An adaptive algorithm for reducing phase error in digital carrier recovery for high-order QAM signals

This paper describes an adaptive software aided technique for phase error reduction in digital carrier recovery (CR) for high-order Quadrature Amplitude Modulation (QAM).Simulations and analytical results illustrate a phase error variance improvement of at least 30 dB compared to conventional CR, leading to more than 3 dB processing gain enhancement for high-order QAM, using the simple 4 th power phase estimation technique.The new technique can be employed to improve the performance of any CR loop, at the cost of slight complexity overhead independent of the modulation order.