Elimination of interference due to IQ imbalance for OFCDM direct conversion receiver

Recently, with a view to reducing the size and power consumption of wireless receivers, research on direct conversion schemes has been carried out extensively. One of the problems in the direct conversion receiver is IQ imbalance. In the direct conversion receiver, a π/2 phase shifter for RF is required. However, it is difficult to operate a phase shifter with an accurate phase shift value over a broad bandwidth. As a result, the IQ balance of the demodulated signals varies. In the case of OFCDM signals, this IQ imbalance affects the demodulated signals as intercarrier interference (ICI). In the present paper, correction of the IQ imbalance by signal processing is considered for reduction of the effect.