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[roseway]

Could someone please provide a list of the bitloading tone ranges used in UK FTTC systems. I've worked out the details of the BT 17a profile from postings here (although I'm unsure of the significance of the overlapping/shared parts) but I presume that there are other profiles in use or planned.

This is to support development of rs-ux, by the way.

[roseway]

This information seems hard to come by. The only real data I can locate comes from users' reports of the output of the command xdslcmd info --pbParams which typically looks like this:

Code: [Select]

# xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY statusStatus: Showtime
Retrain Reason: 2Max:    Upstream rate = 4803 Kbps, Downstream rate = 33572 Kbps
Path:   0, Upstream rate = 4785 Kbps, Downstream rate = 28568 Kbps
Discovery Phase (Initial) Band PlanUS: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959) Medley Phase (Final) Band Plan
US: (0,95) (868,1207) DS: (32,859) (1216,1963)
I've also located a document [1] which includes the table below, specifying the standard VDSL2 profiles. Comparing this table with the above, I'm going to assume pro tem that, apart from profile 30a, all VDSL2 profiles use the same bitloading ranges, although some profiles don't use the higher ranges.

[1] http://www.ictregulationtoolkit.org/en/document.2957.pdf

[asbokid]

Hi Roseway,

Shame Baldy is off duty and shirking.  This is his specialty.

From the horse's mouth is ITU-T G.993.2 Recommendation document. The latest revision 12/2011 lists the bandplans for Profiles 8c, 17a and 30a. See page 27 onwards. [1]

What we worked out is that there is some leeway for vendors to tweak their own VDSL2 bandplans. There are a certain number of tones at the boundaries of the upstream and downstream bands which can be left unused to serve as guard bands. It was found that ECI uses smaller guard bands than Huawei, iirc, which gains slightly more utilisable tones.

cheers, a

[1] http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.993.2-201112-I!!PDF-E&type=items

[roseway]

Many thanks asbo. I think I've now got enough information to cover the immediate UK situation.

[Bald_Eagle1]

Many thanks asbo. I think I've now got enough information to cover the immediate UK situation.

Just for reference, these are the current 17a profile band plans in use at discovery phase:-


ECI DSLAM:-

Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)



Huawei DSLAM:-

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)



Not all connections are able to use at Medley Phase all the tones "discovered" - e.g. my own connection to a Huawei DSLAM:-

Medley Phase (Final) Band Plan
US: (0,95) (868,1207)
DS: (32,859) (1216,1963)



Even longer distance and/or problematic D-side connections are only able to use SOME of the lower of the tone bands at Medley Phase (see attached bit-loading graph):-

Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)

Medley Phase (Final) Band Plan
US: (0,95)
DS: (32,859)

[roseway]

Thanks BE1 and I hope you had a good holiday.