RE: [10GBASE-T] channel model
Attached is a proposed 100 meter Cat 5e channel model for 10GBaseT study (CHANMOD.TXT). This model is defined by complex-valued (X + jY format) insertion gain in the at 500 kHz intervals from DC to 1 GHz.
The proposed model is derived from measurement (at 20 C) of a 100 meter channel (with Cat 5e patch cords and 4 Cat 5e RJ45 connector interfaces). The baseline 100 meter channel model was temperature corrected to 50 C. (122 F.) using the procedure defined in ASTM D4566 Section 26.4. The above mentioned temperature correction method modifies the magnitude but not the phase of the insertion loss. Experimental measurements confirm that temperature effects on the phase are minimal so the approximation is sufficiently accurate.
The most recent proposed model is an extrapolation of the ISO 11801 Class D channel loss limit. The ISO 11801 Class D limit is designed to accommodate expected worst-case measurements below 100 MHz and consequently includes some additional margin to meet this requirement. Since this limit is only specified below 100 MHz, extrapolation of the limit through smooth curve fitting becomes less accurate as it is extended farther beyond its defined boundaries. The new proposed model is based upon measurements beyond 500 MHz and thus validated to at least 500 MHz (and somewhat beyond 500 MHz). As shown in the attached graphs (CHANMOD.DOC), the insertion loss for the proposed model differs from the ISO 11801 Class D 2002 channel limit by less than 0.2 dB from DC to 50 MHz and less than 0.5 dB from 50 to 100 MHz. While it does not represent an absolute worst-case channel, it represents a reasonable model for a feasibility study simulating a maximum length channel under worst-case temperature conditions.
-Larry
-----Original Message-----
From: William Jones
Sent: Wednesday, January 22, 2003 11:19 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] channel model
Xiaopeng
How are the calculations coming? Are you using the models Chris sent out last week?
regards
Bill
-----Original Message-----
From: William Jones
Sent: Wednesday, January 15, 2003 4:08 PM
To: stds-802-3-10gbt@ieee.org
Subject: [10GBASE-T] channel model(part 2)
Bill,
Sure. Once the common channel model (I only need the frequency domain
characteristics) is available, I can begin to work on it.
Regards,
Xiaopeng
----------
Xiaopeng
Would you be willing to sign up for technical feasibility based on an
optimal DFE calculation?
regards
Bill
-----------
Bill,
I has no problem to use TIA or ISO based channel and noise model once it is
standardized. My point is that even using the frequency-domain model we
can still give a quite good estimation of the practically achievable
distance at a throughtput of 10Gbps over CAT-5E or CAT-6 cables.
Regards,
Xiaopeng
-------------
Xiaopeng
We believe, as George discussed in his part of the tutorial in Kauai, that
with an adequate amount of crosstalk cancellation, the throughput is
achievable. The question then becomes can this level of cancellation be
practically achieved, hence, my interest in time domain models.
Until we get the models from the channel modeling Ad Hoc, we could argue
this point endlessly. Until then, I still believe we should not use DSL
models, but, rather something from TIA 568b or ISO 11801.
regards
Bill
chanmod.zip