Forums

OFDM subcarrier overlapping......

Started by mashhur March 9, 2009
Hi all members of DSP!
I am getting familiar to OFDM because of you guys! Thanks a lot!

in frequency domain subcarriers may overlap each other, however
transmitting information doesn't mix. What is the reason?
could somebody explains me, I appreciate a feedback!
thanks again!
On Mar 9, 4:41&#2013266080;am, "mashhur" <mashh...@yahoo.com> wrote:
> Hi all members of DSP! > I am getting familiar to OFDM because of you guys! Thanks a lot! > > in frequency domain subcarriers may overlap each other, however > transmitting information doesn't mix. What is the reason? > could somebody explains me, I appreciate a feedback! > thanks again!
Roughly speaking, as long as the length of the window and the spacing of the tones are chosen such that the center of each tone is in zero-crossings of all other tones, then there is no inter-carrier interference. More precisely, this has to do with the algebra of the Discrete Fourier Transform. It operates on circular signals. Hence if you use the correct amount of cyclic prefix, you get orthogonality. Julius