Low-Complexity EM-based Joint CFO and IQ imbalance Acquisition

—New air interfaces are currently being developed to meet the high spectral efficiency requirements of the emerging wireless communication systems. In this context, OFDM is considered as a promising air interface candidate for both indoor and outdoor communications. Besides spectral efficiency and power consumption, the production cost of the transceiver should also be optimized. Direct-conversion radio frequency receivers are appealing because they avoid costly intermediate frequency hardware. However, they imply analog IQ separation, introducing a phase and amplitude mismatch between the I and Q branches. A communication system based on OFDM is sensitive to synchronization errors, such as CFO, and to front-end non-idealities, such as IQ imbalance. The goal of this paper is to use the iterative EM algorithm to acquire jointly the CFO and the IQ imbalance. The solution relies on a repetitive preamble and does not require the knowledge of the propagation channel. Based on a second o...

• Type: Conference
• Year: 2007
• Where: ICC
• Authors: François Horlin, André Bourdoux, Eduardo Lopez-Estraviz, Liesbet Van der Perre
• Keywords: Communications, ICC 2007, IQ Imbalance, IQ Imbalance Converge, IQ Imbalance Estimate