Self-organized time-division multiple access (STDMA) is a channel access method designed by

Håkan Lans Anders Håkan Lans (born 2 November 1947 in Enskede) is a Swedish inventor. He holds two patents: * a memory controller for a framebuffer: "Data processing system and apparatus for color graphics display". Framebuffer with memory controllers had ...

, based on

time-division multiplexing Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fracti ...

. The term "self-organized" describes the manner in which time slots are assigned to users.

Time-division multiple access Time-division multiple access (TDMA) 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, ...

(TDMA) divides a channel into

frames A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (co ...

, which furthermore are subdivided into a vast number of time slots. Users transmit in rapid succession, one after the other, each using their own time slot. One of the drawbacks of TDMA is that it requires a central station for slot assignment and time synchronisation. STDMA proposes for assigning slots without the involvement of a central station. Time synchronisation is usually taken care of using

Coordinated Universal Time Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently ...

(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 The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international ...

VHF Data Link Mode 4. While the method was patented, a

US patent Under United States law, a patent is a right granted to the inventor of a (1) process, machine, article of manufacture, or composition of matter, (2) that is new, useful, and non-obvious. A patent is the right to exclude others, for a limited ...

ex-parte

reexamination In United States patent law, a reexamination is a process whereby anyone—third party or inventor—can have a U.S. patent reexamined by a patent examiner to verify that the subject matter it claims is patentable. To have a patent reexamined, ...

certificate was issued in 2010 canceling all claims.

USPTO The United States Patent and Trademark Office (USPTO) is an agency in the U.S. Department of Commerce that serves as the national patent office and trademark registration authority for the United States. The USPTO's headquarters are in Alex ...

ex-parte

certificate (7428th), issued on March 30, 2010.

References

External links

Håkan Lans, designer of STDMA
(DMOZ entry)
GP&C Systems International AB
Holding company of STDMA patent rights in Europe {{Channel access methods Maritime communication