Abstract
This research proposes a new low-cost and less complex methodology endeavoring to optimize the performance of OQPSK using the Interactive Kalman Filter (IKF). The design method is based on the use of two Linear Kalman Filters (LKFs) coupled together to be used as a priori phase to an Extended Kalman Filter (EKF) and as an observer to the 2^{nd}LKF to estimate the phase coefficients. We choose to implement the proposed method in the ZigBee receiver because current numbers indicate that ZigBee sales are growing and are expected to dominate the market by 2023 and become the primary wireless protocol for the Internet of Things (IoT). ZigBee is a low data rate wireless personal area network (LR-WPAN) used as a short distance communication system. Therefore, it is a promising technology due to its low cost, low power consumption, and wireless mesh networking standard. There are two types of modulation under the original IEEE 802.15.4/ZigBee standard. The first one is the Offset Quadrature Phase Shift Keying (OQPSK), which is employed in a 2.49 GHz band. The other type is the Binary Phase Shift Keying (BPSK), which is employed in both 868/915 MHz bands. ZigBee 2.49 GHz has a higher data rate and a number of channels than ZigBee 868/915 MHz. The proposed method IKF will be implemented to optimize the OQPSK 2.49 GHz modulated signal. The criterion for novelty is the minimization of the Mean Square Error (MSE) with respect to Signal to Noise Ratio (SNR) values between the output phase signal and the actual value of the phase signal. The proposed phase tracking using the IKF technique reduces the phase deviation error and increases the robustness against Gaussian noise, Non-Gaussian noise, and the Co-Channel Interference (CCI). A MATLAB ZigBee transceiver system model has been created to study the performance of the IKF in the presence of different propagation environments. The proposed IKF has been implemented into the ZigBee receiver to illustrate the superiority of the proposed receiver, as presented in Chapter 4. Ultimately, our motivation for emphasis in this dissertation is twofold. First, the complexity of coherent communication systems, which is based on traditional techniques, can be replaced by a simpler receiver. Second, the introduction of IKF, which is a new non-coherent detection approach for an OQPSK modulated signal and a novel solution to detect the corrupted received signal and reduce the phase deviation error.