Performance Evaluation for OFDM PAPR Reduction Methods

The ultimate goal of Peak to Average Power Ratio (PAPR) reduction for Orthogonal Frequency Division Multiplexing (OFDM) signals is to reduce the signal’s sensitivity to nonlinearity and to improve signal quality and transmitter power efficiency. Performance evaluation has traditionally been based mainly on the PAPR distribution curves. For clipping related methods, however, tradeoffs between PAPR and signal quality must be made, but is often made in a heuristic manner. In this paper, we propose to include amplifier characteristics and use the required backoff to evaluate the performance of PAPR reduction methods. The required backoff OBO* is defined as the minimum required transmit power backoff for the signal to meet quality requirements such as spectrum mask and error vector magnitude constraints. Effective PAPR reduction should lead to smaller OBO*, not just smaller PAPR. Simulation results for IEEE 802.11a wireless local area network signals with clipping related methods are presented. Key-words:OFDM, PAPR Reduction, Clipping, Performance, Intermodulation, Backoff.