Pilot design for Joint Channel and Frequency-Dependent Transmit/Receive IQ Imbalance Estimation and Compensation in OFDM-Based T

Abstract— Nowadays a lot of effort is spent on developing OFDMbased inexpensive wireless transceivers. Direct-conversion radio frequency transceivers are appealing because they avoid costly IF analog components. This kind of transceivers imply analog RF I/Q separation. The mismatch between the analog components in the in-phase and quadrature branches introduces an unwanted in-band interference. Unfortunately, OFDM-based systems are very sensitive to I/Q mismatch, mostly when high order modulation schemes are applied. A digital compensation of this unwanted effect is required. In this paper, we developed a method for compensating the transmitter/receiver frequency-dependent I/Q imbalance jointly with the propagation channel in the frequency domain. Based on a low complexity ML channel estimator, a pilot design criterion is derived for channel and IQ imbalance coefficients estimation. An advanced equalizer is proposed which compensates for the frequency-dependent IQ imbalance. Both st...

• Type: Conference
• Year: 2007
• Where: ICC
• Authors: Eduardo Lopez-Estraviz, Stefaan De Rore, François Horlin, André Bourdoux
• Keywords: Analog Components, Communications, Frequency-dependent I/q Imbalance, ICC 2007, IQ Imbalance