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Error Control for Time Division Multiple Access Satellite Communication

IP.com Disclosure Number: IPCOM000081013D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

West, RL: AUTHOR

Abstract

Time division multiple access (TDMA) satellite communication networks, require inclusion of station identification information in each transmitted message. Transmitted messages are usually numbered serially to allow a recipient earth station to identify the origin of a mutated message, and originate a suitable communication to solicit retransmission of the message. This method has inherent weakness in that the identification number represents corruptible message intelligence, and occupies bandwidth (i.e. time channels) which could otherwise be used more efficiently for data transmission.

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Error Control for Time Division Multiple Access Satellite Communication

Time division multiple access (TDMA) satellite communication networks, require inclusion of station identification information in each transmitted message. Transmitted messages are usually numbered serially to allow a recipient earth station to identify the origin of a mutated message, and originate a suitable communication to solicit retransmission of the message. This method has inherent weakness in that the identification number represents corruptible message intelligence, and occupies bandwidth (i.e. time channels) which could otherwise be used more efficiently for data transmission.

A more efficient identification scheme works as follows. Each station in a TDMA network must possess an extremely accurate clock which is accurately synchronized to the clocks of all other stations, and permits accurate determination of the known transmission delay time between the respective station and the satellite. Messages arrive at the satellite at unique times assigned to the various earth stations. Thus, the satellite arrival time may be treated as implicit message identification information, which need not be transmitted with the message. Upon receipt of a mutated message, the receiving station would broadcast a request for retransmission (in an available time channel) identifying the satellite arrival time of the corrupted message, and the originating station would reacquire and retransmit the message.

The accompanying illustration indicates a system suitable for this purpose, which would permit a message transmitting station to store and reacquire its transmitted messages for later retransmission. A displacement time, corresponding to...