5.8 GHz microwave link for automatic debiting applications

In Europe, Traffic congestion on roads is rapidly increasing to unacceptable levels while the building of new roads tends to be opposed by strong and highly organized protest groups generally supported by public opinion. In order to reduce this congestion, an automatic toll collection or road pricing system is being considered. Such system requires a secure, two-way, high speed digital data communication link between a roadside unit (OBU) placed inside the vehicle. Although a number of technologies can be used for this link, only microwave technology has distinct advantages in realizing a toll collection system. In view of this, a microwave link operating at 5.8 GHz has been proposed as the European standard for automatic debiting systems. The main objective of the design is to ensure that the OBU has a low profile and is inexpensive.