This paper discusses the limitations of implementing Low Power Listening (LPL) on the contention-based IEEE 802.15.4 MAC protocol, and proposes an implementation technique called Virtual Preamble Cross-Checking (VPCC), which enables LPL. The proposed technique uses the concept of virtual preamble and a cross-checking method to meet the requirements of the relationship between preamble length and listening interval. These methods lead to reliable data communication, as well as the reduction of the idle listening. We implemented the mechanism on IEEE 802.15.4compatible RF hardware and validated the performance. The experiment results show that increasing the listening interval within a tolerable latency can optimize the duty cycle of the RF transceiver for low power consumption.