Showing papers on "Mobile telephony published in 1970"

A high-capacity mobile radiotelephone system model using a coordinated small-zone approach

Abstract: Parameters of a large-scale highly coordinated mobile telephone system are discussed, particularly those of system size and frequency spectrum required. The concept of small-zone coverage areas to serve large customer densities is discussed, and the essential properties of small-zone systems are generalized to show that zone size alone is not an adequate parameter to distinguish large- from small-zone systems. A high-capacity small-zone system model using several zone sizes is presented. Advantages of small-zone operation other than spectrum economy are enumerated, as are the attendant disadvantages.

Vehicular location and information systems

Abstract: Various land mobile communities are actively seeking new tools which will offer significant improvements in the efficiency with which they manage the operations of their mobile fleets. The various types of location and information reporting techniques which can be used to supplement existing voice-radio communications to achieve this goal are described. Both fixed- and random-route location systems will be considered in terms of system characteristics as these relate to the needs of specific user groups such as law enforcement agencies and transportation organizations. The location techniques considered will include electronic signposts, trilateration (direct measurement using both wide-band (pulse) and narrow-band (phase) modulation), and automatic navigation systems. System parameters to be discussed will include: spectrum efficiency, Federal Communications Commission licensing considerations, required and achievable location accuracies, data-system speeds and reliability, and elements of cost effectiveness analysis. Finally, requirements for other types of vehicular information which are needed to produce a practical total system will be explored.

Radio transmitter receiver including level and antenna direction control circuitry

Abstract: The invention concerns the field of point-to-point communications in a network of stations equipped for selective calling It concerns a coding system partially of the numerical types, partially of the analogical type, combined with a device for enabling maximum output at the transmission level The main applications are in mobile communications, in particular, between airplanes