13. WCDMA-GSM Cositing

1 © Nokia Siemens Networks Presentation / Author / Date

WCDMA/GSM co-sitingMODULE 13


WCDMA/GSM co-siting

Objectives

After this module the participant shall be able to:-

•Understand main issues related to WCDMA/GSM co-

siting


Module Contents

• Interference 3G-GSM

• Antenna line configuration

• Antenna isolation

• Co-siting examples

• Planning-rules of co-siting


Module Contents







Interference from Other System

• GSM spurious emissions and intermodulation results of GSM 1800 interfere WCDMA receiver sensitivity

• WCDMA spurious emissions interfere GSM receiver sensitivity

• GSM transmitter blocks WCDMA receiver

• WCDMA transmitter blocks GSM receiver

GSM GSM 1800 1800

ULUL

GSM GSM 1800 1800

DLDL

1710-1785 MHz

1805-1880 MHz

UMTS UMTS UL UL

UMTS UMTS DL DL

1920-1980 MHz

2110-2170 MHz

40 MHz


30 40 50 60 70 80 90 100-108

-107.5

-107

-106.5

-106

-105.5

Antenna Isolation (dB)

Noi

se P

ower

(dB

m)

NEW spec: -96 dBm / 0.1 MHz

Interference from Other System

• Two main reasons to isolate GSM and WCDMA• Blocking

• Sensitivity

1More information: TS 25.104 and GSM 05.05

• GSM1800 BTS can have up to -96 dBm / 0.1 MHz = -80 dBm / 4 MHz (relation to 3,84 Mchips) spurious emissions at the antenna connector1

• Thermal noise floor of the WCDMA band is -108 dBm => in theory -108 dBm - (-80 dBm) = 28 dB isolation needed between GSM1800 and WCDMA


Harmonic distortion

• Harmonic distortion can be a problem in the case of co-siting of GSM900 and WCDMA.

• GSM900 DL frequencies are 935 - 960 MHz and second harmonics may fall into the WCDMA TDD band and into the lower end of the FDD band.

GSM900935 - 960 MHz

WCDMATDD

WCDMA FDD1920 - 1980

...

2nd harmonics

fGSM = 950 - 960 MHz

1900 -1920 MHz

2nd harmonics can be filtered out at the output of GSM900

BTS.

f


M Distortion from GSM1800 DL to WCDMA UL

• GSM1800 IM3 (3rd order intermodulation) products hits into the WCDMA FDD UL RX band if:

• 1862.6 f2 1879.8 MHz

• 1805.2 f1 1839.6 MHz

WCDMADL

WCDMAUL

GSM1800DL

GSM1800UL

1710 - 1785 MHz 1805 - 1880 MHz 1920 - 1980 MHz 2110 - 2170 MHz40 MHz

f1 f2

fIM3

fIM3 = 2f2 - f1

X dBc

• For active elements IMproducts levels are higherthan IM products producedby passive components• Typical IM3 suppressionvalues for power amplifiers are -30 … -50 dBc depending on frequencyspacing and offset• Typical values for passiveelements are -100 … -160 dBc


Spurious Emissions from GSM to WCDMA

GSM BTS

• Horizontal separation between antennas

• By proper antenna placement 50dB isolation reachable

• No deterioration in performance if GSM BTS compliant with -96dBm

WCDMA BS



GSM BTS

• Nokia's diplexer/triplexer combines GSM/WCDMA to one feeder cable

• Diplexer/Triplexer isolation > 50dB

• No deterioration in performance if GSM BTS compliant with -96dBm

WCDMA BS

Multiband Antenna

Nokia Diplexer/ Triplexer



GSM BTS

• Multipanel Antenna in use

• Antenna isolation >30dB

• General GSM requirements fulfilled if GSM BTS compliant with -96dBm

WCDMA BS

Multiband Antenna



Non-compliant GSM BTS

• Worst case scenario

• >30dB isolation assumption

• GSM BTS spurious emissions comply "old spec." -30dBm

WCDMA BS

Multiband Antenna

Addiotional filter needed


Module Contents







Without Nokia Mast Head Amplifiers

With Nokia Mast Head Amplifiers

GSM BTS WCDMA BTSWCDMA BTS

Nokia MHAs for GSM

Nokia MHAs for WCDMA

GSM BTS

Nokia Bias-Ts NokiaBias-Ts

Antennas for GSM

Antennas for WCDMA

Typical Requirement for Minimum Coupling Loss between GSM and WCDMA antennas: • Nokia equipment: 30 dB30 dB• Other: 50 dB50 dB

Separate Antenna Lines




GSM BTS WCDMA BTS

GSM AntennaWCDMA Antenna

Nokia GSM / WCDMADiplexer Units

GSM AntennaWCDMA Antenna

GSM BTS WCDMA BTS

Nokia Bias-Ts

Nokia OutdoorBias-Ts

Separate DC feedfor new Nokia MHAsNokia GSM/WCDMA

Diplexer Units withSelectable DC pass

Nokia MHAs for GSM Nokia WCDMA MHAs

Typical Isolation Requirement for diplexers used with:• Nokia equipment: 30 dB30 dB• Other: 50 dB50 dB

Shared Antenna Lines with Separate Antennas


GSM BTS WCDMA BTS

GSM/WCDMA Dual BandX-polarized antenna with2 antenna connectors(1800/WCDMA wideband element orbuilt in diplexer function)

GSM/WCDMA Diplexer Units insideGSM BTS cabinet

GSM BTS WCDMA BTS

NokiaBias-Ts

Nokia OutdoorBias-Ts

Separate DC feedfor new Nokia MHAs

Nokia GSM/WCDMADiplexer Units withSelectable DC pass

GSM/WCDMA Dual BandX-polarized antenna with4 antenna connectors(Separate Elements for both Systems))



Shared Antenna Lines with Shared Antennas


Module Contents







Antenna Isolation Measurement Horizontal

Antenna A(fixed)

GSM1800

Antenna BUMTS

horizontalseparationdistance

Front View

direction of radiation

2000mm

1000mm

400mm

Side View

650mm

Sketch of measurement configuration


Antenna Isolation Measurement Horizontal

GSM1800 65 deg to UMTS 65 degHorizontal co-polar measurements

1900 MHz

1950 MHz

1980 MHz

40.00

45.00

50.00

55.00

60.00

65.00

70.00

75.00

Distance (m)

Isola

tion

(d

B)

1 2 3 4 5 6 7 8 9

50 dB Market


Antenna Isolation Measurements Vertical

Sketch of measurement configuration

10m

Antenna BUMTS

Antenna AGSM1800

(fixed)


Antenna Isolation Measurements Vertical

GSM1800 115 deg to UMTS 65 deg

1900 MHz

1950 MHz

1980 MHz

50.00

55.00

60.00

65.00

70.00

75.00

80.00

85.00

Distance (m)

Isola

tion

(d

B)

Noise Floor

1.50

1.25

1.00

0.75

0.50

0.25


Module Contents







Co-Siting Example - UltraSite & Citytalk

• Base Station Equipment:• Nokia UltraSite WCDMA BTS Suppreme

with 6 Carriers,• Nokia Citytalk BTS with 6 TRXs.

• Transmission Equipment:• Nokia FlexiHopper Microwave Radio

• Separate Antennalines and Shared Antennas:

• 3 pcs GSM/WCDMA Dual Band X-pol antennas 65 deg

• Optional: Mast Head Amplifiers for one or both networks

• Nokia UltraSite Support:• 7.8 kW rectifier capacity with N+1

redundancy• up to 180 Ah battery capacity• Backup time 1 hour

• Site Environmental Data:• Footprint (Width mm x Depth mm)

• Indoor: 1800 mm x 620 mm• Outdoor: 2310 mm x 1110mm

• Weight: Indoor 1030 kg, Outdoor 1290 kg


GSM2+2+2+2+

22

GSM2+2+2+2+

22WCDM

A 2+2+2+2+22 (10 W)

Site Space for 3 cabinets

Co-Siting Example - UltraSite & Citytalk


Module Contents







Planning Rules in Co-siting

• Isolation requirement• With Nokia equipment 30 dB

• Without Nokia equipment 50 dB

• GSM- WCDMA co-siting is possible if antenna isolation requirement is fulfilled

• By proper antenna placement

• minimum Horizontal distance (~0.3 m)

• minimum Vertical distance (0.25 m)

• Di- or triplexer is needed in case feeder and antenna is shared between different systems

• Tighter filtering is needed in Antenna line of Non-compliant GSM BTS to avoid the TX power interference to WCDMA Rx

• Careful frequency planning in GSM won't cause interference to WCDMA


Module 13 – WCDMA/GSM co-siting

Summary

•WCDMA/GSM co-siting can be done without

performance degradation with careful equipment and

configuration selection

13. WCDMA-GSM Cositing

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