Blind synchronization techniques for telephony over HFC networks using M-QAM

This paper describes blind synchronization techniques for cable-telephony systems using M-ary quadrature amplitude modulation (M-QAM). The development of accurate, reliable and economically realizable synchronization algorithms is a challenging problem with significant impact on overall system design and performance. The method of loop timing is used for synchronizing multiple remote units with a single head-end. Each remote transceiver blindly recovers downstream timing and uses it to derive its upstream clock. The issue of overcoming frequency offsets incurred on the cable network is addressed. A novel two-stage search and acquisition procedure comprising of all-digital baseband synchronization algorithms is described