OFDM Error Vector Magnitude Distortion Analysis

Shingo YAMANOUCHI
Kazuaki KUNIHIRO
Hikaru HIDA

Publication
IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.12    pp.1836-1842
Publication Date: 2006/12/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.12.1836
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Emerging Microwave Techniques)
Category: Active Circuits/Devices/Monolithic Microwave Integrated Circuits
Keyword: 
power amplifiers (PAs),  nonlinear distortion,  error vector magnitude (EVM),  wireless LAN,  orthogonal frequency-division multiplexing (OFDM),  

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Summary: 
We derived explicit formulas for evaluating the error vector magnitude (EVM) from the amplitude distortion (AM-AM) and phase distortion (AM-PM) of power amplifiers (PAs) in orthogonal frequency-division multiplexing (OFDM) systems, such as the IEEE 802.11a/g wireless local area networks (WLANs) standards. We demonstrated that the developed formulas allowed EVM simulation of a memoryless PA using only a single-tone response (i.e. without OFDM modulation and demodulation), thus enabling us to easily simulate the EVM using a harmonic-balance (HB) simulator. This HB simulation technique reduced the processing time required to simulate the EVM of a PA for the IEEE 802.11a standard by a factor of ten compared to a system-level (SL) simulation. We also demonstrated that the measured EVM of a PA module for the IEEE 802.11g could accurately be predicted by applying the measured static AM-AM and AM-PM characteristics to the derived formulas.