ISSN : 1796-2021
Volume : 2    Issue : 7    Date : December 2007

Performance Analysis of Zero-IF MIMO OFDM Transceivers with IQ Imbalance
Tim C. W. Schenk, Erik R. Fledderus, and Peter F. M. Smulders
Page(s): 9-19
Full Text:
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This contribution analytically studies the influence of IQ mismatch on the performance of
multiple-antenna orthogonal frequency division multiplexing (OFDM) systems based on the zero-IF
architecture. First a system model for such a multiple-input multiple-output (MIMO) OFDM system
experiencing both transmitter (TX) and receiver (RX) IQ imbalance is derived. This is used to obtain
analytical expressions for the probability of error in symbol detection for MIMO OFDM systems in
Rayleigh faded multipath channels. The derived results can be used to find matching specifications
for the TX- and RX-branches for different multicarrier MIMO systems. It is concluded that in fading
channels RX IQ imbalance is on average more destructive than TX IQ imbalance. Additionally, it is
concluded that the addition of extra RX antennas is beneficial to reduce the dependence on RX IQ
imbalance, but increases at the same time the impact of TX IQ imbalance.

Index Terms
orthogonal frequency division multiplexing (OFDM), multiple-antenna systems, RF imperfections, IQ
mismatch, fading channels, performance analysis