Download TR41 9 1-08-08-008-R1_Draft proposed revisions to VDSL2 LOV

Telecommunications Industry Association
TR41.9.1-08-08-008-R1
Document Cover Sheet
Project Number
PN-3-0016-RV2 (to become TIA-968-B)
Document Title
Draft proposed revisions to VDSL2 LOV Limits.
Source
Verizon
Contact
Trone Bishop
13100 Columbia Pike
Silver Spring, MD 20904
Distribution
TR-41.9.1
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Phone: 301-236-3754
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The document to which this cover statement is attached is submitted to a Formulating Group or subelement thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions
of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of which
provisions are hereby incorporated by reference.
This document has been prepared by Verizon to assist TIA Engineering Committee TR-41. It is proposed
to the TR41.9 subcommittee as a basis for discussion and is not to be construed as a binding proposal on
Verizon. Verizon specifically reserves the right to amend or modify the material contained herein and
nothing herein shall be construed as conferring or offering licenses or rights with respect to any
intellectual property of Verizon other than provided in the copyright statement above.
Abstract
At the May meeting of TR41.9.1, the DSL ad hoc working group agreed to review and
revise the VDSL2 longitudinal output voltage limits in the draft proposed TIA-968-B
standard to better reflect the many new VDSL2 upstream PSD masks introduced by
Amendment 1 of G.993.2. This contribution proposes revisions to the VDSL2 LOV limits.
The proposals were previously distributed to the working group for comment, but due to
a lack of formal approval by that group, the proposals are being submitted as a company
contribution rather than an ad hoc working group submission.
Telecommunications Industry Association
TR41.9.1-08-08-008-R1
Introduction
Transverse balance is measured when terminal equipment is not transmitting. A
sufficient degree of differential to longitudinal balance ensures that terminal equipment
will not allow differential energy transmitted to the equipment from wireline carrier
networks to be converted into longitudinal energy that can more easily crosstalk into
other services in the same cable. Transverse balance testing is limited to the operating
frequency band of the particular technology (both upstream and downstream) based on
the assumption that the network operator will connect compatible network equipment.
Longitudinal output voltage on the other hand is measured while the terminal equipment
is transmitting in each of its modes of operation. If the terminal equipment should
generate significant longitudinal output voltage in any operating mode, then that energy
will easily crosstalk into other pairs in the same cable. Since the services on other pairs
in the same cable may use a different operating frequency spectrum than the terminal
equipment under test, it is necessary to limit terminal equipment LOV in the frequency
spectrums that could be used on other pairs which is not necessarily the same
frequency spectrum being used by the subject terminal equipment.
Currently LOV testing for all VDSL2 equipment is up to 30 MHz. This contribution
proposes a significant reduction in test frequency spectrum for some of the VDSL2
modes. For example, it is possible that 8a, 8b, 8c, and 8d profiles might be used in the
same loop cable as VDSL2 equipment operating with the 12a or 12b profile but it is not
likely that VDSL2 equipment using the 8a, 8b, 8c, and 8d profiles will be used in the
same loop cables as VDSL2 equipment using the 17a or 30a profiles. For this reason,
this contribution proposes limiting the LOV frequency range for profiles 8a, 8b, 8c, and
8d to 12,000 kHz maximum.
Likewise, since VDSL2 equipment with the 12a and 12b profiles might be used in the
same cable as VDSL2 equipment with the 17a profile, but is not likely to be used in the
same loop cables as VDSL2 equipment using the 30a profile, this contribution proposes
to limit the LOV frequency spectrum for profiles 12a and 12b to 21,000 kHz maximum
(which is the limit of the downstream band for profile 17a).
VDSL2 equipment with the 17a profile might be used in the same cable as VDSL2
equipment with the 30a profile, so this contribution proposes to keep the LOV
requirement for profile 17a out to 30,000 kHz maximum.
Since VDSL2 terminal equipment has the widest frequency spectrum of any terminal
equipment currently used in North America and since the VDSL2 bandwidth is currently
limited to 30 MHz, this contribution does not propose LOV limits for VDSL2 terminal
equipment beyond 30,000 kHz.
Proposal
Replace the existing VDSL2 LOV tables with the following tables:
Telecommunications Industry Association
TR41.9.1-08-08-008-R1
Table 5.3.8-7 – Maximum longitudinal output voltage for VDSL2 TE
Maximum longitudinal output voltage
Frequency
(dBVrms) in all 4 kHz bands averaged over
Band
a minimum period of 1 second (see note 3)
(kHz)
(see notes 1 and 2)
Profiles
8a, 8b,
8c, and
8d
Profiles
12a and
12b
Profile
17a
Profile
30a
fa (note 1) to fb (note 2)
-50
-50
-50
-50
fb (note 2) to 3,750
-80
-80
-80
-80
3,750 to 5,200
-50
-50
-50
-50
5,200 to 8,500
-80
-80
-80
-80
8,500 to 12,000
-80
-50
-50
-50
-80
-80
-80
21,000 to 23,000
-80
-80
23,000 to 30,000
-80
-50
12,000 to 21,000
NOTES
1.) Frequency fa is 0.1 kHz for all digital modes and 12 kHz for operating modes
designed to work on the same loop as a voice band service such as POTS.
2.) Frequency fb is the frequency at which the PSD mask is approximately 30 dB below
the peak mask value. The fb values for various VDSL2 upstream PSD masks are given
in Table 5.3.8-8.
3.) If a 3 kHz measurement bandwidth is used rather than the 4 kHz bandwidth on which
the requirements are based, a 1.3 dB correction factor for the smaller measurement
bandwidth is applied to the maximum longitudinal output voltage limits thus decreasing
-50 dBV limits to -51.3 dBV and -80 dBV limits to -81.3 dBV respectively.
Telecommunications Industry Association
TR41.9.1-08-08-008-R1
Table 5.3.8-8 – Values of fb for various VDSL2 upstream PSD masks
Operating
with POTS
designator
All-digital
mode
designator
fb (kHz)
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64
EU-128
ADLU -32
ADLU -36
ADLU -40
ADLU -44
ADLU -48
ADLU -52
ADLU -56
ADLU -60
ADLU -64
EU-128
184
207
230
253
276
299
322
345
368
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