[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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