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:
Sep. 03, 1996
Filed:
Jan. 20, 1995
Douglas D Tang, Chelmsford, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A secure wireless party line system that can be used by a group of mobile users to communicate with each other like a wired party line but without the cumbersome inconvenience of long wired tether. The party line function is achieved by the use of a fixed wireless repeater. The fixed wireless repeater receives spread spectrum transmissions from all N mobile users at a frequency f1, and passes the received signals through an RF amplifier and upconverter, and then to an IF amplifier and power divider, which converts the received signals down to a convenient intermediate frequency (IF), and feeds N receive spread spectrum processors, each dedicated to receive a coded spread spectrum transmission from one user. The received voice outputs from the N users are then combined in a N-channel voice data multiplexer, and broadcast at a frequency f2 to all users with a common spread spectrum code word added by a transmit spread spectrum processor. The commonly coded broadcast messages are processed by an RF amplifier and broadcast at frequency f2. All mobile radio receivers receive on the same common code word used by the fixed wireless repeater for broadcasting. Each mobile user on said party line carries a simple single channel radio transceiver. Spread spectrum transmission provides security and anti-jamming performance. Analog and digital embodiments are disclosed.