Narda Safety Test Solutions

Firma: Narda Safety Test Solutions GmbHName: Holger SchwarzAdresse: Sandwiesenstrasse 7

72795 PfullingenGermany

Telefone: +49 7121 9732 724Fax: +49 7121 9732 790E-Mail: holger.schwarz@narda-sts.deInternet: www.narda-sts.de

Measurement of non-ionising radiation due to WiFi, DECT, 4G

(LTE) or radar

Manmade fields

Safety at Workplace

BroadcastingMobile Radio

Industry Office

Military

Industry

Environmental / Precautional Measurements

Residential Areas

At Home

Public Areas

Typical Equipment for RF Measurements

Broadband Meters Selective Meters (Spectrum Analyzers)

What is major difference between broadband and selective measurement?

Broadband meter measures the sum of emissions for all services

Spectrum Analysis measures the emission

service by service

e.g. NBM and Probe Type EF0691

e.g. SRM Spectrum Analysis

Bandwidth 100 kHz to 6 GHz (means 5.9999 GHz

fixed)

From 10 Hz to 20 MHz

variable

Center frequency

2.99995 GHz fixed From 9 kHz to 6 GHz

variable

Two Challenges on Test Equipment

1. Sensitivity, specially for measurementsAt HomeIn OfficesIn Public Areas

2. BandwidthCompared to previous Systems modern Communication System occupy higher Bandwidth e.g.:

• DVB-T• UMTS• LTE (4G)• …

1. Sensitivity

No problem for workplace safety measurements. There is “sufficient” field strength to by measured by broadband equipment

1. Sensitivity

ICNIRP/RPS3 and Italy

1,00

10,00

100,00

1000,00

10E+3 100E+3 1E+6 10E+6 100E+6 1E+9 10E+9 100E+9 1E+12Frequency / Hz

E / (

V/m

)

ICNIRP Occupational, Australia "RF Worker"

ICNIRP General Public, Australia "NON-RF Worker"

Exposure limits for general public Italy

Attention thresholds and quality targets Italy

1. Sensitivity

0.1 mV/m

0.01 V/m

1000 V/m

100 V/m

10 V/m

1 V/m

0.1 V/m

1 mV/m

Spectrum Analyzer (1 kHz RBW)

200 V/m

60 µV/m

Broadband (3 GHz probe)

320 V/m

0.2 V/m

RF Limit Values

6 V/m (Italy)

27 V/m

Typical indoor and publicmeasurement values

2. Bandwidth

Bandwidth of services is growing rapidly!Bandwidth of services is growing rapidly!

GSM: bandwidth

200 kHz

3G: bandwidth

5 MHz

Analog: bandwidth

3.1 kHz

LTE (4G): bandwidth

20 MHz

2. Bandwidth, Broadband Equipment

AdvantageIt’s broadband:

3, 6, 18 or even 50 GHz bandwidth is no problem

DisadvantageIt’s broadband:

It doesn’t tell you who it isIt’s sensitivity is limited

2. Bandwidth, Selective Equipment

AdvantageIt’s narrowband:

Distinction between different services is no problemSensitivity is high enough to measure even very small signals

DisadvantageIt’s narrowband:

Bandwidth might not be big enough to capture a complete signal of one of the new services

Bandwidth RBW

Which Bandwidth (RBW) has to be selected?

In spectrum analysis a RBW which is equal to the bandwidth of the service you want to measure

Bandwidth of Service < RBW Okay, but the measurement result can also include other services

Bandwidth of Service = RBW Best

Bandwidth of Service > RBW Indication of the marker will be smaller than the total amount. Better to use integration “Integration over frequency”

Examples of occupied Bandwidth

E.G.:LW/MW/SW 10 kHzDRM 4,5 to 20 kHzFM Radio 200 kHzGSM traffic or BCCH 200 kHzDAB 1,5 MHzUMTS 5 MHzAnalog TV 5-8 MHzDVB-T 7 MHzLTE (4G) 1.4, 3, 5, 10, 15, 20 MHzSRM can offer bandwidth from 10 Hz up to 20/32 MHz

RBW available

in traditional handheld SA

GSM Time Slots of Traffic Channels

GSM Time Slot

Facts of GSM:Each GSM-antenna has one Signaling Channel (BCCH) and several Traffic ChannelsEach Channel has a Bandwidth of 200 kHzGSM Traffic Channel has 8 Time Slots each 577 µs

1. Find a Traffic Channel in Spectrum

Find one Traffic Channel in Spectrum Analysis Mode

Using Trigger Events

DECT Phones

DECT

Facts of DECT PhonesFrequency Range: 1880 – 1900 MHzBase Station: permanently onChannel Structure: Number of Channels: 10 Channel Bandwidth 1.728 MHz (f = 1897.344 - n * 1.728 MHz)Cycle Duration: 10 ms with 24 Time Slots each 368 µs

Example Office - DECT Phones

Spectrum Analysis Mode

Scope Mode

W-LAN Safety Measurement

W-LAN Facts

Frequency Range• 2.4 GHz - 2.497 GHz • 5.15 GHz - 5.35 GHz • 5.725 GHz - 5.825 GHz

Channel Structure: Channel Number

• 2.4 GHz: 14 (overlapping), 3 (non-overlapping)• 5 GHz: 12 (non-overlapping)

Channel Bandwidth• 20 MHz but also 10 MHz and 40 MHz (most 16.6 MHz or 20 MHz)

Cycle Duration: 0.25 ms up to 1 … 2ms

W-LAN – 1.) Find the Center Frequency

Spectrum Analysis Mode

WLAN in Scope Mode

WiMax

WiMax - Overview Measurement

WiMax Signal in Spectrum

WiMax Signal (1 Channel with 1 FFT)

WiMax in Scope

LTE Long Term Evolution

The next mobile phone generation!

Summary of technical details

Channel Bandwidth: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHzDL Multiple Access: OFDMADuplexing: FDD and TDDSub-carrier spacing: 15 kHz

Data Modulation: QPSK, 16QAM, 64 QAMFFT size (5MHz): 512Channel Coding: Convolutional coding and turbo codingMIMO: Multi layer pre-coded spatial multi-placing space time / frequency block coding, switched transmit diversity, and cycle delay diversity

LTE - Technical Definition

BANDWIDTHBandwidth between 1.4 to 20 MHz (variable) (1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz)

Measuring LTE in Spectrum = 20 MHz with 1 FFT the whole spectrum is measured

96 % Traffic

LTE in Spectrum – Broadcast Channel

Broadcast Channel + Sync Channel = 1 MHz

LTE Signal in Scope Mode – 1 Frame

Radar

Radar Pulse in Spectrum (PW=1us)

Measurement in lab

Real Radar Measurement

Due to several reflections of environment no clear representation

Information about the Pulse

Pulse width

Reflections

RadarMeasurement Point

Reflection after 2.5 µs (750 m)

Reflection after 300 ns (90 m)