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:
Apr. 05, 1994
Filed:
May. 29, 1992
Mitsuru Seta, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The present invention provides a packet re-transmitting system for a slotted-ALOHA type satellite communication system wherein communications are effected between a central office and a large number of local offices by way of a communications satellite and which decreases a packet re-transmitting time remarkably. The central office transmits a frame synchronizing signal, manages a reception slot number in a predetermined phase relationship with the frame synchronizing signal, detects a condition of a reception signal from any of the local offices and sends back a receiving condition signal including a reception slot number and detection information of a receiving condition at the point of time. Each of the local offices manages a transmission slot number in a predetermined phase relationship with a received frame synchronizing signal, compares a transmission slot number at a point of time when a packet was transmitted with a reception slot number in the receiving condition signal and re-transmits, when the transmission slot number corresponds to the reception slot number in the receiving condition signal and detection information of a received condition indicates irregularity, the transmission packet.