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[STDS-802-3-EPOC] PHY Link frame structure



All,
Currently in our PHY Link frame structure there is a soft FEC. Unlike a Reed Solomon FEC, the LDPC FEC does not give a positive indication of an uncorrectable error. In our MAC data channel we have resolved this with the placement of a CRC in the FEC codeword. I believe this is also the solution DOCSIS 3.1 has taken for it's DS PLC where they have defined several types of message blocks each with it's own CRC. An exception here is the Message Channel MB the conveys MAC frames which already have a CRC and therefore don't need additional protection. A summary of the D3.1 MB structure is shown below (D3.1 folks please correct me if I've misinterpreted anything here).
I think is it reasonable to resolve this problem in EPoC in a similar fashion to what has been done in D3.1, my only question is how closely we want to follow their lead? A thought that has crossed my mind is extending the "Type" field to create EPoC specific fields. For example we could create an EPoC PHY Link MB that includes the Opcode, Count, MDIO Add, and MDIO Data fields with a closing CRC.
Any other thoughts on this idea?
Best Regards,
Duane

DOCSIS 3.1 MBs
Msg Block

Field

bits

TS MB
Type=1

Type/R

4/4

Timestamp

64

CRC24D

24

EM MB
Type=2

Type/R

4/4

CM_ID

16

Wake

32

CM_ID

16

Wake

32

CRC24D

24

TR MB
Type=4

Type/R

4/4

Transaction ID

8

Trigger Group

16

Frame Delay

8

Symbol Select

8

CRC24D

24

MC MB
Type=3

Type/R

4/4

Packet Start

16

Frame

512



FutureWei Technologies Inc.
duane.remein@xxxxxxxxxx
Director, Access R&D
919 418 4741
Raleigh, NC


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