Method and apparatus for reducing the peak-to-average ratio in a multicarrier communication system

A method of reducing a peak-to-average level of a multicarrier signal supporting a simultaneous transmission of information, represented by constellation values on multiple sub-channels, the method comprising the steps of:

• applying identical constellation values to the positive frequency components and negative frequency components of each information-bearing sub-channel;
• applying different functions to the constellation values of each sub-channel to produce a modified data signal;
• generating, from the modified data signal, a time domain representation having real and imaginary parts;
• identifying which of the real and imaginary parts has a lower peak to average signal ratio;
• and
• selecting one of the real and imaginary parts for transmission corresponding to the lower peak to average signal ratio.

A method of reducing a peak-to-average level of a multicarrier signal supporting a simultaneous transmission of information, represented by data values, on multiple sub-channel tones, the method comprising the steps of:

• modulating a data value onto constellation points by applying different functions to respective positive frequency components and negative frequency components of each information-bearing sub-channel tone to produce a modified data signal;
• generating, from the modified data signal, a time domain representation having real and imaginary parts;
• identifying which of the real and imaginary parts has a lower peak to average signal ratio;
• and
• selecting one of the real and imaginary parts for transmission corresponding to the lower peak to average signal ratio.