Low-Complexity Sequence Accumulation Method for Fast-Moving Targets in PMCW Radar Systems

Phase-modulated continuous-wave (PMCW) radar is a promising technology for internet of things (IoT) applications due to its high resilience against interference and compatibility with communication systems. To address the computational burden in PMCW radar, conventional approaches accumulate sequences in the time domain to reduce the number of samples used for Doppler processing in velocity estimation. However, the direct summation of sequences without phase compensation leads to severe performance degradation caused by the Doppler effect, including velocity ambiguity and signal-to-noise ratio loss. Therefore, this paper proposes a low-complexity sequence accumulation method for detecting fast-moving targets. By adjusting the desired velocity search region, the proposed method simultaneously resolves the velocity ambiguity and reduces computational complexity. Simulation results show that the proposed method achieves a processing time approximately 3.5 times faster than the non-accumulation method. In addition, the proposed method compensates for the Doppler phase difference along the slow-time to enable coherent accumulation over sequences, thereby preventing performance degradation and achieving higher detection probability compared to conventional accumulation methods.