Wi-Fi in Ad Hoc Mode: A Measurement Study
PERCOM '04 Proceedings of the Second IEEE International Conference on Pervasive Computing and Communications (PerCom'04)
Broadcast reception rates and effects of priority access in 802.11-based vehicular ad-hoc networks
Proceedings of the 1st ACM international workshop on Vehicular ad hoc networks
The Impact of Multihop Wireless Channel on TCP Performance
IEEE Transactions on Mobile Computing
Overhaul of ieee 802.11 modeling and simulation in ns-2
Proceedings of the 10th ACM Symposium on Modeling, analysis, and simulation of wireless and mobile systems
Comparison of Multichannel MAC Protocols
IEEE Transactions on Mobile Computing
An Adaptive Multi-Channel MAC Protocol with Dynamic Interval Division in Vehicular Environment
ICISE '09 Proceedings of the 2009 First IEEE International Conference on Information Science and Engineering
Adaptive intervehicle communication control for cooperative safety systems
IEEE Network: The Magazine of Global Internetworking
Tree-based double-covered broadcast for wireless ad hoc networks
Proceedings of the 9th ACM international symposium on Mobility management and wireless access
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In IEEE 802.11p/1609-based vehicular networks, the channel access time of a synchronization interval is divided into two fixed-length intervals, i.e. control channel (CCH) and service channel (SCH) intervals. Since the fixed-length intervals cannot be effective for dynamically changing traffic load, some protocols have been recently proposed to support variable-length CCH intervals in order to improve channel utilization. In existing protocols, the CCH interval is subdivided into safety and non-safety intervals, and each interval is dynamically determined based on traffic load. However, they do not consider the presence of hidden nodes. Hence, each interval has no additional room for transmissions from hidden nodes. Consequently, messages transmitted in each interval are likely to overlap with simultaneous transmissions (i.e. interference) from hidden nodes. Particularly, life-critical safety messages can be unreliably delivered due to such interference, which deteriorates QoS of safety applications such as cooperative collision warning. In this paper, we therefore propose a new dynamic safety interval (DSI) protocol. DSI calculates the number of vehicles sharing the channel with the consideration of hidden nodes. The safety interval is derived based on the measured number of vehicles. From simulation study using the ns-2, we verified that DSI achieves better delivery ratio of periodic messages such as beacon.