Modified Active Constellation Extension for PAPR Reduction of Space-Frequency Block Coded OFDM Systems


Department of Electrical Engineering,Sharif University of Technology


In this paper, the Active Constellation Extension (ACE) technique is applied to Space
Frequency Block Coded (SFBC) OFDM systems to reduce the Peak to Average Power Ratio (PAPR). For
the extension of this technique to SFBC systems, it will be shown that the space frequency coded signals are
the combination of several subframes and that the ACE method may be applied to these subframes. Using
this model, an iterative ACE method, based on Projection Onto Convex Sets (POCS), is introduced. At
each iteration, the time domain samples of the subframes are clipped based on their e ect on the samples
of all antennas. Then, the clipped subframes are ltered and the signals of the antennas are constructed
from the modi ed subframes. The simulation results show that the performance of the proposed method is
very close to the performance of the ACE method in the single antenna OFDM system.