Training Symbol Design for Channel Estimation and IQ Imbalance Compensation in OFDM Systems

Emmanuel MANASSEH
Shuichi OHNO

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E95-A    No.11    pp.1963-1970
Publication Date: 2012/11/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E95.A.1963
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Smart Multimedia & Communication Systems)
Category: Communication Theory and Signals
Keyword: 
OFDM,  I/Q imbalance,  MIMO,  MSE,  CE optimization,  training symbol,  convex optimization,  

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Summary: 
In this paper, training symbol designs for estimation of frequency selective channels and compensation of in-phase (I) and quadrature (Q) imbalances on orthogonal frequency division multiplexing (OFDM) transmitters and receivers are studied. We utilize cross entropy (CE) optimization techniques together with convex optimization to design training sequences having low channel estimate mean squared error (MSE) and minimum effects of I/Q mismatch, while lowering the peak power of the training signals. The proposed design provides better channel estimate MSE and bit error rate (BER) performances and is applicable to OFDM systems with and without null subcarriers. The efficacies of the proposed designs are corroborated by analysis and simulation results.