H. Kim, Y. Jin, S. Yun, and J. Ahn (Korea)
IQ imbalance, OFDM, direct-conversion receiver, diversity
In this paper, we analyze the effects of IQ (In-phase/
Quadrature-phase) imbalances at both transmitter and
receiver of OFDM (Orthogonal Frequency Division
Multiplexing) system and show that more diversity gain can
be achieved even though there are unwanted IQ imbalances.
When mixed sub-carriers within an OFDM symbol due to the
IQ imbalances undergo frequency selective channels,
additional diversity effects are expected during the
demodulation process. Simulation results on the symbol error
rate (SER) performance with ML (Maximum Likelihood) and
OSIC (Ordered Successive Interference Cancellation)
receiver show that significant performance gain can be
achieved with the diversity gain caused by the IQ imbalances
combined with the frequency selective channels.