Self-Organized Time Division Multiple Access
Encyclopedia
Self-Organized Time Division Multiple Access (STDMA) is a channel access method which was designed by Håkan Lans
, based on time-division multiplexing
.
The term "Self-Organized" describes the manner in which time slots are assigned to users. Time division multiple access
(TDMA) divides a channel into frames, which furthermore are subdivided into a vast number of time slots. Users transmit in rapid succession, one after the other, each using his own time slot. One of the drawbacks of TDMA is that it requires a central station for slot assignment and time synchronisation. STDMA proposes a method for assigning slots without the involvement of a central station. Time synchronisation is usually taken care of using Coordinated Universal Time
(UTC).
STDMA is in use by the Automatic Identification System
(AIS), a standard marine short range coastal tracking system, and is the base of the International Civil Aviation Organization
VHF Data Link Mode 4 .
While the method was patented, a US patent
ex-parte reexamination
certificate was issued in 2010 canceling all claims.
Håkan Lans
Anders Håkan Lans is a Swedish inventor. His patented inventions are a color graphics processor and an "Arrangement for producing a pattern on a light-sensitive surface"...
, based on time-division multiplexing
Time-division multiplexing
Time-division multiplexing is a type of digital multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as sub-channels in one communication channel, but are physically taking turns on the channel. The time domain is divided into several recurrent...
.
The term "Self-Organized" describes the manner in which time slots are assigned to users. Time division multiple access
Time division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
(TDMA) divides a channel into frames, which furthermore are subdivided into a vast number of time slots. Users transmit in rapid succession, one after the other, each using his own time slot. One of the drawbacks of TDMA is that it requires a central station for slot assignment and time synchronisation. STDMA proposes a method for assigning slots without the involvement of a central station. Time synchronisation is usually taken care of using Coordinated Universal Time
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
(UTC).
STDMA is in use by the Automatic Identification System
Automatic Identification System
The Automatic Identification System is an automatic tracking system used on ships and by Vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations...
(AIS), a standard marine short range coastal tracking system, and is the base of the International Civil Aviation Organization
International Civil Aviation Organization
The International Civil Aviation Organization , pronounced , , is a specialized agency of the United Nations. It codifies the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth...
VHF Data Link Mode 4 .
While the method was patented, a US patent
United States Patent and Trademark Office
The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...
ex-parte reexamination
Reexamination
In United States patent law, a reexamination is a process whereby a third party or inventor can have a patent reexamined by a patent examiner to verify that the subject matter it claims is patentable...
certificate was issued in 2010 canceling all claims.