in a multi user communication system , subcarriers are allocated to subchannels using a quality measurement for each subchannel . an initial sub carrier is allocated to each subchannel , and a quality metric measured . subsequent subcarriers are allocated in dependence upon the quality measurement for each subchannel . the subchannel with the lowest quality measurement receives the first allocation , and the subchannel with the highest quality measurement receives the last allocation . the subsequent allocation is repeated , following a re - sort of the subchannel quality measurements , until all of the subcarriers are allocated .