Development of wireless communication methods for decreasing the power consumption of sensor nodes

We have been developing a novel receiver and communication protocol which can improve the communication efficiency with wireless sensor nodes by minimizing the packet length. Generally, several tens of bits, which is called "preamble", are needed for synchronizing the timing between the bit rate of a transmitter and receiver. In sensor network systems the amount of transmission data is relatively small. In some case, the ratio of the amount of preamble, which is not required essentially for the transmission of measured data, is about 50 % of the packet or more. Our receiver can receive the packet without preamble but including 2 bit fixed word for the detection. We also developed a communication protocol that the number of receiving in a unit time is used for the data, such as activity of an object to be measured. Since the activity data does not needed to be included in the packet, the time for the transmission can be decreased using this protocol.