9th International Conference on Cognitive Radio Oriented Wireless Networks

Research Article

Interference Suppression with Antenna Arrays in OFDM Systems under Transceiver I/Q Imbalance

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  • @INPROCEEDINGS{10.4108/icst.crowncom.2014.255187,
        author={Aki Hakkarainen and Janis Werner and Kapil Dandekar and Mikko Valkama},
        title={Interference Suppression with Antenna Arrays in OFDM Systems under Transceiver I/Q Imbalance},
        proceedings={9th International Conference on Cognitive Radio Oriented Wireless Networks},
        publisher={IEEE},
        proceedings_a={CROWNCOM},
        year={2014},
        month={7},
        keywords={antenna arrays in-phase quadrature-phase (i/q) imbalance orthogonal frequency-division multiplexing (ofdm) uncorrelated fading},
        doi={10.4108/icst.crowncom.2014.255187}
    }
    
  • Aki Hakkarainen
    Janis Werner
    Kapil Dandekar
    Mikko Valkama
    Year: 2014
    Interference Suppression with Antenna Arrays in OFDM Systems under Transceiver I/Q Imbalance
    CROWNCOM
    IEEE
    DOI: 10.4108/icst.crowncom.2014.255187
Aki Hakkarainen1,*, Janis Werner1, Kapil Dandekar2, Mikko Valkama1
  • 1: Tampere University of Technology
  • 2: Drexel University
*Contact email: aki.hakkarainen@tut.fi

Abstract

In this paper, we address the effects of radio frequency (RF) transceiver in-phase/quadrature-phase (I/Q) imbalance in transmission systems which are utilizing orthogonal frequency-division multiplexing (OFDM) waveforms. Special emphasis is on the analysis of external interference sources and their mitigation with receiver antenna array processing, assuming independent fading for the antenna elements. In addition, I/Q imbalance is assumed to be arbitrarily frequency selective and independent in different transceiver branches. We show that I/Q imbalance is especially harmful in the presence of strong interferers when conventional per-subcarrier processing is implemented on the receiver side. Based on these results, we propose a joint subcarrier processing where each of the subcarrier signals is combined with the signal at the image carrier. Such processing is shown to be very efficient in I/Q imbalance mitigation as well as in the total interference suppression.