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Mobile Communications - Science topic

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Could any one please help me in suggesting some resources where I could find a comparison curve between signal strength after Multi Path propagation effect with respect to obstacle positions between transmitter and receiver.
After conduction some experiment I found that the effect was greater near Rx or Near Tx but lesser when the obstacle is in same distance from Rx and Tx. Why such phenomena happens?
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I suppose this depends on what kind of obstacles you are considering and how they are affecting the signals. If you consider an object that is scattering the signal, then the pathloss will be proportional to (d_1*d_2)^2 where d_1 is the distance from the transmitter to the obstacle and d_2 is the distance from the obstacle to receiver. For a given total propagation distance d_1+d_2, it follows that the pathloss is at its smallest when the scattering object is close to the transmitter or the receiver.
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I want to parse signals coming from 4G/5G towers to extract only the ID of the tower and the transmission time (on simplex communication: only downlink). Are these packets (or frames) sent on a regular time interval ?
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You can down load the several software like net monitor in your mobile and you can check the network health ' data rate (TX and rx) tower id, RSSI ' signal to noise ratio etc in stationary as well as in state of mobility .G-net is also useful for primary investigation respective to the different channel ( BCCH' TCH ETC).
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Hi everyone,
I have designed one mobile antenna. When is I was trying to calculate the SAR values for this antenna I got an error "the total mass (0 g) smaller than selected SAR averaging mass? Please select smaller average mass". Did anyone encounter this type of error while calculating SAR value? If yes please help me how I can get a SAR value.
Thank you
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I face the same issue and I have tried to reduce the volume didn't make difference. I don't know how to fix.
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I have initiated an intervention in 2 communities in an area where suicide rates are very high. I will be initiating the same approach in 2 villages in another district where suicide rates are high. I am doing a literature search on intervention for suicide prevention and so far have not found anything. I am approach this initiative as part of the participatory action research paradigm.
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As many as four in 10 UK PhD students may be at “high risk” of suicide, according to a study that underlines the chronic levels of stress among doctoral candidates...
Loneliness and intellectual insecurity highlighted as prime reasons for elevated suicide risk among doctoral researchers...
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In 5G, the mixed-numerology is introduced to support diverse QoS requirements. It is also mentioned in the spec that simultaneous transmission and reception with different numerologies in CA is possible.
However, there is few materials mentions how this is achieved. Does a UE requires multiple antennas to transmit with resources of different numerology at the same time? Or it can be done by a single antenna? If the latter is the truth, how does a UE deal with different SINR values generated by resources with different numerologies? (different SINR values lead to different modulation scheme, how can this be done with single antenna?)
p.s.
I have found one paper that is related to my question:
It seems that a UE can deal with resources with different numerology simultaneously, with different modulation scheme. Yet, this paper does not show how this is achieved by the smartphone.
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It would be nice from you that you define the relation between the communication symbols and numerology??
This is the first time that I hear from such vocabulary in electrical communication systems.
What I know is the different symbols resulting after modulating the binary data.
There are binary symbol where every symbol contains either binary 0 or 1.
There is the the 2-bit symbol representing values from 00,10,01 and 11.
There is 3-bit symbol which has 8 states.
and so on.
This method of M-ary symbols help control the number of bit hertz.
And one can send more data in the same bandwidth by using higher order modulation.
It is known that every channel condition or S/N ratio can allow specific symbols.
If it mean symbols then yes one can control the order of modulation of the symbol.
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Can someone help me to solve this task below.
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What i can’t understundom you Kenechukwu Emmanuel Umeh
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we imply that 5G should not be considered as merely an
evolutionary development of previous mobile systems, but should be considered as
a completely new paradigm in mobile communications. why?
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Wireless technology changes gradually, because the demand for data services and quality-of-service are changing gradually. However, there is hope that 5G will enable a paradigm shift, in the sense of supporting the digitalization of our world. So 10 years from now, when we look back and compare 2021 and 2031, the belief is that 5G will have contributed to radical changes in how vehicles, IoT devices, factories, and work places are now wirelessly connected and support stringent service requirements.
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I am trying to obtain closed-form expressions of outage probability for a user in a given cell. Here I am including inter-cell interference (from other adjacent cells) in the expression of SINR. Now I need to obtain the closed-form expressions of outage probability over a fading channel like Nakagami or Rayleigh. Please suggest any information regarding this. thanking you
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It is generally hard find closed-form expressions. It always the same math involved:
Say that the SINR is S/(I+sigma^2), where S and I are random due to fading. Then the outage probability when communicating at the rate x is:
Pr{ log2(1+S/(I+sigma^2)) < x } = Pr{ S/(I+sigma^2) < 2^x - 1 }.
If you know the distribution of S/(I+sigma^2), then you can compute this directly.
If you only know the PDFs of S and I individually, then you need to rewrite it as
Pr{ S/(I+sigma^2) < 2^x - 1 } = Pr{ S - I (2^x - 1) < sigma^2 (2^x - 1) }.
Now "sigma^2 (2^x - 1)" is a constant, but you need to compute the PDF of "S - I (2^x - 1)", which can be done via integration. The joint PDF of the sum of random variables is obtained by convolution.
At the end of the day, the chance that you get a nice PDF of "S - I (2^x - 1)" so that you then compute the probability is closed form by integration over the PDF from 0 to sigma^2 (2^x - 1) is not so big.
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Both Jakes and Gaussian models are used to characterize the power spectral densities of mobile communication channels.
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welcome!
peace upon you!
My opinion is that these functions are physical functions and not only a mathematical or statistical instructs.
The white noise is generated naturally in resistive and electronic devices and circuits. They appear always as an annoying signal to the useful signal.
Such noise signals are characterized by Gaussian distribution and in the frequency domain they appear as a consatnt spectral power density eqaul to kT.
So, what is the motivation to get an equivalent! What is meant by equivalent distribution!
May be important as the additive white Gaussian Noise is the channel fading and how it attenuates the signal randomly in spatially and temporarily. The probability density function of the signal amplitude follows two models the Rician channel model and the Rayleigh model. While the Rician model has a line of sight components the Rayleigh model assumes complete scattering of the signal.
There are also practical wireless channel models for different environment
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Hi I a doing a Phd in mobile communication .i am facing too much problem to understand the math equations. the main problem is how to use the equation for my work .i am working on Massive Mimo channel estimation and pilot contamination. how i can setup my data from scratch please some one help me how should i start .send me some example if you people have to understand how the data is taken and analyze .Plzzzzzzz need a Help if some one can. waiting for your prestigious advise and help
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Hi!
A good understanding of linear algebra and probability theory is necessary to do good research in this field. If you want examples of how to transfer equations into simulations, you can have a look at my book and the accompanying code:
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The information industry have created a new species, Homo online. Members of this species are connected to various communication systems all the time: they communicate for the sake of communication. It is normal to communicate with other people, but to be constantly online is mentally exhausting and it hinders the development of an independent person. I could not read or write efficiently and with pleasure without silencing the devices around me that could interrupt my thoughts at any moment and for any reason. But Homo online has prevailed, and Homo sapiens has become a species in extinction.
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Species don't evolve that fast, they don't evolve from one generation to the next. However, it is only technological progress that is so dynamic and causes changes in people's behavior, e.g. in terms of the dominant communication standards. Communication is becoming more and more remote, realized via the Internet. In addition, the SARS-CoV-2 (Covid-19) coronavirus pandemic accelerated the processes of digitization and internetization of many spheres of human activity. But it is still the same species of Homo sapiens.
Best wishes,
Dariusz Prokopowicz
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with a well known fact that the success of the 5G technology vastly depends on how well it fared in indoor venues, with analysts claiming that more than 80% of mobile use and tearric originates indoors, what are the available specialized solutions that can make the technology succeed indoors, while keeping both its QoS possible health hazards in check.
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hi Orogun Adebola , 5G brings high speed, not all the time needed , but in IoT standardization 5G offers a best deployment solution for Smart city , self-drive cars, E-commerce an a lot of future solutions.
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What is the maximum speed of user at which GSM link can perform?
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The highest speed of the user during the communication session is determined by the maximum allowed doppler shift variations as the Doppler shift causes fast fading in the channel. This fast fading can be equalized up to some extent and so one has to limit speed of the vehicles to make the distortion affordable and the quality of service acceptable.
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I am new to in NS3. I am working on LTE networks. I was looking for calculation of Load information of each cell and exchange of the same between eNBs (over X2 interface/ based handover). Could any one please help me with pointers to code, or if you already have the code snippet.
I did search through the docs. But still needed some additional help. Could you please help me.
Is it possible to calculate the number of RBs allocated to the UE in NS3?.
Thank you.
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Thank you for all the answers. I will read through the materials.
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I am looking simple method to design 1*16 microstrip power divider for wideband (impedance bandwidth 5GHz) at 30GHz. Please suggest me easy method to design power divider for wideband applications.
Thank you very much
Kanhaiya Sharma
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You can use active divider composed of emitter follower or source follower transistors connected in parallel. Every emitter follower has matching function to transform 50 ohm output resistance to 50 x16=800 ohm.
This will be a very wide band divider consisting of 16 emitter followers connected in parallel. The input will be capacitively coupled.
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By using the Narda SRM 3006 device to measure electromagnetic radiation:
-What is the period of time required for each location or spot to measure?
-How can I insert and name frequencies whether for radio broadcasting, television, mobile communications and wireless communications?
- What are the conditions required necessarily when measuring?
- Some researches say that a person should turn off the transformer while measuring. Other researches say that a person can receive a phone call during measuring. Though I think that switching the mobile off is the right choice. So, What do you think?
-Finally, can we transfer data from the device to the computer in a form of an excel file?
I hope the experts in this field answer me please
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The device senses the electromagnetic radiation by an antenna and amplifies it by a wideband low noise amplifier and then a fast Fourier transform to analyse the frequency spectrum and display it on a screen. It can acquire the field strength in a real time as the stated in Data sheet.
Since it is a wide band electromagnetic sensor one must turn off all interfering sources as the instrument will sense it.
We mad a similar set up to sense the EM radiation:
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I'm working on cellular radiations and I have SRM-3006 to measure field strength. I'm asking for more accurate meter?
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To measure the field strength you can use circular coil whose winding can have an air core or even ferrite core. The emf induced in the coil will e= N dphi/dt,
phi is the magnetic flux= B A , B is the magnetic induction and A is the cross section area of the coil. B=mu Hwith mu is permeability of the core medium and H is the magnetic field. The electric field E= H zw, zw is is the wave impedance which is a Eucharistic of the medium.
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Where we are going ,in which direction
Is this phase of life will leads to on online,mobile communication but one to one communications is going towards ..........
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I would like to bring some clarification here.
There are at least two layers for communication:
-service layer, including user interface
-network layer, including infrastructure
One to one communication at service level will always exist.
One to one "cabling" has been removed in the early days of telephony by switching. A switch is a matrix n x m: n input, m outputs. Calling party 2 can be connected through the switch to receiving party 21...
You had manual switch (telephone ladies in the past, that was discrimination...) then electrical switch (cross bar) and electronic switching. This is why telephone exchanges were large building and are now a chip...
You can add cherries on the cake, but that's what you have inside.
Now you have the social preferences at play: one to one, one to many, many to one, etc...
Group communication, private one to one exchange...
Humans always add features, and rarely suppress any of what they have.
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The mobile cellular communication uses 4G Long Term Advanced Evolution (LTE-A) technology which is a platform for 5G technology.
The fundamentals of D2D communication is to utilize mobile devices as relays that are placed between source and destination. The D2D system is the communication between two adjacent cellular devices by reusing the cellular spectrum without having to do routing to the base station. The D2D communication systems can increase capacity with the shared use of frequency sources between conventional cellular users and D2D users. It also increases the data rate due to the close communication distance.
Papers:
G. Fodor, et al., “An Overview of Device-to-Device Communications Technology Components in METIS,” IEEE Access vol. 4, pp. 3288- 3299, 2016.
C. Yang, T. Jiang, and C. Wang, “cooperative device-to-device communications in cellular networks,” IEEE Wireless Communications, vol. 22, pp. 124-129, June 2015.
S. Chen, S. Sun, Y. Wang, G. Xiao, R. Tamrakar, “A comprehensive survey of TDD-based mobile communication systems from TDSCDMA 3G to TD-LTE(A) 4G and 5G directions,” China Communications, vol. 12, no. 2, pp. 40-60, 2015.
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A comprehensive survey on D2D communications, covering different aspects related to modeling, mobility management, and applications can be found here:
Article A Survey of Device-to-Device Communications: Research Issues...
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With fast growth of mobile communication network, 5G technology has been officially on use. As we all know that 5G can provide extremely wider bandwidth and faster internet speed than 4G. 5G network is absolutely able to transmit high definition media in real-time application, so is it really necessary to compress image or video?
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image/video compression is necessary because of transfer on network from cloud/server to client, fast loading in web pages, and save storage
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Different companding methods such as μ-law, hyperbolic tangent, exponential, linear symmetric transforms, linear asymmetric transforms and threshold log companding are used for PAPR reduction in OFDM.
Is there any other efficient companding methods?
Besides, is there any other method of PAPR reduction in OFDM except companding?
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Dear Abdullah,
welcome,
There are some methods to reduce the peak to average power ratio of the OFDM signal to lower their dynamic range during transmission needing smaller power amplifier. If you go to my research page you will find most of the methods used for this purpose: https://www.researchgate.net/profile/Abdelhalim_Zekry/research
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Hello everybody,
I have identified some technologies that enable the 4th and 5th generation of wireless mobile communications. However, I wonder if there are some other missing technologies in this list, or if some technologies in this list are not really that important  for 4G and 5G. 
Enabling technologies:
- MIMO
- Smart antennas
- SDR
What is your opinion? Thank you in advance.
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Carrier Aggregation, Massive Connections, 3D Beamforming; IoT; M2M; MIMO 128TRx
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it will be useful for removing such pockets for making mobile communication more effectively.
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I think its not related to satellites but depends up on the signal booster network by cellular companies.
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I had the thought today about Facebook, Twitter, and many other online/mobile platforms which continually feed us "top posts" or content based on location.
I don't like this because I like to select my own content. Today I realized that this could be related to self-efficacy. I feel that I have high self-efficacy and therefore I like to select my own content.
People who blindly accept the content "served" to them become functionally helpless, which aligns with low self-efficacy. Of course, it is possible to overcome these content defaults, but it is harder to do, particularly on mobile devices.
In my mind, this may align with stereotypes of the young people in the US who are just transitioning from teenager to adult. The stereotype is that over-protective parents have shielded them from any hint of failure, so they have never learned to solve problems on their own.
So my question is whether lack of choice in our social media feeds contributes in any way to an overall lack of self-efficacy in people today.
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I am for agenda media, for experience suggests that they use lots of different social media already, and for slightly different purposes--some for peer-to-peer networking more information sugest.
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1) How to Reduce the mobile radiation without affecting the effective mobile communication ??
2) How to Reduce the specific absorption rate (SAR) of bio-tissue of electromagnetic radiation found in cellular communication ??
** I want to start in this field but I do not know how to start and I want help. I want to participate with researchers in this field .
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The link given by Dr Arvind Singh is extremely relevant
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1) How can I Reduce the mobile radiation without affecting the effective mobile communication ? .
2)How can I Reduce the specific absorption rate (SAR) of bio-tissue of electromagnetic radiation found in cellular communication ?
**I want to start in this field but I do not know how to start and I want help
**I want to participate with researchers in this field
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Dear Omniea,
welcome,
May be the major effort must be directed to reduce the radio frequency dose incident on the body of a human. This can be accomplished by reducing the power of the source of such radiation. This a matter of the communication system design issues. I do not know whether you are a communication engineer of which is your specialization. There are some methods to reduce the radiated power from the base stations while keeping the achieved data rate constant. The most effective method is using MIMO systems.
The other solution may be to decrease the area covered by every base sations. this will reduce much the power radiated since the distance is proportional to square root of the power.
May be one of the most serious sources are the mobile terminals themselves as most of them are handheld. especially when one makes a talk.
There are some precautions that one uses to reduce his subjection to the rf radiation as to communicate hand free through blue tooth devices.
The other issue is the biological effects of such radiation on human tissues. There are many studies on such biological effects of the rf radiation on the human body.
Best wishes
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Terahertz range of frequencies is the future range of mobile communications what are its pros and cons??
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The "only" reason to go up in frequency is to have access to more bandwidth. More bandwidth also requires higher sampling rate and higher frequencies require transmitter and receivers that are capable of modulating signals of that kind.
Visible light is one example of terahertz signals. Just as visible light is blocked walls and other objects, terahertz applications will be limited in the same way.
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What is the practical operating frequency of FEMTOCELL. What kind of antenna (arrays) is used in the recent models and what is the range?
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I have designed an microstrip multiband antenna...got the frequencies has 12GHz,13GHz 28 GHz and 38GHz... actually mmwave frequencies...can I use it for femtocells is my question??
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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.
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I rally liked your description of the expected disastrous effects of 5G, and I asked Dr. Ted Rappaport (one of pioneering professors from the NYU in the field of mmWave and 5G) about the health effects resulted from using such frequencies and he mentioned that he did this research on that topic before beginning his experiments on the mmWave channel measurements few years ago:
It is obvious that using these frequencies (i.e. mmWaves) is far from ionization that causes health issues for humans if they are used in the right way and according to federal regulations.
Best Regards.
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The non-linearity of power amplifier limits the power output efficiency. So, we can use DPD technique to improve it. But we need to know the power amplifier with the memory effect or memory-less. I hope that i can use some kind of test or experiment to verify it.
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This question iv very interesting. To answer this question clearly one has to define exactly what is the memory effect in the power amplifier. There is a principle concerning the measurement of the quantities. The quantities are measured as they are defined.
Memory means to preserve information when the time elapses. So, it is a direct time domain effect. It is so that one can preserve a analog sample for specific time in a capacitor. So, if the devices are containing energy storage effect they will show some memory effect. The memory effect in an amplifier can be tested by applying a pulse on the amplifier and then observe how long this pulse can last after the input pulse is removed.
If there is no memory effect the two pulses will follow each other in the time variations. This is straight forward from the transfer characteristics of the strictly linear amplifier Vo= AVi with A is the gain, Vo is the output voltage and Vi is the input voltage. So Vo is a replica of the output and no memory effect at all.
So, we have to define the memory effect on time domain and then determine it in the frequency domain.
Best wishes
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Here, I want to make an array of metamaterial microstrip patch antennas for mobile communication to enhance bandwidth and gain. I plan to use HFSS tool for the simulation part.
So, would you help me in directing the ways to follow by any means?
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there is a tutorial at ANSYS. My recommendation - first use eigenmode solver on one cell with periodic boundaries to see approximate dispersion. Floquet port works for wide structues and refracting arrays.
then use standard driven modal. Just my recommendation - add air/material dummies in the structure, near gaps, boundaries, and seed them manually. HFSS can "skip" meshing such things like interdigital capacitors, and give out wrong results.
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Current research focus on 5G is on which bands in the frequency spectrum.
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1) 3.5/3.7GHz : Band n77/n78
2) 4.5GHz : Band n79
3) Upto 6GHz : BW>500MHz (WRC15 band)
4) 10GHz, 17-18GHz, 24-25GHz, 27-30GHz, 32GHz, 36GHz etc (WRC19 band)
5) 26/28GHz : Band n257/258
6) 38GHz, 40.5-43.5GHz, 60GHz etc freq. bands
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A narrow waves - short time (in nanoseconds) -short distance - wide bandwidth 3.1 to 10.6 - low power emission is very attractive for antenna designers, But will it be in some how has a benefits for 5G applications?
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Dear brother Lway,
your question is about the possible use of UWB antenna for 5G. As for the possible applications of the UWB communication system as it is standardized by ITU, it is a very short range communication system. Mobile communication systems are wide area communication systems. So, i agree with you the UWB communication systems are thought to complement mobile communication network like WIFI and blue tooth to save cost and congestion of the wide area networks. For more details about the possible applications of the UWB systems please refer to the link:https://core.ac.uk/download/pdf/29820629.pdf
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Mention some features of Android Pi
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Thank you Prof.Amina Bouraoui
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I am try to do a project on Routing Optimization in mobile communications. What question should I ask so as to what direction to follow in getting the best result for my project?
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You could focus on how close to optimal the routing algorithm is. But getting closer to optimum becomes unimportant after the algorithm's performance becomes good. More important are questions about how much bandwidth is used by the signaling and management overhead of the algorithm, and how robust the algorithm is to changes in the topology of the network.
For example,
(a) How often do the components have to communicate in order to maintain the current network structure and how much information do they need to communicate?
(b) When network components leave the network or new components enter or existing components change their connectivity relationships, how much signaling and management bandwidth is required to keep the network operating efficiently and without disruption?
These questions should probably be posed so that the measures of quality include (1) ratio of overhead bandwidth to useful,, traffic-carrying bandwidth and (2) loss of bandwidth efficiency as the network topology changes and the network is reconfiguring itself.
Also, is the algorithm brittle, so that usual changes might require large amounts of signaling and management to restore near-optimality for trans-network communications, or is it robust to changes so that even as the network morphs, overhead remains small and nearly constant? Are there scenarios where catastrophic reductions in traffic-bearing bandwidth will occur? If so, how should you make the network more robust?
I think that as you consider issues like these in addition to near-optimality issues, other questions will occur to you and you will be on your way to designing a well-engineered real-world system.
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My question regards the real necessity to have subframe (3GPP Rel. 12) or slot (3GPP Rel. 13) aligned transmissions in the unlicensed band.
According to TR 36.889: "Channel reservation refers to the transmission of signals, by an LAA node, after gaining channel access via a successful LBT operation, so that other nodes that receive the transmitted signal with energy above a certain threshold sense the channel to be occupied." This signal is transmitted until the next subframe or slot boundary is reached so that transmissions are aligned.
The channel reservation signal defined by the 3GPP standard adds an overhead to LTE-LAA transmissions that impact on its performance. If there were no necessity for any kind of time alignment to the PCell the SCell performance could be increased.
Therefore, my question is, what would be the possible implications to all LTE layers if the transmissions were not aligned at all? 
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I am still trying to understand if the time alignment to PCell's time frame structure is really necessary. It seems there could be non-time aligned transmissions by the SCell as long as it transmits the necessary signals (RS, PSS, SSS, BCH, etc.).
Does anyone know if there is some kind of limitation to non-aligned transmissions?
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3g and 4g uses the radio frequency band 
well how is the actual planning done for the cellular communication
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Hello,
For 3G and 4G communication, frequency is arranged or taken according to antenna used and feasibility of manufacturing antenna. Wi-Fi frequency is fixed according to IEEE standards which is 2.4 GHz, but to enhance bandwidth to use more and more channels, frequency is increased in limited gain. Now selecting frequency, is depending on other parameters of communication systems.
refer the papers.
Thanks,
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Dear Colleagues:
Our research team wants to do a work to assess the importance of public and private communication systems (social networks, websites, blogs, scientific forums, among others) to foster collaboration with scientists from a country abroad and support their return. I would be grateful if you could provide us references of this interesting topic.
Best Regards
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Kindly see this reference (Paper title: Social Media, Collaboration, and Scientific Organizations).
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How to determine the safe exposure limits of cell tower radiation? Are the current exposure standards are adequate to safeguard our health ?
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I suggest that you look at the Bradford Hill criteria : https://en.wikipedia.org/wiki/Bradford_Hill_criteria
These give you some idea of the data we would need to show significant danger from mobile phone radiation. 
As we stand on the brink of a mass extinction, we have more to worry about than hypothetical dangers. Let's try and work on the real threats to the planet. 
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i've noticed that majority of engineers are focusing on the technical side of development of telecom equipment either in mobile communication or any other sub-field , compared to computer networking ,engineers do their best to develop new security solutions ! 
i don't understand why there's always this  lack of interest in security field in telecom  !! 
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I think maybe we are just talking about different protocol layers? It's a bit like asking why IEEE 802.3, the Ethernet standard, doesn't address security. Security is built on top of Ethernet. At least, that's the typical way of implementing security.
The other point is that a telecom does need to implement security measures, but this is primarily to protect itself. For example, their system management messaging, routing tables and routing protocols, have to be secure, to prevent a hacker from disrupting the system. But it doesn't do much good for the telecom to secure user traffic, if ultimately, at the edges, the traffic has to be sent in the clear. If a user of the telecom wants security, that user must install a solution that protects traffic end to end, from inside his PC or smartphone, all the way to inside the PC or smartphone at the other end. Or in the case of an enterprise network, security could be implemented until the link is inside that enterprise's "secure enclave," perhaps not all the way to the end system. So for example, the enterprise may deploy secure tunnels, through a telecom network, where the end points of those secure tunnels are inside secure enclaves.
Otherwise, anyone along that path would be able to monitor the communications. And there is no reason for a user to trust the telecom itself, ultimately, if that user needs security.
Security can and is implemented at any protocol layer. From the standpoint of a user, though, any security measure that is not end to end would be of questionable value. That's why people use Transport Layer Security so often, when dealing with communications across telecom or other network services. It's security built over the telecom link, carried transparently by the telecom or by the digital network.
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What is the SOMA(Semi orthogonal multiple access) considered for 4.5 G wireless networks.
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Thus it can solve the Uplink capacity shortage of  mMIMO system.
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I don't know my question is correct or not ?
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Rayleigh fading only gives you diversity order of one, while the Nakagami-m fading model will provide you with a diversity order of m. Having said that, both Rayleigh and Nakagami-m model will not describe the line-of-sight (LOS) transmission environments well. Some authors proposed to use the Nakagami-m model to approximate the Rician fading, and such an approximation is not recommended since both models donnot even give you the same diversity order, and Nakagami-m cannot be used to describe the LOS transmission, which has been empirically verified (Read the paper by Molish). Another reason why the Nakagami-m model is popular is because its mathematical form is more analytically tractable.
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My name is Profir Victor.
I study telecommunication master's Technical University Gheorghe Asachi Iasi, Romania.
I need help, my final diploma is on the subject -  LTE Advanced Pro: Effective solutions for modern communications systems
I need documentation on LTE Advanced Pro:
- Problems and solutions for today's mobile communications systems.
- Mobile Network Architecture.Evolution LTE-A pro toward 5G.
- Carrier Aggregation in LTE-Advanced Pro.
Thank you,
Profir Victor
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Dear Dr/ Profir
I will send some of reference about mentioned subjects,
You recommend Books or Papers.
best regards
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Different BSs are having varying transmit powers. So I want to know What is the probability that only one BS, two BSs , three BSs ...., are in the range of a User Equipment.
Please refer me if you have any reference paper or book to read.
Thanks in advance.
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@Javier and @Sudarshan thank you very-much for your valuable advice. 
This will help me in my research. 
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The objective is to understand the contribution made by citizens to the production of science.
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It;s a celebrated method in crowd-sourcing research community. Mobile empowers the network with enormous number of potential nodes around the globe which can be used to collect data, verify it and update it.
Corwdsourced disaster reporting and alerts is a naive use case.
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In 2G and 3G, challenge response method is used to authenticate the mobile SIM. SIM computes SRES for each RAND and sends to Authentication center for authentication. A suite of algorithms are used to compute SRES in 3G. How 4G LTE implements authentication? What algorithms are used?
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Which equation (14 or 15) in the paper (attached in the link) gives us the average outage probability?
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Outage probability is the probability that a system does not function as per the expectations, such as the probability when the instantaneous SNR falls below a threshold SNR. But if the SNR considered is received SNR, then that received SNR which depends on the wireless channel could be considered random. So, we need to average out the received SNRs for various channel realizations. Hope this helps. 
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A signal is transmitted by the transmitter and multiple rays arrive at the receiver as a result of reflections (from the flat obstacles), diffraction (from the edges of obstacles) and scattering.
How do I find the number of clusters in this condition?
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The following document may help you:
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Looking for a way to measure, record, and export raw acceleration from the smart phone's internal accelerometer.
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Hi Alison, 
for teaching biomechanics I often use an app from the a Technical University of Aachen/Germany named 'phyphox'. They also implemented some nice experiments for students.  see details here ----> http://phyphox.org
Regards from Cologne / GER
Bjoern
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I have to get those cdrs in a Nokia's MSS system working on sotware M15 version. 
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I'am looking for a CDR structure for a Nokia's MSS system working on software M15 version too. Is there so easy to get the name of those storage to go there and then download it? Please I would like to know those? Regards 
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Currently, OFDM seems to be the dominant modulation/multiple access scheme in wireless/mobile communications systems. However, research platforms such as Horizon 2020 suggest that the targeted systems for 5G should be significantly more frequency efficient and 10 times more power efficient than the 4G counterparts. It looks like all B4G and 5G trials are stuck with the same level of frequency and power efficiency as the 4G ones.
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As far as I know, this has not been decided yet in 3GPP. But almost all the companies involved in 3GPP have proposed different forms of OFDM. So it is quite likely that 5G will use OFDM with additional filtering or tweak to better support certain types of traffic.
Please note that the modulation choice (such as OFDM) has little to do with increasing the spectral/energy efficiency in 5G. Higher data rates will be achieved by a combination of MIMO transmission and using more bandwidth.
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I have modeled proportional fair (PF), round robin (RR) and best CQI (BCQI) scheduler. I have calculated the fairness of the schedulers using the users throughput. Now, I want to compute the latency of the schedulers.
How can I calculate the latency? 
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hi
It's a difficult question, where are you Implement the algorithms. for example if you implement the algorithms in the C/C++ you must use time.h and sample header files to compute latency time.
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I want to simulate the several traffic models and evaluate their performances in terms of UE throughput.
I have gone through many literature's but ended up on their theoretical aspects only. 
Are there any links or journals or textbooks available that deals with their theory and the associated equations?
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I need to compare my data with existing mobile phone ratings, however, i am not able to find any mobile ratings dataset. Their exist mobile datasets related to signal coverage but not related to how users like a mobile phone or how do they rate a mobile phone.
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Dear Muhammed, 
The specifications of the mobile handsets in the given link may be of interest to you.
In addition mobile phones are built to satisfy the ITU standards.
wish you success
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Can anyone give some idea about the smallest unit of resource that can be assigned to a user in 5G cellular networks? Like in LTE-A it’s known as PRB so what is in 5G?
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Khalid's answer is very interesting, implying that the "smallest unit assignable" would be, ultimately, something like 9.6 kb/s, for a voice cellphone call over 5G, to one MVNO sharing that 5G infrastructure.
In the US, cellular companies have not operated this way, ever. Originally, with analog service, yes, they were sharing each other's infrastructure, but when your phone was out of reach of its "native" service, you would be charged so-called "roaming charges."
Then, with digital 2G and more so 3G service, that roaming practice essentially ended. In my experience, the first 2G phones could roam over someone else's analog, but soon that ended. And in the US, by 2008, all analog cellular stopped.
So, I truly wonder whether the concept of virtual operators, sharing the same infrastructure, will ever happen with 5G in the US.
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I need data related to wireless resource management and interference mitigation for 5G mobile networks. if someone have please share with me.Thanks 
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Major difference in modelling LTE Carrier Aggregation and LTE-WIFI link assisted access (LAA)?
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You might want to look through some of these presentations.
LTE carrier aggregation, including possibly aggregating LTE carriers in the unlicensed spectrum, treats the aggregated LTE carriers as one wide LTE channel. Whereas if LTE offloads traffic to WiFi, that is a separate link, using the WiFi protocol for access, IP routing, and so on. And, importantly perhaps, the cellular carrier will not make revenue off the WiFi session, as the cellular carrier might make if the aggregtaed link were another LTE channel, or even LTE-U (LTE over the unlicensed spectrum).
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Someone knows maybe a white paper about rcs technology?
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Thank you, Michael :-)
And sorry for my late answer
Die gsma hab ich in meinen Recherchen bisher einfach übersehen. :-(
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Interested in analying higher oder modes concerning circular-ring patch antennas
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A circular patch antenna can be treated as a circular cavity and it supports modes which are perpendicular to the patch, as with a rectangular microstrip antenna. The first mode (TM11) produces a broadside radiation pattern. At higher frequencies, the second mode (TM21) get excited and this mode produce conical radiation pattern with lower gain.
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Could UWSim be used for designing pure networking stuff e.g. routing and mac protocols, localization techniques etc? I want to implement a localization technique for mobile underwater sensor networks. For this I expect my simulator to provide me with channel model, mobility model and a mac protocol for underwater sensor networks. Does UWSim provide all these?  Is it a good idea to use UWSim for my work?
Best regards
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P.Xie et al. developed a new UWSN simulation package called Aqua-Sim. This simulation tool follows the object-oriented design style of NS2, supports three
dimensional modeling and it can simulate acoustic signal attenuation, propagation delays and packet collisions. AquaSim integrates very easily the existing codes of NS2 and has an adequate number of MAC and routing protocols specially
designed for UWSN. Finally, because of the lack of a NS2 NAM animator to visualize 3D UWSNs, uses an additional tool, the Aqua-3D animator. on the other side UWSim is also a simulator that has been used for underwater sensor network modeling. This simulator designed and implemented for testing scenarios specific to UWSN environments, such as low bandwidth, low frequency, high
transmission power, and limited memory.The software development follows C# object-oriented programming and it is based on a novel routing protocol proposed by the
developers. Currently, UWSim has support for a limited number of functionalities, it is custom-designed for a specific algorithm and it calls for further extensions to support a wide range of UWSN simulation scenarios.
i hope it's useful.
best regards
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Dear experts, I am a computer scientist and I know that there is some schemes to perform location-updates/page of mobile users within a cellular network. I would like to know if these schemes are standard (i.e. in all generations) or are specific to each generation ?
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Dear Moiz,
sorry, i am not an expert in this field,with my little knowledge i can  say the schemes are valid for that particular generation and of course  there will be backward compatibility with the new generation with a truncation error in the data.
with regards
vasanth 
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I'm making location based alarm.I want to get mobile towers' signal to it.But I don't have any idea about how mobile tower work.
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Hi everyone, I have the masurement channel transfer function for 24 x 24 MIMO channel (point-to-point MIMO). From UCA antenna, dual polarized (12 elements). Basically I want to simulating the large array from these array results, any idea to extrapolate so I can have, let's say 128 x 24 MIMO, etc. Thanks!
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I am unable to attach the paper. Please see:
[1]    W. Wiesbeck, L. Sit, “Radar 2020: The Future of Radar Systems,” in Radar 2014 Conference Proceedings, Lille, France, 15. Oct. 2014
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How can we implement nakagami q and eta-mu fading channels in MATLAB?
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Thanks Sir for ur reply. If we want to simulate the system using monte carlo simulation the what is the procedure? Do we require mean and variance of these channels to implement this?
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I'm interested in the fusion of GPS and WiFi for outdoor and indoor localization. i need the data set of GPS signals (longitude , latitude and altitude) in outdoor area, and the RSSI data set of WiFi access points in indoor environments.
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Hi Marwan,
you can find several traces as datasets in my publications list. I have several papers on a mixed indoor-outdoor environment with associated datasets. Feel free to contact me for more information. As an example, see publications attached to this post. Critical can be the fact that we never recorded the elevation/altitude since we are doing 2D localization. However, you can simply add the altitude as 2 m yourself to the traces since the UAV, we used to sense and record data, was keeping the altitude constant at  2m. Good luck.
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Wide Bandwidth applications (5 Generation Cellular Communication, M2M, IoT)  
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Thank you for your interesting answer.
In my opinion it is not easy to understand this phenomenon.
We need to have a great experience to understand it
 
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Mobile Adhoc Network, Mobile Computing , Wireless Network
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We can classify the power efficient routing protocols into four categories based
on their path selection scheme. The first set of protocols use the energy cost for transmission as the cost metric and aim to save energy consumption per packet. However, such protocols do not take the nodes’ energy capacity into account. Thus, the energy consumption is not fair among nodes in the network. Minimum Total Transmission Power Routing (MTPR) is an example protocol for this category. The second set of protocols use the remaining energy capacity as the cost metric, which means that the fairness of energy consumption becomes the main focus. But, these protocols can not guarantee the energy consumption is minimized. The third set of protocols are similar to the second set, but use estimated node lifetime
instead of node energy capacity as the route selection criteria. Therefore, these protocols still aim to fairly distribute energy consumption. In order to both conserve energy consumption and achieve consumption fairness, Conditional Max-Min Bat-
tery Capacity Routing (CMMBCR) has been proposed to combine these two metrics. CMMBCR is an example of the fourth category of protocols, which use combined metrics to represent energy cost.
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Campbell, S., & Kwak, N. (2011). Mobile Communication and Civic Life. The Routledge Companion to Mobile Media.
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Kapiolani,
I do not think that they consciously compare the two levels of activism and choose one. I think that it is a question of levels of motivation.  Sharing a link or temporarily changing a profile picture is easy to do and may be perceived as "doing a little to help."  
The choice to attend a rally, etc., requires a higher level of motivation...and this motivation is often produced by the persuasive characteristics of the original message, or the perceived threat.
Hum.  Maybe the framework of instrumental versus integrative motivation can be applied here.  Is it possible that low risk online actions can best be seen as mostly externally (instrumentally) motivated, whereas higher-risk engagement is he result of internal integrative motivation?
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In WiMAX communication Scenario ,user is moving at 100km/hr and source is stationary and 64 QAM modulation technique is applied to it , but the BER is more as compared to 16QAM  . how can we minimize this to lower level
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The problem with OFDM, when rapid motion is involved, is Doppler shift, which causes inter-carrier interference. The link below looks into ways of compensating for inter-carrier interference, which would then permit the use of higher modulation levels with less BER degradation.
Another obvious and well known technique, and cheap, which may make it "efficient," is to simply limit the OFDM mode to fewer subcarriers. This improves performance for mobility, but it reduces the tolerance to multipath distortion. All else equal (specifically, if you maintain the same spectral efficiency), the fewer the subcarriers, the shorter the symbol duration, the shorter the guard interval, the less tolerant the system becomes to reflections in multipath propagation.
Just to give an example, in an 8 MHz DVB-T2 channel, if 32K mode is used, the spacing between subcarriers is 250 Hz. If the carrier frequency is 600 MHz, typical for TV UHF, then the Doppler shift at 100 km/h will be up to 111.2 Hz. That's a huge percentage of the 250 Hz subcarrier spacing. If instead you use 2K mode, subcarrier spacing is a much larger 4000 Hz, which makes the Doppler shift of 111.2 Hz rather inconsequential.
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I want to enhance my proposed protocol by using cooperative routing and in a specific condition forward data to the destination cooperatively through a relay node.
I just know that the direct path include the least number of retransmission.
In What condition, it would be a better idea to use cooperative links to send data through the destination?
(I should mention that link metrics are important not node metrics)
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Cooperative communication is a good solution to mitigate interference between users and btween cells in the form of distributed MIMO. Try search LTE-CoMP
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There are three Sectors (each at azimuth of 60, 170, 240 degree) of a telecom Site. Now we require to predict the coverage plots from each Sectors. For this we can use HATA modified algorithm for urban/rural areas. But the issue is to get coverage plots from each Sector in the definite azimuth and beamwidth. Following parameters needs to be taken for predicting coverage from Sector: Power Transmitted, Power Gain, Height, Distance, Azimuth, Beamwidth and optional Terrain Heights, Clutter etc.
Is there any idea/algorithm for predicting coverage from Sectors using any propagation model?
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The most comprehensive coverage model I know is the Longley-Rice model:
Although I have to say that the modified Hata model often gives me very good results, and it is a whole lot simpler!
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I really want to know regarding the handover management in 5th Generation Wireless communication network. Moreover how it could be handled in heterogeneous cloud radio access networks?
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The key technologies in 5G H-CRAN networks include cloud based cognitive processing advanced spatial signal processing, cooperative radio resource management, network function virtualization,  self-organizing traffic-driven and user-centric network.To avoid the inter-tier interference, the cognitive processing technique is utilized to make RRHs and ACEs work cooperatively in the overlaid scenario when the overall system load is not high. The radio resource cloudization  decreases the inter-tier interference and improve the flexibility of radio resource’s reuse and thereby  improves the SE performance when the overall system load is high. Hence the conventional handover management is not of a concern at least at this current stage of technology development.
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The number of wireless devices that use 2.4GHz ISM band can effect on Wireless sensor network using the same frequency band. For that reason, we have to investigate that kind of interference.
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This toolbox might serve as a starting point.
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I am researching on enhanced method to mitigate intermodulation distortion and sideband noise in a co-located wireless network. I thought of introducing hybrid fixed filtering and adaptive cancellation technique
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Hello,
I think it is a good idea because you can control the dynamic range of adaptive filter by using a fixed filter. Fixed filter can be designed to overcome the intermodulation effects as the mean of the total stochastic process. 
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How can we implement Nakagami Channel is WiMAX and obtain the results in term of snr ?
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Dear Ankur,
You can implement any type of channel including the Nakagami m channel for wimax as follws:
-Implement the transmitter of the wimax according to the standards using Matlab/Simulink
- Implement the standard receiver of the Wimax system  using Matlab/Simulink
- Implement the type of the channel you intend between the transmitter and the receiver by  using Matlab/Simulink
Input a test signal inform of random bit stream and simulate to get the corresponding output bit steam.  By comparing the two streams you can get the bit error rate. Chang the signal to noise ratio and repeat until you get the error performance curve of the system.
For more details please see the Link:
Best wishes
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For me it is not clear which model we should use in Matlab simulation to model the fading channel of mobile communication. Because the transceiver is moving, some times you have LOS component in others you don't have it. So, the channel model should vary with time in random nature from Rayleigh to Racian to Rayleigh and so on. Is that true and applicable?
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Depends on what you want to do.
Are you performing a quasi-static simulation where you draw random channel realizations independently of each other, perform some simulation for every channel and average the result over trials? In this case you can just make simulations with and without the LOS component and compare the results, or even average over them (assuming a certain LOS probability).
Or are you trying to make a dynamic simulation where a mobile station moves and you need to have a realistic temporal evolution of the channel? In this case I'd recommend treating LOS and NLOS separately: for the NLOS component you use something like Jakes' model (as Rodolpho Gianini suggested) and for the LOS component you could use a Markov model to make it switch between LOS and NLOS. In any case it's always complex Gaussians, either centered or not centered.
That's for flat fading, anyways. If you also need a realistic multipath it's maybe time to look at existing channel models that do all this (like ITU Pedestrian/Vehicular or SCM(E) or something), you can find Matlab implementations of these freely available.
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How can I make Glossy algorithm effective for mult-hop WSNs?
Huda
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Since the performance of protocols like Glossy depends strongly on how receivers react to collisions on the physical layer I would say that simulations are of very limited value if you use standard tools. The models for packet collisions used in most simulators are very simplistic and rely on the fact that collisions happen rarely.
To get meaningful results, you would have to build a simulation environment that models closely what actually happens on the physical layer first, for example by implementing the collision model in my article. You can have a look at the code for the model on github: https://github.com/mwil/collision