Optimal Pilot Power Allocation for OFDM Systems with Transmitter and Receiver IQ Imbalances

Abstract

In this paper, we derive optimal pilot power allocation for OFDM systems suffering from in-phase and quadrature-phase (IQ) imbalances. Existing works in literature on IQ imbalances optimize for pilot spacings and pilot designs. However, in all these works, optimal power allocation between pilot and data symbols has not been considered. Using a lower bound on the average channel capacity as a metric, we optimize for the pilot and data power allocations. Simulations show that the resulting optimal pilot power allocation increases the channel capacity along with lowering the bit error rate (BER). We further show that the power allocation is flexible in the sense that several power allocation choices exist that improve capacity compared to the equal power allocation scenario.