TC-QAM系统中的载波相位恢复方法

A Carrier Phase Acquisition Scheme for TC-QAM System

针对Trellis Coded QAM(TC-QAM)解调系统中载波相位恢复难、收敛速度慢等问题,提出一种全数字方式实现的载波相位恢复方法。综合应用自动频率控制(AFC)、自动增益控制(AGC)、相位/幅度跟踪、相位模糊检测等算法,在没有任何训练序列的情况下,能准确地恢复调制信号载波相位。软件仿真结果表明,该方法能快速恢复和跟踪载波相位,即使在较低的信噪比情况下,解调系统也能正常工作。

An all-digital carrier phase acquisition scheme was presented to solve the problem of carrier phase recovery, which is specially critical and hard in the demodulation of trellis-coded quadrature amplitude modulation （TC - QAM）. Algorithms, such as automatic frequency control （AFC）, automatic gain control （AGC）, phase-amplitude tracking （PAT）, and phase ambiguity detecting （PAD）, were jointly used in this scheme. Simulations indicated that, in the condition of without any preambles, carrier phase could be acquired fast and tracked steadily, and this scheme still worked well even in low SNR level condition.