Data signaling functions for a cellular mobile telephone system
The Bell System is proposing to provide high capacity mobile telephone service in the 850-MHz band via a cellular system that employs frequency reuse within a geographic area. In this system, mobile units respond to orders received from base station sites, which are in turn controlled by data links from a telephone central office. Since all phases of the mobile telephone call, including call setup, handoff between base stations, and disconnect require extensive data signaling, a reliable data transmission facility must exist between the central office and the mobile units. The transmission facility consists of a land link and a radio link. The reliability of the radio transmission path is relatively low, and therefore error control techniques are necessarily more elaborate for the radio link than for the land link. Descriptions are given of the signaling requirements and of the signaling schemes devised for both the switching office-to-base station land path and base station-to-mobile unit radio path. The anticipated performance of the error control procedures for these paths is also presented.