Re: [802.3_NGBASET] Question about Alien Cross Talk Rejection Test

[Hossein Sedarat <Hossein.Sedarat@xxxxxxxxxxxx>]

Hi Jerome,

 

You’re right that the threshold for Salz SNR was reduced from 32 dB to 28 dB but the _expression_ for Salz SNR was also slightly modified to include a constant background term to capture the effects of other (primarily internal) noise sources. If you refer to my presentation at http://www.ieee802.org/3/bz/public/mar16/Sedarat_3bz_01_0316.pdf, on slide 5 I have a plot that shows the tolerated SNR for external noises. This plot shows that the tolerated SNR still remains at 32 dB for 5G at 100m. However, referring to the same plot, you see that the requirement for 2.5G is reduced from 32 dB to 29 dB. Given these numbers, the level of white noise as shown in slide 6, are -137 dBm/Hz and -125 dBm/Hz. So, the current number in latest spec is correct for 5G but it appears that we failed to adjust the corresponding number for 2.5G. The current number is -127 dBm/Hz which has to be replaced by -125 dBm/Hz.

 

-Hossein

 

 

 

 

From: Jerome-yu [mailto:jerome-yu@xxxxxxxxxxx]
Sent: Wednesday, June 15, 2016 4:57 AM
To: STDS-802-3-NGBASET@xxxxxxxxxxxxxxxxx
Subject: [802.3_NGBASET] Question about Alien Cross Talk Rejection Test

 

 

Hi Hossein,

 

According to your comment at 802d3bz_D1p1_Clause_FINAL.pdf #6.

 

"should result in 32 dB of Salz SNR. When the insertion loss of the channel is at the limit line

defined in 126-10, noise power spectral density is -137 dBm/Hz and -127 dBm/Hz for 5G and

2.5G, respectivley"

 

The white noise level of alien cross talk rejection test is designed to meet Salz SNR 32dB. Since Salz SNR requirement has been changed to 28dB at D2.1, this white noise level is not appropriate for 5G and 2.5G. Should the noise level be reviewed ?

 

 

Sincerely,

Jerome ext. 15413