| 摘要 |
A star network type topology is imple-mented or a network synchronization sys-tem wherein synchronization information ra-diates from a centralized primary reference source (46) comprising the global position-ing system (GPS). A GPS receiver (54) in-stalled at each mobile switching center (14) and base station (18) of a wireless commu-nications network supplies a stratum 1 clas-sified clock pulse to a local clock (40). The local clock trains to this clock pulse and gen-erates a corresponding stratum 1 classified synchronization clock pulse for controlling timing operations of the mobile switching center or base station. In the event the GPS primary reference source fails (72) or its ac-curacy degrades (74), a change is made to a tree or linear network type topology wherein the synchronization information flows down- stream from the mobile switching center lo-cal clocks to the base stations. Operation of the network synchronization system is co- -ordinated through a synchronization man-ager (52) maintained by the transport net-work management system (28) of the net-work. Highly accurate synchronization us-ing these topologies supports the provision of value added services such as mobile station locating (102) and information time stamp-ing.
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