JWCN_V1_N3_RP1 K. Srinivasa Rao B. Prabakararao Journal On Wireless Communication Networks 2320 - 2351 1 3 1 7 PAPR, CCDF, STBC, MIMO-OFDM, Clipping Based-active Constellation Extension, Adaptive Active Constellation Extension In this paper, Adaptive Active Constellation (A-ACE) is analyzed for Peak to Average Power Ratio (PAPR) reduction of OFDM Systems with spectral diversity of Space Time Block Coding (STBC). To support large system capacity with robustness to multipath fading, OFDM and MIMO has been combined as MIMO-OFDM. To overcome the disadvantage of low clipping ratio problem in clipping based-Active Constellation Extension (CB-ACE) technique for PAPR reduction in OFDM systems, the author analyzed ACE algorithm with adaptive clipping control to STBC MIMO-OFDM systems. Simulation results demonstrate that the algorithm can reach the minimum PAPR for severely low clipping ratios, and the performance of this algorithm is superior to the performance of the ACE method in the single antenna OFDM system. October - December 2012 Copyright © 2012 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2048