## Forums Search for: OFDM

## scaling question for PAPR in OFDM

I have a simple question about calculating the PAPR in matlab. I am doing an OFDM simulation where I have say N data points and then I do the IFFT...

I have a simple question about calculating the PAPR in matlab. I am doing an OFDM simulation where I have say N data points and then I do the IFFT on these N data points with 4 times oversampling. Now when I calculate the Peak to Average Power Ratio I get a very small number so what I'm trying to figure out is what number I should multiply it by to get it scaled correctly. Is it 4*N? or am I missi...

## PAPR calculation

Dear All, I would highly appreciate if you share your thoughts on the correctness of the method for calculating PAPR value of OFDM signal as...

Dear All, I would highly appreciate if you share your thoughts on the correctness of the method for calculating PAPR value of OFDM signal as described below. I am using NRZ random bits as the random input data where the n point IFFT outputs are x1,x2..xn(complex values) for one OFDM symbol. peakpower=max(abs(x1).^2,abs(x2).^2,..abs(xn).^2) avgpower=sum((abs(x1).^2,abs(x2).^2..abs(xn).^2)/n

## Modified Jakes, OFDM implementation

inHi, I am trying to simulate on Matlab a Rayleigh channel for my OFDM signal. I am using the code below to generate the channel...

Hi, I am trying to simulate on Matlab a Rayleigh channel for my OFDM signal. I am using the code below to generate the channel coeficients. The output of this code is a matrix in this case: h = (modified_jakes1(100,2000,10,3,100,0)) is 100 coefficients and 3 multipath chanel.(is this correct?) how can i filter my time domain signal with these coefficient? any idea how to equilize the...

## Rayleigh fading channel in an OFDM Tx/RX

inHello, I have already simulated and OFDM system over AWGN channel. Now, I need to apply flat fading and frequency selective fading with...

Hello, I have already simulated and OFDM system over AWGN channel. Now, I need to apply flat fading and frequency selective fading with Rayleigh distribution as my channel effect. I have tried it and my problem is that I do not know which kind of equalizer I should use in order to remove the effect of fading. Anyone has some idea? I would really appreciate it. Sincerely, Saina

## Modeling OFDM multipath channel in Matlab

inDear all, I am a newbie and I have a basic question which I would like to get clarified. My intention is to simulate 802.11a which is based...

Dear all, I am a newbie and I have a basic question which I would like to get clarified. My intention is to simulate 802.11a which is based in OFDM. From the 802.11a standard I know that: -Number of Subcarriers, Nsc = 64 -Sampling Rate, fs = 20e6 sample/sec -BW = 20MHz -Carrier Frequency, fc = 5.25Ghz Now imagine that I have the following multipath channel: taps_delay = [0 10ns 20ns ...

## Repeat data frames in OFDM

Q1: This is with reference to the white paper by TI entitled, "Power Line Modem with E-meter Platform", 2004 (i'm sorry i can't find the...

Q1: This is with reference to the white paper by TI entitled, "Power Line Modem with E-meter Platform", 2004 (i'm sorry i can't find the link to the article) At the part where the paper decribes the Packet Format for the OFDM frames. It says that the data frames are grouped into blocks of 3 frames and each data frame in the block contains i

## PAPR

inHi, I?m trying to calculate the PAPR in OFDM system, but I don?t know why there is no result? I know there is something wrong! Can any one help...

Hi, I?m trying to calculate the PAPR in OFDM system, but I don?t know why there is no result? I know there is something wrong! Can any one help me to get it? this is my program code close all clear all clc; M = 64; % QAM Modulation Level N = 256; % IFFT Size % QAM 16 MODULATION data = qammod(randint(1,N,M),M); % CALCULATE PAPR OF BASELINE OFDM ofdm_out =sqrt(length(data))*iff...

## OFDM overlapped subcarriers plot?

Hi all I want to plot the real and imaginary OFDM overlapped subcarriers by using matlab. How I can plot the spectrum of these subcarriers by...

Hi all I want to plot the real and imaginary OFDM overlapped subcarriers by using matlab. How I can plot the spectrum of these subcarriers by matlab? note: I don't want to plot the composite or absolute values. Thanks in advanced Sami

## pilot aided channel estimation

Hi, I am simulating OFDM.I finished some part of it.I passed it both awgn=20 and multipath fading channel.Now =FD will make chammel estimation...

Hi, I am simulating OFDM.I finished some part of it.I passed it both awgn=20 and multipath fading channel.Now =FD will make chammel estimation by=20 using pilot symbols.But =FD don't have an idea for doing this.For=20 example I will put 4 pilot symbols as H=DDPERLAN/2 for every OFDM=20 symbols.If you know can you give me an idea.Thanks from now... =20

## Multi-user detection in OFDM

Hi everyone, I am doing Masters thesis in multiuser detection in OFDM. The basic model is y=hx+v . y is the mixture signal recieved by the...

Hi everyone, I am doing Masters thesis in multiuser detection in OFDM. The basic model is y=hx+v . y is the mixture signal recieved by the rxr, h is the channel matrix, x is the original signal txd, v is the noise added in the channel. Each rxr Antenna has to separate its corresponding user signal from the mixture of signals. Can I have the Matlab code for this. I have written the initi...

## IFFT in OFDM Simulation

I have met the same problem in simulating an OFDM system in baseband. When I finished a single-user BPSK modulated simulation in flat...

I have met the same problem in simulating an OFDM system in baseband. When I finished a single-user BPSK modulated simulation in flat Rayleigh fading channel. The BER performance is very strange and cannot match the ideal performance for BPSK signals in flat Rayleigh fading channel. When I check the Matlab program, I can find that if I use y=fft(x), x=fadi

## Help me about MIMO OFDM and ICA

Hi All I'm doing my Master Thesis about "Multiuser Detection and Channel Estimation in MIMO OFDM using ICA". I use FastICA algorithm for...

Hi All I'm doing my Master Thesis about "Multiuser Detection and Channel Estimation in MIMO OFDM using ICA". I use FastICA algorithm for complex valued signals by Ella Bingham and Aapo Hyv?rinen (paper about this algorithm is in "A fast fixed-point algorithm for independent component analysis of complex valued signals", International Journal of Neural Systems, Vol. 10, No. 1 (February, 2000)...

## Please help: BER for QPSK in OFDM over Rayleigh matlab code doesn't work.

I try to implement the matlab code on BER for QPSK in OFDM over rayleigh channel (with n taps). However the result is a straight line. There must...

I try to implement the matlab code on BER for QPSK in OFDM over rayleigh channel (with n taps). However the result is a straight line. There must be something wrong in my code but I cannot figure it out what is wrong. Could you please help me to check it. I have to hand the work soon. Please please please help. Thank you very much. [QUOTE]clear; clc; N=64; % FFT size Nsd = 48; % Number of ...

## Simulink (Rayleigh Fading) Help Required

Hello Everyone! I am Ahsan and i am doing my final year (UG) project on OFDM. I was supposed to simulate the effects of noise and...

Hello Everyone! I am Ahsan and i am doing my final year (UG) project on OFDM. I was supposed to simulate the effects of noise and multipath fading on OFDM signal. I am using SIMULINK as the simulation tool.I have completed the noise simulation using the AWGN channel in SIMULINK but when i insert the Multi-path Rayleigh Fading Channel in my model i get the following error: Error rep...

## implementation of ofdm running on dsps by Realtime workshop

Hello I'm working on the implementation of ofdm running on dsps(TMS320c6xxx). I have made my own simulink and matlab mfiles. My question...

Hello I'm working on the implementation of ofdm running on dsps(TMS320c6xxx). I have made my own simulink and matlab mfiles. My question is: Does any one know how to test my work on dsp basd on relating the dsp with my computer by using realtime workshop on matlab 2008 and see how my simulink goes on dsp without writing c or dsp's programming code composer?and then how to optimize this? please ...

## from signal constellation to sinc function in OFDM

i want to investigate the relationship between the signal constellation and the sinc function in OFDM signal i have derived like this ...

i want to investigate the relationship between the signal constellation and the sinc function in OFDM signal i have derived like this FOR EXAMPLE i want to see the effect of 00 then in the signal constellation it can be represented like Aexp(pi/2) in phase domain and in time domain 1/(2*j)[exp(-jwt+pi/2) +exp(-jwt+pi/2)] so i proceed like this i take the integral of t...

## Space-Time decoding in multipath MIMO-OFDM system

inHello, I'm working on a MIMO-OFDM system simulation in Matlab. I assume a 3 tap multipath channel. My question concerns the Space-Time decoding...

Hello, I'm working on a MIMO-OFDM system simulation in Matlab. I assume a 3 tap multipath channel. My question concerns the Space-Time decoding block at the receiver side. When decoding a ST coded signal, ussually a pseudo inverse of a channel matrix H has to be calculated (zero forcing, MMSE, SIC, OSIC algorithms). In a single tap channel this is a trivial problem. However, my problem is that...

## Rayleigh fading channel problem (Simulink)

I want to use the multipath rayleigh channel for my OFDM simulation in Simulink. However i keep getting this error message: Error reported...

I want to use the multipath rayleigh channel for my OFDM simulation in Simulink. However i keep getting this error message: Error reported by S-function 'scomtrigbuff2' in 'ofdm/Multipath Rayleigh Fading Channel/Multipath Fading Channel/Fading Profile/Rebuffer with Input Trigger/S-Function': The minimum input width must an integer scalar > 0 > > > Although i added a buffer block to the

## OFDM rayleigh fading simulation using rayleighchan function.

inHi All, I'm simulating rayleigh fading on an OFDM system. I have a question with regards to the usage of the rayleighchan function....

Hi All, I'm simulating rayleigh fading on an OFDM system. I have a question with regards to the usage of the rayleighchan function. I'm trying to figure out how to do perfect compensation for the fading using this function. In theory, I could use an equalizer, but I would like to do perfect compensation for my theoretical purposes and to keep

## Multipath Rayleigh problem (Simulink)

I want to use the multipath rayleigh channel for my OFDM simulation in Simulink. However i keep getting this error message: Error reported...

I want to use the multipath rayleigh channel for my OFDM simulation in Simulink. However i keep getting this error message: Error reported by S-function 'scomtrigbuff2' in 'ofdm/Multipath Rayleigh Fading Channel/Multipath Fading Channel/Fading Profile/Rebuffer with Input Trigger/S-Function': The minimum input width must an integer scalar > 0 I'm new to Simulink so can anyone help me