Enhancing Data Rate of Asynchronous Pulse Code Multiple Access for Massive IoT

Asynchronous Pulse Code Multiple Access (APCMA) has been proposed as a wireless communication system suitable for Massive IoT, which is resilient against high-volume packet transmissions from numerous devices. Previous studies have demonstrated its effectiveness compared to other Low Power Wide Area (LPWA) protocols by experimentally evaluating it in the 920 MHz band. Chirp Spread Spectrum-based (CSS)-APCMA has also been proposed to enhance the reception sensitivity of APCMA, enabling long-range communication similar to other LPWA systems. In this paper, we evaluate the throughput performance of optimized CSS-APCMA with enhanced time resolution and broader bandwidth. We have implemented the proposed CSS-APCMA using USRP and GNU Radio and conducted experiments to explore the maximum achievable throughput and evaluate its performance in high-density wireless environments. Our experimental results demonstrate a significantly higher throughput compared to conventional APCMA.