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Hi George, Sorry for the confusion. What I mean “ideal channel for 8B6T with PR” refers to ideal 1+D (no extra ISI). This results in a memoryless relationship between only five of the six
symbols with each 6T code-group. The minimum distance improvement for 8B6T with 1+D (in principle PAM5) is different from that for 8B6T PAM3. All six symbols are used in the ML detection to get the decided 6-tuple and then de-mapped to 8 bits. The simulation is to investigate the theoretical SNR for 8B6T with PR, and
what I see is no improvement compared with 4B3T. Best wishes, Tingting 发件人: George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx>
Tingting –
Looking at this in detail (apologies for taking a little while, but preparation for the meeting delayed me), I have a few questions, and am a little puzzled. It seems you are looking at the 8B6T on an ideal channel (slide 2, “Ideal channel without ISI, only AWGN”). The performance gain of ISI comes from the partial response… Not sure where
or how you are adding in the partial response. Secondly, on slide 2 you make a comment that suggests you are using only 5 T of the 6T PAM3 symbols in the bit demapping? (“Bit de-mapping using the relationship between 8 bit and 6T
PAM3 or the last five symbols of 6-tuples). Are you referring here instead to your comment at the top of slide 3, where you state the first (PAM5) symbol of a 6T block depends on the previous 6T block? If you discount the first symbol, and use only 5 symbols,
trying to derive the partial information on the overlapped first PAM5 from without benefit of the sequence, then that may be the source of your loss… Finally, there are many well-known methods for computing minimum distance at the receiver without comparing to every point in the lookup, avoiding an exponential growth in receiver complexity. Looking forward to discussions next week. -george (as an individual) 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 zhangtingting (O) Hi Brian, The presentations for June Ad Hoc show kind of consensus on RS-FEC, dual-mode PCS, and block coding. The main difference is using 8B6T or 4B3T. Regarding 8B6T with partial response, I have the following comments:
1.
ML detection is used for 6-tuple decision to get the performance gain. For each received 6-tuple with noise, every Euclidian distance calculation needs 6 multiplication. Considering 430 reference 6-tuples, 2580
multiplications are needed. The detection complexity is even 2x higher than DEC. Please correct me if I am wrong.
2.
8B6T performance gain is achieved by referring to a
calculated theoretical SNR of 17.9dB. For an ideal channel with only AWGN, simulated BER should be close to theory. However, the results show that in the case of AWGN, 8B6T with partial response requires higher SNR than 4B3T at the same BER. More
details of the simulation can be found from the attachment.
3.
The primary reason of using 8B6T is to achieve coding gain for long-reach transmission. Considering FEC for long distance and high ML detection complexity, 8B6T seems to be a bit overdesigned for 802.3dg. After
all, process industry requires a low-power 100BASE-T1L PHY. Thank you very much. Best wishes, Tingting 发件人: George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx>
(NO, the plenary dates aren’t changed, this is only about 802.3dg and 802.3dm swapping meeting days) All – In order to accommodate schedules and avoid overlap, the meeting times for the IEEE P802.3dg and IEEE P802.3dm Task Forces at the July IEEE 802 plenary session will be swapped. This means that the IEEE P802.3dg task
force will now be meeting at the beginning of the week – in the Monday PM1 and PM2, and Tuesday AM1 and AM2 time slots (afternoon of July 15, and morning of July 16, Montreal time). I will update the 802 calendar shortly with the Webex details.
While this possibility was discussed at the Wednesday June 26 ad hoc (and there were no objections), it is now official. Thank you for your cooperation helping to accommodate for unplanned events. Please note that presentation requests are still due as per
https://www.ieee802.org/3/dg/public/presentproc.html , one week prior to the meeting, with the actual presentations due on Friday before the meeting. I will keep the request deadline on Wednesday
July 10 – 10AM PACIFIC TIME (not AoE, as the meeting would have been started at 10AM pacific…), and the presentation submittal time as Friday, July 12 AoE. Earlier submissions are appreciated, as I will be traveling Friday and in the ITU-T workshop on Saturday
and won’t be able to post for a while after about 10am Friday morning pacific time. -george George A. Zimmerman, Ph.D. Chair, IEEE P802.3dg 100BASE-T1L Task Force 2nd Vice Chair, IEEE 802 LAN/MAN Standards Committee CME Consulting, Inc. 1-310-920-3860 To unsubscribe from the STDS-802-3-SPEP2P list, click the following link:
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