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The $20 Billion Question:

Can Satellite and Terrestrial Wireless

Co-Exist in C-band?

David Hartshorn

Secretary General

Global VSAT Forum

www.gvf.orgWhy Is SatCom Important in C-band?

www.gvf.orgSpectrum

• ITU table of allocations allows FSS only in selected bands

• Bandwidth requirements for traditional FSS applications need to be met in the selected band

• Civilian Use

www.gvf.orgIndustry Supply, User Demand

• Only band where FSS services can realistically be provided with high availability due to rain fade characteristics

• Many satellites available• Well established, increasingly inexpensive

technology• Wide coverage enabling services in remote and

sparsely populated areas and areas with low traffic density

• Important part of the telecommunications infrastructure for many developing countries

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Widely used for a multitude of satellite services

• TV broadcast to cable networks

• TV broadcast to individual receivers

• VSAT networks

• Internet providers

• Point-to-multipoint links

• Satellite News Gathering

• Communication for ships

• Disaster relief

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ILLUSTRATIVEDIAGRAM

• Compare the coverage possibilities over the Pacific Islands region– 1 C-band beam

vs.– Multiple Ku-band

beams

C-band

Ku-band

What connectivity can be provided in C-band and what connectivity in Ku-band

www.gvf.orgExample: IS-701@ 180° E

Global, Hemispheric and Zone C-band beams …

… vs. Spot Ku-band beams

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Newcomers in C-band downlinks

Band commonly used by FSS satellitesAdditional band

(FSS, feederlinks for MSS, …)

Future mobile phone networks(IMT Advanced, 4G, ….)

Broadband Wireless Access (BWA), WiMax, FWA, ….

Is being considered by ITUIs being considered by ITUIs currently being introduced Is currently being introduced country by country worldwidecountry by country worldwide

BWA or IMT in ANY part of satcom C-band downlink will have an impact on FSS reception in ALL of the band

3.43.4 3.53.5 3.63.6 3.73.7 3.83.8 3.93.9 4.04.0 4.14.1 4.24.2Std. CStd. CEtx. CEtx. C

www.gvf.orgImpact on FSS Reception

• In-band interference

• Interference from unwanted emissions (outside the signal bandwidth (e.g. spurious emissions))

• Overdrive of LNB’s

Exclusion zones around earth stations are required if these terrestrial wireless services are to operate in the band

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Distortion of received FSS spectre by BWA signal

B

Att 0 dB*

RBW 300 kHz* VBW 10 kHzSWT 65 ms

*

Ref -35 dBm

Center 1.425 GHz Span 100 MHz10 MHz/

3 PKVIEW

1 PKVIEW

-85

-80

-75

-70

-65

-60

-55

-50

-45

-40

-35

Date: 12.JUN.2006 12:42:16

Overdrive of LNB B

Att 0 dB*Ref -35 dBm

100 MHz/Center 1.35 GHz Span 1 GHz

*

*

RBW 300 kHzVBW 10 kHzSWT 340 ms

3 PKVIEW

2 PKVIEW

-85

-80

-75

-70

-65

-60

-55

-50

-45

-40

-35

1

Marker 1 [T2 ] -31.03 dBm 1.648000000 GHz

Date: 12.JUN.2006 12:49:04

Intermodulation products BWA

carrier

3.3 GHz4.3 GHz

Intermodulation product

Satellite signals

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Overdrive of LNB

1. BWA signal off 3. BWA EIRP 1.6 W

2. BWA EIRP 0.5 W 4. BWA EIRP 5 W

Example of gain compression and intermodulation of LNB by single BWA base station

(BWA signal at 3.505 GHz (bandwidth 3.5 MHz), spectrum plots 3.775-3.675 GHz)

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Example of zone for short-term interference protection* in moderately hilly area

FSS earth station

Protection contour

100 km

100 km

* I/N not to exceed -1.3 dB for more than 0.001667% of the time.

(From Intelsat study to ITU Working Party 8F (Document WP 8F/1109))

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Circles of 150 km radius around earth stations

Registerd earth stations (except TVROs) in Europe operating to satellites within 3 400-4 200 MHz

Impact of protection of earth stations in overlapping frequency bands

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Impact of protection of earth stations in overlapping frequency bands

150 km exclusion zones around one earth station in Washington DC and one in New York City

.

.

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Impact of protection of earth stations in non-overlapping frequency bands (e.g. BWA in 3.5 GHz and FSS in 3.7-4.2 GHz)

.

.

2 km exclusion zones around one earth station at the White House and one earth station at the Pentagon (protection against micro-cell base station used in urban areas)

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International, intergovernmental organizations

• ITU (provisional CPM Report (regarding IMT))– “If FSS is deployed in a ubiquitous manner and/or with no

individual licensing of earth stations, sharing is not feasible in the same geographical area since no minimum separation can be guaranteed.”

• Asia-Pacific Telecommunity (APT, Wireless forum)– “As BWA is being introduced, harmful interference and loss of

service for FSS receivers have been reported many places”

– “However, when the BWA stations and/or FSS earth stations are deployed in a ubiquitous manner and/or without individual licencing or registration, the locations of the stations are not known and hence, no minimum separation distance can be guaranteed. Coexistence of BWA networks operating within the 3400-3800 MHz range and FSS networks operating in any part of the 3400-4200 MHz range therefore in this case becomes difficult within the same geographical area.”

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Conclusions

• BWA or IMT in a part or all of the FSS C-band downlink will be incompatible with general FSS reception in any part of C-band in the same geographical area

• BWA or IMT in a part of C-band may be compatible with FSS reception by a small number of earth stations if:– Appropriate exclusion zones around each of the earth stations are

established

– User terminals are designed not to emit any signals when not in contact with a base station

• Introduction of BWA or IMT by one country can block FSS reception in another country