The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 24, 1977
Filed:
Feb. 12, 1976
Eric John Addeo, Long Valley, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
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.