New carrier and symbol synchronization technique for digital mobile systems

Two coding methods to enable in-band operation of pilot-aided synchronization techniques are introduced. By operating on baseband equivalent QAM, i.e. PAM symbol streams, the new codes generate power spectral notches at the Nyquist frequency with fairly low redundancy. One of the codes, called KF10, generates a power spectral notch at the Nyquist frequency, so that the dual-pilot tone calibration technique can be arranged to convey both a symbol timing and carrier reference to the receiver. The second code, called OF00, generates a notch at zero as well as the Nyquist frequency, and so enables a triple-pilot scheme to be conceived to provide, in addition to a symbol timing, a carrier reference with no 180° phase ambiguity. Through comparison with previous codes used in real systems, it is shown that the codes generate spectral notches of the same quality as others, yet reducing the required redundancy by as much as 400% in the case of 256-QAM application. Various simulation results confirm the coding effects