Patent ID: 8175178
Filing Date: 2012-05-08
Classification: H04L

Abstract:
1. 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 variable 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 circuit operating with the modulator and mapping circuit and configured to turn OFF and ON selected subcarriers pseudo-randomly based on an encryption algorithm to increase transmit power and signal-to-noise ratio per subcarrier and reduce the Inter-Carrier Interference (ICI); and 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 sinuosoid forming the modulated subcarrier carrying the training sequence to produce a low peak-to-average power ratio (PAPR) preamble.