Peak Windowing for Crest Factor Reduction Improved by Signal Interpolation

Abstract

Modern modulation schemes generate signals with high Peak to Average Power Ratio (PAPR). In order to achieve compliance of telecommunication infrastructure to standard specifications, enable distortion-free and energy-efficient operation of radio frequency (RF) power amplifiers (PA), the PAPR value of transmitted signals has to be reduced. We propose Peak Windowing (PW) as a method for PAPR reduction. The method is additionally improved to accommodate different Long-Term Evolution (LTE) signal bandwidths. The improvement is based on utilization of additional low-pass filter and also on signal interpolation. For large waveform bandwidths the data rate of signals entering the PAPR processing block is doubled. The method is validated using 5MHz, 10MHz, 15MHz and 20MHz LTE E-TM 3.1 test waveforms after it has been implemented in Software Defined Radio (SDR) board. In all these cases, we measured PAPR=8dB, EVM=2.0%, ACPR - 52dBc at transmitter output.