Method and apparatus for frequency offset compensation

1. Field of the Invention A simplified method for frequency offset estimation in a TDMA cellular PCS environment using /4-shifted DQPSK comprises the steps of multiplying a complex conjugate of a received complex-valued symbol and a succeeding symbol to produce a comparison vector having an angle equal to the phase angle between the received complex-valued symbol and the succeeding symbol, rotating the comparison vector so that the angle thereof is between 0° and 90°, and estimating the frequency offset by determining a constant deviation of the phase angle from an ideal phase angle value of 45° by calculating an average phase angle for a plurality of successive comparison vectors or correlating the rotated comparision vector against a bank of unit vectors to determine a maximum correlation.