Synchronous system using redundant clock signals used in synchronous transmission network equipment

Abstract

A synchronization system (D) for equipment of a synchronous transport network comprises, firstly, a first synchronization module (MA) comprising i) a first submodule (SM 1 A) delivering a first intermediate clock signal derived from a first external reference clock signal or an internal reference clock signal, ii) a second submodule (SM 2 A) delivering a first main reference clock signal derived from the first intermediate clock signal or a second intermediate clock signal, and iii) a third submodule (SM 3 A) delivering a first output reference clock signal derived from the first main reference clock signal or a second main reference clock signal, and, secondly, a second synchronization module (MB) comprising i) a first submodule (SM 1 B) delivering the second intermediate clock signal derived from another first external reference clock signal and another internal reference clock signal, ii) a second submodule (SM 2 B) delivering the second main reference clock signal derived from thefirst or the second intermediate clock signal, and iii) a third submodule (SM 3 B) delivering a second output reference clock signal derived from the first or the second main reference clock signal.

Description

technical field [0001] The present invention relates to synchronous transport networks, and in particular to a clock synchronization system for use in a device of such networks. Background technique [0002] In this context, the term "synchronous transport network" refers for example to SDH / SONET, TDM and PDH networks and their equivalents. [0003] In this document, the term "equipment" refers to any type of network equipment item that requires time synchronization, such as switches, radio network controllers (RNCs) (also known as base station controllers (BSCs)), media gateways (MGWs), distribution / Add-in multiplexer (ADM) or switch (probably E10 type). [0004] A time synchronization system provides a reference clock signal (also referred to as a "clock reference") to the above-mentioned equipment so that it can perform its time processing, e.g. preparation to provide a service as reliably as possible or to synchronize a transport network processing, so it is extremel...

AI Technical Summary

Problems solved by technology

These synchronous systems do not provide true redundancy since each tier 3 reference clock signal is frequently derived from the tier 2 reference clock signal

[0009] Meanwhile, prior art synchronization systems employ external inter-block jumpers at each input that receives a Level 2 reference clock signal

Therefore, if one of the Tier 2 reference clock signals fails to feed the synchronization system, the continuity of service may be compromised

[0010] Synchronization systems of the prior art have not been sufficiently reliable and / or efficient, so the purpose of the present invention is to improve the situation and, if possible, provide a standard-compliant improved guarantee for a greater number of failures

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