
59
4
pEak-to-avEragE
poWEr ratio
4.1 Introduction
As explained in Chapter 2, the orthogonal frequency division
multiplexing (OFDM) signal is created by the sum of several sinusoidal
signals. is process is performed by the inverse fast Fourier transform
(IFFT) in the OFDM transmitter.
e basic equations of the FFT and the IFFT can be given by
,0,..., 1
2/
Xk xnekN
jknN
∑
() ()
−
−π
(4.1)
()
1
() ,0,..., 1
1
2/
xn
XkenN
N
jknN
∑
−
−π
(4.2)
where N is the transform size or the number of sample points in the
data frame and
. X(k) is the frequency output of the FFT at
kth point where k = 0, 1, …, N – 1, and x(n) is the time sample at nth
point with ...