In an 802.11p (so-called DSRC) network, the WSMP protocol is used for the communication between OBU and RSU. Unlike a wired network, an 802.11p wireless network is prone to fading, shadowing and interferences, which might result in high error rates. However, there is no reliability mechanism embedded in the WSMP protocol, which can become an important issue for mission-critical ITS applications such as ETC (Electronic Toll Collection). In this work, we develop a protocol on top of WSMP to build a reliable session for the message exchanges between RSU and OBU. Our protocol uses a timer-based mechanism for the message retransmission in the case of message losses. In this paper, we first describe the design of our session protocol. We then discuss the implementation of our protocol using the ITRI WAVE box and evaluate its effectiveness on real roads.

In an 802.11p (the so-called DSRC) network, the WSMP protocol is used for the communication between OBU and RSU. Unlike a wired network, an 802.11p wireless network is prone to fading, shadowing, and interferences, which might result in high error rates. However, there is no reliability mechanism embedded in the WSMP protocol, which can become an important issue for mission-critical ITS applications such as ETC (Electronic Toll Collection). In this work, we develop a protocol on top of WSMP to build a reliable session for the message exchanges between RSU and OBU. Our protocol uses a timer-based mechanism for the message retransmission in the case of message losses. In this paper, we first describe the design of our session protocol and evaluate its performance for ETC communication in simulations. We then discuss the implementation of our protocol on the ITRI WAVE box and evaluate its effectiveness on real roads.

In recent years, GPS-based fleet management systems (FMS) have become a powerful tool for fleet companies to better manage their transportation resources in a more efficient and economic manner. Vehicles equipped with a GPS-enabled car kit periodically report their positions to the control center via wireless communication every 30 seconds or so, resulting in rapid accumulation of records in databases and enormous demand on computing resources. SkyEyes, one of leading FMS service providers in Taiwan, has currently established an online commercial fleet with up to 1,500 vehicles. To fulfill the potential market expansion in the future, SkyEyes began a pilot study of introducing Apache Hadoop as the cloud computing platform to enhance the performance and scalability of the current architecture. This paper reexamines the track of study and evaluate the system performance, providing a lesson learned in fleet management industry for future research.