Waveform generation for improved peak-to-average amplitude ratio

A transmitter, comprising:

• an Inverse Fast Fourier Transform (“IFFT”) module coupled to receive an orthogonal frequency division multiplexing (“OFDM”) modulated signal, the OFDM modulated signal having frequency bins;
• a portion of the frequency bins being reserved;
• the IFFT module configured to provide a superposition of the OFMD modulated signal as a discrete time series signal;
• a peak-to-amplitude ratio controller coupled to receive the discrete time series signal;
• waveform storage coupled to the peak-to-amplitude ratio controller, the waveform storage having circularly time-shifted versions of a peak reducing waveform stored therein;
• the peak-to-amplitude ratio controller configured to obtain a version of the circularly time-shifted versions of the peak reducing waveform for phase-alignment and combination with a peak of the discrete time series signal for peak-to-amplitude ratio reduction of the discrete time series signal;
• the circularly time-shifted versions of the peak reducing waveform each obtained at least in part from an IFFT of a simulated signal associated with the OFDM modulated signal;
• the simulated signal having the portion of the frequency bins being reserved, the circularly time-shifted versions of the peak reducing waveform being obtained by recursive iteration of the simulated signal including,
• combining an initial version of the simulated signal with a circularly time-shifted version thereof to obtain a resultant peak reducing waveform having a peak side lobe amplitude less than that of the initial version of the simulated signal;
• wherein the resultant peak reducing waveform is obtained using the frequency bins reserved with respect to the IFFT;
• wherein the resultant peak reducing waveform is orthogonal to the discrete time series signal;
• and
• circularly time-shifting the resultant peak reducing waveform to provide the versions of the peak reducing waveform;
• wherein the peak side lobe amplitude of the initial version of the simulated signal is reduced to enhance a peak-to-side lobe amplitude ratio such that the resultant peak reducing waveform has a more impulse or impulse-like profile than the initial version of the simulated signal.

A storage medium encoded with machine-readable computer program code, which when executed by a processor, causes execution of a method for side lobe amplitude reduction, the method comprising:

• obtaining a data carrying signal waveform, the data carrying signal waveform having sub-carrier signals;
• obtaining an initial peak reduction waveform, the initial peak reduction waveform obtained by selection of a portion of the sub-carrier signals for non-data carrying;
• wherein the initial peak reduction waveform is obtained from reserved frequency bins with respect to an Inverse Fast Fourier Transform;
• wherein the initial peak reduction waveform is orthogonal to the data carrying signal waveform;
• and
• refining the initial peak reduction waveform by at least one recursive iteration, the recursive iteration including,
• combining the initial peak reduction waveform with a circularly time-shifted version thereof to obtain a resultant peak reduction waveform having a peak side lobe amplitude less than that of the initial peak reduction waveform;
• wherein the side lobe amplitude is reduced to enhance a peak-to-side lobe amplitude ratio such that the resultant peak reduction waveform has a more impulse or impulse-like profile than the initial peak reduction waveform.