Asynchronous payload mapping using direct phase transfer
AssigneeNortel Networks Limited
InventorsMatthew D. Brown, Colin G. Kelly, Phil Campbell, Tony Bitzanis
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Abstract
The present invention involves the passing of clock information from a point where a tributary payload is mapped into a carrier to a point where a tributary payload is de-mapped from the carrier. A synchronization signal is generated at the mapping end. Rather than sending clock phase information implicitly by means of the data, as is normally the case, a value of the synchronization signal at a given time, is sent explicitly, independent from the payload data.
Claims19
At a near end of a transmission system, a method of mapping client data into an outgoing block, said outgoing block comprising payload words and overhead words, so as to transfer said client data and clock synchronization information associated with said client data to a far end of said transmission system, said method comprising:
- receiving client words of an incoming flow of said client data;
- generating fill words;
- mapping said payload words into said outgoing block, where:
- each of a first plurality of said payload words comprises one of said client words;
- and
- each of a second plurality of said payload words comprises one of said fill words;
- adjusting a rate at which said client words are mapped such that an average number of said client words mapped is equal to an average number of said client words received;
- including an indication of said rate in said overhead words;
- and
- mapping said overhead words into said outgoing block.
A mapping processor comprising:
- means for receiving client words of an incoming flow of client data;
- means for generating fill words;
- means for mapping payload words into an outgoing block, where:
- each of a first plurality of said payload words comprises one of said client words;
- and
- each of a second plurality of said payload words comprises one of said fill words;
- means for adjusting a rate at which said client words are mapped such that an average number of said client words mapped is equal to an average number of said client words received;
- means for including an indication of said rate in a plurality of overhead words;
- and
- means for mapping said plurality of overhead words into said outgoing block.
A mapping processor comprising:
- a receiver for receiving client words of an incoming flow of client data;
- a fill unit for generating fill words;
- a mapping unit for:
- adjusting a rate at which said client words are mapped such that an average number of said client words mapped is equal to an average number of said client words received;
- including an indication of said rate in a plurality of overhead words;
- mapping payload words into an outgoing block, where:
- each of a first plurality of said payload words comprises one of said client words;
- each of a second plurality of said payload words comprises one of said fill words;
- and
- mapping said plurality of overhead words into said outgoing block.
A mapping processor operable to:
- receive client words of an incoming flow of client data;
- generate fill words;
- map payload words into an outgoing block, where:
- each of a first plurality of said payload words comprises one of said client words;
- and
- each of a second plurality of said payload words comprises one of said fill words;
- adjust a rate at which said client words are mapped such that an average number of said client words mapped is equal to an average number of said client words received;
- include an indication of said rate in a plurality of overhead words;
- and
- map said plurality of overhead words into said outgoing block.
A computer readable medium for providing program control to a mapping processor, said computer readable medium adapting said processor to be operable to:
- receive client words of an incoming flow of client data;
- generate fill words;
- map payload words into an outgoing block, where:
- each of a first plurality of said payload words comprises one of said client words;
- and
- each of a second plurality of said payload words comprises one of said fill words;
- adjust a rate at which said client words are mapped such that an average number of said client words mapped is equal to an average number of said client words received;
- include an indication of said rate in a plurality of overhead words;
- and
- map said plurality of overhead words into said outgoing block.
Dependencies are inferred from the claim text.