(A) low complexity PAPR reduction method in carrier interferometry OFDM systems

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is widely believed as the enabling technology for wireless communication due to its high data rates transmission capacity and robustness against multipath e®ects. A major draw- back in the OFDM system is its high Peak-to-Average-Power Ratio (PAPR). The use of Carrier Interferometry (CI) code in OFDM system signi¯cantly reduces this PAPR as pointed out in the literature. However, this result is achieved based on an assumption that the wireless channel is perfectly known at the receiver, which never occurs in practical systems. Moreover, the construction of the CI code in the conventional CI/OFDM system is too complex to implement. In this thesis, we propose a method to reduce the computational complexity in the con- ventional CI/OFDM systems. We also adapt a method of channel estimation in [16], which uses hidden pilot (HP) sequence, to the proposed CI/OFDM sysems. Then we analyze the PAPR of the proposed systems and show that the PAPR of the proposed system can be reduced by allocating more power to the hidden pilot sequence.