Carrier phase recovery method for long burst linearly modulated signals

In long-burst digital communications, carrier phase varies with time and carrier tracking is required. Conventional open-loop methods fail in carrier tracking of long bursts where phase variations are no longer ignorable. Classical closed-loop methods are also not suitable for burst communications, if high data transmission efficiency is required, because a long pilot header for acquisition is unavoidable. A new method for tracking dynamic phase of long-burst linearly modulated signals is proposed. Using two second order PLLs, and with the help of a short unique word, the proposed structure can successfully track the frequency and phase of the whole burst. Since no long pilot header is needed, this solution may achieve high transmission efficiency.