US Patent 7539200 Line-timing in packet-based networks

In a packet-based (e.g., Ethernet) network, such as the network of central offices and base stations of a wireless telephone system, a node receives one or more incoming packet-based signals from one or more other nodes of the network and recovers a clock signal from each incoming packet-based signal. The node selects one of the recovered clock signals as the node's reference clock signal. When the node is part of a base station, the node uses the selected clock to generate and transmit one or more outgoing packet-based signals to one or more central offices. The node also uses the selected clock to generate the base station's wireless transmissions. In one implementation, the base stations and central offices are connected by Ethernet facilities.