Characterization and compensation of DC offset on adaptive MIMO direct conversion transceivers

The effect of DC offset on multi-input multi-output (MIMO) direct transceivers with adaptive modulation (AM) is discussed in this paper. A variable-rate variable-power (VRVP) AM system with perfect channel state information (P-CSI) at both the transmitter and receiver in a MIMO scenario is considered. The DC offset is modeled as a zero mean complex Gaussian distributed random variable. By this modeling of the DC offset, the analytical expression for degraded bit error rate has been derived. To derive this analytical expression, some approximation has been made. The good agreement between the analytical and simulation results shows that proper approximation has been made and confirms the accuracy of the analytical expressions. Moreover, an approach to compensate the DC offset in these systems is introduced. The compensation technique is applied and the improvement has been examined.