A method, apparatus and system detects a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system such as an OFDM system. A phase-frequency synchronization detector determines when the receiver has lost synchronization with the transmitter based on a phase-frequency...http://www.google.de/patents/US6940933?utm_source=gb-gplus-sharePatent US6940933 - Apparatus and method for synchronization in a multiple-carrier communications system by observing a phase-frequency relationship of a plurality of pilot signals
