Synchronization of wireless sensor networks using a modified IEEE 1588 protocol

A method of precise time synchronization of wireless sensors employing an IEEE 802.15.4 transceiver, and specifically employing the 6LoWPAN protocol, was developed. It uses the IEEE 1588 synchronization standard and the IEEE 1451.5 Smart Transducer Data standard. A Wireless Transducer Interface Module (WTIM) was designed and fabricated. It utilizes the IEEE 802.15.4 transceiver model TI CC2430 which allows access to a hardware sync signal. The difference in timestamps between two WTIMs was measured. The results show that the synchronization precision is better than 10 μs for short synchronization intervals but increases to about 100 μs for longer synchronization intervals (1 sec for crystal accuracies of 50 ppm). The method was tested for 6LoWPAN wireless protocol but would apply to other wireless sensors based on the IEEE 802.15.4 protocols.