dynamic spectrum management
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Dynamic spectrum management (DSM), also referred to as dynamic spectrum access (DSA), is a set of techniques based on theoretical concepts in network
information theory Information theory is the scientific study of the quantification (science), quantification, computer data storage, storage, and telecommunication, communication of information. The field was originally established by the works of Harry Nyquist a ...
and
game theory Game theory is the study of mathematical models of strategic interactions among rational agents. Myerson, Roger B. (1991). ''Game Theory: Analysis of Conflict,'' Harvard University Press, p.&nbs1 Chapter-preview links, ppvii–xi It has appli ...
that is being researched and developed to improve the performance of a communication network as a whole. The concept of DSM also draws principles from the fields of
cross-layer optimization Cross-layer optimization is an escape from the pure waterfall-like concept of the OSI communications model with virtually strict boundaries between layers. Strict boundaries between layers are enforced in the original OSI networking model, where ...
,
artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech re ...
,
machine learning Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence. Machine ...
etc. It has been recently made possible by the availability of software radio due to development of fast enough processors both at servers and at terminals. These are techniques for
cooperative A cooperative (also known as co-operative, co-op, or coop) is "an autonomous association of persons united voluntarily to meet their common economic, social and cultural needs and aspirations through a jointly owned and democratically-control ...
optimization. This can also be compared or related to optimization of one link in the network on the account of losing performance on many links negatively affected by this single optimization. It is most commonly applied to optimize
digital subscriber line Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric di ...
(
DSL Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric dig ...
) performance of a
network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...
. Another potential application of DSM is for
cognitive radio A cognitive radio (CR) is a radio that can be programmed and configured dynamically to use the best wireless channels in its vicinity to avoid user interference and congestion. Such a radio automatically detects available channels in wireless spe ...
. Important and common principles of DSM include: *
Link adaptation Link adaptation, comprising adaptive coding and modulation (ACM) and others (such as Power Control), is a term used in wireless communications to denote the matching of the modulation, coding and other signal and protocol parameters to the conditio ...
*
Bandwidth management Bandwidth management is the process of measuring and controlling the communications (traffic, packets) on a network link, to avoid filling the link to capacity or overfilling the link,https://www.internetsociety.org/wp-content/uploads/2017/08/BWro ...
*
Multi-user MIMO Multi-user MIMO (MU-MIMO) is a set of multiple-input and multiple-output (MIMO) technologies for multipath wireless communication, in which multiple users or terminals, each radioing over one or more antennas, communicate with one another. In cont ...
* Pre-cancellation of estimated interference * Combining unused channels (not pre-allocated) for a single user or bonding


DSM in Digital Subscribers Loop

DSM can be achieved over ordinary copper phone lines' network by reducing or eliminating
crosstalk In electronics, crosstalk is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, induc ...
,
interference Interference is the act of interfering, invading, or poaching. Interference may also refer to: Communications * Interference (communication), anything which alters, modifies, or disrupts a message * Adjacent-channel interference, caused by extr ...
and
near–far problem The near–far problem or hearability problem is the effect of a strong signal from a near signal source in making it hard for a receiver to hear a weaker signal from a further source due to adjacent-channel interference, co-channel interference, d ...
within a DSL network especially affecting the DSL phone lines that are close together in a binder. The technique involves multiple methods: * Continuously monitoring the status of interfering signal levels using current bit-loading compared to maximum achievable
bit rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
, number of errored seconds, number of severely errored seconds, number of
forward error correction In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea is ...
s (FEC) and making decisions about the underperforming scenario's cause and forcing the link to train in a specific way. * Identifying the neighborhood cables in the binders that may be causing unwanted cross-talk and lowering their
upstream Upstream may refer to: * Upstream (bioprocess) * ''Upstream'' (film), a 1927 film by John Ford * Upstream (networking) * ''Upstream'' (newspaper), a newspaper covering the oil and gas industry * Upstream (petroleum industry) * Upstream (software ...
transmission power until bit-rates are optimized for the network. * Increasing or decreasing the amount of forward error correction overhead applied to the signal propagating on the cable in response to the severity of the correlated interferers or jammers. * Modifying the limits on the power levels allowed on cable, the masks of the tones on which bits can be loaded or the masks for power spectral density to allow for minimization of the interference caused due to excess
signal-to-noise ratio Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in deci ...
(SNR) causing degradation of SNR on other lines. * Modem hardware ( consumer premises equipment) adjusting transmission settings in order to achieve the optimized
discrete multitone modulation In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communi ...
(DMT) signal (this is not exactly DSM and can be achieved even without DSM). This hardware adjustment being forced from a central monitoring location and applied to a network of consumer premises equipment, on the whole, to optimize the network performance as a whole.


See also

*
Interruptible spectrum {{multiple issues, {{original research, date=January 2015 {{primary sources, date=January 2015 Radio or wireless systems use radio frequencies or spectrum as the medium for transmitting information from one location to the other. Traditionally each ...


References

{{Reflist


External links


Boost for Internet speeds without fibre-optics

ECI Telecom sets out to double DSL speed

DSM project
— Prof. John Cioffi
Fast Copper Project
Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

Dynamic Spectrum Management Publications
— Raphael Cendrillon Digital subscriber line Telecommunication protocols