Broad band Transmission over Residential Power Lines ...
Transcript of Broad band Transmission over Residential Power Lines ...
International Journal of Science and Modern Engineering (IJISME)
ISSN: 2319-6386, Volume-1 Issue-12, November, 2013
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Abstract: Bridging and Transmission of VDSL2 broadband over
power lines has received considerable attention recently to cater
to broadband distribution within the premises of a residence.
Power lines are fundamentally different from telephone lines
both in topology and load impedance. Power lines have a thicker
gauge and shorter straight lengths, apart from a large number of
bridge taps (BT) with inductive load terminations, which are not
matched to line impedances. In this paper ABCD parameters of
the individual sections are used to analyze the power line
channel of upto 10 bridge taps over a 600 meter length. The
noise profiles considered include periodic impulse noise which is
predominant over power line sections, apart from AWGN.
Impulse noise PSD has been computed.Tone loading profiles
have been obtained using Discrete Multitone Transmission
(DMT) as in VDSL2 over a bandwidth of 30 MHz. This analysis
points to the fact that lower Transmit PSD would suffice to
match the rates achievable by traditional VDSL2 when bridge
taps are open. However with inductive loads in the BTs as is
typical in residences, we recommend a two-step approach of (a)
equipping existing VDSL2 modem front end hybrids with
settable impedances that would approach a conjugate match of
the loaded line along with (b) capability to nominally increase
the Transmit PSD and added subbands to achieve the desired
rates in a seamless manner as in VDSL2.
Index Terms: channel modelling, discrete multitone, Power
line communication
I. INTRODUCTION
Traditional twisted pair copper already laid for plain old
telephone system supports last mile wired access with the
evolution of ADSL2 and VDSL2 standards. Distribution of
broadband over the last mile (local area) and last feet (in
premises) has received considerable attention recently and is
becoming as indispensable as access to electrical power.
There has been a growing interest in the possibility of
exploiting the power grid to provide broadband internet
access to residential customers [1]. The attractive feature is
the presence of a vast infrastructure in place for power
distribution.
Manuscript Received on November 2013.
Mrs.Usha Rani .K .R, Associate Professor, Dept. of ECE, R.V.College of
Engineering, Bangalore, Karnataka, India
Dr. S Ravi Shankar, Professor, Dept. of ECE, R.V.College of Engineering,
Bangalore, Karnataka, India
H.M.Mahesh, Professor, Department of Electronics, Bangalore University,
Bangalore, Karnataka, India
Nandan Nayak, Student, R.V.College of Engg.,Bangalore, Karnataka,India
Vijay Singh, NRB, R.V.College of Engg.,Bangalore, Karnataka,India.
Since 2006 power line standards have begun to evolve that
address the capability of power line network to distribute
broadband within a substation area and within the premises
of a house. The advantages are (a) economy of house cabling
(b) broadband access at all power points in a house and (c)
guaranteed rates unlike in WLAN where there is a loss of rate
due to shadowing effects, externally induced RF
interferences and concerns about long term effects of
Electromagnetic radiation.
The power line poses unique challenges in channel modeling
that have only been partially addressed in literature [5-11].
Apart from a thicker gauge (typically 14 AWG) the power
lines are fundamentally shorter in length (as compared to
telephone lines) but have a large number of parallel bridge
taps with predominantly inductive load terminations that are
often switched in and out of circuit rendering the channel to
be slow time varying frequency dependant. Further unlike
telephone lines that are terminated by modem analog front
ends that meet low, medium and long line length
impedances, power lines are never terminated with anything
that is even close to its characteristic impedance. Top-down
models for PLC channel transfer function employ a time
domain approach as proposed by Zimmermann and Dostert
[8], as well as by Philipps [9]. Bottom-up PLC channel
models use matrix representation for transfer functions
derived from transmission line theory as obtained by S. Galli
[1], H. Meng [7] and Huangqiang Li, Yunlian Sun [10].
However existing literature [20 - 22] on the data rates
achievable for typical in house PLC do not include the
presence of the dominant impulse noise, effect of loads being
switched in and out and consider a well defined Transmit
PSD. Further no recommendations to improve the data rates
are provided. In this paper we address the issue of data rates
achievable over Power line Carrier (PLC) for Discrete
Multitone (DMT) based line codes in the presence of impulse
noise and with inductive unmatched loads at BT
terminations. In an effort to reuse the signal processing tasks
of a DSL modem, we examine the Transmit PSD masks
employed in VDSL2 for Non-echo cancelled Frequency
division multiplex over typical PLC channel models. We
present the received signal to noise ratio (SNR) profiles of
typical PLC considering AWGN and impulse noise which is
predominant over power lines [17]. Rate adaptive tone
loading profiles have been presented with and without
impulse noise cases for loops upto 600 meters with upto ten
bridge taps when they are
shorted, open and terminated
with typical inductive loads.
When the bridge taps are open
Broad band Transmission over Residential
Power Lines Employing VDSL2: The Channel
Capacity Analysis
Usha Rani K R , Ravishankar S , H.M.Mahesh , Nandan Nayak, Vijay Singh
Broad band Transmission over Residential Power Lines Employing VDSL2: The Channel Capacity Analysis
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or short there is enough usable SNR available to meet rates of
80 Mbps or so the Transmit PSD can be reduced in such
cases. However, with inductive impedances present at the
bridge tap terminations there is a need to provide
approximate conjugate impedance to the line impedance seen
by the modem, so as to meet the required rates. It is
recommended that the modem be equipped with switchable
impedances in its hybrid arm to reasonably approach the
actual conjugate impedance as seen by the modem. The
constantly changing transfer function of the PLC due to the
load impedances getting switched in and out of BTs may be
managed by monitoring the SNRs in the sync frame for a
sudden drop, and initiate a seamless change in the rate like
the Quick rate adaptation scheme of VDSL2 by altering the
hybrid impedance on the fly. The paper is organized as
follows - In section II the transfer function of PLC models
have been developed based on the two-port network theory.
The channel capacities for different network topologies, with
impulse noise, unmatched load conditions employing DMT
are analyzed in section III, and Simulation results for
different topologies are presented in section IV.
II. POWER LINE MODELLING
Power lines were originally designed for transmission of
power at 50Hz. Unshielded power line has a very hostile
channel characteristic for high frequency signal propagation
up to 30 MHz needed for broadband distribution within a
house. There are two methods of modeling viz; the top-down
method and bottom-up method. In the Top-down method,
model parameters are obtained from measurements [5].
Accuracy of this model is affected by measurement
equipment and measurement methods. In this paper we use
the bottom-up approach to analyze the indoor power line
theoretically [2, 6]. In the bottom-up method the indoor
power line is modeled as a cascade of two-port networks with
„n‟ distributed elements, each one with system characteristics
described by either transmission or scattering matrices [7].
The main advantage of matrix representation is that it
intrinsically considers all the impedance discontinuities,
regardless of the network complexity [10]. In the following
subsections we describe the propagation parameters followed
by the analysis.
A. Power line parameters:
The live and neutral cables can be used as a PLC two-wire
transmission channel and regarded as a distributed
parameter network. Hence, it can be described by circuit
parameters that are distributed over its length viz; inductance,
capacitance, resistance and conductance given by [14]
f
aR
2
(1)
(2)
a
dC
1cosh
(3)
tan2 fCG (4)
Where „a‟ and „d‟ are the diameter and separation distance of
the power lines respectively. Here „µ‟ is permeability in free
space, „‟ its permittivity in free space, „σ‟ the conductivity
of conductor, and „δ‟ is the depth factor. Based on
transmission line theory, the propagation constant „γ‟ is [14]
22
2
22
2
81
81
2 L
RLCj
L
R
L
CR
(5)
Here „ω‟ is the angular frequency. Attenuation is the Real
part „α‟ of the propagation constant and the imaginary part
„β‟ is the phase constant.
A uniform transmission line can be modeled as a two- port
network. ABCD parameters are useful for characterizing
two-port networks shown in Fig 1.
Figure 1: Two-port model of power line
The transfer function of the network is given by [16]
BAZ
Z
v
vfH
L
L
1
2
(6)
The parameters A and B are elements of the transfer
matrix T described in the following sub-section.
B. Channel model:
Indoor power line network consists of a main (straight)
propagation path and multiple distribution paths (bridge
taps). The transfer matrix of main propagation Ts (straight
path) is [13]
f
R
a
dL
2cosh 1
International Journal of Science and Modern Engineering (IJISME)
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)cosh()sinh(
1
)sinh()cosh( o
linelineo
lineline
llZ
γlZγl
Ts
(7)
Where „lline‟ is the length of the line and γ is its propagation
constant.
The transfer matrix of distribution branch Td is [13]
dZ
TDC
BA
tapin
1
101
_ (8)
For a BT line with an open end the
)coth(_ tapZZ l
otapin
Where „ltap‟ is the length of the tap.
And for a BT line terminated with an inductive load the tap
input impedance is
)1(coshsinh
)1(sinhcosh
_
oR
oR
o
tap
o
tap
oR
oRtaptap
tapin
ZZ
ZZ
Z
l
Z
l
ZZ
ZZll
Z
C. Model analysis:
PLC employs thicker cables, AWG12 and AWG14 that
have far less attenuation compared to telephone cables.
However because of a significant number of the bridge taps
inside the house, there is an additional attenuation in power
cables. The topologies of indoor power lines considered for
analysis are shown in Figure 2. We compute the frequency
dependent transfer functions using the method described in
section B above. Specifically
1. Compute the ABCD parameters Ts and Td using
equations (7) & (8) respectively for 14AWG Power
cable for both cases with open bridge taps i.e ZL =
Infinity.
2. Repeat the same as in step 1 with an inductive load of
600mH that is typical in Fans and machines inside a
house.
3. Obtain the transfer function H(f) for cases 1 and 2 .
Figure 2: Indoor power line network topologies
The frequency dependent normalized transfer functions
20log are shown in Figures 3 to 6 for the loops shown
in Figure2. Note the presence of a dip in Figures 4 - 6 is due
to the presence of a bridge taps in loops 2 – 4, that act as
tuned LC circuit.
0 0.5 1 1.5 2 2.5 3
x 107
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
frequency
Tran
sfer
func
tion
H(f)
DB
simulated channel frequency response
Figure 3: Frequency response of loop 1]
0 0.5 1 1.5 2 2.5 3
x 107
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Tra
nsfe
r fu
nctio
n H
(f)D
B
frequency
Figure 4: Frequency response of loop 2
0 0.5 1 1.5 2 2.5 3 3.5
x 107
-1000
-800
-600
-400
-200
0
200
Tran
sfer
func
tion
H(f)D
B
frequency
simulated channel frequency response
Figure 5: Frequency response of loop 3 with BT open.
Broad band Transmission over Residential Power Lines Employing VDSL2: The Channel Capacity Analysis
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0 0.5 1 1.5 2 2.5 3 3.5
x 107
-3000
-2500
-2000
-1500
-1000
-500
0
Tra
nsfe
r fu
nction H
(f)D
B w
ith inductive load
frequency
simulated channel frequency response
Figure 6: Frequency response of loop 3 with
an inductive loaded BT.
III. ANALYSIS OF POWER LINE
CHANNEL CAPACITY IN THE
PRESENCE OF PERIODIC IMPULSIVE
When computing the channel capacity, the transmit
Power spectral density up to 30 MHz as per the VDSL2
standard G993.2 [12] is employed. Energy and bits in every
tone are allocated adaptively according to the channel
characteristics. The classification and characterization of
impulse noise over PLC networks has been reported by
Zimmermann [19] and Degardin et al in [20]. Periodic
impulse noise is predominant in power lines due to inductive
loads being switching in and out at the bridge tap
terminations. Measurements made on fifty kinds of
appliances shows that 95% of these appliances generate
periodic impulse noise [17]. The switching operations of
these appliances generate high di/dt and dv/dt and creates
conducted and radiated disturbance. This noise takes the
form of impulse train. The delay between two successive
impulses is in the range of 5μs to 100 μs. The pulse is
approximated by the sum of damped sinusoids [17] shown in
equation 9 below. The parameters of the damped sinusoids
are estimated from the measurement using genetic
algorithms [23] for 14 gauge is provided in the table below
(9)
Where A1,A2,:Amplitude, ω1,ω2: pulsation, α1 α2,:Damping
ratio.
A1 0.058
A2 0.01
ω1 2π*11*10^6 rad/s
ω2 2π*26*10 ^6 rad/s
α1 5*10^6
α2 2*10^6.
The Power spectrum of periodic impulse noise may now be
obtained and is shown in Fig 7. This PSD used as the noise
component in further computations along with AWGN
0 5 10 15 20 25-18
-16
-14
-12
-10
-8
-6
-4
Frequency (MHz)
Pow
er/
frequency (
dB
/Hz)
Power Spectral Density
Figure 7: Impulse noise PSD
In [24] the effect of impulse noise was analyzed on the
channel capacity by corrupting few tones in a frame. In this
paper impulse noise PSD has been obtained.
The SNR at the receiver is computed from
2))(())((
)()( fH
AWGNfsepowerimpulseNoi
fwerTxSignalpofSNR
(10)
SNR from equation 10 is obtained for the loops described in
Fig 2 using the transfer function H(f) given in the equation
(6). Upstream (US) SNR plots along with transmitted signal
PSD for both cases; without and with impulse noise are
shown in the fig.10 and figure11 for the two loops.
Downstream (DS) SNR plots without and with impulse noise
for the two loops are shown in figure.12 and 13. The tone
loading is obtained from these SNRs using a modified
version of Shannon‟s theorem
]1[log)( 2
i
iiSNR
roundbroundb
(11)
Here SNRi is the SNR in the ith tone whose center
frequency is i*4.3125 KHz, and the gap factor
τ=9.8+6=14.8db. The value of 9.8 assures that a bit error rate
(BER) of 10^-7 would be met in the channel along with a 6db
degradation margin [16].Water filling of energy across all
the tones ensures that the total energy does not exceed the
standards specified limit of +21dbm across all usable tones.
Fine gains across all tones ensure that the surplus energies
are redistributed among the tones.
With the DMT symbol rate is kept at 4000 symbols/sec as
for DSL the total channel capacity can now be obtained by
summing the bits loaded in each sub-channel considering the
usable tones in the up-stream and down-stream transmitted
signal PSD. Channel capacity is given by
bpsbC
i
i )4000)(( (12)
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IV. RESULTS AND DISCUSSIONS
Modems supporting VDSL2 for telephone lines may be
reused with changes in the analog hybrid section only.
Simulations were performed to compute the line rates for the
various loops using the Transmit spectral density of VDSL2
standard [12] for US and DS under different load conditions
described below.
(a) Loops with single open BT, five open BTs and ten
open BTs.
(b) More realistic cases of loops with BTs terminated by
typical inductive loads of 600mH.
(c) SNR computations and bit loading pattern for the
loops shown in figure 2 were performed using
equations 9 to 11.
The results for various cases are presented in the
following order
1. As a reference, the US and DS capacities for a plain
loop (fig 2a) are shown in Table 1.
2. For loop2 with open bridge tap, the SNR profiles are
shown in figures 10 and 12 for US and DS.
3. The SNR profiles in the US and DS bands for loop 3
with all BTs open are shown in figures 11 and 13.
The resonance effect of the bridge tap degrades the
SNR, which gets further reduced due to the addition
of impulse noise.
4. Using the bit loading profiles the channel capacities
were computed as above, and shown in table 1 for all
the three loops with open ended terminations at the
bridge taps. An observation is that, SNR is high
enough to support non zero bit loading over a portion
of the stop bands corresponding to US and DS bands.
In this case the gain value for the stop band would be
set to zero to ensure no energy is transmitted in that
band.
We now examine the practical case of loops with bridge
taps that are terminated by inductive loads as found in
residences.
5. As a first example consider the BT in loop 2 (fig 2b)
to be terminated in an inductive load of 600mH and
with impulse noise. The US and DS SNR profiles
obtained are shown in figures 14 and 15.
6. Bit-loading profile for loop 2 US and DS with
inductive load and impulse noise with conjugate and
new PSD are shown in the figure 20 and 21.
7. In the case of loop 3 and 4 (figs 2c, 2d), when the BTs
are terminated in inductive loads of 600mH, the US
and DS SNRs are too low to support any positive tone
loading as shown in column 2 of Table 4. This is
primarily due to impedance mismatch since the
modem is not matched to the new line impedance.
To overcome this we need to ensure that the modems have
switchable impedances in their hybrids to closely match a
variety of line impedances with inductive loads terminated in
their BTs. The hybrid impedances could be switched in based
on a rapid SNR computation done in VDSL2 „Quick rate
adaptation‟ along with analysis to determine the next
impedance to be set in. This scheme along with a capability
to increase the Transmit PSD along with added subbands
nominally would suffice to meet the rate requirements.
8. When the SNRs are already high enough to support a
non-zero bit loading profile a nominal increase in
Transmit PSD would suffice as is evidenced for loop
2 with BT terminated in an inductive load. These
improvements are shown in columns 3 and 5 of
Table 2 & 3.
9. As an example of improved rates obtained by
conjugate matching close to the line look in
impedances, we revisit the cases of loop 3 and loop 4
with their BTs terminated in inductive loads of
600mH. The US and DS SNRs along with bit loading
profiles with impulse noise are shown in figures 16
through 19 for loop 3 and in figures 22 through 25
for loop 4. The rates are tabulated in Table 4 &5.
Note the improvement in rates for loop 3 when the
impedance is changed to a value closer to line look in
impedance of loop 3. Small rate improvements can
now be obtained by a nominal increase in transmit
PSD along with added subbands. This can be seen in
the column 3 & 5 in Table 4 and column 2 & 4 in
Table 5.
0 1000 2000 3000 4000 5000 6000 7000-150
-100
-50
0
50
100
150
Tones
SN
R &
Sig
nal P
SD
noise US: Line length(600mt) with a tap after 550mts
snr without imp.noise
snr with imp.noise
signal PSD
Figure 10: US SNR of loop 2 with and without impulse noise
0 1000 2000 3000 4000 5000 6000 7000-1000
-800
-600
-400
-200
0
200
Tones
SN
R
noise US: Line length(1000mt) with a taps after 100mts
snr without imp.noise
snr with imp.noise
Figure 11: US SNR of loop 3 with and without impulse noise
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0 1000 2000 3000 4000 5000 6000 7000-150
-100
-50
0
50
100
150
Tones
SN
R &
Sig
nal P
SD
DS:line length(600mt) with a tap after 550mt
snr without noise
snr with noise
Figure 12: DS SNR of loop 2 with and without impulse noise
0 1000 2000 3000 4000 5000 6000 7000-1000
-800
-600
-400
-200
0
200
Tones
SN
R
DS:line length(600mt) with a tap after 300mt
snr without noise
snr with noise
Figure 13: DS SNR of loop 3 with and without impulse noise
0 1000 2000 3000 4000 5000 6000 7000-200
-150
-100
-50
0
50
Tones
SN
R &
Sig
nal P
SD
noise US: Line length(600mt) with a tap after 550mts
snr without imp.noise
snr with imp.noise
signal PSD
Figure 14: US SNR of loop 2 with inductive load and with
impulse noise PSD
0 1000 2000 3000 4000 5000 6000 7000-200
-150
-100
-50
0
50
100
Tones
SN
R &
Sig
nal P
SD
DS:line length(600mt) with a tap after 550mt
snr without noise
snr with noise
singnal PSD
Figure 15: DS SNR of loop 2 with inductive load and with impulse noise
PSD
0 1000 2000 3000 4000 5000 6000 7000-1000
-800
-600
-400
-200
0
200
Tones
SN
R
noise US: Line length(1000mt) with a taps after every 100mts
Figure 16: US SNR of loop 3 with inductive load, with
impulse noise PSD and conjugate
0 1000 2000 3000 4000 5000 6000 7000-1000
-800
-600
-400
-200
0
200
Tones
SN
R
DS:line length(1000mt) with a tap after 100mt
snr without noise
snr with noise
Figure 17: DS SNR of loop 3 with inductive load, with impulse noise PSD
and conjugate
0 1000 2000 3000 4000 5000 6000 70000
2
4
6
8
10
12
14
16
18
tones
bit
patt
ern
for
uplo
adin
g
bit loading pattern for uploading for vdsl
Figure 18: Bit-loading profile for loop 3 US with inductive
load and impulse noise with conjugate
0 1000 2000 3000 4000 5000 6000 70000
1
2
3
4
5
6
7
8
tones
bit
patt
ern
for
dow
nloa
ding
bit loading pattern for downloading for vdsl with inductive load
Figure 19: Bit-loading profile for loop 3 DS with inductive
load and impulse noise with conjugate
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0 1000 2000 3000 4000 5000 6000 70000
5
10
15
20
25
30
35
40
45
tones
bit p
att
ern
for
uplo
adin
g
bit loading pattern for uploading for vdsl
Figure 20: Bit-loading profile for loop 2 US with inductive
load and impulse noise with Conjugate and
new PSD
0 1000 2000 3000 4000 5000 6000 70000
5
10
15
20
25
30
35
40
tones
bit
patt
ern
for
dow
nloa
ding
bit loading pattern for downloading for vdsl
Figure 21: Bit-loading profile for loop 2 DS with
inductive load and impulse noise with
Conjugate and new PSD
0 1000 2000 3000 4000 5000 6000 7000-1000
-800
-600
-400
-200
0
200
Tones
SN
R
noise US: Line length(1000mt) with a taps after every 100mts
snr without imp.noise
snr with imp.noise
signal PSD
Figure 22: US SNR of loop 4 with inductive load,
with impulse noise PSD and conjugate
Figure 23: DS SNR of loop 4 with inductive load, with
impulse noise PSD and conjugate
0 1000 2000 3000 4000 5000 6000 70000
5
10
15
20
25
tones
bit
patt
ern
for
uplo
adin
g
bit loading pattern for uploading for vdsl with inductive load
Figure 24: Bit-loading profile for loop 4 US with
Inductive load and impulse noise with
conjugate
0 1000 2000 3000 4000 5000 6000 70000
2
4
6
8
10
12
14
tones
bit
patt
ern
for
dow
nloa
ding
bit loading pattern for downloading for vdsl with inductive load
Figure 25: Bit-loading profile for loop 4 DS with
Inductive load and impulse noise with conjugate
0 1000 2000 3000 4000 5000 6000 70000
5
10
15
20
25
30
35
tones
bit p
att
ern
for
uplo
adin
g
bit loading pattern for uploading for vdsl
Figure 26: Bit-loading profile for loop 3 US with inductive
Load and impulse noise with Conjugate (Zo=1+0.1i) and New PSD
increased 10dB
0 1000 2000 3000 4000 5000 6000 70000
5
10
15
20
25
30
35
40
tones
bit
patt
ern
for
uplo
adin
g
bit loading pattern for uploading for vdsl
Figure 27: Bit-loading profile for loop 3 US with inductive
Load and impulse noise with
Conjugate (Zo=0.6+0.1i) and New
PSD increased 10dB
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TABLE 1: CAPACITY ESTIMATION FOR DIFFERENT
LOOP S (WITHOUT LOAD).
TABLE 2: CAPACITY ESTIMATION FOR LOOP2
(US)WITH INDUCTIVE LOAD
TABLE 3: CAPACITY ESTIMATION FOR LOOP2
(DS)WITH INDUCTIVE LOAD
TABLE 4: CAPACITY ESTIMATION FOR LOOPS 3,4
(US)WITH CONJUGATE
TABLE 5: CAPACITY ESTIMATION FOR LOOPS 3,4 (DS) WITH
CONJUGATE
V. CONCLUSION
Recognizing that broadband distribution within a residence
is gaining importance with the maturing of telephone line
based DSL, in this paper we analyze the performance of an
indoor power line (AWG14) with upto ten BTs, using ABCD
matrix channel model based on two- port network theory.
SNR profiles and bit-loading
profiles have been computed
using VDSL2 masks that
Line
Topolo
gy
US
capacity
without
impulse
noise
US
capacit
y with
impuls
e noise
PSD
DS
capacity
without
impulse
noise
DS
capacit
y with
impuls
e noise
PSD
Loop 1 111.744
Mbps
59.469
Mbps
160.588
Mbps
87.444
Mbps
Loop 2
BT
open
102.420
Mbps
50.978
Mbps
134.528
Mbps
65.112
Mbps
Loop 3
BT
open
71.736
Mbps
24.420
Mbps
85.92
Mbps
52.776
Mbps
Line
Topolo
gy
US rates
with
inductiv
e load
US rates
with
inductive
load and
imp. noise
US
rate
with
and
conju
gate
imped
ance
US rate
with new
VDSL2
PSD and
conjugate
impedanc
e
Loop 2 2.673
Mbps
0 Mbps 78.10
4
Mbps
121.564
Mbps
Line
Topology
DS
capac
ity
with
induc
tive
load
DS
rates
with
induct
ive
load
and
imp.
noise
DS
rate
with
and
conju
gate
imped
ance
DS rate
with new
VDSL2
PSD and
conjugate
impedance
Loop 2 12.40
8
Mbps
1.116
Mbps
77.048
Mbps
168.388
Mbps
Line
Topology
US &
DS
rates
with
indu
ctive
load
only
US
rates
with
conjuga
te
Impeda
nce
Zo in
Hybrid
With
load
US rates
with
inductive
load and
imp.
Noise
PSD and
conjugat
e
Impedan
ce
Zo in
Hybrid
US rates
with new
VDSL2
PSD
increase
by 10dB
in
transmit
bands
and
conjugat
e
Impedan
ce
Zo in
Hybrid
Loop 3
Zo=1+0.1i
0
Mbps
14.184
Mbps
4.780
Mbps
18.468 Mbps
Loop 4
Zo=1+0.1i
0
Mbps
51.05
Mbps
16.577
Mbps
33.081
Mbps
Loop 3 Zo=0.6+0.1i
0
Mbps
32.676
Mbps
9.276
Mbps
43.464 Mbps
Line
Topology
DS rates
with
conjugate
Impedanc
e
Zo in
Hybrid
With load
DS rates
with
inductive
load and
imp. Noise
PSD and
conjugate
Impedanc
e
Zo in
Hybrid
DS rates
with new
VDSL2
PSD increase
by 10dB in
transmit
bands and
conjugate
Impedanc
e
Zo in
Hybrid
Loop 3
Zo=1+0.1i
9.432
Mbps
1.118
Mbps
1.176
Mbps
Loop 4
Zo=1+0.1i
52.88Mbps 19.472
Mbps
19.472
Mbps
Loop 3
Zo=0.6+0.1i
32.14
Mbps
7.224
Mbps
7.188
Mbps
Loop 3
Zo=0.1+0.1
i
81.568 Mbps
40.104
Mbps
58.820
Mbps
International Journal of Science and Modern Engineering (IJISME)
ISSN: 2319-6386, Volume-1 Issue-12, November, 2013
52
Published By:
Blue Eyes Intelligence Engineering
& Sciences Publication
Retrieval Number: L05291111213/2013©BEIESP
employ DMT line code along with the presence of dominant
Impulse noise apart from AWGN. The current Transmit PSD
suffices for open ended BTs. However BTs when inductive
loaded result in severe shortfall in data rates due to mismatch
between line impedance and characteristic impedance. Data
rates are shown to be considerably improved by adopting
settable values of conjugate impedances in the hybrid of the
modem that match with the line look-in impedance. We thus
recommend a combination of settable hybrid impedances and
a capability to nominally increase Transmit PSD along with
added subbands to achieve desired rates. This method has a
distinct advantage in that it reuses the entire digital portion
of existing ADSL and VDSL2 modems.
REFERENCES
1. S.Galli, Anna scagllone,k. Dostert. “Broadband is power: Internet
access through the power line network” IEEE Communications
Magazine, Guest editorial, PP. 82-83, May 2003.
2. Yu-ju Lin, Hanipath A.Latchman, and Minkyu Lee “A power line
communication network infrastructure for the smarthome” IEEE
Wireless Communications, 1070- 9916/02, Dec.2002.
3. Alexandre Matov “Measurements and Modeling of Power Line
Channel at High Frequencies” Integrated systems Lab.Swis federal
institute of tech,. Lausanne, Switzerland
4. Yu-ju Lin, Hanipath A.Latchman, and Minkyu Lee “A power line
communication network infrastructure for the smarthome” IEEE
Wireless Communications, 1070- 9916/02, Dec.2002.
5. Huaiyu Dai,H.Vincent poor “Advanced Signal Processing for Power
Line Communications” IEEE Communications Magzine,
vol..0163-6804/03, PP.107,.May 2003.
6. Matthias gotz, Manuel rapp, and Klaus dostert, “Power line channel
characteristics and their effect on communication system design” in
IEEE communication magazine, April 2004
7. H.Meng, S.Chen, Y.L.Guan “ Modeling of Transfer Characteristics for
the Broadband Power Line CommunicationChannel” IEEE
Transactions on power delivery, vol.19, No.3,july 2004.
8. M.Zimmermann and K.Dostert “A Multi path model for the power
line channel” IEEE transactions on communications, vol. 50, no4,
April 2002
9. Huangqiang LI, Yunlian Sun, Yao Yao “ The indoor power line
channel model based on two-port network theory” IEEE
Xplore ,2008
10. Soo-young jung, Tae-hyun kim, myung-un Lee, Wook-hyun kwon,
“Modeling and Simulation of power line channel” School of
Electrical engineering Seoul t‟l University.
11. ITU Recommendation,G.993.2 (02/2006 )Very high speed Digital
subscriber lines,Telecommunication standardization sector of ITU.
12. Thomas Starr, John.m.Cioffi, Peter.J.Silverman, Understanding
Digital Subscriber Line Technology, PrenticeHal
Publication,1999
13. David.k.Cheng, Field and wave electromagnetics, 2nd edition.,
Pearson Education Inc. 2006
14. H.Meng,Y.L.Guan, “Modeling and Analysis of noise effects on
broadband power-line Communications” in IEEE transactions on
power delivery, vol.20, no.2, April 2005.
15. Mohamed Tlich, Hassina Chaouche, Ahmed Zeddam, Pascal Pagani,
“Novel Approach for PLC Impulse Noise Modeling” in IEEE Explore
978-1 -4244-3790-0/90. ISPLC 2009.
16. D.Chariag,D.Guezgouz,Y.Raingeaud,J-C.Lebunetel, “Channel
Modeling and Periodic Impulsive Noise Analysis in Indoor Power
Line” in IEEE International Symposium on Power Line
Communications and its Applications, 2011
17. Y.H.Ma,P.L.So, E.Gunawan,Y.L.Guan, “ Analysis of impulse Noise
and Multipath Effects on Broadband Power Line Communications” in
International Conference on Power System Technology, Nov.2004,
Singapore.
18. M.Zimmermann and K.Dostert “ Analysis and Modeling of
Impulsive Noise in Broad- band Powerline Communication” in
IEEE Transactions on Electromagnetic Compatability, Vol.44, No.1,
Feb.2002
19. V.Degardin, M.Lienard, A.Zeddam,F.Gauthier, P.Degauque,
“Classification and Characterization of Impulsive Noise on Indoor
Power Line Used For Data Communications” IEEE Explore 2002.
20. Shinya Honda, Daisuke Umehara, Taro Hayasaki, Sathosaisuke
Umehara, Taro Hayasaki, Sathoshi Denno and Masahiro Morikura,
“ A Fast Bit Loading Algorithm Syncit Loading Algorithm
Synchhronized with Commercial Power Supply for Inhome PLC
Systems” 978-1-4244 -1976-0/08, IEEE 2008.
21. Nikoloas Papandreou, Theodore Antonakopoulos, “A New
Computationally Efficient Discrete Bit- Loading Algorithm for
DMT Applications” in IEEE Transactions on Communications, VOL
53, NO.5,May 2005.
22. Sobia Baig,Nasir D.Gohar, “ Discrete Multi- tone(DMT) Transceiver
with Dynamic Rate Adaptive Water-Filling Bit- oading Technique for
-home Power Line Communication Networks” Proceedings IEEE
INMIC 2003
23. David E. Goldberg, ” Genetic Algorithms in search Optimization and
Machine Learning” Addison Wiley Publishing company Inc.,1989
24. Usha Rani.K.R,Dr.S.Ravishankar, “Performance Analysis for
Broadband over residential power lines using VDSL2 Profiles” in the
proceedings IEEE International Conference Signal processing,
Communication & Computing (ICSPCC2011), 14th -16th Sept.2011,
Xi‟an, China.
AUTHOR PROFILE
First Author Profile
Mrs.Usha Rani .K .R, Associate Professor,
R.V.College of Engg.Bangalore,Karnataka, India,
email: [email protected]
PPPofessor
ngalore
International conferences:
1. UshaRani.K.R,Dr.S.Ravishankar,Dr.H.M.Mahesh, "Analysis of
noise and load effects on broadband performance over residential
power lines employing VDSL2" India Conference (INDICON
2011), Annual IEEE, 16-18 Dec.2011, BITS, Hyderabad.
2. Usha Rani.K.R,Dr.S.Ravishankar, " Performance Analysis for
Broadband over residential power lines using VDSL2 Profiles" in
the proceedings IEEE International Conference Signal processing,
Communication & Computing (ICSPCC2011), 14th -16th
Sept.2011, Xi'an, China.
3. Usha Rani.K.R,Dr.S.Ravishankar,Dr.H.M.Mahesh,M.Bharathi,
"An Analysis of Broadband Capacities with Impulse Noise over
Residential Power lines" in the proceedings International
Conference on advances in Recent Technologies in Communication
and Computing 2010,( ARTCom 2011), 14th-15th Sept.2011,
Bangalore.
4. UshaRani.K.R,Dr.S.Ravishankar,Dr.H.M.Mahesh,M.Bharathi,
"Analysis of Power Line Networks for Broadband Transmission" in
the proceedings International Conference on advances in Recent
Technologies in Communication and Computing 2010,( ARTCom
2010).,Kottayam, Kerala, 15th-16th October 2010
5. M.Bharathi,Dr.S.Ravishankar, Usha Rani.K.R "Frequency
Domain Reflectometry based SELT Approach for Loop Topology
Estimation" in the proceedings International Conference on
advances in Recent Technologies in Communication and
Computing 2010 ( ARTCom 2010).,Kottayam, Kerala, 15th-16th
October 2010
6. M.Bharathi,Dr.S.Ravishankar, Usha Rani.K.R "Capacity
Estimation of ADSL Line Using Frequency domain based SELT
technique" in the proceedings International conference on advances
in computing, control and telecommunication technologies
,Organized by ACEEE , Kerala, Dated Dec 26-28 2009.
7. M.Bharathi,Dr.S.Ravishankar, Usha Rani.K.R "Frequency domain
SELT approach for line length estimation", Second International
conference on signal and image processing, Vidya Vikas Institute of
Technology, Mysore, Dated 12-14 Aug 2009.
National conferences:
1. UshaRani.K.R,Dr.S.Ravishankar,M.Bharathi 'Review of channel
modeling for power line communication', National conference on
Advances in communication and computing, Karpagam college of
Engineering, Coimbatore, Dated 18th Sep 2009.
Broad band Transmission over Residential Power Lines Employing VDSL2: The Channel Capacity Analysis
53
Published By:
Blue Eyes Intelligence Engineering
& Sciences Publication
Retrieval Number: L05291111213/2013©BEIESP
Second Author Profile
Dr. S Ravi Shankar, Professor, R.V.College of Engg.,Bangalore,
Karnataka,India,
email: [email protected]
sor
M.Tech IIT Kharagpur, Ph.D IIT Madras
Papers Published in National and International
Journals:
1. Narasimhan, M.; Ravishankar, S,”Radiation from aperture
antennas radiating in the presence of a dielectric sphere”, IEEE
Transactions on Antennas and Propagation, Volume: 30 Issue: 6
Nov 1982, Page(s): 1237- 1240
2. Narasimhan, M.; Ravishankar, S,” Probe uncompensated near-field
to far-field transformation for scanning over an arbitrary surface”,
IEEE Transactions on Antennas and Propagation, Volume: 33
Issue: 4 Apr 1985, Page(s): 467- 472
3. Narasimhan, M.; Ravishankar, S. “Multiple scattering of EM waves
by dielectric spheres located in the near field of a source of
radiation”, IEEE Transactions on Antennas and Propagation,
Volume: 35 Issue: 4 Apr 1987, Page(s): 399- 405
4. Ravishankar, S.; Biswagar, Prakash “Analysis of Dielectric Lens -
Adaptive Array Antennas for Shaped Beam Applications”, Sarnoff
Symposium, 2006 IEEE 27-28 March 2006, Page(s): 1-4 Digital
Object Identifier 10.1109/SARNOF.2006.4534746
5. S.Ravishankar & M.S.Narasimhan, “The Effect of probe
Directivity in spherical Near Field Antenna Measurements” April –
June 1982, Vol 2, No 2, Electromagnetics Journal.
6. S.Ravishankar “EM Scattering by bodies of arbitrary shape and
unknown Constitution” April 1993. EMC Test and Design, IEEE
EMC/ ESD Conference Proceedings, Denver Colorado.
International and National Conference:
1. Ravishankar, S.; Rukmini, T.S.; Kumaraswamy, H.V.; Sunit, S.;
Karthik, Y.; Vinay, P.; Ravishankar, A,”Analysis of hemispherical
Dielectric lens antennas for wireless applications”, Applied
Electromagnetics, 2007. APACE 2007. Asia-Pacific Conference on
4-6 Dec. 2007, Page(s): 1-6. Digital Object Identifier
10.1109/APACE.2007.4603917
2. Ravishankar, S.; Padmaja, K.V.; Uma, B.V, “Implementation of
Novel Bit Loading Algorithm with Power
Cut-Back in ADSL Transmitter on DSP”, International Conference
on Computational Intelligence and Multimedia Applications, 2007,
Volume: 1 13-15 Dec. 2007, Page(s): 570-574, Digital Object
Identifier .1109/ICCIMA.2007.139
3. Ravishankar, S.; Uma, B.V.; Shreeprasad, M, “Rate-reach
performance improvements in ADSL
interference environment using adaptive wavelet threshold”,
International Conference on Wavelet Analysis and Pattern
Recognition, 2008. ICWAPR '08, Volume: 2 30-31 Aug. 2008,
Page(s): 634-638, Digital Object Identifier
10.1109/ICWAPR.2008.4635856
4. Ravishankar., S; Padmaja., K.V; Sridhar, Santosh,
“Implementation of dual latency operation in VDSL2 with
downstream power back off on DSP chip”, International Conferece
on Signals and Electronic Systems, 2008. ICSES '08, 14-17 Sept.
2008 Page(s): 427-430 Digital Object Identifier 0.1109
/ICSES.2008.4673456
5. Ravishankar, S.; Uma, B. V.; Shreeprasad, M. “Application of
wavelet for improvement of rate-reach performance in ADSL
interference environment”, International Conference on
Communication
Technology, 2008. ICCT 2008. 11th IEEE 10-12 Nov. 2008,
Page(s): 565-568 Digital Object Identifier
10.1109/ICCT.2008.4716124
6. Ravishankar, S.; Uma, B.V.; Padmaja, K.V,”Realization of
Adaptive Filters for NEXT Crosstalk Mitigation in Two Wire
ADSL on DSP”,Conference on Computational Intelligence and
Multimedia Applications, 2007. International Conference on
Volume: 1 13-15 Dec. 2007, Page(s): 567-569
Digital Object Identifier 10.1109/ICCIMA.2007.136
7. Dr. Ravishankar S, Mahesh A," Spherical Mode Analysis of patch
array antenna", Conference on IEEE sponsored International
conference on Antenna & Wave propagation, Barcelona, Spain,
April 12-16 2010.
8. Dr. Ravishankar S, Mahesh A," Gain enhancement of micro strip
array antenna with dielectric lens antenna: comparative study",
Conference on IEEE-AEMC, kolkata, India, Dec-14-16 2009.
9. Dr. Ravishankar S, Mahesh A," Design of 2X2 microstrip patch
array antenna embedded in hemispherical dielectric lens for
airborne mobile communications", Conference on IEEE Sponsored
International Radar symposium IRSI 2009, India, Dec 8-11, 2009.
10. Dr. Ravishankar S, S.K.Thakur ,Mahesh A," Collimation
Properties of Micro strip Patch Fed Dielectric Lens Antenna for
Broadband Mobile Communication", Conference on IEEE
sponsored International Conference on Future Computer and
Communication, Kuala Lumpur, Malaysia, Pages 522-526 Year of
Publication: 2009 ISBN:978-0-7695-3591-3, India, Dec 8-11,
2009.
11. Dr. Ravishankar S, M.Bharathi,Usha Rani.," Capacity Estimation
Using Frequency Domain Based SELT", Conference on Advances
in Computers Control and Telecommunication Technologies (ACT
2009), 26-28 Dec 2009.
12. Dr. Ravishankar S, M.Bharathi,Usha Rani.," Frequency domain
SELT approach for line length estimation", Conference on Second
International conference on signal and image processing, Vidya
Vikas Institute of Technology, Mysore, 12-14 Aug 2009.
International Workshop:
1. Ravishankar, S, “Analysis of shaped beam dielectric lens antennas
for mobile broadband applications”, IEEE International Workshop
on Antenna Technology: Small Antennas and Novel Metamaterials,
2005. IWAT 2005, 7-9 March 2005 , Page(s): 539- 542, Digital
Object Identifier 10.1109/IWAT.2005.1461135.
International Symposium:
1. Ravishankar, S.; Biswagar, P, “Spherical modal analysis of shaped
dielectric lens antennas for mobile broadband applications (MBS)”
Antennas and Propagation Society International Symposium, 2005
IEEE Volume: 2A 3-8 July 2005, Page(s): 454- 457 vol. 2A
2. S.Ravishankar & M.S.Narasimhan, “Near Field to Near Field
Transformations - Spherical Modal Approach” IEEE International
Radar Symposium India - 83, Oct 1983.
3. S.Ravishankar, “The Effects of antenna Mounted Bodies on the
Radiation from VSAT Earth Station Antennas”, Sept 1993, The
Third IEEE/URSI International Symposium on antennas and EM
Theory, NANJING, Peoples Republic of China.
Patents:
1. US Patent 10/ 684363 filed Oct 15, 2003, S.Ravishankar and Satya
Sudhakar – Assignee Texas Instruments,“Determining distance to
echo points in a wire line medium”.
2. US Patent 10/ 757987 filed Jan 16, 2004, S.Ravishankar –
Assignee Texas Instruments
“Antennas supporting High Density of wireless users in specific
directions”.
3. Indian Product patent, 4592/416/MAS/2000 dated June 2000,
S.Ravishankar, Satcom
Lab ITI, M: N Redundancy switches for Modems and Converters
with transponder and
Polarization Hopping”.