Iterative Decision-Directed Channel and CFO Estimation Algorithm for Wideband Telemetry System

With the increasing demand for wideband transmission for telemetry systems, multipath fading causes the performance degradation of synchronization. The commonly-used algorithms are least square (LS) and linear minimum mean square error (LMMSE) channel estimation instead of the conventional phase and timing synchronization. The carrier frequency offset (CFO) is also estimated considering the multipath interference, which is different from conventional CFO estimation methods. The mentioned channel and CFO estimation reduce the synchronization performance degradation under multipath channels compared to the traditional synchronization methods used in narrow systems. The higher accuracy channel and CFO estimation means the better performance of the receiver. In this paper, we propose a decision-directed channel and CFO estimation algorithm for SOQPSK-TG to improve the synchronization performance. It uses the detected symbols to refine the estimated channel impulse response and CFO iteratively. The SOQPSK-TG signal has the detected symbol error propagation when reconstructing the modulated signal. We also present a simple method to avoid error propagation. The numerical results demonstrate the performance improvement of our proposed methods compared to the conventional estimation methods.