (SPA) in Octave for BPSK. I am having trouble with getting the equations for updating check nodes and variable nodes for QPSK. I could map with 64 QAM constellation diagram.

I have not studied coding theory or probability in detail. I had read about LDPC codes and decided to implement it in Octave.

I did an antenna design on Sonnet EM simulator and wishes to view the far field on Matlab or any other possible means.

Any advice is highly appreciated.

OFDM - Orthogonal frequency division multiplexing (orthogonal sub carriers)