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Teledesic




Key Data


Teledesic will use a large number (288 plus spares) of Low Earth Orbit (LEO) satellites to offer access to fibre-like broadband digital transmission telecommunications services across the world. The main services LEO's will provide include computer networking, fast broadband internet access, interactive multimedia and high-quality voice technology.

Investors are Craig McCaw, Bill Gates, Motorola, Abu Dhabi Investment company, Boeing Company and His Royal Highness Prince Alwaleed Bin Talal Bin Abdul Aziz Alsaud. Motorola joined the effort to build the Teledesic Network in 1998, and is leading the team developing and deploying the network, with this targeted to begin in 2004.

Teledesic will expand by developing alliances with service partners across various countries worldwide. This will enable the service partners to expand their services, both geographically and in the scope of services they can offer. Ground-based gateways will enable service providers to offer seamless links to other wireless and wireless networks such as the internet. Teledesic will also offer services direct to clients.

TECHNICAL DETAILS

The system will be able to support millions of simultaneous users, all using 'standard' user equipment. Most users will have two-way connections providing 64Megabits per second (Mbps) on the downlink and 2Mbps on the uplink, although higher-speed terminals will provide 64Mbps or more of two-way capacity.

As it is able to handle multiple channel rates, protocols and service priorities, it is flexible enough to support a wide range of applications including the internet, corporate intranets, multimedia communication, LAN interconnect and wireless backhaul. Its flexibility is, of course, critical since many of the applications and protocols Teledesic will serve in the future have yet to be conceived.

The network will consist of 288 satellites split into 12 planes each with 24 satellites. To reduce environmental pressures, between six and eight satellites will be launched with each rocket. Each satellite is a node in a fast-packet-switch network and has intersatellite communication links with other satellites in the same and adjacent orbital planes. This 'mesh' network is robust and is tolerant to faults and local congestion.

The satellites will be made of a tough composite material, and thereforewill be able to sustain impacts from space debris. In the occasion that one of the satellites were to be destroyed or damaged, the aggregate system will compensate and another of the 36 spare satellites can be launched to take its place.

Within any circular area with a 100km radius the Teledesic Network can support more than 500Mbps of data to and from user terminals. The network supports bandwidth-on-demand, which allows the user to request and release capacity as and when it is needed. This means that the user only pays for the capacity they actually use, and the network can support a larger number of users.

Teledesic will operate in the high-frequency Ka-band portion of the radio spectrum, equivalent to 28.6-29.1GHz uplink and 18.8-19.3GHz downlink. Since it utilizes LEO satellites it eliminates the long signal delay normally experienced with traditional geostationary-earth-orbit (GEO) satellites and enables the use of low-power terminals and antennae. Teledesic's LEO satellites will orbit at 1,375km, some 25 times closer than geostationary satellites that orbit at around 36,000km. Since low-power terminals and antennae can be used, compact terminals can be fitted to a rooftop and connected to a PC or computer network inside a building.

AFRICAN FOCUS

Since Teledesic satellites move in relation to the Earth, the service is the same quality and capacity to all parts of the world, including those that could not be served economically by any other means. The Teledesic Network will cover 100% of the world's population and 95% of the landmass.

The Teledesic Corporation believes that its project could be extremely effective and profitable in areas such as Africa. In the majority of the African nations there is low teledensity (less than one phone line per 100 people), limited interconnectivity between the countries and a growing, unmet demand for telecommunication services (less than a quarter of African nations have direct access to the internet), which makes the African telecommunication issue a considerable challenge.

African nations realise the importance of having an effective communication system to promote international investments, which in turn will lead to job creation and improvement in the standards of living of the African people. The issue so far has been how to ensure a cost-effective access to advanced telecommunication while respecting the national sovereignty.

Using a constellation of several hundred low Earth orbit satellites, Teledesic should enable affordable, world wide access to fibre-like telecommunications services such as broadband internet access, digital voice, data, video-conferencing and interactive multimedia.