Co-Existence of S-Band Radar and 4G Mobile Networksaoc-gardenstate.org/archive/Coexistence of S-Band Radar...Co-Existence of S-Band Radar and 4G Mobile Networks Dr. Steffen Heuel Technology

Co-Existence of S-Band Radar and 4G Mobile Networks

Dr. Steffen Heuel

Technology Manager Aerospace & Defense

Test & Measurement Division

Rohde & Schwarz Munich, Germany

ASR-NG

Radar

ASR-2000

~1.5km

ITU radio regulations in the 2.5 GHz to 3.1 GHz band

2.70 GHz to 2.90 GHz

Aeronautical radionavigation

f

2.5 GHz to 2.69 GHz

Mobile

Earth exploration

satellite, radio astronomy


Radionavigation

Frequency and bandwidth

Often frequency hopping several MHz depends on radar system

2.70 GHz 2.90 GHz

2.50 GHz

2.69 GHz

2.62 GHz

2.57 GHz

Radar

?

ITU radio regulations in the 2.5 GHz to 3.1 GHz band


Aeronautical radionavigation

f

2.5 GHz to 2.69 GHz

Mobile

Earth exploration

satellite, radio astronomy


Radionavigation

Frequency and bandwidth

Often frequency hopping several MHz depends on radar system

2.50 GHz

2.69 GHz

2.62 GHz

2.57 GHz

2.70 GHz 2.90 GHz

Radar

?

critical frequency allocation

LTE Networks and Radar Systems

Russia

Japan

Taiwan

Hong KongIndia

New Zealand

Sri Lanka

Saudi Arabia

Worldwide Usage of the 2.6 GHz BandOperators using resources in the 2.6 GHz Band

South Africa

Gambia

Gabon

Nigeria

Libya

Europe

America

Brazil

GuineaGhana

China

Singapore

data source: www.gsacom.com

Country Operator using 2.6 GHz

Germany Telekom, Vodafone, o2

UK EE

Norway Telenor, Netcom

USA Sprint

Sweden 3 Sweden, Net4Mobility, TeliaSweden

France Bouygues, Free Mobile, Orange France, SFR

China China Mobile, China Telecom

Poland, Chile, Estland, Finland, Hong Kong, Italy, Columbia, Kuwait, Litauen, New Zealand, Austria, Singapore, Spain, Russia ...

755 Mio LTE subscriptions worldwide, 442 commercially launched LTE networks (02 Nov 2015)

in 147 countries. forecast: 460 commercial networks by the end of 2015

755 Mio LTE subscriptions worldwide, 442 commercially launched LTE networks (02 Nov 2015)

in 147 countries. forecast: 460 commercial networks by the end of 2015

LTE: TDD or FDD

ı Most deployed systems make use of FDD

ı Some Countries use TDD heavily, e.g. China, India

ı About 39 commercial LTE TDD systems in 26 countries (source: www.gsacom.com 8/8/2014)

Germany: all FDD, 2.6 GHz, Band 7 FDD (Telekom)

USA: 2.5 GHz, TDD (Sprint), all others FDD

subframe 1ms

radio frame: 10 x 1ms

which duplex scheme is

disturbed more easily?

LTE FDD Downlink Frame

ı How does an LTE frame

look like?

ı What has to happen in

order to

disturb a frame?

lower the CQI

lower the throughput

take the network down?

LTE FDD Downlink (DL)Frame Structure Type 1

LTE FDD Downlink Frame: DL frame disturbances?

Physical Downlink Control Channel (PDCCH):carries between others the downlink allocation information

Physical Control Format Indicator Channel (PCFICH):used to signal the length of the PDCCH

The synchronization signals (PSS and SSS) for the UE to discover the LTE cell and do the initial synchronization

pulses that hit PDCCHs,or the PSS / SSS may cause system degradation (although PSS is more robust against interferences)

LTE FDD Downlink (DL)Frame Structure Type 1

LTE Uplink Frame: UL frame disturbances?

LTE FDD Uplink (UL) FramePhysical Uplink Shared Channel (PUSCH):carries L1 UL transport data incl. control informationQPSK, 16 QAM, 64QAMSC-FDMA

Physical Random Access Channel (PRACH):for initial access and when the UE losses its uplink sync.

Physical Uplink Control Channel (PUCCH): control information

Sounding reference signals (SRS) used by the enodeB to estimate the uplink channel conditions

Reference signals (RS) used by the enodeB to estimate the uplink channel to decode the terminal uplink transmission

A certain frequency band is allocated continuously

frequency has to match

LTE TDD Frame: frame disturbances?

Physical Downlink Control Channel (PDCCH):carries between others the downlink allocation information

Physical Control Format Indicator Channel (PCFICH):used to signal the length of the PDCCH

DwPTS facilitates downlink synchronization, and UpPTSfacilitates uplink synchronization,GP Guard Period to let the UE switch from TX to RX

LTE TDD Frame Structure Type 2

every DL frame has a PDCCH, frame 0 and frame 6 carry PSS / SSS as in FDD.additional DwPTS / GP / UpPTS interference may cause degradation

Disturbance due to...

Frequency

Pow

er

Spe

ctr

al D

ensity

Partial Band

Jamming

Single Tone

Jamming

Single Off-Tone

Jamming

Multi Off-Tone

Jamming

MultiTone

Jamming Barrage Jamming

Pilot Tone Jamming

S-Band RadarTypical Radar Parameters

Frequency 2.7, …, 2.9 GHz

Transmit power 2 kW - 20 MW

Maximum range 100 km - 500 km

Antenna opening

angle

0.4° - 2.5°

Pulse duration < 1µs - 400µs (most ATC radars use double

pulses, e.g. 2 x 1µs or 2 x 2µs)

With frequency diversity in a distance of

about 10-20 MHz

Pulse period < 1ms - 4ms

Antenna rotation time 5 rounds/min - 15 rounds/min

Antenna gain 25 dBi - 40 dBi

Radar

German Airbase Büchel(near Koblenz)

Check radar specification and/or analyze the radar

S-Band Radar Spectrum AllocationAirport Measurements

Radar

0.84 dBm

Two radar systems

operating at 2.82 GHz / 2.88 GHz


Two radar systems



Recording usingan IQ recorderRecording usingan IQ recorder

Replay possibilityin the labusing a vector signal generator

Replay possibilityin the labusing a vector signal generator

S-Band Radar Pulse Airport Measurements

Radar

2.5 µs PW


Radar

Pulse repetition 1.1 ms

Pulse repetition 1 ms


Pulse repetition 1.1 ms

Pulse repetition about 1 ms

TDD (frame structure Type 2)special subframes:

DwPTS Downlink Pilot TimeslotGP Guard PeriodUpPTS Uplink Pilot Timeslot

Radar

FDD (frame structure Type 1)

radio frame: 10 mssubframe: 1 msslot: 0.5 ms

Interference Scenarios

Interference Scenarios

RXTX

TX

TX

TX

RX

RX

RX

TXTX

RX

RX

Interference of the mobile communication services

Interference of the mobile communication services

Interference of the radar

Interference of the radar

Interference of the Radar

Mobile terminal (MT)Operating LTE band 7, 2620 - 2690 MHz

Radarin-band > 2700 MHzout-of-band < 2700 MHz

Base station (BS)in 2620 – 2690 MHz

TX

RX

TX

TX

RX

FDD UL TDD FDD DL Radar

25

00

MHz

25

70

26

20

27

00

Allocation

Radar bandwidth

Base stationin-band emission

Base station out-of-bandemission

Mobilein-band emission

Mobile out-of-bandemission

4. Limiting amplifier & filter3. 2nd amplifier & filter2. 1st amplifier & filter1. LNA

Amplifier overload

Increased noise power

Radar

increase of Pfa and reduction of PD

reduction of Rmax

blind spots

increase of Pfa and reduction of PD

reduction of Rmax

blind spots

Interference of the Mobile Service

Mobile terminal (MT)in-band < 2690 MHzout-of-band > 2690 MHz

Radar2700 MHz to 2900 MHz

Base station (BS)in-band < 2690 MHzout-of-band > 2690 MHz

RX

TX

RX

RX

TX

FDD UL TDD FDD DL Radar

25

00

MHz

25

70

26

20

27

00

Allocation

Radarin-band emission

Radar out-of-bandemission

Radar

Increased noise power

2. BPF & amplifier1. BPF & LNA Amplifier overload

signal and synchronization loss throughput reduction signal and synchronization loss throughput reduction

Performance Indicators and Measurement Needs

ı Radar

increasing Pfa and reduction of PD

reduction of Rmax

blind spots might occur

ı LTE

signal and synchronization loss

throughput reduction

increased EVM

network degradation

UE Downlink (DL) Data Throughput BLER Channel Quality Indicator

UE Uplink (UL) Error Vector Magnitude

Different Key Performance Indicators for User Equipment (UE) DL and UL measureable without direct software access to the UE

<

DL

UL

Key Performance Indicators MDS, PD and Rmax

to be measured at the radar system

using e.g. a radar target generator that generates “reference targets” with defined RCS at certain range and Doppler

targets of opportunity add interference (e.g. LTE signals)

Measurements (LTE)

Test of the Mobile Terminal in Presence of a Radar

ı Measurement Needs

ı Base Station Emulation, Record and Replay of a Radar Signal

LTE Signaling: Base Station Emulator

Record Signal: IQ recorder with Spectrum Analyzer

Replay Signal: Signal Generator

ı Base Station Emulation and ARB Signal Generation

LTE Signaling: Base Station Emulator

Pulse Sequencer Software with Signal Generator

UE Downlink- Data Throughput- BLER - Channel Quality Indicator

UE Uplink- Error Vector Magnitude

ı Base Station Emulator

LTE-FDD / TDD RF Generator, RF Analyzer

Network Emulation, Protocol Test

End-to-End application Test

Mobile connected according to receive sensitivity

level test (7.3 in 3GPP’s technical specification 36.521-1)

DL 51.021 Mbit/s, 64 QAM, 100 RB

UL 4.565 Mbit/s, QPSK, 75 RB

RX

TX

TX

1. Base Station Emulation, Record and Replay of a Radar Signal

LTE Signal ATC Radar Signal

RB: Resource BlockDL: DownlinkUL: Uplink

LTE Throughput MeasurementNo radar present

RX

TX

LTE Signal

LTE base stationRS EPRE:-104.5 dBm/15kHz CQI of 5-6

Mobile terminalMax power (+23 dBm)Follow wideband

RS EPRE: energy per resource element (EPRE) of the reference signal (RS)CQI: Channel Quality Indicator

LTE Throughput MeasurementRadar present

Replay of I/Q radar dataRadar frequency: 2.700 GHzPower: -40 dBm

LTE base stationRS EPRE:-104.5 dBm/15kHz CQI of 4-5


Activation of the pulse

radar

Activation of the pulse

radar


RX

TX

TX

Throughput MeasurementRadar present


RX

TX

TX


LTE base stationRS EPRE: -98.0 dBm/15kHz CQI of 6-7


increased RS EPRE increased RS EPRE

equidistant drops in data throughputequidistant drops in data throughput

Throughput MeasurementRadar present


RX

TX

TX


LTE base stationRS EPRE: -83.0 dBm/15kHz CQI of 6-7


further increaseof RS EPRE further increaseof RS EPRE

equidistant drops in data throughputequidistant drops in data throughput

2. Base Station Emulation and ARB Signal Generation

RX

TX

TX

LTE Signaling

Base Station Emulator (CMW500)

Vector Signal Generator (SMW200A)+

Radar Signal+

Arbitrary Signal Generation: Pulse Sequencer Software

1

1

2

2 3

3

R&S Pulse Sequencer Software

Project Data Base

Project Work Spaceı Scenario configuration

ı Waveform Generation

ı Instrument Control & Waveform

Download to generator

ı Simulation Display

Scenario Simulation Typeı Localized Emitter

ı Emitter, collection of emitters

ı Pulse Train

ı Sequence(s)

ı Overlay

34

Powerful Sequencer & Inter Pulse Modulation

35

Simple Loop and Pulse Trains

with repetition of same pulse

Loop with e.g. 2 pulses and

customized static phase offset,

amplitude offset,PRI, frequency

offset, delay per pulse …

Nested loop

Two signals in parallel at

the same time

Single Pulse, multiple pulses

or inter pulse modulationor or

Pulse Sequencer SW Antenna Patterns & Scan

36

ı Cosecans Beam in Elevation

ı Pencil Beam in Azimuth

ı Pencil Beam in Azimuth

ı Pencil Beam in Elevation

ı Cos-square taper in both directions

ı Helical antenna scan

ı Raster Scan

ı 2D cut through antenna pattern

ı Pencil Beam with taper

ı Polar antenna plot

ı 2D cut through antenna diagram

ı Cosecans Beam

ı Polar antenna plot

37

Scenario Simulation on 2D map in North/East/Down coordinate system

Interferer

Receiver

Emitters

2D map with coordinate system

UE DL: BLER and Throughput Measurement

LTE Signaling

Base Station Emulator CMW500, LTE Settings and UE ReportFull Cell BW Power: -57.2 dBmRS EPRE: -85 dBm/15kHzRSRP: 56 (-85 ... 84 dBm)RSRQ: 19 (-10.5 ... -10 dB)

Vector Signal Gen. SMW200APulsed Chirp LFM: 20 MHz, On: 72 µs, PRI: 1ms, Repetition: 10Tigger on LTE Frame 1

+

Radar Signal+

ı Generate a pulse signal which hits each PDCCH

ı What power and frequency is necessary to disturb the DL completely?

Disturbing Signal (1), Radar in Long Range Mode

ı Signal should be similar or alike an ATC radar signal which operates in long range mode

LFM, long pulse, low PRI

may include the antenna pattern, antenna turn, position etc.

UE DL: Throughput Measurement ResultsFollow WB

-68-66

-64-62

-60-58

-56-54

-52-50

-48-46

-44

26452649

26532657

26612665

0

10

20

30

Jammer Pwr [dBm]

UE DL, Follow WB, 2665 MHz, 10MHz BW:

TP vs. Jammer Pwr vs. Freq. (Pulse 72us On, 1ms PRI)

Freq. [MHz]

Tro

ughput [M

bit/

s]

LTE Signaling:

DL 64 QAM, UL QPSK,

DL Band 7, 2665 MHz

Full Cell BW Power: -57.2 dBm

RS EPRE: -85 dBm/15kHz

RSRP: 56 (-85 ... 84 dBm)

RSRQ: 19 (-10.5 ... -10 dB)

Pulsed Chirp LFM: 20 MHz, On: 72 µs, PRI: 1ms, Repetition: 10

ATC Radar in long range mode

UE DL: Throughput / BLER Measurement ResultsFollow WB

Throughput in Mbit/s BLER in %

-68 -66 -64 -62 -60 -58 -56 -54 -52 -50 -48 -46 -442645

2649

2653

2657

2661

2665

UE DL, Follow WB, 2665 MHz, 10MHz BW:Throughput vs. Jammer Pwr vs. Freq. (Pulse 72us On, 1ms PRI)

Jammer Pwr [dBm]

Fre

q. [M

Hz]

0

5

10

15

20

25

-68 -66 -64 -62 -60 -58 -56 -54 -52 -50 -48 -46 -442645

2649

2653

2657

2661

2665

UE DL, Follow WB, 2665 MHz, 10MHz BW: BLER vs. Jammer Pwr vs. Freq. (Pulse 72us On, 1ms PRI)

Jammer Pwr [dBm]

Fre

q.

[MH

z]

0

10

20

30

40

50

60

70

80

90

ATC Radar in long range mode

Disturbing Signal (2), Radar in Short Range Mode

ı Should be similar or alike an ATC radar signal which operates in short range mode

No modulation, short pulse, high PRI

May include the antenna pattern, antenna turn, position etc.

UE DL: Throughput Measurement ResultsFollow WB

-52-50

-48-46

-44-42

-40-38

-36-34

-32-30

26452649

26532657

26612665

0

10

20

30

Jammer Pwr [dBm]

UE DL, Follow WB, 2665 MHz, 10MHz BW: TP vs. Jammer Pwr vs. Freq. (Pulse 1us On, 200µs PRI)

Freq. [MHz]

Tro

ughput

[Mbit/s

]

LTE Signaling:

DL 64 QAM, UL QPSK,

DL Band 7, 2665 MHz

Full Cell BW Power: -57.2 dBm


RSRP: 56 (-85 ... 84 dBm)

RSRQ: 19 (-10.5 ... -10 dB)

Pulsed Chirp No Modulation, On: 1 µs, PRI: 200µs, Repetition: 50

ATC Radar in short range mode

UE DL: Throughput / BLER Measurement ResultsFollow WB

-52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -302645

2649

2653

2657

2661

2665

UE DL, Follow WB, 2665 MHz, 10MHz BW: TP vs. Jammer Pwr vs. Freq. (Pulse 1us On, 200µs PRI)

Jammer Pwr [dBm]

Fre

q.

[MH

z]

0

5

10

15

20

25

-52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -302645

2649

2653

2657

2661

2665

UE DL, Follow WB, 2665 MHz, 10MHz BW: BLER vs. Jammer Pwr vs. Freq. (Pulse 1us On, 200µs PRI)

Jammer Pwr [dBm]

Fre

q.

[MH

z]

0

10

20

30

40

50

60

70

80

90

100

Throughput in Mbit/s BLER in %

ATC Radar in short range mode

ı same setup, but EVM

Uplink Measurement

using the base station

emulator

LTE Signaling:

DL 64 QAM, UL QPSK,

UL Band 7, 2535 MHz

Full Cell BW Power: -57.2

dBm


RSRP: 56 (-85 ... 84 dBm)

RSRQ: 19 (-10.5 ... -10 dB)

ı no disturbing signal

present results in an

EVM Avg: 3.67 %

UE UL: EVM Measurement ResultsFDD, QPSK, Follow WB

ı same setup, but EVM

Uplink Measurement

using the base station

emulator

LTE Signaling:

DL 64 QAM, UL QPSK,

UL Band 7, 2535 MHz

Full Cell BW Power: -57.2

dBm


RSRP: 56 (-85 ... 84 dBm)

RSRQ: 19 (-10.5 ... -10 dB)

ı AWGN 3.84 MHz BW

present (using SMW)

power: -57 dBm

EVM Avg: 11.64 %



ı Same setup, but EVM Uplink

Measurement using CMW500

ı AWGN 20 MHz BW present (using

Vector Signal Generator)

ı Center frequency 2535 MHz

ı Power varied from -78 to -48 dBm

ı Anything more than -48 dBm

AWGN power resulted in “out of

sync” of the UL channel.

-80 -75 -70 -65 -60 -55 -50 -450

5

10

15

20

25

30

EV

M [

%]

Noise Power [dBm]

UE UL: EVM vs. Noise Pwr (AWGN 20 MHz BW)

Avg


ı Same setup, but EVM Uplink

Measurement using CMW500

ı Pulse 1µs, 200µs PRI present

(using SMW)

ı Center frequency 2535 MHz

ı Power varied

ı Anything more resulted in “out of

sync” of the UL channel.

-80 -70 -60 -50 -40 -300

5

10

15

20

25

30

35

EV

M [

%]

Disturbing Signal Pwr [dBm]

Avg EVM (Pulse)

Max EVM (Pulse)

Avg EVM (AWGN)

Measurement Setups to test the Radar

Test of the Radar in Presence of LTE SignalsConducted Test

ı Coexistence of Primary Airport Radar, LTE & weather radar

ı Base Station Emulation using a Signal Generator (SMW, SMBV)

Rotating Primary surveillance antenna

LTE Base Station

ı Rotating primary radar antenna at

airport is interfered by LTE signals for

example

Radar ReceiverHW

ı Generate Radar Signal and interference

signal and perform a conducted test

ı Include real world effects like antenna

patterns and turns, noise,….

Test Case for radarreceiver

Test of the Radar in Presence of LTE SignalsConducted Test using Pulse Sequencer

2D Map for gaming area

(drag & drop positioning of players)

Sequence(s)

Frequency Offset

Antenna Pointing

2D gaming area

Beam

Emitter N

Mode 1

Emitter 2 Emitter 1

Mode 1Mode 1

BeamBeam

Antenna Pattern & ScanAntenna Pattern & ScanAntenna Pattern & Scan

ı Receiver

ı Interferer

ı Emitters

Test of the Radar in Presence of LTE SignalsConducted Test using Pulse Sequencer

52

ı 3 Emitters

Antenna Pattern & Scan

EIRP of Emitter

Emitter Waveform

Carrier Frequency

ı Receiver

Receiver Antenna & Scan

ı Localization

ı x/y/z coordinates of Emitter & Receiver

ı Attitude

Bearing and Elevation Angle of Emitter

and Receiver antenna pointing

ı Interferer

WinIQSim2 waveform e.g. LTE

ı Propagation Model

Free space loss assumption

ı Simulation Scenario

All players at same time

Test of the Radar in Presence of LTE Signals Preview of simulation of one localized emitter in 2D space

53

Line of sight between emitter

and receiver and pointing

Vectors for t=0s

Antenna Diagram

Receiver

Raster Scan

Receiver

Receiver location with attitude

information

Circular Scan

Emitter

Emitter Antenna

Diagram

Emitter location with

attitude information

Preview of normalized receive antenna output signal amplitude

Preview time

for simulation

Emitter

summary

Visualization

Visualization time

Slow motion or

Accelerated

view

Test of the Radar in Presence of LTE SignalsIntegration with Radar Target Simulation

I/Q Data Stream Reference

Radar

RF RX/TX

RX

TX

R&S®Radar Target Generation

1. generate Radar Echo Signals

2. add disturbing signals, e.g. LTE signals

radar TX signal

radar RX signal+ noise + LTE

55

Results from tests with a coast guard vesselOver the air testing with navigation radar in S- and X-band

SX-band navigationradar under test

Shelter withantennas on a mast

Tx antenna

Rx antenna

Radar TX pulses @ 9.1 GHzand 3.05 GHz

Radar RX signal with generated radar echoesby SMW200A

56

First Results with coast guard vesselRadar screen of coast guard vessel with 4 echoes

ı Four static targets with different

ranges configured

ı No Doppler configured

ı Same RCS per target

ı SMW and FSW in shelter in the

harbor

ı Azimuth spread of generated

echoes result from certain half

power beam width of connected

antennas at SMW and FSW

ı Possible to add LTE Signals

Clutter

RX

TX

-10 dBm

-20 dBm

-30 dBm

-40 dBm

-50 dBm

-60 dBm

-70 dBm

-80 dBm

-90 dBm

SWT 15ms

1AP

Clrw

Ext

Ref 0.00 dBm

CF 115.0 MHz Span 120.0 MHz

Tx Channel Standard: NONE

Replay of LTE base station signals

1 to 14 base stations each 5 MHz bandwidth FDD mode 64 QAM scheme up to 600 W PEP

R&S TS6650 Interference Test System for ATC Radar

Test of the Radar in Presence of LTE SignalsOver The Air Test

RX

TX

Measurement in UK Royal airforce base

Honignton carried out with Ofcom

(Office of Communications, UK)

(unmodified) Watchman radar 2.751 GHz / 3.048 GHz (frequencies are not used for normal operation)

S-Band Radar vs. LTE Base Station Radar Performance Measurement

2.685 GHz, 35 dBm

2.685 GHz, 50 dBm

pointed towardsthe radar

Summary

ı LTE Networks and S-Band Radar

ı Interference Scenarios

ı Measurements Possibilities

LTE Base Station Emulator + Record and Replay

LTE Base Station Emulator + Pulse Sequencer Software

Radar Target Generation

ı Measurement Results

LTE Mobiles operating at 2.6 GHz with 20 MHz bandwidth

throughput reduction, BLER increase, CQI decrease

S-Band ATC Radar

reduced probability of detection and reduced maximum range

Documents

Co-Existence of S-Band Radar and 4G Mobile Networksaoc-gardenstate.org/archive/Coexistence of S-Band Radar...Co-Existence of S-Band Radar and 4G Mobile Networks Dr. Steffen Heuel Technology