Patent ID: 6185259
Filing Date: 2001-02-06
Classification: H04L

Abstract:
A communications method for transmitting information bits from a transmitter to a receiver comprising the steps of:assembling the information bits into N-bit groups of bits to form half-symbols;encoding even numbered ones of said half-symbols into one of two to the power N possible amplitude levels of a cosine wave at even instants of a half-symbol clock and odd numbered ones of said half-symbols into one of the same number of amplitude levels of a sine wave at odd instants of said half-symbol clock;using said cosine and sine waves together to form complex symbols for transmission, each complex symbol carrying 2N information bits;transmitting said complex symbols as a transmission signal on a designated frequency channel to a receiver;receiving said transmission signal on said designated frequency channel and converting said received transmission signal to representative complex numerical values at a sampling rate of one complex sample per half-symbol interval; andforming a set of prerotated samples from said representative complex numerical values by rotating alternate ones of said representative complex numerical values by plus or minus 90 degrees in phase angle relative to the representative complex numerical values in between the alternate ones of the representative complex numerical values;processing said prerotated samples to recover said information bits.