Dynamic Threshold Selection for Frame Length-Based Wake-Up Control

In frame-length based wake-up control, a wake-up receiver smoothens the signal envelope by low-pass-filtering (LPF) before frame length detection. However, the LPF also has a side effect of distorting the rising and falling edges of the envelope. This letter analyzes the effect of LPF on frame length detection, and suggests measuring potential frame lengths with multiple thresholds and from them selecting the correct one. The analysis shows that using thresholds with exponential intervals helps to achieve a good performance with only a small number of thresholds. The effectiveness of the proposed scheme is also confirmed by experimental results.