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First of all, I am very glad to see the discussion continuing here on the reflector – we will make better progress if we use this between meeting sessions, and to build understanding among the
groups. Technically, I would like to comment that the way I understood the discussion of code groups yesterday, the code groups are intended to increase the minimum distance between valid code groups.
This would apply regardless of whether it is AWGN or impulsive (EFT) noise. You would need a larger voltage event to traverse the distance. One thing that needs to be considered is correlation in the noise samples within a code group. If there is substantial
correlation on noise, that would also tend to impact other coding schemes, such as RS-FEC. Sometimes the impact is helpful, sometimes it degrades performance. (and when it does, if it is a predictable type of correlation, you can usually turn it to your advantage)
If you expect a particular type of correlation, that would be worth contributing to the discussion. George Zimmerman, Ph.D. President & Principal CME Consulting, Inc. Experts in Advanced PHYsical Communications 310-920-3860 From: stds-802-3-spep2p@xxxxxxxxxxxxxxxxx <stds-802-3-spep2p@xxxxxxxxxxxxxxxxx>
On Behalf Of Zhuangyan (Yan) Hi Brian, Thank you for the response and bring to the list… Noticed that the disparity of 8B6T code pair in 100BASE-T4 is
±1 and your proposal is ±3, any reason for that? And also, with code group, it may provide SNR margin against AWGN, but there still have concern on the EFT (even under 1kv, the signal is still impact, not even
for the 2kv worst case in 61000-4-4). Thank you very much~ Best Regards, Yan From: Murray, Brian <Brian.Murray@xxxxxxxxxx>
Yan 8B6T line coding was used in 100BASE-T4, 802.3u-1995.
23. Physical Coding Sublayer (PCS), Physical Medium Attachment (PMA) sublayer and baseband medium, type 100BASE-T4 So this coding scheme has been around for a long time. I don’t know what RS coding scheme might be used or if we need to use RS coding. That requires some more study. Brian From: Zhuangyan (Yan) <zhuangyan.zhuang@xxxxxxxxxx>
Hi Brian, Thanks for your presentation today. But still confused with how 8B6T LC works... May I ask any reference in IEEE 802.3 that previously introduce this code groups? Can you elaborate a bit on this? Also, with this coding scheme, which RS FEC do you think we can choose for the 500m reach? Thank you very much~ Best Regards, Yan Brian To unsubscribe from the STDS-802-3-SPEP2P list, click the following link:
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