Raised-cosine window for OFDM intersymbol transitions

Language: Matlab

Processor: Not Relevant

Submitted by Markus Nentwig on Oct 21 2010

Licensed under a Creative Commons Attribution 3.0 Unported License

Raised-cosine window for OFDM intersymbol transitions

Calculates a raised-cosine window pair for OFDM windowing. Results in a smooth transition between symbols that causes less interference to adjacent frequency bands.

% *************************************************************

% Raised cosine window for OFDM intersymbol transitions

% *************************************************************

% Use the window for the guard period between adjacent symbols

% to smoothen the waveform transition, limit sidelobes and prevent 

% unwanted emissions into adjacent frequency ranges

%

% reference:

% Data transmission by Frequency Division Multiplexing 

% using the Discrete Fourier Transform

% S.B. Weinstein and Paul M. Ebert

% IEEE transactions on Communications technology, No. 5,

% October 1971

% *************************************************************

% Length of the guard period in samples

n=64; 

index=linspace(0, 1, n+2);

index=index(2:end-1);

windowNextSymbol=(1-cos(pi*index))/2;

windowPreviousSymbol=fliplr(windowNextSymbol);

% plot

figure(); title('raised cosine window for OFDM symbol transitions');

xlabel('sample index into the guard period between symbols');

ylabel('window weight');

hold on; 

plot(windowPreviousSymbol, 'r+');

plot(windowNextSymbol, 'b+');

legend({'cyclic extension of symbol i-1', 'cyclic extension of symbol i'});

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posted by Markus Nentwig
Markus received his Dipl. Ing. degree in electrical engineering / communications in 1999. Work interests include RF transceiver system design, implementation, modeling and verification. He works as senior architect for Renesas Mobile Europe in Finland.

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DSP Code Sharing > Raised-cosine window for OFDM intersymbol transitions

Raised-cosine window for OFDM intersymbol transitions

Raised-cosine window for OFDM intersymbol transitions