Nonlinear digital phase estimation for mobile communications

The nonlinear digital carrier synchronization structure is a coherent demodulation technique that has many advantages for mobile communications. The nonlinear digital synchronizer is investigated in the presence of time varying fading for BPSK, QPSK, and pi /4-QPSK modulations. This paper addresses the design of optimal unconstrained smoothing filters for the nonlinear synchronizer structure. An approximate bit error probability analysis demonstrates that performance is quite near ideal and that no error floor exists in time varying fading.<
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