Patent ID: 8165232

Claim:
A communications device, comprising: a source of communications data and a training sequence corresponding to a preamble; a modulation and mapping circuit that modulates the communications data and training sequence into a plurality of multiple subcarriers that are orthogonal to each other to form an Orthogonal Frequency Division Multiplexing (OFDM) communications signal having modulated subcarriers carrying the communications data forming a data payload and modulated subcarriers forming the preamble; a pseudo-random signal generator operative with the modulation and mapping circuit and configured to generate pseudo-random signals to the modulation and mapping circuit using an encryption algorithm and to: frequency hop each subcarrier at an OFDM symbol rate, change subcarrier center frequencies at an OFDM symbol time according to the encryption algorithm, and turn ON and OFF selected subcarriers pseudo-randomly; wherein said modulation and mapping circuit is configured to apply a quadratic modulation to each of the subcarriers carrying the training sequences and apply a specific phase angle to each sinusoid forming the modulated subcarrier carrying the training sequence to produce a low peak-to-average power ratio (PAPR) preamble.