I'm simulating an OFDM transceiver to be later converted and implemented on a C6713 DSK. I'm currently facing a problem with the simulation and...

I'm simulating an OFDM transceiver to be later converted and implemented on a C6713 DSK. I'm currently facing a problem with the simulation and i'm at my wits end trying to figure out what is wrong. Thus i'm really hoping you guys can lend me some help otherwise i can't proceed anymore... Here are 2 pictures of my OFDM simlation in Simulink. Pic1 is the model with the convolutional enco...

Hie all, I am now doing the OFDM Simulation for Power Line Communication. I have written a very simple code for OFDM and have the impulse response...

Hie all, I am now doing the OFDM Simulation for Power Line Communication. I have written a very simple code for OFDM and have the impulse response of the power line channel. I am facing the problem that the BER of my result are high and constant along the SNR. So I would like to know whether my simulation is correct or not, and hope that someone can give me an advice on the simulations. I am using...

Im a little confused about how you employ coherent demod in OFDM. After the FFT at the receiver, how do I perform a coherent demodulation-dont I...

Im a little confused about how you employ coherent demod in OFDM. After the FFT at the receiver, how do I perform a coherent demodulation-dont I need a carrier for phase estimation in case of BPSK, QPSK etc. Also this is what coherent OFDM is, right?

Hi, i am learning about OFDM currently. And i am learning to implement the model in SIMULINK. Yet, i am stuck at the 'training symbols'. I...

Hi, i am learning about OFDM currently. And i am learning to implement the model in SIMULINK. Yet, i am stuck at the 'training symbols'. I dont really understand why training is needed in channel estimation and what forms those training symbols. Can recommend some nice books for OFDM or simulink? Thanks for ur patience.

Hi all, I've been looking at MIMO-OFDM based systems for about the last week (802.11n and 802.16) and have a couple of questions that I was...

Hi all, I've been looking at MIMO-OFDM based systems for about the last week (802.11n and 802.16) and have a couple of questions that I was hoping someone out there could answer. Here goes: 1) I want to look (in detail) at one of the more computationally demanding blocks of a typical MIMO-OFDM reciever. The main blocks that I have really been looking at have been a QR-based channel estim...

I have a question that why in 802.11a IEEE standard, the PLCP long training sequence takes the GI2(Guard interval 2) as the prefix of two OFDM...

I have a question that why in 802.11a IEEE standard, the PLCP long training sequence takes the GI2(Guard interval 2) as the prefix of two OFDM symbols, not one GI before one OFDM and the other GI before the second OFDM symbol? What is the advantage of that?? The following includes the IEEE 802.11a 1999 version: http://standards.ieee.org/getieee802/802.11.html Thanks.

Here's my question: In doing the OFDM (like DVB-T) demodulation, why do people just talk about carrier frequency sync and carrier phase noise...

Here's my question: In doing the OFDM (like DVB-T) demodulation, why do people just talk about carrier frequency sync and carrier phase noise but not carrier phase itself? Does that mean OFDM is not coherently demodulated? Thank you for your help! -- Harry

This code was used for making the practical measurements in section 2.3 of my thesis. This Matlab code allows an OFDM signal to be...

This code was used for making the practical measurements in section 2.3 of my thesis. This Matlab code allows an OFDM signal to be generated based on an input data file. The data can be random data, a grey scale image, a wave file, or any type of file. The generated OFDM signal is stored as a windows wave file, allowing it to be viewed, listened to and manipulated in other programs. The modif...

Hi~ everybody~ I have one thing about OFDM to want to know. In general OFDM system, DC sub-carrier is not used, that is, null is inserted...

Hi~ everybody~ I have one thing about OFDM to want to know. In general OFDM system, DC sub-carrier is not used, that is, null is inserted there. Suddenly I come to curious about the reason. According to the some documents that I found in the web, the reason is due to direct conversion which cannot pass DC component. Is it correct? and is it the only reason why DC sub-carrier was stuf...

hi, i am working on the development of an ofdm receiver (dab receiver). After frequency synchronisation, when i differentially decode the ofdm...

hi, i am working on the development of an ofdm receiver (dab receiver). After frequency synchronisation, when i differentially decode the ofdm symbols, i get 5th symbol corrupted i.e. the constellation of 5th symbol is not centerd on the multiples of pi/4. When i shift the fft window for 5th symbol 7 samples backward, the contellation improves, but it is still very noisy and not centerd at the mu...

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

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;...

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, 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 +...

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 ...

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 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...

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: ...

Dear comp.dsp, Though I did try looking at the previous posts related to this, my question has not been answered. So, here goes: I have a...

Dear comp.dsp, Though I did try looking at the previous posts related to this, my question has not been answered. So, here goes: I have a simple OFDM+QPSK code wherein I use one symbol to estimate the channel and do the zero forcing (multiply by reciprocal of channel FFT) to get derotated QPSK symbols. Note that the data is uncoded and not interleaved. 1. BER for QPSK+OFDM in an AWGN ...

Hi, I'm trying to visualize the sub-carriers in my ofdm model. What I do is I generate a BPSK OFDM symbol and after IFFT I...

Hi, I'm trying to visualize the sub-carriers in my ofdm model. What I do is I generate a BPSK OFDM symbol and after IFFT I plot the FFT of transmitter output. I only get one Sinc graph not the overlapping sub-channels. Could you please correct me to get a proper view of sub-carriers? Best regards Shahin