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The simulation should involve mobile users, dynamic environments with data, voice, command & control, position location, and ISR video transport over waveforms in UHF, L-band, and S-band frequencies. I am using NetSim, but guidance involving other tools is also welcome.
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Nihal Sanil The propagation models PDF in https://tetcos.com/netsim-documentation.html explains the BER calculations.
Another option is to ask NetSim AI https://tetcos.com/netsimai.html
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I want to design a diversity reciver (in a single input multiple output (SIMO)) where i have the following specifications.
1. i have 100MHz RF bandwidth
2. i use simple BPSK
3. No of transmitting antennas are only one.
4. I want to achive 1Gbps speed
I want to know is there any clear procedure to find the number of antennas required to achieve the desired data rate. Please let me know if any one has done such a design with an SDR board or any thing. Thank you.
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One uses the receive diversity to improve the signal to noise and interference ratio. So one sends say one signal and receives it by N antennas. Assuming the transmission coefficient of the nth antenna is hi then the received signal r can be expressed by
r= sum (hi S +ni) ,
where S is the sent signal amplitude ,
The system capacity C = BW Sum (log ( 1 + Ihi SI^2/ ni^2) from i=1 to N
The most simple idealized solution of this problem is to assume that the paths are all similar and the above equation reduces to
C= N BW log ( 1 + Ihi SI^2/ ni^2) This is assuming 10 separate receivers.
It the recieved signal power is combined directly after the antenna then
the recieved power will R sum of Ri^2 across the N channels, where Ri= hiS
Then the recieved combined power R= Nhi^2S^2 assuming identical paths.
and the capacity C
C= BW log2(1 + Nhi^2 S^2/ N) where N is the noise power of the combined receiver.
This rate is much less than the first rate using N separate receivers.
The rate may decrease under this rate by considering the spatial variations of hi.
Best wishes
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I try to transmit LFM signal using SDR platform (usrp-2932) and receive The Signal using another usrp of The same version , The TX and RX ports are connected through RF Cable With certain length .
MY question is : it Must appear single bin at certain frequency after applying FFT, but The received pin is very fast , what is The factors that affect this phenomena?
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Hello Mohamed, I'm not so sure I understand your question but you seem to be asking why the receiver response is at a single frequency and what are the factors that may cause the target response to be smeared over neighbouring frequency cells (please correct me if I am wrong). I shall answer my interpretation of the question in the hope this is what you want to know about.
After the FFT processing of the baseband or IF signal of an LFM radar the frequency bins correspond to range. A single stationary target, ideally a point scatterer, will yield a single frequency in the baseband or IF of a LFM radar. It may be possible that this response sits in just one frequency cell (i.e. one range cell) but it could be straddling two neighbouring cells, depending on the precise range of the target. An extended target could give a response extended over several neighbouring range cells, i.e. frequency cells, and will definitely do so if its down range extent exceeds the range resolution of the radar. Furthermore, if the frequency modulation is not truely linear, then the response of a point scatterer will become smeared over several neighbouring cells. The extent of the smearing depends of the degree of non-linearity in the FM and tends to worsen with increasing range. I hope this helps.
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Does anyone know is there is an Open-Source Software-Defined-Radio (SDR) implementation of the Bluetooth Low Energy (BLE) Physical Layer ?
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We made previously a trial to implement the bluetooth physical layer using the SDR kit of Ettus. Ettus is now belongs to National instruments.
I would like that you follow our paper:
Hope you find it useful.
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Different Global Navigation Satellite Systems are vulnerable to different kinds of intereferne, some are intentional while others are unintentional. Jamming and spoofing are 2 types of intentional intereferne that affect the accuracy of a GNSS or RNSS measurements
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I think in order to cancel the intercept signal you have to detect it and that what you want to realize by your software defined radio. So need a software defined radio developing kit that work in the frequency band of the global position systems. You may use the national instrument software defined radio kits which are based on Ettus kits.
Here I would like to pay your attention that the GPS signals are spread spectrum signals which are primarily more immune against narrow band jamming.
So, may not need extra precautions against the interference.
One must study how far these signals are immune against jamming.
I would like that you refer to the paper in the link which deals with generations
and
Best wishes
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This managed to throw me for a loop. When I'm assessing the presence of outliers before I conduct my moderation analysis I use SPSS to split the data file based upon the dichotomous moderator. I test my assumptions separately and perform a simple linear regression of the IV on the DV at each level of the moderator to generate studentized deleted residuals (SDR) and Cook's distances, so far so good!
The confusion I'm running into is that in Cohen et al. (2003) he recommends a different cutoff score for considering potential outliers: SDR +- 2 for small sample sizes and +- 3 for large sample sizes. This sort of information makes a lot of sense in the context of a standard multiple regression but when dealing with a dichotomous moderator in which assumptions are tested separately for each level I'm just wanting to do a bit of a sanity check.
I've assumed that if there is a small group size in one dichotomous level that I am applying these SDR cutoffs separately based upon size of the group and NOT overall sample size.
Similarly, I prefer using the 4/n cutoff of Cook's distance for considering potentially high leverage values rather than just looking for values greater than 1 (I could swear these are only present in artificial datasets).
All the articles I've come across so far always express n as sample size and so again I run into this slight confusion about if it's correct of me to have two different cut off scores of Cook's distance that is specific to the group size. I mean after all, the regression line, the residuals, and the produced Cook's distance are specific to that level of the moderator and therefore should have their own group cutoff.
Thanks in advance for taking the time to read and weight in!
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Cohen, J., Cohen, P., West, S. G., & Aiken, L. S. (2003). Applied multiple regression/correlation analysis for the behavioral sciences (3rd ed.). Mahwah, NJ: Lawrence Erlbaum Associates.
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Dear Robert,
I would say everything you said is correct so far, but not your conclusion:"Two regression equations are therefore still being calculated when we're doing this assumption testing."
Why "two" regression equations? It is one equation, one model, in which you insert two different values and calculate the residuals. For example, take a simple independen t-test. Typically, the assumption of normality/no outliers is tested by testing the distribution for each group separately (in my opinion the reason why most of the peope believe that this assumption is about the normality of the data....) OR by calculation the residuals of the overall model. This is the same thing, as the model is only two scalars, the estimated mean values, which are subtracted from the original data within each group, to get the residuals. Therefore, the residuals are just shifted in their location.
Same thing applies to more complex models, in which it is not practical or possible to calculate the residuals for each level separately. A dichotomous moderator is just a special case of a metric one. Would you consider to calculate a regression line for each metric value of the moderator separately? I guess not. Hence, there is no need to calculate ist separately, the residuals of the overall model ARE already calculated for each level of the moderator. The residual IS the difference between the datum and the predicted value, where the predicted value needs to account for the accordingly value of the moderator.
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Hello,
As in the topic i want to decode transmission recorded from 433MHz humidity and temperature sensor. I have file with recorded transmission, and i want to read this two values in MatLAB.
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Good answer Abdelhalim Zekry
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Dear all, I would like to start a discussion on ASTM D 2843-16 a technical standard for measuring the smoke density. The standard has usually a poor repeatability and you need to make a lot of measurements to understand the “direction” of your results.
The smoke chamber works with a burner and a photometric system measuring the absorbance (A%) in 4 minutes and smoke density rating, SDR, is the ratio b/w the area below A (%) curve and total area multiplied x 100.
We usually check the calibration of photometric system before each set of measurements, the temperature of the chamber (stopping the measurements if temperature is over 50 °C), but I guess the critical point is the burner. We noted that slight differences of flux, caused by partial clogging of nozzle due to carbonaceous deposits from particularly dense smokes, can give results with huge differences. That because a flame with less energy causes a delay of the emission of the smokes affecting a lot the area below the curve. Usually we can prevent the clogging error with repeated measurements of an internal standard with known SDR and verifying if some drift is about to start. So we open the burner, we clean the nozzle and the remaining items of the burner in ultrasound bath, we reassemble the burner and we checked again the SDR of the standard. Obviously this procedure is time consuming with the risk to compromise the correct functioning of the burner itself.
Another problem affecting the results is related on kind of formulations. Test specimens obtained with quite soft PVC formulations tends to “follow” the flame. So the flame shape them and the top of test specimen remains unburnt (see the picture). We usually tie the sample or we block it with a wide mesh net but the problem remains.
Any tips or suggestions to perform the standard with more repeatable results?
Thank you
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Found a comparison online between the two tests and shared the link below. One interesting point was that the orientation of the light path is vertical in the E662 and horizontal in the D2843. The author below claims that stratification of the smoke in the chamber can lead to higher smoke measurement variability in the D2843. I suspect the larger sample size of the E662 (I recall using 3 mm thick specimens) would also help with the reproducibility of that test versus the D2843. I gained access to cone calorimeters in the mid 90's and really haven't used anything else in the last 15 years, not everyone has that luxury! https://books.google.com/books?id=Bb0Ea4Q3dHoC&pg=PA59&lpg=PA59&dq=Differences+between+ASTM+D+2843+and+E+662&source=bl&ots=U1g9Od-dIp&sig=ACfU3U0q9kz4q_oAyr3p6NtMGS3fN6XHxA&hl=en&sa=X&ved=2ahUKEwjNnKyRoO7jAhUJm-AKHQ7uA4wQ6AEwA3oECAgQAQ#v=onepage&q=Differences%20between%20ASTM%20D%202843%20and%20E%20662&f=false
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Hello Sir,
I working on SDR implementations. I did not have good idea on cellular communication systems, means, I am not much aware of synchronization channels, transport channels, and PHY implementation algorithms used in cellular systems. Can you please suggest any books related to these?
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The information about the physical layers specifications and requirements can be best obtained from the ITU standards for the 4G and 5G. There is the longterm evolution LTE advance 4G which specifies an details the physical layers of the of the 4G. There is also matlab implementations and fpga implementations of such physical layer. Please refer to the papers:
Best wishes
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We are using WaTEM/SEDEM to estimate soil erosion and SDR in a watershed. Although we prepared all the input layers with appropriate format according to the attached model manual, we can not run the model software because of some unknown errors. All kindly helps are appreciated.
The model software is attached, but introducing any different version of the software to solve the problem is also appreciated.
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Dear Dr. Khaledi
We also tried to test WATEM/SEDEM in a watershed in Guilan. It was really difficult to run the model. Firstly, the software is sensitive to windows version, so I recommend to use an older version of Windows. Second, all layers have to have exactly the same raster size and number of rows/columns. The DEM has been recommended to be bigger than the watershed.
Finally, I recommend to search and see the discussion already has been run in Research Gate in this case. following link:
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Me and a group of first year undergrads from my college are working on building a horn-antenna for radio astronomy similar to this http://rishi-patel.blogspot.in/2013/10/summary-of-horn-antenna-project.html.
How to analyse the raw samples from the RTL-SDR USB dongle receiver using Python. I know basic programming in python. is that enough to analyse the data? If not what additional courses should I learn ?
I would like to plot the rotation curve of galaxies and calculate the dark matter distribution. Is it possible using the horn-antenna?
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Cool project! Reproducing the first detection of the 21 cm line by Ewen and Purcell in 1951.
But why re-invent the wheel, in software terms? CASA (https://casa.nrao.edu/ ) is the "industry standard" software for radio astronomy data analysis. Works on Linux and Mac OSX, with an iPython interface. And it's free.
Your horn antenna data could be analysed in CASA in the same way as "single dish" data - the only real difference is that a horn has poorer angular resolution (larger beamwidth) than a parabolic dish of the same collecting aperture.
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I need to test on SDR hardware and compare the results both software and hardware results
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Dear Srilatha,
In order to sense the electromagntic spectrum in certain location you gave at first define y spectrum band in which you want to observe the activity of radio waves in it. Say you want to sense in the UHF band from 300MHz to 3GHz then you have to build an rf receiver which is composed of antenna with the appropriate bandwidth say a wide band antenna, then you have to amplify the detected signal by a low noise wide band amplifier. if the signal is of sufficient level you can analyse it by a spectrum analyser, which iscan be implemented by fft fast Fourier transform of the acquired signal by the rf receiver.
All these building blocks can be built both in matlab or by using your SDR kit.
The type which i described is called the wide band spectrum sensor.
There is also the narrow band sensor in which the band to be sensed is divided into narrow bands and one can build a hetetrodyne rf receiver to sense at all required subbands.
If you are interested in it please till me. It could be built also by the SDR kit.
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Hello, please I would like to know if it is possible to re-prgramme a commercial SDR like those proposed by OUTERNET (http://outernet.is/) which are designed to receive satellite data so that the SDR receive GSM data?
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This is the very purpose of "SDR": within the limits imposed by the hardware (bands, bandwidth, SNR etc.) virtually "everything" is possible.
I did not check the device you're targeting but - provided it's supporting the GSM bands - this should be possible.
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Actually , I need to test the performance ,capabilities of Software defined radio and cognitive radio modules (spectrum sensing algorithms) on an USRP platform.Then depending on the results I want to see if it is applicable on wireless sensor networks.
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Hi, we used a USRP and Gnu Radio to implement spectrum detection by energy and ciclostationary methods. I believe it is the best combination for begin to work with software defined radio, since it is generic and you can implement energy detection and other radios do you like. However, if you just need to implement spectrum detection, you can buy a Dongle SDR and working with GNU Radio you can do it. Please visit gnuradio.org and you will find more details.
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For sensing a real time signal by using SDR what is the procedure to follow to set the threshold value. In most of the documents its mentioned as trial and error method. Is it the average of the power. But then if noise power is more  or less then it leads to mis-detection  and false alarm. Can any one suggest a way to set the threshold to detect a real time signal using SDR?
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Mr. Kishore,
The threshold setting depends on the spectrum sensing technique to be used.
The first thing you must do is to estimate the signal power when the channel is idle (white space). Assuming that the noise is zero mean, and follows a Gaussian distribution, the sensing threshold (in case of the energy detection) depends on the false alarm probability (Pfa) you need by means of the Marcum-Q function (or the Gamma cumulative distribution function). The desired Pfa determines the appropriate threshold value, according to some noise variance (noise power).
Important: if your application is real-time, the sensing time to use is an important parameter. You must select a number of samples to do signal processing, without decreasing so much the overall throughput of your system. This is a fundamental tradeoff.
I recommend to take a look to the paper attached for more details. It's a performance comparison between spectrum sensing techniques. The corresponding equations for threshold setting are given for different techniques.
You can specially use equation 10, where \gamma is the threshold value and N is the number of samples (sensing time). Note that the test statistic used is the normalized energy (see equation 9), where you need to estimate the noise variance (noise power in white spaces).
Note that in equation 10, the threshold value must be cumputed from the INVERSE Gamma cumulative distribution function. In MatLab this can be done using the funtion "gaminv(P,A,B)", where P is the Pfa, A = N/2 and B = 2/N.
I hope this helps.
Best regards,
Luis M Gato.
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I'm wondering if there are any low cost SDR Satellite Channel Emulators.
I'm looking at emulating the Doppler Shift for VHF & UHF frequencies as seen by ground stations that don't dynamically tune. In this instance the ground stations have a fixed central frequency.
Has anybody tried using a HackRF to emulate Doppler Shift? Probably for something like GPS and or GNSS?
This:
versus:
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Thank you for your help. 
So far I'm attempting to emulate the Doppler shift associated with satellites in LEO so I can see how different receivers will interoperate. So far I haven't found anyone else working on this. I was hoping others had started experimenting with similar equipment in field of study.
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i want to test the efficiency of my sensing algorithm using R820T2 RTL-SDR. Is any one there who is working on this
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I think you have a good pick with R820T2 RTL-SDR. We did use a much inferior RTL-SDR some time ago (RTL2832U Elonics E4000) as a cheap spectrum analyzer and it impressed us.
According to this: http://www.rtl-sdr.com/rtl-sdr-tests-r820t-vs-r820t2-stability-tests-for-radio-astronomy/ , the R802T2 should have pretty good performance for spectrum sensing if you are targeting the 1.0-1.7 GHz frequency range.
However please note that these devices are limited to 8-bit resolution and (for good frequency stability, as stated in the link above) 1.6 MS/s of sampling rate. You need to check if this is sufficient for your sensing algorithm. For example, if you were trying to find the best way to put cognitive radio signals inside empty GSM channels, you would need to see if these specs are enough for your algorithm to monitor sufficient GSM channels. 
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There are many models for estimating sediment delivery ratio, often for large watersheds have been developed but few models have been introduced for small watersheds.
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Dear Seyed Ali Asghar
Please find the attached files including some papers about your interested topic.
Regards
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Is it in any way related to spectrum sensing, e.g. is it a part of the spectrum sensing process? And what will be the course of action if the channel quality of the sensed spectrum (white space) is very poor?
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There is no need to do channel estimation in case of spectrum sensing or detection. You can use channel estimation in case there is a feedback link between transmitter/receiver of a cognitive radio set. You can not perform channel estimation unless you have exact replica of the transmitted signal in order to assess the received signal and hence process the channel effect. Therefor, in case you have spectrum sensing task only, then advise to move away from channel estimation as it will lead to nowhere.
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Currently the USRP I am using for my work can be equipped with 2 RF daughter boards so that you can connect 2 antennas. How can I extend this to more antennas?
Can I use the technique of antenna selection and use a RF switch between the antennas and daughter boards?
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It depends on the USRP version you are using. For the USRP N2xx series, you can connect two USRPs together to share the same FPGA clock, so you can have a 2x2 MIMO.
Look at this page, there is (a bit) more info:
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H/W boards which support SDR components, open source tools to verify and develop.