Smart Notching – New concepts for EMC coordination

European Technology CenterAndreas Schwager (1)

Smart Notching – New concepts for EMC coordination

Andreas Schwager, Sony Deutschland GmbH, European Technology Center (EuTEC), Stuttgart, Germany,

[email protected]

Prof. Dr. Holger Hirsch, Universität Duisburg-Essen, Energietransport und –Speicherung, Duisburg, Germany,

[email protected]

mailto:[email protected]

mailto:[email protected]


Outline

• Overview of today‘s EMI coordination• Adaptive EMI mitigation techniques

– Satellite Communications– Overlay OFDM– Dynamic Notching for PLT

• Motivation of PLT• Interference problems and solutions

• Implementation of a Prototype system

• ETSI PLT plugtest with EBU– Results & EBU Statement

• Conclusions


EMC-Coordination

ideal conditions

emission level

emission limit

compatibility level

immunity limit

immunity level

Coordination of emission and immunity requirements to guarantee the EMC of an electrical device

real conditions

variance due to manufacturingdisturbances not considered

level

cum. probability

level

emission level

immunity level

compatibility level

EMC coordination: risk management !Frequ


Adaptive EMI mitigation techniquesare in use for lots of applications

– Satellite Communications

– Overlay OFDM– Dynamic Notching for PLT


Frequency Management for Mobile Satellites

From:Rickerson, D.; Rhoads, “Symphony or calliope-frequency management with mobile satellite services” M.;Military Communications Conference, 1996. MILCOM '96, Conference Proceedings, IEEE Volume 3, 21-24 Oct. 1996 Page(s):943 - 947 vol.3

http://ieeexplore.ieee.org/xpl/RecentCon.jsp?punumber=4198


From:Rakesh Rajbanshi “OFDM-Based Cognitive Radio for DSA Networks” September 2007, University of Kansas

Overlay OFDM systems


Air Traffic Control

From:B-VHF – An Overlay system concept for future ATC communication in the VHF bandM. Schnell, E. Haas; German Aerospace Center (DLR)M. Sajatovic, C. Rihacek, B. Haindl; Frequentis GmbH

23rd Digital Avionics System Conference (DASC); Oct. 24-28, 2004; Salt Lake City, Utah, USA


Same Concept will be used for Powerline Communications


Heterogeneous Home Network

• Wireless solution suffers from insufficient coverage

• PLT provides Broadband coverage in solid-wall households without new wires

• PLT as in-home backbone media, complementary to wireless

• High comfort/convenience factor for the user

A/V Home ServerAudio System

Baby Monitor

HDTV

PDA

PC


PLT Interference problems SW Radio Broadcast <-> In-home

amplitude

frequency

• Frequency range of PLT is identical to SW radio.

in-home BPL spectrum

HomeServer

www

SW Radio spectrum

• Interference avoidance techniques, like ‘Smart Notching’ remove interference to all receivable radio carriers

DSLRouter



amplitude

frequency


HomeServer

www

SW Radio spectrum

DSLRouter

• Frequency range of PLT is identical to SW radio.

• Interference avoidance techniques, like ‘Smart Notching’ remove interference to all receivable radio carriers



amplitude

frequency

• Video recorded in a real building:

• AM reception

• DRM Reception

• Worst case of interference:

• PLT transmitter in vicinity of SW-receiver


HomeServer

SW Radio spectrum

PLT Sink


Video recorded in a real building: AM reception (Sony ICF-SW77)


Screen shot of user interface of Sony PLT system


ETSI PLT plugtest

PLT Modem

STF 332: http://portal.etsi.org/STFs/STF_HomePages/STF332/STF332.asp

http://portal.etsi.org/STFs/STF_HomePages/STF332/STF332.asp


Frequency hop of Skelton Radio transmission

Time in sec

• Skelton transmission toggled from 7225kHz to 7320kHz. There are 2 radios tuned to each frequency. In parallel there is PLT transmission inside the building from Sony’s Smart Notching demonstrator:

1st Radio tunes to 7225kHz. This frequency is notched by PLT system. No interference!

Strong PLT interference noticealbe at the 2nd radio (tuned to 7320kHz).

Transm

ission on 7225kH

z switc

hes off

0

Transm

ission on 7320kH

z switc

hes on

13

AM modula

tion o

n 7320

kHz s

tarts

14

Inte

rfere

nce

from P

LT o

n 2nd

Rad

io sto

ps b

y

inser

ting

a no

tch

17

PLT re

uses

722

5kHz

69


Test procedure

• A SW radio receiver did an automatic frequency scan in all ITU-R radio bands– Sony ICF-SW77 was used (the most sensitive, we found)

• At all broadcast services where the automatic scan stops an SINPO assumption was done

• ITU-R Recommendation BS.1284: "General methods for the subjective assessment of sound quality“http://stason.org/TULARC/radio/shortwave/08-What-is-SINPO-SIO-Shortwave-radio.html

– PLT active, no notches– PLT active, smart notching installed– PLT off

http://stason.org/TULARC/radio/shortwave/08-What-is-SINPO-SIO-Shortwave-radio.html


Field tests: SINPO assumption

• 168 times SINPO assumption performed

DRM

FM quality (DRM only can provide

this in SW-frequencies)

Good AM quality

Music might be enjoyed

News talker could be

understood

Not useableQuality of the radio service:


European Broadcasting Union Union Européenne de Radio-Télévision

Technical Department Département technique

9 January 2008

EBU S/EIC1

Statement with regard to ETSI specification of PLT "Smart Notching" system

The latest version of the Coexistence Specification (ETSI TS 102 578 v1.1.16 – 2007-11; PowerLine Telecommunications (PLT) Coexistence between PLT Modems and Short Wave Radio Broadcasting) services was considered by the EBU S/EIC group at its meeting on the 28th and 29th November 2007. Within the provisions: the document concerns itself specifically with a system of dynamic notching (referred to as “Smart Notching”) whereby a PLT modem omits, or ‘notches’ certain frequencies and frequency ranges from the signal which it uses to communicate with other PLT modems. Other aspects of PLT systems and system design outside the scope of the specification are excluded; - the protection (dynamic notching) system is designed only to protect HF broadcast

transmissions services in specified bands between 2 MHz and 30 MHz; - the EBU S/EIC group is content that any system fully meeting the specification will

offer adequate protection to HF (Short Wave) broadcast transmissions. The EBU S/EIC group will therefore recommend to EBU members that are also members of ETSI that they should support the adoption of the specification within ETSI.

Further to this a representative of the EBU, Mike Hate, was present during the tests described in document ETSI TR 1XX W124 v2.1.x (PLT44_TD_12r1_ETSI_TR_WI24_Part2_V2_0_3.doc. The EBU S/EIC group confirms that this document is a fair and accurate report of the tests carried out and the results obtained.

1 S/EIC stands for: Spectrum management Committee / Electromagnetic Interference and

Compatibilities. This is one of many EBU project groups dealing with different subjects relevant to Broadcasting.


Conclusions

• There is a wide range of Applications allocating frequency spectrum dynamically.

• Online analysis allows an adaptation of the system on the current local situation.

• EMI is not guaranteed at manufacturing of the device but due the concept of operation.– For PLT ETSI specified a TS including verification mechanism

• Protection of existing radio applications is guaranteed

• Adaptive Mitigation techniques are state of the art in today’s standards & norms:– EN 50065-1: Signaling on low-voltage electrical installations in the

frequency range 3 kHz to 148,5 kHz• §4 Frequency bands and classifications

NOTE: Additional provisions may apply in the event of interference to radio communication service.

Smart Notching – New concepts for EMC coordination

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