AUTHORS: Qingqing Wu, Jingqi Wang, Wen Wu
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ABSTRACT: The main disadvantage of Orthogonal Frequency Division Multiplexing (OFDM) signal is the high peak-to-average power ratio (PAPR) which influences the system power efficiency and system performance in the presence of nonlinearities within the high power amplifier (HPA). The error vector magnitude (EVM) is one of the performance metrics by communications standards in OFDM system. In this paper, a novel EVM reduction method from geometric angle analysis is proposed which keeps the bit-error-rate (BER) performance after PAPR reduction. In our method, a threshold vector circle is designed in frequency domain in order to adjust the amplitude and phase of the OFDM signal constellation points to near the ideal points. Simulation results show that PAPR of a QPSK modulated OFDM signal is reduced from 10.56dB to 7.496dB with an EVM reduction of 2.34%. This technique should vastly improve the performance of OFDM signal in communication system
KEYWORDS: Error vector magnitude (EVM), orthogonal frequency division multiplexing (OFDM), peak-toaverage power ratio (PAPR), threshold vector circle method
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