10107056 - Telecommunications Industry Association

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TR-30.1/01-07-056
Telecommunications Industry Association
(TIA)
Baltimore, MD 16-20 July, 2001
COMMITTEE CONTRIBUTION
Technical Committee TR-30 Meetings
Source:
Agere, AMD, Conexant, Broadcom, Intel
Contributor:
Name:
Phone:
E-mail:
Project:
PN-4643
Title:
For Information: G.pnt.pml Contribution presented to May 2001 ITU-T Q4/15
Rapporteur Meeting
Distribution:
Members of TR-30.1 and meeting attendees
Keith Chu
+1 (949) 579-4121
keith.chu@mindspeed.com
Abstract
The attached contribution on G.pnt.pml was recently presented at the May 2001 Q4/15
meeting in Red Bank, NJ. It is presented here for information.
The contributor grants a
incorporate text contained
publication; to copyright in
contribution; and at TIA's
standards publication.
free, irrevocable license to the Telecommunications Industry Association (TIA) to
in this contribution and any modifications thereof in the creation of a TIA standards
TIA’s name any TIA standards publication even though it may include portions of this
sole discretion to permit others to reproduce in whole or in part the resulting TIA
Introduction
As most members of TR-30.1 are no doubt aware, ITU-T Recommendation G.989.1, Phoneline
networking transceivers – Foundation, was approved by SG15 earlier this year. TR-30.1 project
PN-4643 was instrumental in progressing this work, and the source companies on this contribution
wish to thank other TR-30 members for their assistance in this effort.
G.989.1 defines the frequency spectrum, header and trailer format, and MAC procedures for PNT
transceiver. It does not, however, define a payload format. An open project in Q4/15, G.pnt.pml,
seeks to accomplish this.
The attached contribution, defining modulation and constellation encoding for a G.pnt.pml layer, was
presented at the ITU-T Q4/15 Rapporteur meeting in Red Bank, NJ. It was accepted by Q4 at that
meeting as working text for inclusion in a proposed G.pnt.pml Recommendation. It is being presented
at this meeting for information and in order to progress the work on PN-4643 and the G.pnt-series of
Recommendations.
The source companies on this contribution expect to present further contributions on G.pnt.pml at the
August meeting of Q4/15 and the September meeting of TR-30, with the goal of reaching Consent on
a G.pnt.pml Recommendation at the October meeting of ITU-T Study Group 15.
2
ITU - Telecommunication Standardization Sector
Temporary Document RN-081R1
STUDY GROUP 15
Original: English
Red Bank, NJ - 21-25 May 2001
Question: 4/15
SOURCE1: AMD
Broadcom
Conexant Systems
ESS Technology
Intel
Lucent Technologies
Motorola
TITLE:
G.pnt: Modulation for G.pnt.pml
________________________________________________________
ABSTRACT
This contribution proposes text to be used in draft Recommendation G.pnt.pml. It describes the modulation
to be used.
1 Introduction:
The following text defines the modulation to be used in a G.pnt.pml frame; i.e., the portion of a G.989 frame
bounded by the G.989.1 Frame Type octet, and the G.989.1 EOF octet.
2 Modulation
The G.pnt.pml frame shall use Quadrature Amplitude Modulation (QAM).
The two-dimensional symbol rate shall be 4,000,000 symbols/s, with a tolerance of ±0.01%.
4.2.
Carrier Frequency and Tolerance
The carrier frequency shall be 7 MHz.
The carrier clock shall be locked to the symbol clock.
4.3.
Transmit Filters
Transmit filtering sufficient to meet the PSD mask defined in G.989.1 shall be applied.
Note: Identical transmit filtering is used for all symbol mappings and bit encodings.
4.4.
Transmitter Symbol Response
The magnitude transmitter output shall be upper-bounded by the following temporal mask. The response
shall be measured across a 100Ω load between tip and ring at the transmitter’s W1 interface.
1
3
Contact:
Intel Corp.
Barry O’Mahony
T: +1 (503) 264-8579
E: barry.omahony@ties.itu.int
Normalized Magnitude
1
0.4
0.25
0.07
0.056
0.015
0.01
0.005
0 0.045 0.1 0.15 0.23
0.8
1.4
2.5
4.0
5.0
t (sec)
Figure 2.1Transmitter Symbol Response Magnitude Mask
Output before t = 0 and after t = 5.0 microseconds shall be < 0.032% of the peak amplitude.
4.5.
Symbol Mapping
The G.pnt.pml frame shall use the 4D symbol mapping defined in § 4.5.5. Optionally, a portion of the
G.pnt.pml frame may use the 2D symbol mapping defined in § 4.5.6.
4.5.5. 4D symbol mapping
Each 4D symbol shall consist of two consecutive 2D symbols. The first 2D symbol shall be modulated with
2 to 8 data bits using the constellation encoding in § 4.6. The second 2D symbol shall be transmitted with
zero amplitude.
4.5.6. 2D symbol mapping
Each 2D symbol shall be modulated with 2 to 8 data bits using the constellation encoding in § 4.6.
4.5.7. 2D – to – 4D transition
When switching from 2D to 4D symbol mapping within a given G.pnt.pml frame, an additional zero amplitude
symbol shall be transmitted immediately following the last 2D symbol and immediately preceeding the first
4D symbol.
4.6.
Constellation Encoder
4.6.5. Bit to Symbol Mapping
The incoming bits shall be grouped into N-bit symbol intervals, where 2 ≤ N ≤ 8. Each N-bit group shall be
mapped to a 2D symbol as shown in Figure 2.2 through Figure 2.8 The symbol values are shown with bits
ordered such that the right-most bit is the first bit in time and the left-most bit is the last bit in time
All constellations except for 3 bits-per-symbol lie on a uniform square grid, and all constellations are
symmetric about the real and imaginary axes. The 3 bits-per-symbol constellation points are equally spaced
around an equal-amplitude circle.
Figure 2.2 – 2 bits-per-symbol
4
Figure 2.3 – 3 bits-per-symbol
Figure 2.4 – 4 bits-per-symbol
Figure 2.5 – 5 bits-per-symbol
Figure 2.6 – 6 bits-per-symbol
5
Figure 2.7 – 7 bits-per-symbol
6
Figure 2.8 - 8 bits-per-symbol
4.6.6. Symbol Mapping Transitions
Symbol mapping transitions within a G.pnt.pml frame shall occur on a data bit octet boundary, for transitions
between 2D and 4D symbol mapping or for transitions in bits-per-symbol mapping. If the number of data
bits mapped to the symbol immediately preceding such a transition is less than the current value of N, a
sufficient number of bits of value zero shall be appended to the data bits in order to complete this last
symbol in the sequence.
4.6.7. Scaling
The relative scaling of different constellations is given by Table 1. The constellation points shall be scaled
such that the reference points have the values shown, within a minimum-distance tolerance of ±4%.
7
Bits per
Symbol
2
Reference
Point
00
4D mapping
amplitude
1
3
000
1
4
0000
5
00000
6
000000
7
0000000
8
00000000
2D mapping
amplitude
1
3
1
4
1
7
1
9
1
15
1
2
1
2
1
3 2
1
4 2
1
7 2
1
9 2
1
15 2
Table 1 Constellation Reference Points
Note: The constellation points are scaled such that the outermost points have
approximately equal magnitude.
3 Summary:
This paper should be presented under the G.pnt agenda item.
It is proposed that the above text be used in draft Recommendation G.pnt.pml as a description of the
modulation method.
8
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