Re: [802.3_ISAAC] [EXT] Re: [802.3_ISAAC] Comment on presentation today

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Hi Mehmet,

You my have noticed that I highlighted the word “theoretically” in my response below. The theoretical analysis in the presentation showed that theoretically it is possible to achieve 25Gbps over the 15m coax being evaluated. Based on your response you agree that this is theoretically possible, but you correctly point out that there are additional practical considerations that need to be discussed.

If we want to do a more detailed analysis of under what condition we can transfer 25Gbps over coax, it would require more detailed technical discussion in the Task Force. I believe that this discussion is best done in the Task Force, rather than having the Study Group exclude all rates above 10Gbps.

I was originally of the opinion that we should limit the development in ISAAC to 10Gbps and below, partially because I thought it would make the task easier. However, the material that has been presented to the Study Group has clearly shown that competing technologies are working on data rates above 10Gbps and we know that it is feasible to operate at rates above 10Gbps. I therefore believe that we would be undercutting the success of ISAAC if we do not even consider data rates above 10Gbps.

Ragnar

From: Mehmet Tazebay <00002b0d1a6e9d74-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, January 9, 2024 11:35 AM
To: STDS-802-3-ISAAC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_ISAAC] [EXT] Re: [802.3_ISAAC] Comment on presentation today

Hi Ragnar,

My takeaway is quite different. German and Ahmad’s presentation showed what is theoretically feasible without any in-car noise contribution, aging, temperature effects and etc. Also, it clearly states that the in-car noise measurements and an analysis is required for automotive channels in order to understand and conclude the technical feasibility. If you believe that the automotive noise for the new and aged cables can be completely rejected -as assumed in German and Ahmad’s presentation- then, please provide the data to the group. I believe this is required in order to conclude the technical feasibility for 25Gbps. Without that information, I do not agree that we can conclude 25bps is feasible for automotive applications.

Thanks,

Mehmet

Ps. Regarding to increased TX power, I’d theoretically agree with you for the benefit but how much higher power can be attained for high speed transceivers at small geometry process technologies? Also, how will the increased power affect the camera side in terms of power and heat?

On Jan 9, 2024, at 10:49 AM, Ragnar Jonsson <rjonsson@xxxxxxxxxxx> wrote:

Hi Mehmet,

My takeaway from German’s and Ahmed’s presentation today was that 25Gbps is clearly theoretically feasible over 15m coax. The presentation was not completely clear on the assumed transmit signal level, but my understanding is that it was either -3dBm or -6dBm. For comparison, 802.3ch and 802.3cy both assumed that the transmit power would be around 0dBm. If we would increase the transmit power by 3dB or 6dB, the SNR margin in the presentation become positive. Further increase in transmit power should result in even higher SNR. So theoretically, 25Gbps is possible over the channel in German’s and Ahmad’s presentation.

Ragnar

From: Mehmet Tazebay <00002b0d1a6e9d74-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, January 9, 2024 10:35 AM
To: STDS-802-3-ISAAC@xxxxxxxxxxxxxxxxx
Subject: [EXT] Re: [802.3_ISAAC] Comment on presentation today

External Email

Hi Ariel,

That is not entirely correct. The ASA spec was made available to 802.3 working group. Also, we have seen today that 25Gbps is not theoretically feasible over a typical 17m coax channel even without automotive noise conditions, aging, temperature effects and etc. Therefore, I’d question the technical feasibility of 32Gbps over the target (15m?) length without seeing a proof.

Thanks,

Mehmet

On Jan 9, 2024, at 10:13 AM, Ariel Lasry <00002b0585801bb1-dmarc-request@xxxxxxxxxxxxxxxxx> wrote:

Hi Mehmet,

You are correct. The A-PHY v2.0 is not publicly available.

This is the same as for all the other SerDes mentioned in the presentation of Conrad.

The point of Ragnar’s question was about the trend in support for higher data rates for example with A-PHY 32Gbps.

To this Conrad replied that 32Gbps was realized with 2 Lanes with A-PHY.

Which is correct for A-PHY v1.1 with STQ cable.

To that I have just added the comment that from A-PHY v2.0, 32Gbps is supported over a single Lane over Coax or STP cable.

That is all.

Thanks

Ariel

From: Mehmet Tazebay <00002b0d1a6e9d74-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, January 9, 2024 6:56 PM
To: STDS-802-3-ISAAC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_ISAAC] Comment on presentation today

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Hi Ariel,

Thank you for the information. However, I think the white paper is not a sufficient condition as it only defines the features of the technology but not the technical details. I believe that the standard and technical details of APHY 2.0 are not publicly available, correct? If so, how can we review and discuss the technical feasibility of 32Gbps as it is claimed in the white paper?

Thanks,

Mehmet

On Jan 9, 2024, at 7:09 AM, Ariel Lasry <00002b0585801bb1-dmarc-request@xxxxxxxxxxxxxxxxx> wrote:

Hi all,

comments on Conrad’s presentation today on the 32Gbps A-PHY, since there was a question on that topic.

In A-PHY v2.0 it is on a single Coax or STP.

Reference: MIPI White Paper: Introduction to MASS

Thanks

Ariel

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