Modified Gardner algorithm for bit synchronization in high-order QAM system

Gardner algorithm is a simple and effective bit synchronization scheme. Many modified or improved Gardner algorithms have been studied and proposed. However, these algorithms pay little attention to carrier frequency error. In this paper, modified Gardner algorithms in high-order quadrature amplitude modulation (QAM) system are proposed, which are able to solve the traditional timing error detector (TED) problem and also correct the carrier frequency error. Simulation results show the feasibility and stability of the proposed algorithms.