A Fractionally Asymmetric Sub-Nyquist Baseband Receiver Design and Implementation for Phase Modulated Signals

Sub-Nyquist sampling is a technique which has various applications in signal processing and communication technologies. Memory relaxation, peripherals operating at relatively lower speeds, and consequently low-power consumption designs are prominent motivations in sub-Nyquist receiver studies. Although these motivations seem to be attractive, instability and information loss are major drawbacks of sub-Nyquist approaches in comparison with Nyquist-Shannon sampling applications. Nevertheless, sub-Nyquist receivers could still provide several ways of recovering information to some extent in case they are fortified with appropriate interpolation mechanisms. Hence, this study proposes a fractionally asymmetric sub-Nyquist baseband receiver design for phase modulation (PM) signal reception. The proposed method takes advantage of statistical behaviors of the received signal passing through physical propagation medium and adopts an autoregressive process to recover the phase information required. The proposed design is implemented on a software-defined radio (SDR) platform operating in near real-time and tested in a real-world communication environment. Results and discussions are provided along with the future directions.