A Novel Phase Tracking in ZigBee Receiver Using Extended Kalman Filtering over AWGN Channel

Abstract

This paper aims at investigating the performance of applying Extended Kalman Filter (EKF) to track the phase changes of Binary Phase Shift Keying (BPSK) in ZigBee receivers. EKF is used to optimize the BPSK modulated signal by minimizing the phase error in the presence of the Additive White Gaussian Noise (AWGN) channel. A MATLAB-based simulator is developed to implement the EKF in the ZigBee receiver to correctly track the phase changes of the BPSK as the performance of tracking is measured by Mean Square Error (MSE) for different Signal to Noise Ratio (SNR). The MSE is used to measure the phase deviation error from the true phase. The phase tracking measured by MSE for different SNR values show that EKF has less phase error deviation than Costas Phase Locked Loop (CPLL) for all SNR values. The results show that EKF is novel and track the phase changes correctly more than the Costas PLL. For example, for SNR of 5, the MSE for our EKF is 3.5e-05 whereas it is 6.25e-05 for Costas PLL, i.e. ours has an improvement of 78%. The proposed EKF has less phase error deviation than CPLL for all SNR values and the improvement can be from 5% to 81%, depending on SNR.