Water-filling algorithm: Difference between revisions

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'''Water filling algorithm''' is a general name given to the ideas in [[communication systems]] design and practice for [[adaptive equalizer|equalization]] strategies on [[channel (communications)|communications channels]]. As the name suggests, just as water finds it level even when filled in one part of a vessel with multiple openings, as a consequence of [[pascals law]], the amplifier systems in communications network repeaters, or receivers amplify each channel upto the required power level compensating for the channel impairments. See, for example, channel power allocation in [[MIMO]] systems.

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'''Water filling algorithm''' is a general name given to the ideas in [[communication systems]] design and practice for [[adaptive equalizer|equalization]] strategies on [[channel (communications)]]. As the name suggests, just as water finds it level even when filled in one part of a vessel with multiple openings, as a consequence of [[pascals law]], the amplifier systems in communications network repeaters, or receivers amplify each channel upto the required power level compensating for the channel impairments. See, for example, channel power allocation in [[MIMO]] systems.

==Single Channelchannel Systemssystems==

In a single channel communication system the deamplification and loss present on the can be simplistically taken as attenuation by a percentage ''g'', then amplifiers restore the signal power level to the same value at transmission setup by operating at a gain of 1/ (1-g). E.g. if we experience 6dB attenuation in transmission, i.e. 75% loss, then we have to amplify the signal by a factor of ''4x'' to restore the signal to the transmitter levels.

==Multichannel Systems==

Same ideas can be carried out in presence impairments and a multiple channel system. Amplifier nonlinearity, crosstalk and power budgets prevent the use of these waterfilling algorithms to restore all channels, and only a subset can benefit from them.

==See also==

#[[Zero Forcingforcing equalizer]]

#[[Robert Lucky]]

#[[Amplifier systems]]

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# Proakis, Digital Communication Systems, 4th Ed., McGraw Hill, (2001).

[[Category:TelecommunicationsTelecommunication theory| ]]

[[Category:Error detection and correction]]

[[Category:Information theory]]

[[Category:Communication]]

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