In
telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
s, an interference is that which modifies a
signal
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...
in a disruptive manner, as it travels along a
communication channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for informa ...
between its
source
Source may refer to:
Research
* Historical document
* Historical source
* Source (intelligence) or sub source, typically a confidential provider of non open-source intelligence
* Source (journalism), a person, publication, publishing institute o ...
and receiver. The term is often used to refer to the addition of unwanted signals to a useful signal. Common examples include:
*
Electromagnetic interference (EMI)
*
Co-channel interference
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same channel. Co-channel interference can be caused by many factors from weather conditions to administrative and design issues. Co-channel interference ...
(CCI), also known as
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 ...
*
Adjacent-channel interference (ACI)
*
Intersymbol interference
In telecommunication, intersymbol interference (ISI) is a form of distortion of a signal in which one symbol interferes with subsequent symbols. This is an unwanted phenomenon as the previous symbols have a similar effect as noise, thus making ...
(ISI)
* Inter-carrier interference (ICI), caused by doppler shift in
OFDM
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 commu ...
modulation (multitone modulation).
*
Common-mode interference Common-mode signal is the voltage common to both input terminals of an electrical device. In telecommunication, the common-mode signal on a transmission line is also known as longitudinal voltage.
In most electrical circuits the signal is transferr ...
(CMI)
*
Conducted interference
Noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...
is a form of interference but not all interference is noise.
Radio resource management Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, ...
aims at reducing and controlling the
co-channel
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same channel. Co-channel interference can be caused by many factors from weather conditions to administrative and design issues. Co-channel interference ...
and
adjacent-channel interference.
Interference alignment
A solution to interference problems in
wireless
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
communication networks
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, messag ...
is interference alignment, which was crystallized by
Syed Ali Jafar at the
University of California, Irvine
The University of California, Irvine (UCI or UC Irvine) is a public land-grant research university in Irvine, California. One of the ten campuses of the University of California system, UCI offers 87 undergraduate degrees and 129 graduate and pr ...
.
A specialized application was previously studied by Yitzhak Birk and Tomer Kol for an index coding problem in 1998. For interference management in wireless communication, interference alignment was originally introduced by Mohammad Ali Maddah-Ali, Abolfazl S. Motahari, and Amir Keyvan Khandani, at the University of Waterloo, for communication over wireless X channels. Interference alignment was eventually established as a general principle by Jafar and Viveck R. Cadambe in 2008, when they introduced "a mechanism to align an arbitrarily large number of interferers, leading to the surprising conclusion that
wireless networks
A wireless network is a computer network that uses wireless data connections between network nodes.
Wireless networking is a method by which homes, telecommunications networks and business installations avoid the costly process of introducing c ...
are not essentially interference limited." This led to the adoption of interference alignment in the design of wireless networks.
Jafar explained:
According to
New York University
New York University (NYU) is a private research university in New York City. Chartered in 1831 by the New York State Legislature, NYU was founded by a group of New Yorkers led by then-Secretary of the Treasury Albert Gallatin.
In 1832, the ...
senior researcher
Paul Horn:
See also
*
Distortion
In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal ...
*
Inter-flow interference
In wireless routing, inter-flow interference refers to the interference between neighboring routers competing for the same busy channel.
The inter-flow interference routing metric is incorporated in MIC and iAWARE wireless routing protocol.
See ...
*
Intra-flow interference
Intra-flow interference is interference between intermediate routers sharing the same flow path.
Application
In wireless routing, routing protocol WCETT, MIC and iAWAREA. P. Subramanian, M. M. Buddhikot, and S. C. Miller, “Interference Aware R ...
*
Meaconing
Meaconing is the interception and rebroadcast of navigation signals. These signals are rebroadcast on the received frequency, typically, with power higher than the original signal, to confuse enemy navigation. Consequently, aircraft or ground stat ...
*
Signal-to-interference ratio
The signal-to-interference ratio (SIR or ''S/I''), also known as the carrier-to-interference ratio (CIR or ''C/I''), is the quotient between the average received modulated carrier power ''S'' or ''C'' and the average received co-channel interfere ...
(SIR)
*
Signal-to-noise plus interference In information theory and telecommunication engineering, the signal-to-interference-plus-noise ratio (SINR) (also known as the signal-to-noise-plus-interference ratio (SNIR)) is a quantity used to give theoretical upper bounds on channel capacit ...
(SNIR)
References
External links
Overview of interference mitigation techniques in mobile networks
{{DEFAULTSORT:Interference (communication)
Noise (electronics)
Interference
Telecommunications
fr:Interférence