Not related to G.INP but there's a trial starting early April in some parts of the UK on FTTC circuits regarding SNR levels which will increase speeds. That's all I can say, you can probably figure out what I mean.

3db?

Seems like it...

Oooh.

IIRC, BT figures after activation of G.INP for Huawei cabs were that 60% of lines went error-free. I guess that meant they had a zero ES total per day.

This probably allows them to drop SNR in exchange for an increase in errors - which can still be coped with by retransmission. I'd imagine they could make this exchange dynamically through DLM, and I don't see why they'd have to move the target in increments of 3dB either.

Vice-versa would be true too: increase SNR in exchange for a decrease in errors.

Edit: old rule-of-thumb data I had calculated a year ago...

My rule of thumb for what an extra 3dB of noise margin is worth in the downstream direction:
- For speeds around 20Mbps, 3dB is worth 3Mbps
- For speeds around 40Mbps, 3dB is worth 6Mbps
- For speeds of 60Mbps or more, 3dB is worth 11Mbps.

The figures comes from using the 3dB to buy one extra bit on each tone. If that can happen across all downstream tones (about 2750 tones), it buys 11Mbps.

Edited by deleted (Mon 28-Mar-16 21:10:15)

I said a year ago they could probably now rollout 3db profiles with g.inp. But god BT are slow.

I havent even got g.inp yet (still waiting a 14 months after they started hauwei rollout).

It took them a year to announce this trial for 3db.

I can only assume this is only hauwei cabinets as they will probably need a year to decide to do it for ECI as well.

Do you think adsl power cutback tones will still gain a bit?

Edited by Chrysalis (Tue 29-Mar-16 06:03:56)

Yes, there's no need to move in 3dB increments.

Who said anything about Huawei only? I just thought the people in this thread would appreciate the news.

Edited by deleted (Tue 29-Mar-16 07:59:04)

I would assume its hauwei only at this point as they have not much data on ECI cabinets, but if no issues then I would expect ECI to get next year.

Maybe just take the hint from my last post

That's great news, thanks for sharing

I know the feeling. I'm still waiting for G.INP too, will be glad to see the back of traditional interleaving soon hopefully. 3dB SNRM is also an impressive step forward, pity it can't currently be for both upstream and downstream though (as upstream doesn't get G.INP). Still, it's something good to look forward to eventually. I seriously doubt ECI will get second class service this time as it's just a change in SNRM target. If it wasn't for the fact that DLM limits the maximum sync rate instead of adjusting the SNRM I could override the DSLAM's default downstream SNRM target of 6dB to a downstream SNRM target of 3dB when G.INP is enabled .

EDIT: G.INP is enabled this morning as of a few minutes ago, woo! About a 3Mbps attainable downstream rate gain, 0.3Mbps upstream rate gain. Downstream sync rate is currently capped by DLM at 55Mbps but I might switch from the Draytek Vigor 2860 to the ASUS DSL-AC68U again as it works fine as long as G.INP is on the line.

Edited by Ixel (Tue 29-Mar-16 11:20:52)