‘‘Unlocking the Unlocking the 28GHz Band’ Band’

Matt Hobby – System Engineer

The Last Mile

Last Mile

City - UrbanSuburban

RuralLocal Loop

End User Point of Presence

Existing Technologies

ADSL + Low Cost - Future Proof

Satellite + Nationwide Coverage

-Latency-Cost/ Contention

Leased Line + Speed - Rollout Cost

LIBRA

LIBRA

• Low-cost Internet Broadband Radio– Licensed 28 GHz spectrum– 40 km radius super-cell– Uses conventional BFWA equipment– 15,000 uncontended symmetric

connections– Places a 30m mast within 1 km of every

subscriber

Satellites, HAPs, LAPs & TowersSatellite @ 300+ km

HAP @ 21 km

LAP @ 1.5 km

Tower @ 0.3 km

Like a HAP but . . . . . .

• Based on existing technology

• Station keeping guaranteed by tether

• Power requirements guaranteed

• Spectrally efficient backhaul via tether

• Low cost!

Equivalent Tower Model

Aerostat

CPE

Free Spaceregion

30 m mast

Shadowing & LOS

80%+ LOS @ 40 km

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Pro

babili

ty

Range (km)

Probability of LOS path

The Link Budget

• Extremely High Gain BS antenna

• QPSK modulation

• Standard 60 cm CPE dish @ boundary

• 99.9% availability

• Rain band F assumed

Technology

Trials

Target Cost to End User

• > 2 Mbit/s

• Uncontended

• Symmetric

• ~ £300 per link to Network Operator

• End User cost of ~ £350

Roadmap

Integratepayload

Commercialdemonstrator

Full systemdeployment

April 2003 January 2004 January 2005

ConclusionLIBRA

The LONG TERM solution for Broadband Britain !

Aerostat Advantage @ 1 km