papr_windowing

   reduction to papr in ofdm with Peak Windowing: The basic idea of peak windowing is to multiply the envelope of OFDM signal with a weighting function . Therefore, ~xE (t)= xE (t) f (t) where XE(t) =[x(t)] The weighting function given by: f (t)= 1-Σ α .w(t- t ) t-t w(t) : is the window function. t : denotes the position of a local maximum of the envelop xE(t) . α : attenuation constant . When the amplitude of envelop amplitude of the OFDM signal exceeds a threshold, a window function is applied to the envelop of the OFDM signal to eliminate the peak amplitude. windowing results in a smooth signal. Hanning window function will be used for w(t) As a matter of fact , other windows such as cosine, hamming and Kaiser may be employed.