Ieee 802.15.4-based Vehicle Monitoring System

This thesis mainly introduces a new vehicle identification and management system based on IEEE802.15.4, using unique 8-byte IEEE MAC address as vehicle specific ID. IEEE802.15.4 is a standard ultra-low complexity, ultra-low cost, ultra-low power consumption, and low data rate wireless short-range communication. The carrier band in use is 2.4GHz, a global license free industrial scientific medical (ISM) frequency band. The raw data rate is 250 kb/s. Direct sequence spread spectrum and a 16-ary quasi-orthogonal modulation technique is employed in the 2.4GHz band. Its bit error rate is lower than Bluetooth and IEEE802.11 and receiver sensitivity is so high that available communicate radius can be beyond 100 meters. IEEE802.15.4 employs a fully handshake protocol with ITU-16 CRC and CSMA/CA for data transfer reliability and embeds the Advanced Encryption Standard (AES) for data transfer security.The whole vehicle identification and management system consists of two kinds of modules: on board unit(OBU) and road side unit(RSU). They both mainly constructed by using MSP430 and CC2420. MSP430 is a ultra-low power microcontroller. CC2420 is a 802.15.4 compliant wireless RF transceiver with low power. As defined by IEEE802.15.4, RSU is full-function device as Coordinator of wireless network and OBU is reduced-function device. When a vehicle with OBU enters the RSU radio sphere, OBU will detect RSU and communicate with RSU. RSU can get the 64-bit IEEE address of OBU and send it to the highway management center. The center can identify and manage the vehicle.According to the application object, an improvement of communication process is made to save time as the same time the reliability is guaranteed.