Statistical time-division multiplexing

Statistical multiplexing is a type of digital communication link sharing, sometimes abbreviated as STDM.^[1]^[2] It is very similar to dynamic bandwidth allocation (DBA). In statistical multiplexing, a communication channel is divided into an arbitrary number of variable bitrate digital channels or data streams. The link sharing is adapted to the instantaneous traffic demands of the data streams that are transferred over each channel. This is an alternative to creating a fixed sharing of a link, such as in general time division multiplexing (TDM) and frequency division multiplexing (FDM). When performed correctly, statistical multiplexing can provide a link utilization improvement, called the statistical multiplexing gain.

Statistical multiplexing is facilitated through packet mode or packet-oriented communication, which among others is utilized in packet switched computer networks. Each stream is divided into packets that normally are delivered asynchronously in a first-come first-served fashion. In alternative fashion, the packets may be delivered according to some scheduling discipline for fair queuing or differentiated and/or guaranteed quality of service. It is also found in fibre optic circuits where communications are made on a statistical basis.^[3]

Statistical multiplexing of an analog channel, for example a wireless channel, is also facilitated through the following schemes:

Random frequency-hopping orthogonal frequency division multiple access (RFH-OFDMA)
Code-division multiple access (CDMA), where different amount of spreading codes or spreading factors can be assigned to different users.

Statistical multiplexing normally implies "on-demand" service rather than one that preallocates resources for each data stream. Statistical multiplexing schemes do not control user data transmissions.

^ Stallings, William (2007). Data and Computer Communications. Upper Saddle River, NJ: Prentice Hall. p. 240. ISBN 978-0-13-243310-5.
^ FitzGerald, Jerry; Dennis, Alan (2009-01-09). Business Data Communications and Networking. Hoboken, NJ: John Wiley & Sons. p. 82-83. ISBN 978-0-470-05575-5.
^ Weik, Martin (2012-12-06). Fiber Optics Standard Dictionary. New York, NY: Springer Science & Business Media. p. 967. ISBN 978-1-4615-6023-4.

[n851-1] Stallings, William (2007). Data and Computer Communications. Upper Saddle River, NJ: Prentice Hall. p. 240. ISBN 978-0-13-243310-5.

[h652-2] FitzGerald, Jerry; Dennis, Alan (2009-01-09). Business Data Communications and Networking. Hoboken, NJ: John Wiley & Sons. p. 82-83. ISBN 978-0-470-05575-5.

[t766-3] Weik, Martin (2012-12-06). Fiber Optics Standard Dictionary. New York, NY: Springer Science & Business Media. p. 967. ISBN 978-1-4615-6023-4.

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