Water filling algorithm

<h2 id="single-channel-systems">Single channel systems</h2>
<p>In a single channel communication system the deamplification and loss present on them can be simplistically taken as attenuation by a percentage <i>g</i>, then amplifiers restore the signal power level to the same value at transmission setup by operating at a gain of 1/ (1 − <i>g</i>). E.g. if we experience 6 dB attenuation in transmission, i.e. 75% loss, then we have to amplify the signal by a factor of 4<i>x</i> to restore the signal to the transmitter levels.
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<h2 id="multichannel-systems">Multichannel systems</h2>
<p>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.
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Water-pouring_algorithm/3I0kVuPU">Water-pouring algorithm</a></li>
<li><a href="/facts/Zero-forcing_equalizer/WWwCfSxp">Zero-forcing equalizer</a></li>
<li><a href="/facts/Robert_Lucky/eSmDSa6q">Robert Lucky</a></li>
<li>Amplifier system</li>
<li><a href="/facts/EDFA/1Fj9Pfes">EDFA</a></li></ul>

<ul><li>Proakis, Digital Communication Systems, 4th Ed., McGraw Hill, (2001).</li></ul>

Water filling algorithm open-in-new

Water filling algorithm