1. Communications Research Laboratory 1 ITS Experiments at Yokosuka Research Park Front Vehicle (Transmitter) Back vehicle (Receivers) Antenna & RF Devices for Diversity Antenna & RF Devices Test site in YRP

2. Communications Research Laboratory 2 Problems in High speed Wireless Access Systems Narrow service coverage – Very small cell size; only 10-100m – Services are limited in spot areas ? – How to expand service coverage ? HAPS? Difficult for High Speed Vehicles – Because of frequency selective fading – Only for indoor and pedestrian ? – How to expand service for high speed mobiles? Connection to Backbone Networks – Seamless connections to Internet – Broadband access to Internet Competition with optical fiber networks – Mobile communications and last one mile communications

3. Communications Research Laboratory 3 Are there other broadband access systems? Satellite system – Low earth orbit systems » Iridium(Mobile : only voice, 2.4kbps) » Teledesic(Fixed : ２ Mbps-64Mbps) » M-Star(Fixed : 52 Mbps) – Geostationary orbit systems » Giga-bit satellite : under R&D The third system ? – Stratospheric platforms !

4. Communications Research Laboratory 4 Advanced PCS Advanced terminals High-speed WAN Multimedia services Broadband INTERNET SkyNet STA/MPT SkyNet STA/MPT SkyNet STA/MPT SkyNet STA/MPT Merged services Optical inter-platform links Subscriber access radio links Stratospheric Broad-band Access Network -Skynet : High speed network using Airship stations-

5. Communications Research Laboratory 5 Altitude : 20km, Max.wind : 30m ／ s Solar Cells Side Propeller Regenerati ve Fuel Cells Helium Gas Bag Catenar y Curtain Back Propell er X-shaped Tail Assembly Unmanned large aircraft which stays stationary in the stratosphere. Ideal for radio relay stations (HAPS) and for remote sensing. HAPS : High Altitude Platform Station What is a Stratospheric Platform? Conceptual Image of the Platform Airship