I want to modify my OFDM program into a MIMO-OFDM one. But I dont know where I should modify? channel matrix? Can anybody share a simple...

I want to modify my OFDM program into a MIMO-OFDM one. But I dont know where I should modify? channel matrix? Can anybody share a simple MIMO matlab program and tell me how I can do it?

Hi, I understand that simplified equalization is one of the good reasons for going with OFDM. But, how do they manage it ? That is, The OFDM...

Hi, I understand that simplified equalization is one of the good reasons for going with OFDM. But, how do they manage it ? That is, The OFDM may be viewed as using many slowly-modulated narrowband signals rather than one rapidly-modulated wideband signal. So, The Differential modulation such as DPSK / DQPSK if applied to each sub-carrier, equalization can be completely omitted. ( Reason - ...

I am doing a project on OFDM equalization. So far, i have been doing equalization for one ofdm symbol. I wish to ask how could i add...

I am doing a project on OFDM equalization. So far, i have been doing equalization for one ofdm symbol. I wish to ask how could i add more subcarriers in by using Simulink? Is there any example that i can refer to? Thanks alot.

Could anyone tell me if my understanding for the acronym of ICI is right or not? There are 2 types of ICI, one is Inter Carrier Interference...

Could anyone tell me if my understanding for the acronym of ICI is right or not? There are 2 types of ICI, one is Inter Carrier Interference which is caused by the frequency offset between transmitter and receiver in OFDM system, and another is Inter Code Interference which is caused by the Code Divison Multiplexing in OFDM-CDM system.

Hello, I have a confusion regarding the channel correlation of an OFDM system. In the OFDM receiver, after the FFT, the frequency-domain...

Hello, I have a confusion regarding the channel correlation of an OFDM system. In the OFDM receiver, after the FFT, the frequency-domain output is given as: Y = XH + W Y,X,H and W are matrices with X being a diagonal matrix with constellation points. My question is regarding channel estimation. Usually in MMSE, we need the channel correlation R_HH ('_' denotes the subscript}. And it ...

Hello, I am wondering there is so much literature about carrier and timing recovery in communications*. However as far as I understand, OFDM...

Hello, I am wondering there is so much literature about carrier and timing recovery in communications*. However as far as I understand, OFDM uses a different approach in synchronization. My question is since OFDM is becoming more and more popular does this mean that these algorithms will cease to be used in future? * synchronization in software radios (chris dick, fred harris, michael ric...

Hello Everyone, My name is Rohith and I recently started working on OFDM. I am trying to simulate 4 carrier OFDM system using QPSK...

Hello Everyone, My name is Rohith and I recently started working on OFDM. I am trying to simulate 4 carrier OFDM system using QPSK modulation. I am not sure if my current test model is correct or not. Could you please review this and let me know if I am doing anything wrong? Here is the link to my simulink model: http://rohithramnath.googlepages.com/home Thank you so much. Re...

Hi, I'm trying to understand how synchronision might work in an OFDM receiver with respect to the consequences it has for how the baseband or...

Hi, I'm trying to understand how synchronision might work in an OFDM receiver with respect to the consequences it has for how the baseband or IF signal is sampled. I have tried to read widely, but the IEEE literature around OFDM synchronisation never seems to mention the sample rate or the hardwarey aspects. Below is brief background to try and illustrate where I am coming from, followed by ...

Hi, The ofdm symbols when placed in the freq domain say for QPSK, all the spectrum components have the same value. Hence it results in a flat...

Hi, The ofdm symbols when placed in the freq domain say for QPSK, all the spectrum components have the same value. Hence it results in a flat square frequency spectrum. Hence the time domain OFDM symbol shoul be a sinc pulse. Am I right ??

Hello, everyone. I would like to discuss OFDM's robustnesss againt freq-selective channel. 1) I'm using BPSK( for some reasons, even though...

Hello, everyone. I would like to discuss OFDM's robustnesss againt freq-selective channel. 1) I'm using BPSK( for some reasons, even though mostly we use QPSK, or QAM..) on a very very wide channel. 2) I didn't employ a channel equalizer at the frontend before fft. 3) I, as a reference, followed Richard Van Nee's 'OFDM for wireless multimedia communications' to set the parameters: [1] wor...

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...

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...

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

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.

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...

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.

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?

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...

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...

hi all, I have a question regarding FFT in OFDM. why do we use FFT in OFDM systems? thanx.

hi all, I have a question regarding FFT in OFDM. why do we use FFT in OFDM systems? thanx.