OFDM systems

Started by patrick12 in comp.dsp13 years ago 2 replies

Hallo, In an OFDM systems, if the users are not orthogonal, how does the multiuser interference affects the mapping of SNR to BER (BLER).I do...

Hallo, In an OFDM systems, if the users are not orthogonal, how does the multiuser interference affects the mapping of SNR to BER (BLER).I do have only a vague idea about this. Could anyone help me in the right path/ any literatures. Thanks a lot in advance Cheers, Patrick


Sampling Clock Problem in OFDM

Started by Anonymous in comp.dsp12 years ago 1 reply

I have made a simulation of ofdm on baseband and it works fine. to simulate the sampling clock synchronization problem, i have resampled the...

I have made a simulation of ofdm on baseband and it works fine. to simulate the sampling clock synchronization problem, i have resampled the baseband waveform using resample function in MATLAB. yt = resample(yt, 1601, 1600); Now, even with such a small offset, my receiver does not work (yt contains 1600 samples comprising 20 ofdm symbols each of 64 point + 16 cyclic prefix = 80 samples). M...


Digiatal Sampling correction Interpolation/Decimation in e OFDM Modem

Started by nqh in comp.dsp13 years ago

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: ...


OFDM transmission under rayleigh fading

Started by dude23 in comp.dsp13 years ago

Hi all, I would like to find theoretical 802.11g BER performances in the case of a transmission under rayleigh channel. I found theoretical...

Hi all, I would like to find theoretical 802.11g BER performances in the case of a transmission under rayleigh channel. I found theoretical M-QAM curves, but I don't know how to compute BER curves for OFDM transmission due to the use of several sub-carriers... Is the OFDM BER something like that: BER = (1/N)*SUM(BER_i, i=1..N) where N is the number of sub-carriers and BER_i the BER on e...


OFDM and channel modeling

Started by cpshah99 in comp.dsp11 years ago 4 replies

Hi All. I have never worked on OFDM but still I have a doubt. I know how to model time varying frequency selective channel for...

Hi All. I have never worked on OFDM but still I have a doubt. I know how to model time varying frequency selective channel for single carrier system in *time domain*. I am pretty sure that exactly the same way you can model the time varying frequency selective channel for OFDM. But is it something like you can model the time varying frequency selective channel for OFDM in *frequency domai...


MLE in OFDM.SOS!

Started by mib in comp.dsp14 years ago 2 replies

Hi All! I have written a section of codes according to the J.J. van de Beek's , but the result is wrong. I do not know why, I hope someone can...

Hi All! I have written a section of codes according to the J.J. van de Beek's , but the result is wrong. I do not know why, I hope someone can help me,thanks! clear all; %********************** preparation part *************************** para=128; % Number of parallel channel to transmit (points) fftlen=128; % FFT length no


Looking for books on OFDM

Started by Nikos Annitsakis in comp.dsp16 years ago 1 reply

Hi all: I am looking for books to read about OFDM. Could you offer some suggestions? Thanks, Nikos

Hi all: I am looking for books to read about OFDM. Could you offer some suggestions? Thanks, Nikos


implementation of OFDM-MFSK

Started by shamma in comp.dsp11 years ago 7 replies

hi can anyone have the idea how to implement OFDM-MFSK in matlab . Regards

hi can anyone have the idea how to implement OFDM-MFSK in matlab . Regards


Does OFDM based system use PLL or DLL for synchronization?

Started by xsong in comp.dsp9 years ago 9 replies

I have been wondering if OFDM based system use PLL or DLL as in single carrier system e.g. GSM to do synchronization at all? Currently, a lot of...

I have been wondering if OFDM based system use PLL or DLL as in single carrier system e.g. GSM to do synchronization at all? Currently, a lot of ofdm based systems talk about implementing the frequency offset and time offset compensation in the digital domain. Do they also implement the time and frequency synchronization in hardware?


OFDM Transceiver code

Started by wate...@yahoo.com in comp.dsp14 years ago 7 replies

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...


OFDM simulation

Started by sheen2411 in comp.dsp13 years ago 1 reply

hi all I hope that you can help me. I actually have to simulate an ofdm system to show the graph of magnitude against frequency. I am...

hi all I hope that you can help me. I actually have to simulate an ofdm system to show the graph of magnitude against frequency. I am however stuck... part my initial codes are as follows: % generating 400 symbols (block 20 x 20)-> transmitted signal qpsk= exp(j*[pi/4 3*pi/4 5*pi/4 7*pi/4]'); s=qpsk(randint(20,20,4)+1); %convert to time dom


WLAN modeling and OFDM

Started by ayp in comp.dsp14 years ago 1 reply

Hi guys I've got my OFDM system up and running in MATLAB. Now I want to parameterize it in terms of BW and T_s etc. I want to use the WLAN...

Hi guys I've got my OFDM system up and running in MATLAB. Now I want to parameterize it in terms of BW and T_s etc. I want to use the WLAN channel model but I don't know how many tabs the channel length should be and what the gains are. Can anyone help on this? thanks


CFO in STBC-OFDM

Started by Anonymous in comp.dsp12 years ago 3 replies

i am doing CFO in STBC-OFDM as my M.Tech project.....I am not avaliable to find how to estimate frequency offset at receiver....I am using...

i am doing CFO in STBC-OFDM as my M.Tech project.....I am not avaliable to find how to estimate frequency offset at receiver....I am using MATLAB......Please help me it is urgent for my project.....


book for OFDM

Started by sami in comp.dsp11 years ago 9 replies

please i need your advice 1_what the best book that explain the idea of OFDM 2_ what is the best book for matlab for digital com

please i need your advice 1_what the best book that explain the idea of OFDM 2_ what is the best book for matlab for digital com


OFDM or SC-FDMA

Started by Ammankumar in comp.dsp11 years ago 5 replies

Hi All, 1) I want to implement MODEM with 128Kbps at 100Khz with high doppler shift channel. Which modulation technique would be suitable...

Hi All, 1) I want to implement MODEM with 128Kbps at 100Khz with high doppler shift channel. Which modulation technique would be suitable . Whether I can go with OFDM or SC-FDMA? Any suggestions 2) Is it possible to simulate 128Kbps with Matlab Thanks & Regards, Ammankumar.S


SINR estimation in OFDM systems

Started by jia in comp.dsp13 years ago 5 replies

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 +...


OFDM & Simulink

Started by alexgiul in comp.dsp13 years ago 3 replies

Hi to everybody, I'm a new user of this forum; I'm trying to realize a model in simulink with I can simulate an ofdm trasmitter and receiver. I...

Hi to everybody, I'm a new user of this forum; I'm trying to realize a model in simulink with I can simulate an ofdm trasmitter and receiver. I have seen the model proposed from mathwork and I want to insert the effect of a channel and not only the noise; Has anybody any information about this task? Thanks, AlexGiul


Do we have to use null tones in OFDM modulation?

Started by phil in comp.dsp12 years ago 4 replies

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...


Digiatal Sampling correction Interpolation/Decimation for application in flexible OFDM Modem.

Started by nqh in comp.dsp13 years ago 3 replies

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...


ofdm:cdma

Started by hildaa in comp.dsp10 years ago

Hello i need a matlab code about combinaition of OFDM/CDMA

Hello i need a matlab code about combinaition of OFDM/CDMA