tailieunhanh - Báo cáo hóa học: " Research Article Analysis and Compensation of Transmitter and Receiver I/Q Imbalances in Space-Time Coded Multiantenna OFDM Systems"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Analysis and Compensation of Transmitter and Receiver I/Q Imbalances in Space-Time Coded Multiantenna OFDM Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 391025 16 pages doi 2008 391025 Research Article Analysis and Compensation of Transmitter and Receiver I Q Imbalances in Space-Time Coded Multiantenna OFDM Systems Yaning Zou Mikko Valkama and Markku Renfors Institute of Communications Engineering Tampere University of Technology 553 33101 Tampere Finland Correspondence should be addressed to Yaning Zou Received 30 April 2007 Revised 27 August 2007 Accepted 30 October 2007 Recommended by Hikmet Sari The combination of orthogonal frequency division multiplexing OFDM and multiple-input multiple-output MIMO techniques has been widely considered as the most promising approach for building future wireless transmission systems. The use of multiple antennas poses then big restrictions on the size and cost of individual radio transmitters and receivers to keep the overall transceiver implementation feasible. This results in various imperfections in the analog radio front ends. One good example is the so-called I Q imbalance problem related to the amplitude and phase matching of the transceiver I and Q chains. This paper studies the performance of space-time coded STC multiantenna OFDM systems under I Q imbalance covering both the transmitter and the receiver sides of the link. The challenging case of frequency-selective I Q imbalances is assumed being an essential ingredient in future wideband wireless systems. As a practical example the Alamouti space-time coded OFDM system with two transmit and M receive antennas is examined in detail and a closed-form solution for the resulting signal-to-interference ratio SIR at the detector input due to I Q imbalance is derived. This offers a valuable analytical tool for assessing the I Q imbalance effects in any STC-OFDM system without lengthy data or system simulations. In addition the impact of I Q imbalances on the channel estimation in