PAPR Reduction Scheme for OFDMA Uplink System in WiMAX with Different Modulation Schemes and Subcarrier Assignments

The better Distortion-less technique for Peak-To-Average-Power ratio (PAPR) reduction in OFDM is Selected Mapping Schemes (SLM).The SLM has a disadvantage of complexity due to increase in IFFT´s and phase search complexity. The PAPR reduction performance depends on the selection of random phase sequences. This also requires transmission of side information to recover at the receiver. This paper proposes, generation of hadamard matrices for selection of phases. Complexity due to IFFT´s is reduced by generating the candidate signals in time-domain by performing cyclic shifts. The number of cyclic shifts is chosen such that the corresponding frequency domain phase vectors have equal gain. The proposed architecture satisfies the equal gain constraints and is suitable for either interleaved or sub band OFDMA uplink systems and gives better PAPR reduction compared to SLM with DCT. And provides channel estimation to the OFDMA systems.