Patent ID: 7054385

Claim:
A method of altering a communications signal to reduce an average-to-minimum power ratio thereof, the communications signal being formed using pulse-shaping techniques applied to instances of a pulse of a given form, the communication signal using constellation points, the method comprising, for at least one signal component: setting a desired signal envelope minimum; mapping a digital stream of bits onto a symbol constellation to generate a sequence of symbols; generating signal sample points from the sequence of symbols; identifying two or more signal sample points between which a communications signal is likely to reach a local envelope minimum; using a mathematical model of the communications signal, the two or more signal sample points lying in between two constellation points; determining a minimum of the communications signal envelope between the signal sample points and a time at which the minimum between the signal sample points occurs; determining a measure of at least one of magnitude and phase of the communications signal corresponding to the minimum of the communications signal; and if said minimum of the communications signal is less than the desired signal minimum: in accordance with said one of magnitude and phase, forming a scaled corrective pulse; and adding to the signal component the scaled corrective pulse, in timed relation to the signal, to form a modified communications signal having a reduced average-to-minimum power ratio.