Multi input timing recovery over packet network

摘要

In a method of recovering timing information over packet networks, a receiver receives a plurality of packet streams over different paths from the same source. The raw delays experienced by the timing packets for each stream are filtered to provide a filtered delay for each stream. The filtered delays are weighted based on the quality of each stream, and the weighted filtered delays are then combined to form an aggregate delay estimate. Frequency adjustments for a local clock at the receiver are derived from the aggregate delay estimate.

主权项

1. A method of recovering timing information over a packet network, comprising:
receiving a plurality of timing packets, each of the timing packets being derived from the same clock source and proceeding to a receiving block over a different path through the packet network, each of the timing packets being time-stamped with a transmitter time-stamp; time-stamping the received timing packets with a local time-stamp; arranging the timing packets received over different paths into a plurality of separate timing packet streams, each said timing packet stream corresponding to a different path through the network; measuring the raw delays experienced by each of the timing packets in each of the respective timing packet streams by determining the difference between the transmitter time-stamp and the local time-stamp; filtering the measured raw delays of the timing packets in each of the timing packet streams to account for network packet delay variations so as to provide a separate filtered delay for each of the respective timing packet streams; weighting the filtered delays based on the quality of each of the respective timing packet streams to produce a weighted filtered delay for each timing packet stream; combining the weighted filtered delays of the respective timing packet streams to form an aggregate delay estimate for all the timing packet streams; and determining frequency adjustments from the aggregate delay estimate for a local clock at the receiver, and wherein the weights of the individual timing packet streams are calculated based on a non-linear function of the packet rate and an estimated residual error for the filtered delay.