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60 Threads found on edaboard.com: **Carrier Ofdm**

in 802.11a, 48 sub-**carrier**s are used to transmit data, and they are not carrying conjugate data on index like sub-**carrier**(x) and sub-**carrier**(N-x).
also in some thsis I come across designs that transmit conjugate data on sub-**carrier**s that are symmetric around the FFT size N, which results in waste of half the bandwidth. (...)

Digital Signal Processing :: 11-08-2016 02:33 :: bravoegg :: Replies: **1** :: Views: **540**

Hi,
What is the performance difference of MMSE equalizer and ZF equalizer in a
**ofdm** system. I have simulation 3 tap Rayleigh channel for QPSK ODFM system
and found out that both the equalizers give the same performance.
But in Single **carrier** Frequency Domain Equalization, MMSE performs
significantly better than ZF.
I modeled the equal

Digital communication :: 02-11-2015 09:58 :: danM :: Replies: **0** :: Views: **1183**

........ from the introduction in this link i understand that **ofdm** **carrier** is generated by modulating a complex waveform with original data and this resulting waveform is the **ofdm** sub**carrier**s and these sub **carrier**s r bundled by ifft to obtain the **ofdm** signal... (correct me if i'm wrong)....

Digital communication :: 11-02-2014 05:07 :: preethi19 :: Replies: **0** :: Views: **529**

Hello all,
Why when we use space-time block coding (STBC) with single-**carrier** frequency-domain equalization (SC-FDE) we use a permutation matrix, while we don't use it in case of orthogonal frequency division multiplexing (**ofdm**)?
Thanks

Digital communication :: 10-24-2014 23:02 :: David83 :: Replies: **0** :: Views: **752**

please explian me synchronisation and frequency offset problem in **ofdm**

Digital communication :: 07-01-2014 12:37 :: Priya274 :: Replies: **0** :: Views: **549**

Hi,
I am working on the **ofdm** transmitter system. I have observed that the **carrier** signal peak power level is -3dBm whereas the peak power level of the **ofdm** (256 sub **carrier**s) signal observed is -42dBm. Also the channel power measured is -42dBm . Frequency of operation is 2.45GHz. Power amplifier used is MMZ25332BT1.
I (...)

Digital communication :: 03-03-2014 11:20 :: Srihari P :: Replies: **0** :: Views: **759**

One reference says that: "we know that the CFO (**carrier** frequency offset) causes the phase distortion in the **ofdm** symbol which can be denoted as 2πβn/N where B describes the CFO effect..""
so, any one can explain how this phase distortion (2πβn/N) is obtained?? Plz explain...

Digital communication :: 12-21-2013 12:47 :: munirp :: Replies: **0** :: Views: **576**

This picture is from book MIMO-**ofdm** Wireless Communications with Matlab by Cho Y.S. The MATLAB code is located in book directly below the figure.
function y_CFO=add_CFO(y,CFO,Nfft)
% add CFO (**carrier** frequency offset)
% y : Received signal
% CFO = IFO (integral CFO) + FFO (fractional CFO)
% Nfft = FFT size
nn=0:length(y)-1; y_CFO = y.*exp(j*2*pi*C

Digital communication :: 11-11-2013 18:06 :: zemtcov :: Replies: **5** :: Views: **1007**

I am trying to understand the relations between **ofdm** symbol duration and sub**carrier**s far as i went ,i understood that regarding W and R as total bandwidth & transmission rate of transmission respectively the duration of a distinct sub**carrier** is just T ,where T=N*Ts with Ts the symbol duration in the single **carrier** case (...)

Digital communication :: 06-14-2013 13:49 :: sotts :: Replies: **0** :: Views: **807**

My input signal is a multi-channel/**carrier** **ofdm**. Each channel have 5MHz bandwitdh.
Now, I would like to simulate a 2-tone test for its IMD. I plan to measure the 3rd order at say +/-0.2 MHz offsets from the edge (4.8MHz and 5.2MHz).
My computation is a spacing of F**carrier** +/-1.8GHz, in order to create the 3rd order tones.
Is this correct?

RF, Microwave, Antennas and Optics :: 05-12-2013 12:07 :: RFegg :: Replies: **2** :: Views: **894**

My system uses 0to2khz freqs. Hence I do not want to use any RF it possible to generate **ofdm** signal in this BW range and transmit it without using any **carrier**. If so what factors determine the **carrier** freqs and no of **carrier**s. My BW and Symbol time is known and fixed.
Thanks

Digital communication :: 12-07-2012 08:56 :: warriorwithin :: Replies: **9** :: Views: **850**

Hai
What is difference between **carrier** interferometry uwb signal format and uwb-**ofdm** signal format......Please give answer.....

Electromagnetic Design and Simulation :: 11-30-2012 05:06 :: petrishia :: Replies: **0** :: Views: **590**

The following code is used to estimate and correct the frequency offset errors for a single **carrier** system
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
freqOffset = 0; phaseOffset = 0;
hPFO = comm.PhaseFrequencyOffset('FrequencyOffset', freqOffset, ... 'PhaseOffset', phaseOffset, ... 'SampleRate', samplesPerSymbol/Ts);
rx_signal1l = step(

Digital communication :: 10-11-2012 10:21 :: ReComm :: Replies: **1** :: Views: **868**

Digital communication :: 10-10-2012 13:35 :: miri23 :: Replies: **0** :: Views: **525**

1.how com discrete **carrier**s(present in ifft) modulate input sequence?
2.which parameter of **carrier** is changing?(after this base band or band pass modulation?
4.why **ofdm** spectrum is continues? i,e sinc each having null at center of adjacent **carrier**..

Digital communication :: 07-03-2012 15:13 :: bvishwanath :: Replies: **2** :: Views: **835**

Here is a better explanation of the PAR (crest factor):
As you see, almost every signal have some kind of peak to average.
For a multi-**carrier** signal (as **ofdm**) generally the peak-to-average can be calculated with:
PAR = 10*LOG(Number-of-**carrier**s)
For example the PAR of a 12 **carrier**s signal would

RF, Microwave, Antennas and Optics :: 06-04-2012 19:11 :: vfone :: Replies: **3** :: Views: **1709**

In MIMO-**ofdm** system a delay (cyclic delay diversity) is added to the sub-**carrier** in each antenna in order to have different spacial dimensions for the signals but this done before adding the cyclic prefix for a reason what is it???

Digital communication :: 06-03-2012 16:15 :: mohhroub :: Replies: **2** :: Views: **573**

Hi All,
I'm really in trouble because of this awgn. I am trying to add noise awgn to oversampled **ofdm** signal. my signal is oversampled 20 times and modulated on a high frequency **carrier**. After applying band pass filter I have tried to do this
SNR = EbNo + 10*log10(k) - 10*log10(upsamp)
corrupted = awgn(usig, SNR,'measured','dB');
where u

Digital communication :: 02-09-2012 14:29 :: Mishaal :: Replies: **2** :: Views: **1483**

I think you gave yourself a difficult task.
I would still go for the synchronous data stream- you can asynchronously transform the "wild" data onto sync data.
I do not think the 432 MHz band offers enough bandwidth for your ten OOK data channels.
I think there are 432,434, etc, SAW resonators available for small keychain oscillators. I would s

RF, Microwave, Antennas and Optics :: 11-28-2011 17:50 :: jiripolivka :: Replies: **28** :: Views: **2431**

Perheaps the reason of the failure is the Peak-to-Average of the modulated signal. Most of the single **carrier** digital modulations have a Peak to Average in a range of about 4dB to 8dB. Multi-**carrier** modulation types (as **ofdm**) have even higher peaks.
If your PA works fine at P1dB using a CW signal, when the input reach higher peaks (due to (...)

RF, Microwave, Antennas and Optics :: 11-07-2011 22:33 :: vfone :: Replies: **6** :: Views: **785**

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