Patent ID: 7397860

Claim:
A method for reducing the peak-to-average ratio of a single-carrier or a multi-carrier modulated signal, the method comprising: storing an original signal; extending the original signal by adding a suffix to form an original extended signal; interpolating and upsampling the original extended signal at a fractional sampling rate to form an extended interpolated signal; localizing the extended interpolated signal to form a localized neighborhood; setting a threshold for the extended, interpolated signal within the localized neighborhood; tracing back across all the signal samples to detect for and mitigate the peaks that exceed the threshold in the localized neighborhood; generating sequences basis (Q) by partitioning the available bins into a number of subsets, and taking N-dimensional inverse Fourier transforms of each subset at the rate of T; locally generating a PAR lowering sub-sequence (J) at T, in the time-domain locally combining the PAR lowering sub-sequence (J) and a highest peak source at the scale of one extended symbol for multi-carrier modulation and at one or more of symbols for single-carrier modulation; locally interpolating the combination of the sub-sequences and the highest peak source; finding and determining if the PAR for one of the locally combined sub-sequences and the highest peak is a PAR-lowering sequence; storing the PAR-lowering, locally combined sub-sequences and the highest peak; from the stored, locally combined PAR lowering sub-sequences finding the one that yields the lowest PAR at the local rate of T/K; generating the best PAR-lowering sub-sequence for all the samples at the rate of T; and combining the best PAR-lowering sub-sequence and the originally stored signal and, transmitting the signal.