Adaptive SOICAF Algorithm for PAPR Mitigation in OFDM Systems

Orthogonal frequency division multiplexing (OFDM) technology widely used in wireless communications applications for its high data rate. The major limitation of OFDM is the peak-to-average power (PAPR) problem. Several techniques were applied to mitigate PAPR in OFDM application systems. One of the schemes used for PAPR mitigation is Iterative clipping and filtering (ICAF). It uses the same or identical signals for recursive clipping with a constant threshold level for distinct levels of iterations. This scheme drives signal processing blocks like Fast-Fourier transform (FFT)/inverse FFT (IFFT) blocks the number of times to achieve the required level of PAPR, thereby consumes the average system power and takes more computational time. For further improvement, a new adaptive algorithm to mitigate PAPR in OFDM systems proposed. The proposed adaptive algorithm Lagrange multiplier optimization. Results after simulation justify that depending on the threshold value, PAPR reduction achieved with a slight degradation in BER compared with other existing techniques. BER remains same for low threshold level value, but for high threshold level values it is little bit degraded. Over all PAPR reduction, it performs better by 4 dB when compared to the other schemes. In the case of BER tradeoffs, the complexity of the design and computational speed of resources usage minimized. By carefully selecting the clipping threshold, we can achieve same BER with good reduction in PAPR.