Virgin Media Lays Groundwork for Faster Upload Speeds (Article)

[snozski]

https://www.ispreview.co.uk/index.php/2022/08/virgin-media-o2-uk-lays-groundwork-for-faster-upload-s...

Great news if true 🙂  I saw some users on here have pasted stats showing 3.1 docsis upstream channels activated. 

I have maintenance in my area on Tuesday wonder if I'll receive these extra channels too 

[Unknown67]

Faster uploads and lower latency sounds good to me. Will have to check when I finish work..

[Unknown67]

Just checked 3.1 enabled on the upstream now.

[gitty]

Some average numbers:

	Width: 10 MHz Mbps	Total with 5 x SC-QAM
QPSK	12	147
8-QAM	21	156
16-QAM	27	162
32-QAM	31	166
64-QAM	42	177
128-QAM	52	187
256-QAM	60	195
512-QAM	69	204
1024-QAM	76	211
2048-QAM	80	215
4096-QAM	90	225

If they migrate three of the SC-QAM to get a wider OFDMA:

	Width: 30 MHz Mbps	Total with 2 x SC-QAM
QPSK	40	94
8-QAM	60	114
16-QAM	87	141
32-QAM	109	163
64-QAM	130	184
128-QAM	149	203
256-QAM	174	228
512-QAM	201	255
1024-QAM	222	276
2048-QAM	245	299
4096-QAM	264	318

They are currently using 50 kHz subcarrier spacing. They can get a few more Mbps out of it, if they move to 25 kHz.

[Miggle]

so upload on 1gbs may be 100mbps but provisioned at 110mbps by looks of it looking at the maths?

8QAM is high error correction (ie robust) but less bandwidth as a result.

[gitty]

The modem starts with a single data profile (very robust). It may be that the modem shows that profile and not profiles added later with higher modulation.

Someone that have the channel could check the event log and see if it says something about other profiles.

[olisun]

---

@gitty wrote:

Someone that have the channel could check the event log and see if it says something about other profiles.

---

Thu Aug 18 16:16:32 2022

6

US profile assignment change. US Chan ID: 7; Previous Profile: 12; New Profile: 11.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

[gitty]

Profile 13 is the first profile, with lowest modulation. The modem always has that to fall back on. Profile 12 is higher than 13, and 11 is higher than 12.

[olisun]

I can see that it is jumping between profiles.

[gitty]

The modem only displays 8-QAM, right? The examples I've seen so far do that. It may be jumping in your case, but it uses something that is higher than 8-QAM.