Encoding for efficient use of an upstream channel in burst mode
AssigneePMC-Sierra, Inc.
InventorJeff Mandin
Life of this patent
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Abstract
Alignment-enabled secondary nodes of a DAMA network monitor the alignment of for-transmission data as it is received, and actively align the data frames into encoded blocks such that the number of blocks occupied by encoded data resulting from an unencoded datastream of a particular length is predictable rather than variable. In some embodiments, the network is an Ethernet passive optical network and the alignment includes aligning a XGMII word having a start control code to a first position in a 72 bit word input to a 66B/66B encoder, thereby encoding a start-of-frame (/S/) code to a first byte of an encoded first Ethernet 66b block.
Claims10
A method of data communications between a headend node and a plurality of secondary nodes, the method providing an efficient use of an upstream channel in burst mode with a variable number of data frames, the method comprising the steps of:
- a) monitoring a variable length data burst at one of the secondary nodes in a demand assignment multiple access (DAMA) data communication system, as said data burst is packed into the variable number of data frames for transmission in a respective assigned TDM slot;
- b) aligning the variable number of data frames into a variable number of encoded blocks defining a variable transmission time, said aligning aligns a start-of-frame (/S/) of the variable number of data frames to a start of said variable number of encoded blocks, said variable number of encoded blocks being deterministically derived from said variable number of data frames and is predictable by the headend node;
- and
- c) transmitting said variable number of encoded blocks from said one secondary node to the headend node of the data communication system via the upstream channel.
A system, comprising:
- a) a headend network node for a demand assignment multiple access (DAMA) data communication system;
- b) a plurality of secondary alignment-enabled network nodes;
- and
- c) a shared time-division multiplexed (TDM) channel managed by said headend node and used for upstream transmission of variable length burst data packed into a variable number of data frames from each said secondary alignment-enabled network node to said headend network node in burst mode and wherein said data frames are aligned into a variable number of encoded blocks by each said secondary alignment-enabled network node so that the variable number of said encoded blocks defines a variable transmission time, said data frames are aligned so that a start-of-frame (/S/) of said data frames to a start of said variable number of encoded blocks, said variable number of encoded blocks being deterministically derived from said variable number of data frames and is predictable by said headend network node.
Dependencies are inferred from the claim text.