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We propose a high-accuracy, low-cost UWB-IR wireless location system based on the quasi TDOA method. The system consists of anchor nodes, a synch node and a location server. The anchor nodes synchronize each other as regulated by the synch node so that synchronization is always precise in the location process. To make the anchor node simple, the location system uses acquisition and tracking functions that can measure the time when a signal is received as accurately as pulse signal width. In addition, we performed a wireless location experiment indoors and the average error of the location measurement was 22-cm.

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An intermittent wireless communication system has been developed for low-power sensor networks that improves sensor network efficiency by promoting cooperative optimization among the hardware architecture, communication protocol, and multiple access scheme. The intermittent communication protocol together with hardware for intermittent function contributed to reduce power consumption and extended sensornode battery lifetime. A multiple access scheme based on the R-ALOHA protocol is used for the wireless link; it works efficiently with the protocol and hardware. Due to its inter-layer optimization, the system has low power consumption regardless of the traffic load and is thus flexible enough to support a wide range of sensor network applications.