Mitigating interference caused by IEEE 802.11b in the IEEE 802.15.4 WSN within the environment of smart house

Using wireless sensor network (WSN) to provide environmental data is becoming an increasingly important topic in the research area of building a smart house. As the standard designed for low data rate and low cost wireless personal area network, the IEEE 802.15.4 standard is widely employed in the construction of home sensor networks to assist the smart house application with a real-time environment information infrastructure. However, its working frequency (2.4 GHz ISM band) and low transmission power (typically 1 mW) make the system easily open to interference caused by other powerful wireless systems or signals which also work on the same frequency band, especially by Wi-Fi (IEEE 802.11b) systems. In this paper, we analyze the factors, which cause interference of the IEEE 802.15.4 system by Wi-Fi, and propose an interference mitigation strategy which utilizing the interferer´s transmission interval to enable the IEEE 802.15.4 network to maintain communications during times of interference.