Improved Estimation of the Ricean K Factor from I/Q Samples

Knowledge of the Ricean K factor is important in many communication applications as it reveals the fading severity experienced by a wireless receiver. In this paper, a statistical analysis of the maximum likelihood estimator (MLE) of K from complex (I/Q) Ricean channel samples is derived. Based on our analysis, an improved estimator of the K factor is proposed with superior bias and efficiency properties for short data records. The lack of robustness of the tractable MLE in mobile applications is addressed by incorporating a reliable estimator of the specular Doppler shift. The simulation results show that the proposed technique can outperform prior methods for I/Q mobile channel snapshots.