SG 9 - some key areas of study -
High altitude platform stations (HAPS)
- balloon-supported platforms at ~21 km altitude
- telecom services to a city and surroundings
- spectrum allocation at ~ 47 GHz
- additional allocations sought in range 18-32 GHz
- technical and operational characteristics
- impact on other services
- interference mitigation techniques
Notes:
Proposed system for bb telecoms, principally for metropolitan area area but also extending out to rural environment. [Subscribers transmit directly to platform where on-board switching routes traffic to other subscribers within same platform coverage area. For subscribers outside platform area, traffic routed through ground stations to public networks or to other platforms; 250 platforms worldwide; coverage of each platform could extend from ~ 40 km to km, depending on service to be provided.] Also plans for HAPS to provide a bb service for mobile/portable users as part of IMT-2000 (i.e. using 2 GHz band).
WRC-2000 requested more studies on interference potential with other services, since allocated band is shared. Also requested to look at potential for other frequencies for HAPS in range 18-32 GHz. Studies so far concentrated on i) tech and op characteristics in this frequency range; ii) impact of HAPS systems on existing services, e.g. EESS (passive services) and RAS around 31 GHz; iii) interference mitigation techniques (e.g. antenna patterns, elevation angle limitation, shielding by airship, dynamic channel assignment, APC).