Showing papers on "Mobile telephony published in 1976"
24 Mar 1976
TL;DR: In this paper, a mobile radiotelephone system designed to upgrade present day Land-Mobile services to provide facilities comparable to those obtainable within any national land-based automatic switching telephone system is presented.
Abstract: This paper covers a mobile radiotelephone system designed to upgrade present day Land-Mobile services to provide facilities comparable to those obtainable within any national land-based automatic switching telephone system. It shows a system which may provide national coverage, requiring minimal cooperation from individual participating RCC's, by use of interactive base stations.
136 citations
Patent•
12 Feb 1976TL;DR: In this article, a radio communication system of the cellular type where sets of communication channels are reused in different adjacent sets of cell areas within a common mobile communication service area, each cell base station is assigned a different supervisory tone to be modulated on all of its channels.
Abstract: In a radio communication system of the cellular type wherein sets of communication channels are reused in different adjacent sets of cell areas within a common mobile communication service area, each cell base station utilizing a given set of channels in common with other base stations is assigned a different supervisory tone to be modulated on all of its channels. Any mobile unit receiving such channel transponds the modulated supervisory tone and sends it back to the base station. At each base station the transmitted and received supervisory tones for any given channel are compared to produce an indication of whether or not the sending mobile unit is actually communicating on the transmitted channel of the same base station. At each mobile unit, reference tones are generated which are spectrally located between adjacent ones of the possible supervisory tones for the mobile communication area, and the spectral position of a received tone with respect to the reference tones is determined. Signals representing that determination are translated into a digital character corresponding to the name of the received tone, and that name is compared with the name of the tone for the mobile unit's assigned channel. A name mismatch is utilized to quiet the mobile unit receiver for the duration of the mismatch. In addition, if that duration exceeds a predetermined interval, the mobile unit controller is actuated to initiate the dropping of communication on the assigned channel.
41 citations
TL;DR: This paper presents a survey of diversity techniques as applied to mobile radio, with emphasis on systems designed for analogue communication, and includes a unified approach to systems based on the double-heterodyne phase-stripper principle.
Abstract: After discussing the nature of the electromagnetic field in urban environments, and the use of diversity techniques in fading media, the paper presents a survey of these techniques as applied to mobile radio, with emphasis on systems designed for analogue communication. It includes a unified approach to systems based on the double-heterodyne phase-stripper principle. The discussion is not restricted to present-day receivers only, but includes considerations which may apply in future designs.
32 citations
TL;DR: The important role that land mobile communication systems play in the effective operation of an emergency medical services (EMS) system is discussed in this article, where the need for EMS systems, classification of types of communication subsystems, FCC Rules and Regulations for EMS, what to do before designing communication systems, and examples of several systems are given.
Abstract: The important role that land mobile communication systems play in the effective operation of an emergency medical services (EMS) system is discussed. The need for EMS systems, classification of types of communication subsystems, FCC Rules and Regulations for EMS, what to do before designing communication systems, and examples of several systems are given.
6 citations
24 Mar 1976
TL;DR: An overview of the digital controller within the mobile Logic Unit, a digital controller that allows mobiles to communicate with Cell Sites by means of a high-speed radio data link, and interacts with the user via switches and displays is presented.
Abstract: In the BTL-developed High Capacity Mobile Telecommunications System, a digital controller within the mobile Logic Unit allows mobiles to communicate with Cell Sites by means of a high-speed radio data link, and interacts with the user via switches and displays. This paper presents an overview of the controller. The switching and control functions that it performs and digital messages involved are first briefly described. This is followed by a description of its hardware design that exploits a microprocessor as the central processing unit.
4 citations