Comments on: Inter Carrier Interference (ICI) in OFDM due to frequency offset http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/ Signal Processing for Communication Fri, 10 Feb 2012 01:03:15 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Krishna Sankar http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-73908 Krishna Sankar Sun, 30 Oct 2011 14:29:29 +0000 http://www.dsplog.com/?p=689#comment-73908 @Ahmed: How about sum(a.^2)./sum(a) in matlab ? Note the dot (.) @Ahmed: How about sum(a.^2)./sum(a) in matlab ? Note the dot (.)

]]> By: Ahmed http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-73394 Ahmed Wed, 26 Oct 2011 22:22:45 +0000 http://www.dsplog.com/?p=689#comment-73394 Hello, Can you told me, how to simplify sum(a^2)/sum(a) where a is a vector of N complex variables. Hello,

Can you told me, how to simplify

sum(a^2)/sum(a)

where a is a vector of N complex variables.

]]> By: Krishna Sankar http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-56103 Krishna Sankar Sun, 22 May 2011 21:46:01 +0000 http://www.dsplog.com/?p=689#comment-56103 @nanu: Am sure you will be able to identify the problem in reshape() yourself :) @nanu: Am sure you will be able to identify the problem in reshape() yourself :)

]]> By: nanu nadoda http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-55606 nanu nadoda Wed, 18 May 2011 10:26:45 +0000 http://www.dsplog.com/?p=689#comment-55606 hi krishna find here with program for standard OFDM simulator in MATLAB %%OFDM simulator ep = [0 .15 .3 ]; % Es/No EbNo=0:30; % NS = number of OFDM symbols to transmit NS = 100; % Modulation type modulation = 'psk'; M = 4 % N = number of carriers in OFDM symbol N = 52; % BPS = number of bits per OFDM symbol BPS = N*log2(M); % index for carriers in OFDM symbol carriers = (1:52) + 2; % IFFT size ifftsize = 64; % Input Bit Stream is normally Distributed input_bit_stream = sign(randn(1,BPS*NS)); input_bit_stream(input_bit_stream == -1) = 0; % PERFORM SERIAL TO PARALLEL CONVERSION parallel_data = reshape(input_bit_stream, log2(M)); % PERFORM MODULATION modulated_data = dmodce(parallel_data, 1, 1, modulation, M); % CREATE OFDM SYMBOLS disp('Transmitting OFDM symbols') %Normalize %modulated_data = (modulated_data/max(abs(modulated_data))); for ll= 1:length(ep) for l=1:length(EsNo) k = 1; for n = 1:NS ofdm_symbol = zeros(1,ifftsize); % Map modulated data to FFT bins in OFDM symbol ofdm_symbol(carriers) = modulated_data(k:k+51); % Time Signal to transmit tx_signal = ifft(ofdm_symbol,ifftsize); % DOPPLER SHIFT rx_signal = tx_signal.*exp((j*pi*ep(ll)/ifftsize)*(0:ifftsize-1)); noise = sqrt(1/(2*log2(M)*10^(EsNo(l)/10)))*(randn(1,64)+j*randn(1,64)); rx_signal = rx_signal + noise; % FFT received_ofdm = fft(rx_signal, ifftsize); % Extract data from carriers in OFDM symbol received_symbols(k:k+51) = received_ofdm(carriers); k = k + 52; end % PERFROM DEMODULATION received_data = ddemodce(received_symbols, 1, 1, modulation, M); %PERFORM PARALLEL TO SERIAL CONVERSION output_bit_stream = reshape(received_data, log2(M)); % CALCULATE BER BER(ll,l)= sum(xor(input_bit_stream, output_bit_stream))/length(input_bit_stream); end end =================================================== i am experiencing problem in reshape. if you can rectify then i will be highly oblige. send me reply on my mail : nbnadoda@yahoo.co.in hi krishna
find here with program for standard OFDM simulator in MATLAB
%%OFDM simulator
ep = [0 .15 .3 ];
% Es/No
EbNo=0:30;
% NS = number of OFDM symbols to transmit
NS = 100;
% Modulation type
modulation = ‘psk’;
M = 4
% N = number of carriers in OFDM symbol
N = 52;
% BPS = number of bits per OFDM symbol
BPS = N*log2(M);
% index for carriers in OFDM symbol
carriers = (1:52) + 2;
% IFFT size
ifftsize = 64;
% Input Bit Stream is normally Distributed
input_bit_stream = sign(randn(1,BPS*NS));
input_bit_stream(input_bit_stream == -1) = 0;
% PERFORM SERIAL TO PARALLEL CONVERSION
parallel_data = reshape(input_bit_stream, log2(M));
% PERFORM MODULATION
modulated_data = dmodce(parallel_data, 1, 1, modulation, M);
% CREATE OFDM SYMBOLS
disp(‘Transmitting OFDM symbols’)
%Normalize
%modulated_data = (modulated_data/max(abs(modulated_data)));
for ll= 1:length(ep)
for l=1:length(EsNo)
k = 1;
for n = 1:NS
ofdm_symbol = zeros(1,ifftsize);
% Map modulated data to FFT bins in OFDM symbol
ofdm_symbol(carriers) = modulated_data(k:k+51);
% Time Signal to transmit
tx_signal = ifft(ofdm_symbol,ifftsize);
% DOPPLER SHIFT
rx_signal = tx_signal.*exp((j*pi*ep(ll)/ifftsize)*(0:ifftsize-1));
noise = sqrt(1/(2*log2(M)*10^(EsNo(l)/10)))*(randn(1,64)+j*randn(1,64));
rx_signal = rx_signal + noise;
% FFT
received_ofdm = fft(rx_signal, ifftsize);
% Extract data from carriers in OFDM symbol
received_symbols(k:k+51) = received_ofdm(carriers);
k = k + 52;
end
% PERFROM DEMODULATION
received_data = ddemodce(received_symbols, 1, 1, modulation, M);
%PERFORM PARALLEL TO SERIAL CONVERSION
output_bit_stream = reshape(received_data, log2(M));
% CALCULATE BER
BER(ll,l)= sum(xor(input_bit_stream, output_bit_stream))/length(input_bit_stream);
end
end
===================================================
i am experiencing problem in reshape. if you can rectify then i will be highly oblige.
send me reply on my mail : nbnadoda@yahoo.co.in

]]> By: Krishna Sankar http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-40082 Krishna Sankar Wed, 17 Nov 2010 00:32:42 +0000 http://www.dsplog.com/?p=689#comment-40082 @Urbie: No problem. Glad that you have solved it. @Urbie: No problem. Glad that you have solved it.

]]> By: Krishna Sankar http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-40062 Krishna Sankar Tue, 16 Nov 2010 23:35:10 +0000 http://www.dsplog.com/?p=689#comment-40062 @Thavamaran: Ok, good luck @Thavamaran: Ok, good luck

]]> By: Thavamaran http://www.dsplog.com/2009/08/08/effect-of-ici-in-ofdm/#comment-40046 Thavamaran Tue, 16 Nov 2010 19:24:31 +0000 http://www.dsplog.com/?p=689#comment-40046 I am surprised as well Krishna, its the non-linear dynamics of the laser. I am still analyzing now. thanks anyway I am surprised as well Krishna, its the non-linear dynamics of the laser. I am still analyzing now. thanks anyway

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