Vehicle GPS Positioning Over Cellular Networks

Cellular networks provide an efficient infrastructure for voice communications for mobile users. These networks are designed to provide voice communications as the user moves between cells with little or no interruption. Most cellular networks provide excellent coverage in urban areas with extended coverage along major freeways between cities. Cellular networks provide a poor environment for transmitting data. To resolve this problem, the cellular carrier industry is developing standards that will provide data transfer over cellular networks. In addition, the data communications equipment industry has also enhanced existing data modem protocols for cellular data communication. These changes in cellular data communication methods and equipment will enable AVL applications to operate over cellular networks. This paper reviews the characteristics of the different cellular networks. It reviews circuit-switch methods for AVL operation over both analog and digital based cellular networks. The paper also reviews new packet-switch data standards being established by the cellular industry.