OFDM-Based OOK Transceiver for Threshold-Free Detection for WUR and Ambient IoT Applications

The wake up radio (WuR) technology represents a significant advancement in low-power wireless communication, enabling the main radio of a low-power device to remain in deep sleep mode until it is awakened by the WuR, which, in turn, is triggered upon detecting a specific wake up signal (WuS). Despite its benefits, the detection of the WuS remains energy-inefficient in practice. This letter proposes an enhanced method for WuS generation and detection based on a least square (LS) approach. The proposed scheme employs two frequency bands to simultaneously generate an On-Off Keying (OOK) sequence and its inverted version. At the receiver side, non-coherent parallel energy detectors are utilized, allowing a simple energy comparison to recover the embedded OOK information. Theoretical bit error rate (BER) expressions are derived and analyzed, and the performance of the proposed technique is compared to that of conventional threshold-based detection method.