Performance Analysis of WAVE Control Channels for Public Safety Services in VANETs

Vehicular Ad hoc network (VANET) is researched for public safety of vehicles.Safety applications exchange the safety messages among I2V (Infrastructure to Vehicle) and V2V (Vehicle to Vehicle) in VANETs.As several safety applications are running and generating periodic messages on a vehicle, they consume a sizable resources on communication channel.Several organizations identify the high-priority safety applications and recommend safety message generating patterns.These safety messages are carried by WAVE (Wireless Access in Vehicular Environment) and 802.11p standards.We analyze the theoretical maximum vehicle number when the high-priority safety applications are running on vehicles on highly congested communication channel condition.The analysis shows that a few dozen of vehicles can communicate with each other even without any collision on the communication channel.It means that the transmission mechanism of safety messages must be improved to reduce the generated date rate and EDCA mechanism should be improved without changing 802.11p standard.We propose two simple mechanisms.One is used to reduce the transmission data rate and the other for EDCA improvement.Even with these improvements, one hundred vehicles can be accommodated on the 10MHz control channel allocated by US FCC.