Telecommunications Industry Association
(TIA)
TR-30.1/99-08-027
Quebec City, Quebec, 19 August 1999
COMMITTEE CONTRIBUTION
Technical Committee TR-30 Meetings
SOURCE1: 3Com, AMD, Broadcom, Compaq, Conexant, Lucent Technologies, Motorola, Texas
Instruments
CONTRIBUTOR:
Name:
Phone:
Fax:
E-mail:
Don Shaver1
Rohit Gaikwad
972-997-5200
972-997-5693
[email protected]
TITLE:
Spectral compatibility of home phoneline network transceivers (G.PNT) with
xDSL and other existing in-home services
PROJECT:
PN-4643
DISTRIBUTION:
Members of TR-30.1 and meeting attendees
ABSTRACT
This contribution addresses the compatibility of future home phoneline network transceivers (G.PNT) with existing inhome services such as POTS, ISDN, and G.lite, and also G.PNT compatibility with G.dmt and G.VDSL services.
Particularly, G.PNT and G.VDSL compatibility is addressed in this contribution, since these services may operate in the
same spectral region. The source companies recommend that a "compromise PSD spectral mask" be used for G.PNT.
With the compromise mask, G.PNT – G.VDSL crosstalk is mitigated and RFI interference to/from radio amateurs is
addressed. The maximum PSD level of the compromise mask is -73.5 dBm/Hz in the 4-10 MHz band. The source
companies recommend that this G.PNT mask should not be further compromised to avoid degraded performance on
"challenging", in-premise networks, and to allow for increases in G.PNT data rates in the future beyond a 10 Mbps data
rate. The analyses provided in this contribution summarize the impact on G.PNT and G.VDSL transceiver performance
with several combinations of crosstalk scenarios, in-premise wiring topologies, G.VDSL spectral masks, and VDSL
loop ranges. The results indicate that a solution to the crosstalk issue with overlapping G.PNT – VDSL spectrum could
be close at hand with further work.
Copyright Statement
The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) to incorporate
text contained in this contribution and any modifications thereof in the creation of a TIA standards publication; to
copyright in TIA’s name any TIA standards publication even though it may include portions of this contribution; and at
TIA's sole discretion to permit others to reproduce in whole or in part the resulting TIA standards publication.
1
Texas Instruments Inc.
Dallas, Texas
1
1.
Introduction:
This contribution was previously presented at the ITU-T SG15/Q4 meeting in Nuremberg, Germany on August 2, 1999.
The results provided in this document are essentially the same as the original, except that the G.pnt – VDSL crosstalk
summing models [6] have been updated per the agreement [7] made at the Nuremberg meeting. All analyses provided in
this document are consistent with the analysis models provided in the T1E1.4 spectrum management document [8].
Robust performance of future phoneline network transceivers (G.PNT) is required over a wide range of home wiring
topologies, in the presence of other services attached to the same in-premise wire pair, and in the presence of interferers
outside the customer premises.
Additionally, plug-and-play will be an important G.PNT requirement facilitating widespread deployment of the service.
Requiring that a network isolation filter (NIF) be installed by consumers, or by G.PNT manufacturers, could inhibit
widespread deployment of G.PNT devices in the marketplace. Therefore, the analyses provided in this contribution
mainly focus on G.VDSL – G.PNT compatibility, assuming a NIF is not present at the network interface.
Previous home networking spectral compatibility studies have shown that high speed communications, in bands below
10 MHz, can co-exist with EXISTING services in customer premises, and can also be compatible with G.dmt [1]. For
G.PNT, the source companies recommend the use of a –73.5 dBm/Hz "compromise PSD spectral mask" in the 4-10
MHz band. This G.PNT mask should not be further compromised to avoid degraded performance on "challenging", inpremise networks, and to allow for increases in G.PNT data rates in the future beyond 10 Mbps.
The main objective of this document is to show, through analyses, that both G.PNT and G.VDSL services can co-exist,
and at the same time achieve their respective “required” throughput when G.PNT transmitters conform to this
“compromise” mask. The detailed analyses provided in this contribution aim at providing a foundational body of
information associated with a broad range of deployment scenarios, spectral masks, in-premise wiring topologies to
increase the understanding on how these interact with one another to influence transceiver performance. The data
provided herein, using the compromise PSD mask, suggest that a spectrally compatible solution may be close at hand.
2.
G.PNT – VDSL Spectral Compatibility
G.PNT – xDSL spectral compatibility analysis highlights include a –73.5 dBm/Hz compromise transmit spectral mask,
six fixed VDSL spectral masks, the inclusion of the compromise G.PNT spectral mask into the FSAN model package,
and three of the HomePNA-defined, in-premise test loops. The FSAN modeling package was used as a point of
reference to determine the affect of G.PNT crosstalk on VDSL performance for each of the selected VDSL masks.
Alternately, the affect of VDSL disturbers on G.PNT performance are provided.
2.1
G.PNT Compromise Spectral Mask
To reduce the possibility of interference with other services, particularly VDSL, while maintaining the bandwidth
necessary for robust transmission over a wide range of home wiring topologies, a “compromise” mask is proposed by
the source companies. The compromise mask, shown in Figure-1, has a maximum PSD of –73.5 dBm/Hz in the 4-10
MHz band. Additionally, the compromise mask, used in this analysis, has an 11.5 dB notch between 7.0 and 7.3 MHz to
reduce RFI egress in the amateur radio band. G.PNT mask out-of-band characteristics should be specified through
rigorous analysis and trade-offs in the future.
Additional G.PNT spectral mask compromises are discouraged by the source companies, since further compromises
would affect the viability of G.PNT as a high-performance home networking standard.
The compromise mask is hereafter referred to as PNTMASK.
2
-73.5 dBm/Hz
7.0 - 7.3 MHz
-11.5 dB notch
Figure-1: G.PNT Compromise Mask Passband PSD
2.2 G.PNT – G.VDSL compatibility analysis
Although G.PNT communications are not intended for locations outside the premises, some level of signal is present on
the subscriber loop pair which is attached to the premises wiring. Normally this does not cause a problem – the
proposed G.PNT signal is almost always attenuated below the ambient noise floor before reaching the CO end of the
subscriber loop. However, where the subscriber loop pair is combined with other pair into a cable, the potential exists
for crosstalk into such adjacent pair. In particular, where adjacent pair carry VDSL services, and the downstream
VDSL signal overlaps the G.PNT band – the G.PNT signal may appear as crosstalk in the receiver of the VDSL CPE
modem.
Since the frequency plan for VDSL is not yet established, it is difficult to definitively estimate the impact of G.PNT on
VDSL. The severity and frequency of occurrence of such potential crosstalk is highly dependent on many variables, not
yet accurately captured in deployment models. Further study is required in this area.
Figure-2 illustrates a possible future scenario where one or more homes in a neighborhood subscribe to a G.VDSL
service, while adjacent homes contain two or more G.PNT transceivers, without G.VDSL services. For the purpose of
this contribution, we refer to the transceiver closest to the network interface as the “near” transceiver, and the
transceiver further into the interior as the “far” receiver. Crosstalk analyses employing in-premise test loops, refer to
these transceivers at either end.
G.PNT
stations
VDSL
Modem
no splitter
Near xcvr
Far xcvr
VDSL upstream
& downstream
G.PNT
XTalk
VDSL
XTalk
G.PNT
signals
coupling in binder
Figure-2: Crosstalk between G.VDSL and G.PNT Near/Far Receivers
3
This report does not address G.PNT FEXT interference into G.VDSL at the CO. For short range VDSL loops, the
VDSL CPE modem has the option to operate in the power backoff mode. This is another case for further study. In the
power backoff mode, VDSL NEXT into G.PNT will be reduced significantly. However, G.PNT FEXT into VDSL at
the CO should be considered at the same time. The G.PNT FEXT into VDSL should be the subject of a future study.
2.2.1
FSAN simulation environment including the compromise G.PNT mask
The objective of the simulation tool is to concentrate the FSAN results into one simulation package to facilitate
evaluation of VDSL proposals and scenarios. The FSAN modeling package was used as a point of reference as an
evaluation tool for this contribution, since this comprehensive modeling facility is publicly available for crosstalk
analyses, and the results using this package will be consistent with other contributors studies. The FSAN simulation tool
is aimed at supporting the evolving standardization process of VDSL.
A number of scenarios (specific topologies and traffic patterns) are implemented and the FSAN noise models are
directly available in this tool. Besides the predefined FSAN scenarios and models, it is possible for the user to define
their own scenarios, noise models, various noise levels, and spectral masks. As part of the background effort for this
contribution, we incorporated the PNTMASK. Another advantage of the FSAN model is that the tool is line code
independent. Users may input estimates on efficiency loss corresponding to, e.g., cyclic extension (DMT) or excess
bandwidth (SCM) which then can be taken into account by the tool.
Simulation conditions:
The G.VDSL and the G.PNT channels are assumed to be Gaussian channels. The maximum bit rates are obtained from
the Shannon capacity expression [3] for Gaussian channels:
Bits = 0.5 * log2(1+SNReff) bits/transmission,
where, SNReff = 10^(minimum(SNRtot, SNRmax)/10) in magnitude
SNRtot = SNRrecv – SNRgap – margin in dB
SNRrecv = Received SNR in dB
G.VDSL:
 5 dB noise margin, 9.8 dB SNRgap, SNRmax = 45 dB (this corresponds to about maximum of 15 bits/transmission)
 Background additive white Gaussian noise (AWGN) of –140 dBm/Hz assumed in all simulations
 Two cases of VDSL self-interferers: 0 and 5
 0, 1, 5, and 49 (or 44) G.PNT disturbers
 VDSL loop lengths of 300m (short), 900m (medium), 1200 m (long), and 4500 ft. (long)
 Efficiency loss=0
 Crosstalk summing models as per [9]
G.PNT:
 0 dB noise margin, 9.8 dB SNRgap, SNRmax = 45 dB (this corresponds to about maximum of 15 bits/transmission)
 Background additive white Gaussian noise (AWGN) of –140 dBm/Hz assumed in all simulations
 Two cases of G.PNT self-interferers: 0 and 5
 0, 1, 5, and 49 (or 44) VDSL disturbers
 Disturber VDSL loop lengths of 300m (short) and 900m (medium)
 G.PNT test loops as shown in the Appendix A
 Efficiency loss=0
Three spectral masks were selected from the FSAN package, and three additional spectral masks were added. These are
all shown in Appendix B. The existing ETSI FSAN masks used in the simulation are as follows:
1. VDSL-FDD
2. VDSL-FDD-Z-sym-FTTCab
3. VDSL-FDD-Z-s2a-FTTCab
The first mask, VDSL-FDD, supports symmetric transmission with it’s upstream band coincident with the G.PNT band.
The second mask, VDSL-FDD-Z-sym-FTTCab, also supports symmetric transmission; however, portions of it’s
4
upstream and downstream bands overlap the 4-10 MHz G.PNT passband. VDSL-FDD-Z-s2a-FTTCab supports
asymmetric transmission, and has portions of it’s upstream and downstream band overlapping G.PNT.
Two “user defined” masks were used in the simulations:
4. VDSL-FDD-sym-NA2
5. VDSL-FDD-asym-NA2
Finally, the VDSL-FDD “power backoff” mask:
6. VDSL-FDD-Up-80dBm/Hz
These latter three spectral masks tend to have less crosstalk impact on G.PNT than the first set of masks. The VDSLFDD-sym-NA2 mask supports symmetric transmission and has about ½ of it’s downstream band in the G.PNT band and
no upstream overlap. VDSL-FDD-asym-NA2 supports asymmetric transmission, with downstream overlapping G.PNT.
Finally, the structure of VDSL-FDD-Up-80dBm/Hz is identical to VDSL-FDD; however; the upstream band is
attenuated by 20 dB in order to allow studies to determine the performance G.PNT in the presence of reduced VDSL
NEXT (such as a power backoff mode), and to also determine if VDSL can sustain adequate performance in this
situation.
A 20 dB notch at HAM band frequencies was included in all six VDSL transmit masks.
Table-1 provides the G.VDSL bitrates per the T1E1.4 VDSL requirements specification [4]. Then, it is assumed that
there is no impact due to G.PNT crosstalk into VDSL as long as the required throughput is maintained as specified in
the table.
Table-1: Required G.VDSL Downstream/Upstream Bitrates
Loop Type/Range
Short symmetric (304.8 m/1000 ft.)
Short asymmetric (304.8 m/1000 ft.)
Medium symmetric (914.4 m/3000 ft.)
Medium asymmetric (914.4 m/3000 ft.)
Long symmetric (1371.6 m/4500 ft.)
Long asymmetric (1371.6 m/4500 ft.)
2.2.2
Downstream Bitrate
26.0 Mbps
52.0 Mbps
13.0 Mbps
26.0 Mbps
6.0 Mbps
13.0 Mbps
Upstream Bitrate
26.0 Mbps
6.4 Mbps
13.0 Mbps
3.2 Mbps
6.0 Mbps
1.6 Mbps
G.PNT crosstalk into G.VDSL
As a practical worst case for this analysis, the source companies have assumed that the G.PNT signal PSD exiting the
premise wiring, and prior to entering the binder cable external to the customer premises, is reduced by 3 dBm/Hz. This
can be justified, since there will be a 3 dBm/Hz loss due the power dissipated in one or more G.PNT transceivers
connected to the in-premise wiring. Then, also, there will be a much greater power reduction when G.PNT transmitters
are located further away from the network interface towards the interior of the home.
Table-2 and Table-3 summarize G.VDSL performance for each of the six VDSL spectral masks for short, medium, and
long range loops and in the presence of 0, 1, 5, and 49 G.PNT disturbers. A 5dB margin is maintained in each case. As
shown in Table-2, medium range VDSL loops appear susceptible in the case of the Sym-NA2 and Asym-NA2 masks.
Also, for the same spectral masks, performance on the long range loops is degraded somewhat; although the NA2 masks
do not appear to support the required VDSL performance even without interferers for long range loops.
Table-2: VDSL performance in the presence of G.PNT disturbers and the
absence of self-interferers using FSAN models for VDSL PSD masks
5
VDSL
Loop
Range
Short
(300m)
S: 26/26
A: 52/6.4
Medium
(900 m)
S: 13/13
A: 26/3.2
Long
(1200m)
S: 6.4/6.4
A: 6.4/2.1
Long
(4500 ft.)
S: 6/6
A: 13/1.6
# of
G.PNT
Distur
bers
0
1
5
49
0
1
5
49
0
1
5
49
0
1
5
49
Maximum VDSL Downstream/Upstream Rates (in Mbps)
(0, 1, 5, 49 G.PNT disturbers; 0 G.VDSL disturbers; 1% worst case; 5dB margin)
FDD
Z-sym
Z-s2a
Sym-NA2
Asym-NA2
Up-80 FDD
(Sym)
(Sym)
(Sym)
(Sym)
(Asym)
(Sym)
47.33/105.5 66.01/90.04
70.29/85.76
57.06/75.42
114.5/15.11
47.33/61.76
47.32/89.83 43.82/81.70 50.12/76.85
45.53/75.15
72.09/15.11
47.33/44.30
47.32/82.33 39.57/78.11
46.35/72.82
42.30/75.12
64.04/15.11
47.33/37.14
47.32/70.96 33.69/72.65
41.15/66.69
37.73/75.11
52.96/15.11
47.33/27.16
34.90/14.38 29.77/21.07
34.01/16.83
26.21/17.58
32.12/14.63
34.90/1.33
34.90/14.35 18.65/21.07
24.81/16.83
12.95/17.58
15.20/14.63
34.90/1.32
34.90/14.30 18.41/21.07
24.66/16.83
12.26/17.58
14.74/14.63
34.90/1.31
34.90/14.08 18.29/21.06
24.59/16.74
11.84/17.58
14.49/14.63
34.90/1.26
24.68/1.39
16.84/10.75
20.32/7.28
9.73/14.13
10.15/12.76
24.684/0.05
24.68/1.39
15.51/10.75
19.46/7.28
6.51/14.13
7.93/12.76
24.684/0.05
24.68/1.39
15.50/10.75
19.46/7.28
6.49/14.13
7.91/12.76
24.684/0.05
24.68/1.39
15.50/10.75
19.46/7.27
6.48/14.13
7.91/12.76
24.684/0.05
19.15/0.21
13.92/6.96
16.59/4.29
4.59/12.05
5.10/11.15
19.15/0.01
19.15/0.21
13.71/6.96
16.48/4.29
3.90/12.05
4.71/11.15
19.15/0.01
19.15/0.21
13.71/6.96
16.48/4.29
3.90/12.05
4.71/11.15
19.15/0.01
19.15/0.21
13.71/6.96
16.48/4.29
3.90/12.05
4.71/11.15
19.15/0.01
Table-3 results are similar. The main difference is that 5 VDSL disturbers are assumed in the binder group in addition
to the G.PNT disturbers. Table-3 also illustrates that the degradation due to G.PNT NEXT for NA2 medium range
loops is exacerbated in the presence of simultaneous VDSL NEXT.
Table-3: VDSL Performance in the Presence of G.PNT Disturbers and 5 VDSL
self-interferers using FSAN Models for VDSL PSD masks
VDSL
Loop
Range
Short
(300m)
S: 26/26
A: 52/6.4
Medium
(900 m)
S: 13/13
A: 26/3.2
Long
(1200m)
S: 6.4/6.4
A: 6.4/2.1
Long
(4500 ft.)
S: 6/6
A: 13/1.6
2.2.3
# of
G.PNT
Disturb
ers
0
1
5
44
0
1
5
44
0
1
5
44
0
1
5
44
Maximum VDSL Downstream/Upstream Rates (in Mbps)
(0, 1, 5, 49 G.PNT disturbers; 5 G.vdsl disturbers; 1% worst case; 5dB margin)
FDD
Z-sym
Z-s2a
Sym-NA2
Asym-NA2
Up-80 FDD
(sym)
(sym)
(sym)
(sym)
(asym)
(sym)
29.70/38.78
32.49/37.45
36.23/33.71
25.95/28.26 45.58/10.24
29.70/37.71
29.70/38.78
31.32/37.45
35.14/33.71
25.76/28.17 43.94/10.24
29.70/35.25
29.70/38.77
30.00/37.44
33.93/33.71
25.47/28.16 42.00/10.24
29.70/30.84
29.70/38.68
26.85/37.41
31.08/33.67
24.44/28.15 37.09/10.24
29.70/22.54
23.75/11.92
21.55/15.35
24.36/12.53
16.38/10.32
22.66/ 8.26
23.75/ 1.31
23.75/11.92
12.78/15.35
16.98/12.53
8.11/10.32
9.88/ 8.26
23.75/ 1.31
23.75/11.92
12.53/15.35
16.83/12.53
7.44/10.32
9.42/ 8.26
23.75/ 1.30
23.75/11.90
12.41/15.35
16.76/12.53
7.04/10.32
9.18/ 8.26
23.75/ 1.25
19.56/ 1.35
12.89/ 9.24
15.72/ 6.41
8.11/ 8.79
8.72/ 7.79
19.56/ 0.05
19.56/ 1.35
11.62/ 9.24
14.91/ 6.41
5.17/ 8.79
6.60/ 7.79
19.56/ 0.05
19.56/ 1.35
11.61/ 9.24
14.90/ 6.41
5.14/ 8.79
6.59/ 7.79
19.56/ 0.05
19.56/ 1.35
11.61/ 9.24
14.90/ 6.41
5.13/ 8.79
6.58/ 7.79
19.56/ 0.05
16.07/ 0.21
11.21/ 6.28
13.62/ 3.87
4.18/ 8.26
4.72/ 7.51
16.07/ 0.01
16.07/ 0.21
11.01/ 6.28
13.52/ 3.87
3.52/ 8.26
4.34/ 7.51
16.07/ 0.01
16.07/ 0.21
11.01/ 6.28
13.51/ 3.87
3.51/ 8.26
4.34/ 7.51
16.07/ 0.01
16.07/ 0.21
11.01/ 6.28
13.51/ 3.87
3.51/ 8.26
4.34/ 7.51
16.07/ 0.01
G.VDSL crosstalk into G.PNT
Table-4 provides maximum G.PNT bitrates with no G.VDSL and no G.PNT Disturbers (near = transceiver close to the
network interface; far = transceiver attached to the other end of the test loop located further into the premise interior ).
6
This illustrates the potential performance of the home phoneline network transceivers in the absence of any FEXT or
NEXT outside the home.
Table-4: Maximum G.PNT bit rates over in-premise test loops
Test Loop
1 (A.1)
Maximum G.PNT receive rates
in Mbps using fixed –73.5
dBm/Hz compromise transmit
mask; 0 dB margin, no VDSL
disturbers, no framing/preamble
overhead
(near/far)
89.25/89.25 Mbps
2 (A.2)
85.89/85.89 Mbps
3 (A.3)
73.21/73.21 Mbps
Table-5 and Table-6 provide G.PNT throughput estimates at the “near” transceiver and at the “far” transceiver in the
presence of 1, 5, and 49 VDSL interferers, for each of the G.PNT test loops (see Appendix A). Table-5 provides results
for a VDSL 300 meter short range loop (900 meter medium range loop for Table-6). As shown in both tables, VDSL
transceivers using the “VDSL-FDD” mask have most impact on G.PNT performance, since VDSL-FDD upstream
totally overlaps the G.PNT transmission band. The increase in bitrates between Table-5 and Table-6 is associated with
the reduced VDSL FEXT into G.PNT when the loop range is increased from 300 m to 900 m. In all cases, except for
the VDSL-FDD spectral mask, good performance is achieved by G.PNT transceivers.
Table-5: G.PNT performance in the presence of VDSL disturbers and absence of selfinterferers using FSAN models for VDSL PSD masks, and short range VDSL loop
Test
Loop
# of
VDSL
Disturb
ers
1
1
5
49
1
5
49
1
5
49
2
3
Maximum G.PNT near/far transceiver receive rates in Mbps using fixed –73.5 dBm/Hz
compromise transmit mask; G.PNT test loops; 1% worst case; 0 dB margin; 1, 5, 49
VDSL disturbers; 0 G.PNT disturbers; VDSL loop range fixed at 300m
FDD
Z-sym
Z-s2a
Sym-NA2
Asym-NA2
Up-80 FDD
13.84/29.71
8.34/21.92
3.33/12.11
9.59/29.84
5.38/22.06
2.02/12.26
6.86/29.55
4.14/21.82
1.72/12.06
23.71/39.98
17.48/32.09
10.34/21.69
18.61/40.03
13.15/32.19
7.15/21.83
15.42/39.67
11.27/31.92
6.37/21.61
22.78/39.02
16.59/31.14
9.62/20.79
17.71/39.08
12.34/31.24
6.61/20.92
14.48/38.71
10.37/30.97
5.60/20.71
7
64.22/70.03
61.19/66.84
57.32/62.44
58.92/68.08
56.34/64.90
53.28/60.50
47.50/56.02
44.88/52.83
41.57/48.45
30.42/47.76
22.80/49.71
13.28/28.48
24.37/47.67
17.38/39.67
9.46/28.47
15.96/46.10
11.11/38.67
6.18/27.79
50.23/68.06
41.98/60.00
30.44/48.31
43.70/67.39
35.53/59.79
24.32/48.36
32.46/63.10
25.30/57.30
16.57/47.37
Table-6: G.PNT performance in the presence of VDSL disturbers and absence of selfinterferers using FSAN models for VDSL PSD masks, and medium range VDSL loop
Test
Loop
# of
VDSL
Disturb
ers
1
1
5
49
1
5
49
1
5
49
2
3
Maximum G.PNT near/far transceiver receive rates in Mbps using fixed –73.5
dBm/Hz compromise transmit mask; G.PNT test loops; 1% worst case; 0 dB
margin; 1, 5, 49 VDSL disturbers; 0 G.PNT disturbers; VDSL loop range fixed at
900m
FDD
Z-sym
Z-s2a
Sym-NA2
Asym-NA2 Up-80 FDD
13.85/29.72
8.34/21.92
3.33/12.12
9.59/29.85
5.38/22.06
2.03/12.26
6.87/29.56
4.15/21.83
1.73/12.06
28.55/44.76
22.27/36.92
14.86/26.53
23.35/44.68
17.72/36.96
11.14/26.64
20.12/44.24
15.75/36.65
10.12/26.40
27.07/43.25
20.84/35.42
13.63/25.07
21.91/43.18
16.37/35.47
10.09/25.19
18.64/42.74
14.30/35.15
8.83/24.95
67.78/73.69
64.58/70.47
60.09/65.93
62.19/71.71
59.18/68.52
55.16/63.99
50.74/59.64
47.70/56.45
43.56/51.94
39.45/56.89
31.50/48.87
20.76/37.46
33.06/56.66
25.39/48.77
15.59/37.43
22.79/53.83
16.72/47.08
9.95/36.53
50.23/68.06
41.98/60.00
30.44/48.32
43.70/67.39
35.53/59.79
24.32/48.36
32.46/63.10
25.30/57.30
16.57/47.37
It is observed that G.PNT transceiver performance, in the presence of VDSL interferers, is best in the NA2 spectral
mask cases. However, the NA2 loops do not meet the minimum VDSL throughput requirements for long loops.
The Z sym and Z s2a masks support VDSL operation within the VDSL requirements specified rates, in the presence of
G.PNT interferers. However, G.PNT performance is lower in the presence of VDSL Z sym and s2a crosstalkers, than
when the NA2 spectral masks are used for VDSL. This decrease in relative G.PNT performance is due to the increased
VDSL upstream NEXT into the G.PNT band when Z sym and Z s2a masks are employed.
3.
Conclusions:
The source companies recommend adoption of the following points:
1) Spectrum choices for future home phoneline networking transceivers (G.PNT) starting above 10 MHz would not
result in robust operation. Based on the analysis in [5], the source companies strongly recommend that the G.PNT
transceiver operate below 10 MHz.
2) A compromise spectrum band (-73.5 dBm/Hz maximum, 4 MHz-10 MHz) should be chosen for the basis of
development of G.PNT
3) Spectrum compatibility should be considered with G.VDSL frequency plans that have either
a) no overlap,
b) have some overlap, but allow G.PNT and G.VDSL to simultaneously achieve their respective throughput
requirements
4) The compromise spectrum mask should address interference from/to radio amateurs.
5) That G.PNT should be spectrally compatible with EXISTING services distributed on in-premises wiring (POTS,
ISDN, G.992.2/G.lite).
The source companies recommend further study on the following
6) Analyze and specify the G.PNT out-of-band characteristics. Complexity, transceiver performance, and spectral
compatibility should be considered.
4.
Summary
Open Issue
Open Issue
Should the spectrum band for PNT devices be defined as –73.5 dBm/Hz maximum
with limits at 4 to 10 MHz
Should the G.PNT out of band characteristics be analyzed and the complexity,
transceiver performance, and spectral compatibility be considered.
5. References
8
[1]
ITU-T Temporary Document MA-055, Q4/15, G.gen: HomePNA 1.0 Spectral Compatibility, Australia 29
March – 2 April 1999
[2]
T1E1.4/99-120, Coexistence of 1 Mbps HPNA and DMT VDSL via Multiuser Detection and Code Division
Multiplexing, March 8, 1999
[3]
R.G. Gallager, “Information Theory and Reliable Communication,” New York: Wiley, 1968
[4] T1E1.4/98-043R6, Very-high speed Digital Subscriber Lines – System Requirements Draft Technical Document
[5]
ITU-T Temporary Document NG-101, Q4/15, G.PNT: Spectrum selection for home phoneline selection for
home phoneline networking, Nuremberg, Germany 2 –6 August 1999
[6]
ITU-T Temporary Document NG-102, Q4/15, G.PNT: Spectrum compatibility of home phoneline network
transceivers (G.pnt) with xDSL and other existing in-home services, Nuremberg, Germany 2 –6 August 1999
[7]
ITU-T Temporary Document NG-118R1, Q4/15, G.PNT: G.pnt: Ad hoc group report, Nuremberg, Germany 2 –
6 August 1999
[8]
ANSI T1E1.4/99-002R4, Spectrum Management for Loop Transmission Systems
[9]
TIA TR30.1/99-08-025, Crosstalk analysis models, G.pnt PSD spectral mask, and G.pnt test loops for G.pnt
compatibility analyses, Quebec City, Quebec, 19 August 1999.
9
Appendix A: HomePNA test loops
A.1 Test Loop-1
Figure A-1:Test Loop#1
A.2 Test Loop-2
Figure A-2:Test Loop#2
10
A.3 Test Loop-3
Figure A-3:Test Loop#3
11
Appendix B: VDSL Spectral Masks
In order to minimize the combinations considered in this contribution, we have selected five FSAN VDSL masks to
focus the analysis. The selected masks should broadly represent the possible mask combinations of interest.
B.1 VDSL-FDD-with-ITU-HAMBAND
B.2 VDSL-FDD-Z-sym-FTTCab-with-ITU-HAMBAND
B.3 VDSL-FDD-Z-s2a-FTTCab-with-ITU-HAMBAND
12
B.4 VDSL-FDD-sym-NA2-with-ITU-HAMBAND
B.5 VDSL-FDD-asym-NA2-with-ITU-HAMBAND
B.6 VDSL-FDD-Up-80dBm/Hz- with-ITU-HAMBAND
13