Performance of differentially detected /spl pi//4 DQPSK in the presence of IQ phase imbalance

The effect of circuit level distortions on system level performance is becoming an important issue in optimizing the design of low power receivers. Circuit level distortions which in the past were insignificant in full power designs, must be accounted for in the link budgets of low power systems. In this paper, we present an analysis that demonstrates and quantifies the effect of one such distortion. We present a closed form expression for the BER of differentially detected /spl pi//4 DQPSK in the presence of AWGN and distorted by an IQ phase imbalance in the receiver.