Hi all, My project is Digiatal Sampling correction Interpolation/Decimation for application in flexible OFDM Modem. I'm implementing in Matlab...

Hi all, My project is Digiatal Sampling correction Interpolation/Decimation for application in flexible OFDM Modem. I'm implementing in Matlab the 5_taps optimized interpolator which will improve the performance for long data OFDM bursts. I used control parameters basepoint index (m(k)) and fractional interval (mu(k)) (reference to FM Gardners article "Interpolation In Digital Modems---PART1: ...

Hi all, My project is Digiatal Sampling correction Interpolation/Decimation for application in flexible OFDM Modem. I'm implementing in Matlab...

Hi all, My project is Digiatal Sampling correction Interpolation/Decimation for application in flexible OFDM Modem. I'm implementing in Matlab the 5_taps optimized interpolator which will improve the performance for long data OFDM bursts. I used control parameters basepoint index (m(k)) and fractional interval (mu(k)) (reference to FM Gardners article "Interpolation In Digital Modems---PART...

Hello, Assume you have 2 OFDM transmitters that are simultanously transmitting different data and the data is somehow coded (ie...

Hello, Assume you have 2 OFDM transmitters that are simultanously transmitting different data and the data is somehow coded (ie CDMA). After IFFT the ofdm symbol of each transmitter , X1 and X2, passes a freq. selective fading channel: Y = X1.G1 + X2.G2 + N My question is at the receiver, before or after the FFT, how to remove the effect G1 and G2 which are the fading coeffici...

Hi, i'm an undergraduate student doing some project on Stochastic Processes and i have a few questions on OFDM. There are few things that i...

Hi, i'm an undergraduate student doing some project on Stochastic Processes and i have a few questions on OFDM. There are few things that i don't quite understand and they are mainly in Digital Signal Processing domain (that is not my field of expertise). I'm writing code in MATLAB for transmitting data using sound and use OFDM modulation. Mathematically the transmitted multicarrier ...

HI, here People usually estimate the SINR in the OFDM systems in the following way. 1. Estimate over each specific pilot subcarrier of...

HI, here People usually estimate the SINR in the OFDM systems in the following way. 1. Estimate over each specific pilot subcarrier of different OFDM symbols. (i.e. CINR estimation) 2. Then average over all pilot subcarriers (i.e. average CINR) to approximate the SINR. The problem is, most CINR estimation algorithms are based on a simpliied channel model assumption. That is, "y = h*a +...

Dear all, I want to know what is the difference of power spectrum of OFDM with no added cyclic prefix and power spectrum of OFDM with added...

Dear all, I want to know what is the difference of power spectrum of OFDM with no added cyclic prefix and power spectrum of OFDM with added cyclic prefix. Please help me to overcome this problem. Thanks in advance. Best regards, awi

Hi everbody, I am doing my M.SC thesis on the topic "ICI cancellation in OFDM". I have very limited time, if you can help me I will be...

Hi everbody, I am doing my M.SC thesis on the topic "ICI cancellation in OFDM". I have very limited time, if you can help me I will be grateful to you.... I can implement the OFDM structure in AWGN channel, it works very well.. But when i try to implement the system in a "rayleighchan", I obtain very bad BER results. -------------------------- N=3D256 ; % carriers GI=3DN/4;...

Does anyone has experience of using SystemC for OFDM based design. Please share your experience. I'm new in SystemC so not sure how to start. If...

Does anyone has experience of using SystemC for OFDM based design. Please share your experience. I'm new in SystemC so not sure how to start. If you know any good books/websites for OFDM in C/C++ please post here. kind regards, Rezwan

I would like to know why the OFDM Out of band sidelobes , reduce as the number of carriers/FFT size increases?What is the reason for this? Is...

I would like to know why the OFDM Out of band sidelobes , reduce as the number of carriers/FFT size increases?What is the reason for this? Is this ever a consideration in choosing the FFT size, because if I consider sidelobes due to PAPR driving PA to saturation, then its the other way round. More carriers will cause more spectral regrowth.

Hi all!! I am performing LS & MMSE channel estimation in an OFDM system with the DVB-H parameters, where the pilots are not equally spaced as...

Hi all!! I am performing LS & MMSE channel estimation in an OFDM system with the DVB-H parameters, where the pilots are not equally spaced as the case with WIMAX. I am facing a severe problem as the BER of both MMSE and LS are identical. I am sure that the LS is correct and that the problem is with MMSE. I've tried everything to make a difference between them. The only successful attempt was to i...

hi all, I"m working on a simulation of comparing OFDM with different modulation schemes (QPSK,QAM) etc'... My question is about the conversion...

hi all, I"m working on a simulation of comparing OFDM with different modulation schemes (QPSK,QAM) etc'... My question is about the conversion from Es/No to Eb/No I'm not sure if I need to take the cyclic prefix under consideration for instance: Es/No=Eb/No+10log10(log2M * Nc) + 10log10(CodeRate) + ... .. 10log10(Tinf/(Tinf+Tcp)) is the last part correct? where Tinf - is the inf...

Hello, I am testing different OFDM Channel estimation (CE) approaches by modelation in Simulink, and I am having a problem, that might be...

Hello, I am testing different OFDM Channel estimation (CE) approaches by modelation in Simulink, and I am having a problem, that might be stupid but is taking to much of my time without finding a solution. My problem comes when I want to compare several methods to ideal LMMSE CE. I know the channel from measurements, so I have the attenuation coefficients for each subcarrier, i.e. the column...

Hi, I'm simulating an OFDM system with Multipath and AWGN channels. One thing that i'm observing is that whenever I simulate the system on...

Hi, I'm simulating an OFDM system with Multipath and AWGN channels. One thing that i'm observing is that whenever I simulate the system on baseband the AWGN command adds almost the correct noise but whenever I modulate the baseband signal to a carrier and then add the noise, it adds very little noise compared to previous case. I have implemented the system as follows. ============================...

Hi i am simulating a baseband OFDM system Digital down converter. I have a problem regarding decimation and interpolation. In the last stage of...

Hi i am simulating a baseband OFDM system Digital down converter. I have a problem regarding decimation and interpolation. In the last stage of the DDC, i am doing low pass filtering of the data. My problem is when i make a sharp transition filter i.e. ( Fpass = 250e3; % Passband Frequency Fstop = 300e3; % Stopband Frequency the OFDM constellation is scattered. But...

hi i am using this code for simulation of ofdm clear all; Fd=1; % symbol rate (1Hz) Fs=1*Fd; % number of sample per...

hi i am using this code for simulation of ofdm clear all; Fd=1; % symbol rate (1Hz) Fs=1*Fd; % number of sample per symbol M=4; % kind(range) of symbol (0,1,2,3) Ndata=128; % all transmitted data symbol Sdata=8; % 8 data symbol per frame to ifft Slen=16; % 16 length symbol for IFFT X=zeros(Ndata,1); Y1=zeros(Ndata,1); Y2=...

Hi all, I am trying to simulate a data flow according to the wimax standard. Could someone please help to understand how to manage the...

Hi all, I am trying to simulate a data flow according to the wimax standard. Could someone please help to understand how to manage the data flow dimensions after encoding before mapping to ofdm symbols? More precisely: I generate, for example, a message of 72 words having in mind a 16 QAM modulation, with an overall coding rate 3/4. This, after rs and cc coding, interleaving and puncturi...

Hi there, I calculate SINR for OFDM system as: (TP. pathloss.|CG|^2)/(cov + TP_ou. pathloss_ou.|CG_ou|^2) where, TP: Transmit...

Hi there, I calculate SINR for OFDM system as: (TP. pathloss.|CG|^2)/(cov + TP_ou. pathloss_ou.|CG_ou|^2) where, TP: Transmit Power TP_ou: Transmit Power of other users CG: Channel Gain CG_OU: Channel Gain of other users cov: Covariance of AWGN Then, how can I calculate SINR for OFDMA systems. What will be the effect of multiple access on SINR? Thank you!

Hi, I am quite confused with the variance of the noise in the OFDM system. Should it be equal to N0 or N0/2? N0: Single sided noise power...

Hi, I am quite confused with the variance of the noise in the OFDM system. Should it be equal to N0 or N0/2? N0: Single sided noise power spectral density. Please help. Thanks.

I have a basic question here regarding OFDM digital front end. if i have a very efficient clock of say 10ppm, can i downsample the signal to the...

I have a basic question here regarding OFDM digital front end. if i have a very efficient clock of say 10ppm, can i downsample the signal to the sampling frequency of transmitter. i.e. the sampling frequency at which i will get 64 samples for a 64 sample FFT block? for example, the FFT output at the transmitter is at 500 kHz. Now can i directly down sample this signal to 500 kHz baseband sign...

This freescale appnote: http://www.freescale.com/files/dsp/doc/app_note/AN3059.pdf talks about all the different kinds of channel estimation...

This freescale appnote: http://www.freescale.com/files/dsp/doc/app_note/AN3059.pdf talks about all the different kinds of channel estimation schemes for OFDM reception. They discount differential modulation, but how does it compare with the simplest channel estimation techniques: Least Square (LS)? Alan