Hi, I would like to understand more and more about OFDM and its applications for my work. I need to simulate it with Matlab. If possible,...

Hi, I would like to understand more and more about OFDM and its applications for my work. I need to simulate it with Matlab. If possible, could you supply me matlab code which will be enable me to simulate OFDM ( that will be very helpful for understanding OFDM and its concept). Thx in advans, Karthik Balaguru

Hallo everybody, I've just finished my OFDM-Simulation, but I'm still facing a little problem with the AWGN-function provided by Matlab. The...

Hallo everybody, I've just finished my OFDM-Simulation, but I'm still facing a little problem with the AWGN-function provided by Matlab. The transmitted OFDM-Signal s(k) consists of samples of the komplexe baseband signal. (As I've implemented a diskrete time OFDM-baseband-system). The channel should add white Gaussian noise n(k). An the resulting signal r(k) = s(k) + n(k) will than be process...

Hi, What is the difference between DMT and OFDM. Why isn't OFDM used in the xDSL technologies? If I have to guess the difference, I think...

Hi, What is the difference between DMT and OFDM. Why isn't OFDM used in the xDSL technologies? If I have to guess the difference, I think that OFDM has several carrier frequencies that are orthogonal. DMT I think uses carriers seperated by some space on the frequency spectrum. Kind Regards, Jaco

Hi, I understand the problem of high Peak to Average Power Ratio in OFDM. However, I am not sure how the average power of an OFDM signal...

Hi, I understand the problem of high Peak to Average Power Ratio in OFDM. However, I am not sure how the average power of an OFDM signal is calculated. Suppose you have an N-carrier transmitter where the average power per carrier is p, what would the average power of the OFDM signal be? Thanks.

Hi, I am doing project in OFDM .I have doubts regarding the functionality of IFFT & DAC in OFDM TX. In OFDM block Where the carrier comes...

Hi, I am doing project in OFDM .I have doubts regarding the functionality of IFFT & DAC in OFDM TX. In OFDM block Where the carrier comes into picture?. After IFFT what is exactly done in DAC block?. There we are using any carrier suppliers?. IF possible anybody can explain the flow of data in OFDM Tx. can anybody help me out regarding the above queries. Thanks & Regards Lakku Raji...

Hi all, I have a mini question and need yr help pls. It is simply about the understanding of sample scheme of OFDM. For convenience, the...

Hi all, I have a mini question and need yr help pls. It is simply about the understanding of sample scheme of OFDM. For convenience, the parameters of a OFDM system are presented as follows. .the sample period: T .FFT/IFFT point: N .the OFDM symbol period: N=B7T Then we obtain that, .the carrier spacing: 1/(N=B7T) .the frequency of the first "baseband" carrie...

OK, now that I've got my OFDM question off my chest, here's a related question. If one used a normal single-carrier signal in place of OFDM,...

OK, now that I've got my OFDM question off my chest, here's a related question. If one used a normal single-carrier signal in place of OFDM, you'd have a relatively huge bandwidth to deal with, which means your single-carrier data rate is going to be many times higher than the rate across any one carrier of a comparable OFDM signal. Well, given all that freakin' bandwidth, it seems that ...

Dear all I am doing a block for a OFDM receiver that receives as input the ofdm received signal and gives as output a rectangular signal...

Dear all I am doing a block for a OFDM receiver that receives as input the ofdm received signal and gives as output a rectangular signal (for synchronization) in which each pulse represents a peak in the autocorrelation function realised over the ofdm received signal. How can i define a threshold to detect this peak of the correlation function? Is there another way to do this? I will use di...

hi all , Recently , I have generated a OFDM signal , but meanwhile I have noticed that my Analytical & Computer Simulation of my SER are...

hi all , Recently , I have generated a OFDM signal , but meanwhile I have noticed that my Analytical & Computer Simulation of my SER are totally difference, Moreover , the Numbers of Errors in my signal also quite large, therefore i am wondering whether there are some Errors in my signal detection or the progress of generate OFDM signal. Actually I should generate channel estimation of OFDM sig...

Hello, everyone. In SISO-OFDM, we usually employ a frequency domain equalization after the receiver FFT module, as a way to compensate for the...

Hello, everyone. In SISO-OFDM, we usually employ a frequency domain equalization after the receiver FFT module, as a way to compensate for the channel distortion along frequency bins. We depend on OFDM channel estimation and simple inversion for this purpose. In MIMO-OFDM, either multiplexed system or diversity system, what is the best way to implement a frequency-domain equalization for the...

Dear all, I have a basic question regarding modeling of a multipath channel for OFDM in Matlab and would appreciate your help. My intention...

Dear all, I have a basic question regarding modeling of a multipath channel for OFDM in Matlab and would appreciate your help. My intention is to simulate an 802.11a transmission which uses OFDM. From the 802.11a standard I know that: -Number of Subcarriers, Nsc = 64 -Sampling Rate at the receiver, fs = 20e6 samples/sec -BW = 20Mhz -Carrier Frequency, fc = 5.25 Ghz Now consider that I...

hey all, I made an ofdm simulation in matlab, I want it to output Ber/EbNo plot, and I use the awgn function in order to add white noise in...

hey all, I made an ofdm simulation in matlab, I want it to output Ber/EbNo plot, and I use the awgn function in order to add white noise in the channel, and as u know the awgn function requires SNR as input, so I need to convert from Eb/No to SNR. I know this: Es/No(dB)=10log10(Tsymb*Fs)+SNR(dB) now I need to convert the Es/No of the ofdm signal to Eb/No: Es/No(dB)=Eb/No(dB)+10log10(...

Hello: I have a question regarding filtfilt function in Matlab. Due to forward and backward filtering, filtfilt function will have zero-phase...

Hello: I have a question regarding filtfilt function in Matlab. Due to forward and backward filtering, filtfilt function will have zero-phase response at any frequency. If I apply this filter to a time domain OFDM sequence, does that mean I can set the FFT start window the same as the transmitted IFFT starting point? In my test, I have an OFDM sequence of 5 symbols each with 80 samples at 20 M...

I am simulating an OFDM system and want to employ concatenated codes with different modulation schemes. I have a few queries about it. 1. RS code...

I am simulating an OFDM system and want to employ concatenated codes with different modulation schemes. I have a few queries about it. 1. RS code works on frame-by-frame basis like for a shortened code RS(32,24) on byte boundary. In this case, I need a minimum of 24*8 uncoded data bits. If i work on this boundary, the resulting symbols dont map completely to the OFDM symbol. How can i make it sat...

Hi, in 802.16e-2005, table 266 is Rx SNR for OFDM and table 338 is Rx SNR for OFDMA. I find that the Rx SNR is different for OFDM and OFDMA, why...

Hi, in 802.16e-2005, table 266 is Rx SNR for OFDM and table 338 is Rx SNR for OFDMA. I find that the Rx SNR is different for OFDM and OFDMA, why is that?

Hi there, I have a question on OFDM. As we know, most OFDM systems nowadays do not use all the available tones (subcarriers) for data...

Hi there, I have a question on OFDM. As we know, most OFDM systems nowadays do not use all the available tones (subcarriers) for data modulation. Let us say we have 64 tones in total and we might end up with 48 data tones, 4 pilot tones, 3 DC tones and 9 null tones, which is kind of an typical setup. My question is regarding the null tones, which are usually placed on the two boundaries...

Hi all!! I'm a student and for my thesis I have to implement a flexible OFDM modulator in VHDL. That means that it has to be applicable in...

Hi all!! I'm a student and for my thesis I have to implement a flexible OFDM modulator in VHDL. That means that it has to be applicable in more than one systems. For example DVB and WiMAX. The elements to implement are the Mapper the OFDM and the Guard Interval Insertion. As you understand the mapper part should support all the possible constellations given from those two standards and th...

Hello, I m currently simulating a channel estimation based preamble in OFDM system. The ofdm signal is convolved with the channel taps which...

Hello, I m currently simulating a channel estimation based preamble in OFDM system. The ofdm signal is convolved with the channel taps which is in this case 3 taps. The technique is to correlate the received preamble with its local copy in time domain before FFT. This kind of correlation should give an impulse as the result and in this matter, these impulses should be the channel taps. But th...

Hi guys I have a question about the use of LDPC codes and different bit- loadings which naturally occur as part of a large number of...

Hi guys I have a question about the use of LDPC codes and different bit- loadings which naturally occur as part of a large number of OFDM systems (802.16e, for example). I have seem a few methods in the literature for using LDPC with multi-level (e.g. BICM, MLC, etc.) but none of them seem to tackle the problem I'm interested in. Specifically, consider two of the sub-carriers in an OFDM ...

I recently started simulating a HiperMAN/WiMAX PHY on MATLAB. However, in the standard available in the ETSI website, there is mention of a...

I recently started simulating a HiperMAN/WiMAX PHY on MATLAB. However, in the standard available in the ETSI website, there is mention of a "sampling frequency" and a term "bandwidth over sampling frequency". I haven't a clue as to what these terms mean and where they're used in the OFDM process. Could somebody shed some light on what these terms mean in the context of OFDM? Thanks Neelabh...