Cumulative radiated emissions from metallic broadband data distribution systems
Download
1 / 55

Cumulative Radiated Emissions From Metallic Broadband Data Distribution Systems - PowerPoint PPT Presentation


  • 110 Views
  • Uploaded on

Cumulative Radiated Emissions From Metallic Broadband Data Distribution Systems. Dr I D Flintoft Dr A D Papatsoris Dr D Welsh Prof A C Marvin York EMC Services Ltd. University of York. Scope. ionosphere. Sky Wave. 3-30 MHz. Space Wave. 0.1-30 MHz. Ground Wave. 0.1-3 MHz. London.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cumulative Radiated Emissions From Metallic Broadband Data Distribution Systems' - lee


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Cumulative radiated emissions from metallic broadband data distribution systems

Cumulative Radiated Emissions From Metallic Broadband Data Distribution Systems

Dr I D Flintoft

Dr A D Papatsoris

Dr D Welsh

Prof A C Marvin

York EMC Services Ltd.

University of York


Scope
Scope Distribution Systems

ionosphere

Sky Wave

3-30 MHz

Space Wave

0.1-30 MHz

Ground Wave

0.1-3 MHz

London

Rome

Near Field

suburban

rural

average UK ground

0 km

5 km

200 km

1500 km


Contents
Contents Distribution Systems

  • Overview of PLT and xDSL technologies

  • Modelling methodology

  • RF launch models and measurements

  • Sky wave propagation of PLT & VDSL

  • Ground wave propagation of ADSL &VDSL

  • Spectrum management

  • Conclusions


Spectrum and technologies
Spectrum and Technologies Distribution Systems

30 kHz

300 kHz

3 MHz

30 MHz

Low Frequency (LF)

Medium Frequency (MF)

High Frequency (HF)

Ground Wave

Sky Wave

Space Wave

ADSL (25 kHz-1.1 MHz)

VDSL (1.1-30 MHz)

DPL (2.9 & 5.1 MHz)


Power line telecommunication plt
Power Line Telecommunication (PLT) Distribution Systems

  • Propriety systems

  • PowerNET: 9-95 kHz (EN50065)

  • Digital Power Line (DPL)

  • Frequencies: 2.2-3.5 & 4.2-5.8 MHz

  • 2 Mbit/s channels demonstrated

  • Uses low voltage (LV) network


Mains network topology
Mains Network Topology Distribution Systems

DPL Cell

= Data Terminal

Medium Voltage (MV) Network

Low Voltage (LV) Network

Secondary

Substation

Transformer

50 single phase services off each distributor

Primary

Substation

Transformer

To High Voltage (HV) Network

250 m


Physical structure of lv network

CU Distribution Systems

Physical Structure Of LV Network

Armoured Cable

  • Underground and overhead distribution

  • Armoured cable

  • Conditioning units (CU) may be used

Conditioning Unit (CU)

LV network

Network

internal mains network

MV network

CU

LV network

substation

data port

data network


Input power for a dpl cell
Input Power For A DPL Cell Distribution Systems

  • DPL cell – coherently excited segment of network

  • Physical channel shared by all users in cell

  • Multi-user access scheme: TDMA

  • Power spectral density from terminal = –40 dBm/Hz = 1 mW in 10 kHz bandwidth

  • 10 kHz = typical HF AM radio bandwidth


Digital subscriber line xdsl
Digital Subscriber Line (xDSL) Distribution Systems

  • Overlay technology enabling broadband services on telephony metallic local loop

  • Symmetric and asymmetric upstream/downstream data rates

  • Data rates up to 50 Mbit/s (VDSL)

  • CAP, QAM, DMT modulation techniques


Telecommunications network
Telecommunications Network Distribution Systems

overhead distribution

overhead drop

MDF

underground distribution

cross connect

cross connect

50 m

1.5 km

footway junction box

exchange

4 km

300 m

= Data Terminal

underground drop


Xdsl varieties
xDSL Varieties Distribution Systems

FTTEx = Fibre To The Exchange, FTTCab = Fibre To The Cabinet


Physical structure
Physical Structure Distribution Systems

Balance of UTP

  • Bundles of unshielded twisted pair (UTP)

  • Designed for POTS – up to a few kHz

  • Cable balance – degrades with frequency

  • Network balance – interfaces

  • Splitters

  • Three wire internal cabling

(New cable under controlled conditions)


Input power for xdsl
Input Power For xDSL Distribution Systems


Modelling methodology
Modelling Methodology Distribution Systems

  • Identify coherently excited network elements

  • Determine the radiative characteristics of these network elements

  • Construct an effective single source for cumulative emissions – pattern & power

  • Use these effective sources in propagation calculations


Rf launch models
RF Launch Models Distribution Systems

  • Numerical Electromagnetics Code

  • Sommerfeld-Norton lossy ground model

  • Common-mode current model

  • Predict antenna gain and radiation efficiency of the network elements

  • Underground cables not considered  these will be conservative estimates


Network elements
Network Elements Distribution Systems

PLT

House Main Ring

Street Lamp

10 m

3N m

xDSL

6 m

Overhead Drop (Splitter)

Overhead Drop (No Splitter)

N Storey Building (N=1,2,…, 10)


Antenna patterns for xdsl
Antenna Patterns For xDSL Distribution Systems

  • At low frequencies (ADSL) patterns are omni-directional

  • Model using an effective short vertical monopole

Normalised gains at 1 MHz


Validation measurements
Validation Measurements Distribution Systems

  • Measurements on UTP aerial drop cable

  • Balanced and unbalanced connections

  • Results used to calibrate the NEC launch models


Measured balance parameters
Measured Balance Parameters Distribution Systems


Cumulative radiated power
Cumulative Radiated Power Distribution Systems

  • Digital data transmission is a random process which can be modelled as a noise source

  • Cumulative field from incoherently excited network elements calculated by noise power addition (REC. ITU-R PI.372-6)

  • Phase effects ignored


Sky wave propagation
Sky Wave Propagation Distribution Systems

  • Time of day

  • Time of year

  • Transmitter antenna power

  • Transmitter antenna pattern

  • Transmitter antenna position

  • We have considered transmission on a February evening


Its institute for telecommunication sciences hf propagation software
ITS (Institute For Telecommunication Sciences) HF Propagation Software

  • Package caters for area coverage or point to point predictions

  • Allows choice of several propagation models: ICEPAC, VOACAP, REC533

  • We chose to use REC533 model based on advice from RAL and the ITU

  • Launch power and antenna pattern


Cumulative dpl antenna pattern
Cumulative DPL Antenna Pattern Propagation Software


Dpl source power for london
DPL Source Power For London Propagation Software

  • Power in 10 kHz bandwidth: 1 mW

  • Area: 2500 km2

  • Size of DPL cell: 0.28 km2 (diameter 600 m)

  • Total number of cell: 2500/0.28  8925

  • Total input power: 8925  1 mW = 8.9 W  40 dBm

  • Antenna gain: –15 dB

  • Total radiated power: 40 – 15 = 25 dBm


Coverage of london at 5 1 mhz
Coverage Of London At 5.1 MHz Propagation Software

0

Subtract 15 dB to read true dBmV/m, .i.e. for 15 dBmV/m read 0 dBmV/m

London cumulative antenna

Isotropic antenna


Cumulative dpl sky wave from many urban areas
Cumulative DPL Sky Wave From Many Urban Areas Propagation Software

  • Since the coverage from each urban area is Europe wide we need to sum the field from many urban areas

  • Major sources over UK would be the Ruhr area of Germany, London, Birmingham and Manchester

  • Total field over UK due to these major sources plus other major UK cities is predicted to be between 5 and 11 dBV/m

  • Established ITU noise floor is 8 dBmV/m (rural area)


VDSL Source Power For London Propagation Software

  • Drop model without internal cables

  • Average of 1000 homes per km2

  • 25 % technology penetration

  • Antenna gain of –25 dB (corresponds to 20 dB cable balance parameter)

  • Terminal input power –60 dBm/Hz or –20 dBm/10kHz

  • Total radiated power 13 dBm (20 mW)


Coverage of london at 8 mhz
Coverage Of London At 8 MHz Propagation Software

Subtract 27 dB to read true dBmV/m, .i.e. for 15 dBmV/m read -12 dBmV/m


Cumulative VDSL Sky Wave From Many Urban Areas Propagation Software

  • Sum powers from major UK cities and Ruhr area of Germany

  • Cumulative field over UK at 8 MHz is –6 dBmV/m in 10 kHz bandwidth

  • Established ITU noise floor is 8 dBmV/m (rural area)

  • 10 dB lower than DPL


Groundwave propagation theory 1
Groundwave Propagation Theory (1) Propagation Software

  • Sommerfeld (1909), Norton (1936, 1937)

  • (V) fields >> (H) fields

  • A(d,f,,) for (V) polarised fields

  • Attenuation factor calculated according to ITU-R P.368, originally developed by GEC


Groundwave propagation theory 2
Groundwave Propagation Theory (2) Propagation Software

  • The E-field formula applies to a linear short (h<<) radiative element

  • NEC used to determine the equivalent FMPt of radiative structures associated with xDSL

  • Calculations done for upstream and downstream mode of transmission

  • Radiation patterns omnidirectional for ADSL

  • Balance, attenuation of UTPs


Calculation strategy of cumulative emissions 1
Calculation strategy of cumulative emissions (1) Propagation Software

  • Electric fields Ei from uncorrelated individual sources add incoherently, i.e.,

  • A: area enclosing all radiating sources in m2

  • pi: percentage of building type associated with ith radiating source

  • Di: density of installations per unit area

  • Mpi: fraction of market penetration

  • Li: fraction of installed lines used concurrently


Calculation strategy of cumulative emissions 2
Calculation strategy of cumulative emissions (2) Propagation Software

  • Step 1. Definition of radiating medium, A=25km2

  • The RSS summation, lends itself to an active spreadsheet implementation


Calculation strategy of cumulative emissions 3
Calculation strategy of cumulative emissions (3) Propagation Software

  • Step 2. Definition of makeup of city buildings


Calculation strategy of cumulative emissions 4
Calculation strategy of cumulative emissions (4) Propagation Software

  • Step 3. Specify reference radiating efficiencies, balance and attenuation at frequencies of interest for upstream and downstream transmission


Calculation strategy of cumulative emissions 5
Calculation strategy of cumulative emissions (5) Propagation Software

  • Step 4. Define the appropriate transmission spectral mask, i.e., for ADSL PSD=-34.5dBm/Hz (upstream 138-276 kHz), PSD=-36.5dBm/Hz (downstream 138-1104 kHz).

  • Step 5. Calculate the unattenuated electric field for each radiative element, i.e.,


Calculation strategy of cumulative emissions 6
Calculation strategy of cumulative emissions (6) Propagation Software

  • Step 6. Calculate the appropriate electric field correction factor for each radiative element.

  • Step 7. Evaluate the total electric field by performing the RSS summation over all xDSL installations.


Test cases and results adsl 1
Test cases and results ADSL(1) Propagation Software

  • Case 1. A=25 km2, bal=40dB, Mpi=20%, Lui=10%


Test cases and results adsl 2
Test cases and results ADSL(2) Propagation Software

  • Case 2. A=25 km2, bal=30dB, Mpi=50%, Lui=10%


Test cases and results adsl 3

Balance Propagation Software

Radiation levels increase by a margin equal to the balance difference in dB.

E(bal2)=E(bal1)+bal, bal= bal1 - bal2

Market Penetration

E(M2)=E(M1)+M, M=10log(M2/M1)

Distance

-20 dB/decade for f(100kHz - 400kHz)

-25 dB/decade for f(600kHz - 800kHz)

-30 dB/decade for f(1000kHz)

Test cases and results ADSL(3)


Summary of results for adsl
Summary of results for ADSL Propagation Software

  • Emission electric fields resulting from cumulative ATU-R upstream and MDF downstream transmissions at distance 1km away from the effective emission centre.(M=20%, L=10%, Typical bal=30 dB)


Graph of current noise floor itu r p 372
Graph of current noise floor, ITU-R P.372 Propagation Software

  • Median noise electric field at a receiver with bandwidth 10kHz at 12 noon in a residential location in the central UK.


Adsl and current noise floor
ADSL and current noise floor Propagation Software

  • No likely change to the established median electric noise field for the well balanced city (bal=50 dB) model at d>1km away from the MDF centre.

  • For the typically balanced city model ADSL fields are predicted above the current noise floor (cnf)

    • ATU-R field > cnf by 5dB - 10dB at d<2km

    • MDF field > cnf by 10dB - 20dB at d<3km

  • For distances > 10km, ADSL<cnf


Summary of results for vdsl
Summary of results for VDSL Propagation Software

  • Emission electric fields resulting from cumulative NT-LT upstream and LT-NT downstream transmissions at distance 1 km away from the effective emission centre. (M=20%, L=20%, Typical bal=20 dB.)


Vdsl and current noise floor
VDSL and current noise floor Propagation Software

  • No likely change to the median electric noise field for the well balanced small city (bal=30 dB) model at d>1km away from the emission centre.

  • For the typically balanced city model VDSL fields are predicted above the current noise floor (cnf):

    • NT-LT field > cnf by 10dB - 20dB at d<1.5km

    • LT-NT field > cnf by 5dB - 15dB at d<1.5km

  • For distances > 5km, VDSL<cnf.

  • Radiation diagrams of radiative elements give rise to significant space wave component.


Spectrum management issues
Spectrum management issues Propagation Software

  • AM broadcasting in band 6 (MF)

    • For ‘good’ quality reception

      • 88dBV/m, 74dBV/m, 60dBV/m for typical city/industrial, city/residential and rural/residential areas, respectively.

    • AM transmitter serving designated metropolitan area enclosed by a 50km radius in UK.

      • =15, =10mS/m, Pt=10kW

      • PR=30dB, thus interfering field 44dBV/m

      • xDSL(d>1km)< 44dBV/m, but Gaussian in nature

    • For rural locations near xDSL fields important


Spectrum management issues1
Spectrum management issues Propagation Software

  • Digital MF broadcasting

    • DRM consortium preliminary specification

      • Narrow bandwidth (max 10kHz), thus:

        • very efficient source coding scheme [MPEG-4 AAC]

        • multi-carrier modulation to overcome multipath, Doppler, [OFDM]

        • high state linecode modulation scheme, [QPSQ, 16QAM, 64QAM depending on service requirements]

      • Protection ratios:

        • AM interfered with by DM, [f/kHz=0, PR=36dB]

        • DM interfered with by AM, [f/kHz=0, PR=0dB]

        • DM interfered with by DM, [f/kHz=0, PR=15dB]


Spectrum management issues2
Spectrum management issues Propagation Software

  • Digital MF broadcasting

    • DRM consortium preliminary specification

      • Carrier-to-noise ratios:

      • C/N of 24dB for BER=1x10-5 is at least required.


Spectrum management issues3
Spectrum management issues Propagation Software

  • Power savings of 4-8dB can be made by DM transmitters, for same daytime coverage.

  • xDSL(d<1km)>C/N, near xDSL ?

  • assessment of xDSL mux and mod techniques


Spectrum management issues4
Spectrum management issues Propagation Software

  • AM transmitters to be phased out by 2020

    • Lower PR could be used, 10-15 dB less than the currently assumed for AM, thus:

      • reduced radiation of digital transmitter power

      • much quieter EM environment

    • If xDSL>planned interference value:

      • DM power must increase (financial implications?)

      • concerted actions of broadcasting authorities to restore the service

      • xDSL near fields at remote locations?


Xdsl and aeronautical services
xDSL and aeronautical services Propagation Software

  • Services likely to be affected are:

    • Radiolocation & mobile communications

  • NEC simulations show a significant space-wave propagation component for f>1MHz

    • most radiation is directed towards elevation angles ranging between 30 and 60 degrees

  • Space wave stronger than ground wave


Xdsl and government services
xDSL and government services Propagation Software

  • Services likely to be affected are:

    • Military mobile communications in HF

      • low data rate systems work even 8 dB below ambient noise in a 3 kHz receiver bandwidth

      • 9.6 kbps and above data rates at 3 kHz bandwidth are standardized requiring a minimum 33 dB C/N ratio

      • 3 - 5MHz, critically important for short/medium length communications paths at night when other HF frequencies do not work


Conclusions 1
Conclusions (1) Propagation Software

  • Active spreadsheet tool for RA

  • Preliminary calculations suggest:

    • AM and DM broadcasting may be unfavourably affected

      • xDSL(d<1km) & selected areas

      • xDSL near fields need to be assessed

      • lower PR for DM mean very low power Tx resulting to a much quieter EM environment, fossil fuel savings and reduction in greenhouse gases


Conclusions 2
Conclusions (2) Propagation Software

  • Preliminary calculations suggest:

    • Aeronautical services may be unfavourably affected

      • xDSL(d<1km) & selected areas

      • Further study is needed

        • cumulative space wave emissions

        • technical and operational characteristics of aeronautical NDBs, current and future mobile communications

    • Government services may be unfavourably affected

      • Mobile communications

      • Further study is needed


Conclusions 3
Conclusions (3) Propagation Software

  • It is therefore provisionally suggested that xDSL emissions should be contained at a maximum level of 20dB above the established radio noise floor near the effective radiation centres (d=1km). (For the UK lower values than those in the ITU-R P.372 can be used.)


ad