water filling algoritm OFDM system

[harsha]

hello people,
can you tell me what is the water filling or the greedy algorithm for power allocation in an OFDM system?thanks in advance

harsha

[ahmedslh]

hello harsha,

water filling algorith is used based on a simple concept, consider this example with me, suppose you have two channels you can send information on, one of them with attenuation 0 dB and the other with attenuation 80 dB on which channel will you send your information? ofcourse on the first one since the second isn't reliable at all. Now the waterfilling algorithm uses this concept to load the channels with the amount of power that leads to maximum throughput or maximum transmission rate or minimum BER, simply we want to maintain a certain SNR in all sub channels within the transmission channel given that the amount of power to be transmitted is constant, then u begin to fill in the subchannels with power in a manner that let you reach the required level of SNR in all subchannels.

i hope that's clear

[signal]

hi ahmed ,

could you please suggest me some good material or paper which explains water filling algorithm in OFDM.

I will be highly obliged.

thank you,

[aya2002]

many thanks ahmed
do you have more information about ofdm programming by matlab?

thank you