Traffic Information Dissemination System: Extending Cooperative Awareness Among Smart Vehicles with only Single-Hop Beacons in VANET

Abstract

Today's high-end vehicles are technologically more sophisticated and smarter than the `old machines with engine and wheels'. These vehicles are anticipated to provide consumers with safe, reliable, and infotainment-rich driving experience through intelligent transportation system, realized through a technology referred to as vehicular ad hoc network (VANET). VANET offers a plethora of applications to the consumers ranging from safety to infotainment. Among other messages defined by the dedicated short range communication standard, cooperative awareness messages (CAMs) are of paramount importance for the VANET applications. In VANET, vehicles share their frequent mobility information in the form of CAMs with neighbors for cooperative awareness, traffic view construction, maneuver, and cruise control. In this work we target the CAM-based traffic information dissemination. VANET applications construct short-range local and long-range extend traffic views with the information contained in scheduled CAMs (also known as beacons). To construct aforementioned traffic views, naive approach is multi-hop communication; however, historically multi-hop communication does not scale efficiently in dynamic VANET due to computational and communication overhead. Therefore another alternative approach is essential to address the problems of the multi-hop communication in highly ephemeral VANET and to achieve maximum degree of the information dissemination in VANET. To fill the gap, in this paper we propose a geocast-based abstract piggybacking mechanism for traffic information dissemination in VANET through single-hop CAMs. In the proposed scheme, vehicles compress their local traffic view constructed through single-hop CAMs. The compressed local traffic view is referred to as traffic data unit (TDU). Every vehicle broadcasts its own TDU along with a number of TDUs received from other vehicles in the next scheduled CAM, in order to construct a long-range extended traffic view, also known as compressed data word (CDW). In other words, CDW is encapsulated into normal CAM in order to share it with the neighbors in the vicinity. The receivers of CDW use the received TDUs to construct the desired length of the long-range extended traffic view. The proposed scheme leverages only single-hop beacons data to construct both local and extended traffic views. Our simulation results show that the extended traffic view up to 1 km can be constructed with only single-hop beacons at the expense of 10 % of extra information with the regular CAM. The results also show that the effect of the extra overhead is not phenomenal from overhead standpoint. The proposed virtual multi-hop communication paradigm with single-hop CAM will reduce the overall communication thereby saving the bandwidth for other important safety related communications.