Water-filling algorithm: Difference between revisions

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==Introduction==

Water filling algorithm, is a general name given to the ideas in [[communication systems]] design and practice for [[channel equalization]] strategies. As the name suggests, just as water finds it level even when filled in one part of a vessel woth 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.

==Single Channel Systems==

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==

[[ZeroZeror forcing equalizer]]

[[Robert Lucky]]

[[Amplifier systems]]

==Refernces==

[[EDFA]]