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A Frequency-domain Compensation Scheme for IQ-Imbalance in OFDM Receivers

2011/05/27 by Wang Mao, Feng, Shu, Shi Xiajie +7
Engineering · #Advanced Power Amplifier Design #Advanced Wireless Communication Techniques #C.2.1 #FOS: Computer and information sciences #Multimedia (cs.MM) #Networking and Internet Architecture (cs.NI) #Radio Frequency Integrated Circuit Design

paper · pdf · doi:10.48550/arxiv.1105.5553

openalex publication_date 2011/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

A pilot pattern across two OFDM symbols with special structure is devised for channel estimation in OFDM systems with IQ imbalance at receiver. Based on this pilot pattern, a high-efficiency time-domain (TD) least square (LS) channel estimator is proposed to significantly suppress channel noise by a factor N/(L+1) in comparison with the frequency-domain LS one in [1] where N and L+1 are the total number of subcarriers and the length of cyclic prefix, respectively. Following this, a low-complexity frequency-domain (FD) Gaussian elimination (GE) equalizer is proposed to eliminate IQ distortion by using only 2N complex multiplications per OFDM symbol. From simulation, the proposed scheme TD-LS/FD-GE using only two pilot OFDM symbols achieves the same bit error rate (BER) performance under ideal channel knowledge and no IQ imbalances at low and medium signal-to-noise ratio (SNR) regions whereas these compensation schemes including FD-LS/Post-FFT LS, FD-LS/Pre-FFT Corr, and SPP/Pre-FFT Corr in [1] require about twenty OFDM training symbols to reach the same performance where A/B denotes compensation scheme with A being channel estimator and B being equalizer.

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