Sky Station Stratospheric Telecommunications System, A High Speed Low Latency Switched Wireless Network

Sky Station is a novel telecommunications network, which employs a proprietary stratospheric platform technology to provide broadband wireless communications, services around the world. The stratospheric platform is a super-pressurized helium-filled solar/fuel-cell powered airship with enough payload and power capacity to support all of a metropolitan area's broadband communications requirements. The Sky Station airship uses propulsion and thermal control to keep it stationary for no less than 5 years at 21Km altitude. Through the stratospheric infrastructure, the Sky Station stratospheric telecommunications system (STS) will offer fixed, or transportable, full duplex E-l uplink and lOMbps downlink services to the desktop or laptop. This is sufficient to support such multimedia services as video-telephony, low cost video-conferencing, and high speed Internet connectivity. The services will include user authentication, location registration, link encryption, and bandwidth-on-demand. The build-in security measure provides wire-line equivalent privacy (WEP) to insure high degree of privacy of communications. The Sky Station STS employs an end-to-end ATM architecture using UNI 4.0 and PNNI signaling protocols and can support AAL5 ABR/VBR and CBR services. The first generation SSI STS will have a capacity of 7Gbps between the user terminals and the STS platform, and another 4.IGbps of highspeed trunk links between the platform and the ground stations for PSTN and Internet connectivity. The subscriber uplink uses a multi-frequency TDMA protocol, QPSK modulation, and convolutional FEC to achieve I-bit/Hertz data rate. The uplink packets are ATM cells with additional encoding for header protection. Downlink is TDM with QPSK and FEC. A modified DAMA is used in conjunction with ATM multiplexers for efficient utilization of limited uplink bandwidth. To mitigate potential high rain attenuation in the 47/48GHz bands in some part of the world and to maintain high availability, we will present an adaptive rate FEC coding scheme that ensures both low BER ( 30dB margin for the portable terminals and > 40dBfor the fixed terminals.