Teledesic

Today, advanced telecommunications infrastructure is limited to the developed urban areas of the world. This leaves most of the world’s population without access to even basic communications services. Even those areas with basic voice service get access through 100-year-old technology — analog, copper networks — that for the overwhelming part will never be upgraded to support digital, broadband services. And even the areas that do have broadband access are often unable to receive a guaranteed end-to-end quality of service that meets the needs of enterprises.

Teledesic is building a global, broadband Internet-in-the-Sky^TM network. Using a constellation of low-Earth-orbit satellites, Teledesic and its international partners are creating the world’s first network to provide affordable, worldwide, fiber-like access to telecommunications services such as computer networking, broadband Internet access, high-quality voice and other digital data needs. On Day One of service, Teledesic will provide guaranteed end-to-end quality of service to meet the broadband needs of enterprises, businesses, schools and individuals around the world. The Teledesic Network will accelerate the spread of knowledge throughout the world and facilitate improvements in education, health care, and other crucial global issues.

Teledesic represents the vision of telecommunications pioneer Craig McCaw, the company’s chairman. Teledesic’s primary investors are McCaw, Bill Gates, Motorola, Saudi Prince Alwaleed Bin Talal, the Abu Dhabi Investment Company and The Boeing Company. Service is targeted to begin in 2005. Founded in 1990, Teledesic is a private company based in Bellevue, Wash., a suburb of Seattle.

Teledesic has received support from the developed and developing world alike, resulting in both international and domestic satellite service designations for the frequencies necessary to accommodate the Teledesic Network. In March 1997, the U.S. Federal Communications Commission licensed Teledesic to build, launch and operate the Teledesic Network. Teledesic cleared another significant regulatory hurdle when the International Telecommunication Union’s 1997 World Radiocommunication Conference finalized its designation of international radio spectrum for use by non-geostationary fixed satellite services, such as those Teledesic will provide.

The Teledesic Network
The Teledesic Network will enable service providers in countries worldwide to extend their networks, both in terms of geographic scope and in the kinds of services they can offer. Ground-based gateways will enable service providers to offer seamless links to other wireline and wireless networks, such as the Internet.

The Teledesic Network will consist of 288 operational satellites, divided into 12 planes, each with 24 satellites. To make efficient use of the radio spectrum, frequencies are allocated dynamically and reused many times within each satellite footprint. Within any circular area of 100 km radius, the Teledesic Network can support more than 500 megabits per second (Mbps) of data to and from user terminals. The Teledesic Network supports Bandwidth-on-Demand, allowing a user to request and release capacity as needed. This enables users to pay only for the capacity they actually use, and for the network to support a much higher number of users.

Teledesic will operate in a portion of the high-frequency Ka-band (28.6-29.1 GHz uplink and 18.8-19.3 GHz downlink). The Teledesic Network’s low orbit eliminates the long signal delay experienced in communications through traditional geostationary satellites and enables the use of small, low-power terminals and antennas. The compact terminals will mount on a rooftop and connect inside to a computer network or PC.

The Teledesic Network is designed to support millions of simultaneous users. Most users will have two-way connections that provide up to 64 Mbps on the downlink and up to 2 Mbps on the uplink. Broadband terminals will offer 64 Mbps of two-way capacity. This represents access speeds up to 2,000 times faster than today’s standard analog modems. For example, transmitting a set of X-rays may take four hours over one of today’s standard modems. The same images can be sent over the Teledesic Network in seven seconds.

End-user rates will be set by service providers, but Teledesic expects rates to be comparable to those of future urban wireline rates for broadband connectivity.

Seamless Compatibility with Terrestrial Networks
Without knowing for certain all the applications and data protocols a broadband network will be called upon to accommodate in the 21^st century, it is reasonable to assume that those applications will be developed in the advanced urban areas of the developed world — where fiber-optics sets the standard. Satellite systems offer the capability to provide location-insensitive, switched, broadband access, extending the reach of networks and applications to anywhere on Earth. But to ensure seamless compatibility with those networks, a satellite system should be designed with the same essential characteristics as fiber networks — broadband channels, low error rates and low delays.

Satellite systems are of two general types: geostationary-Earth-orbit (GEO) and non-geostationary, primarily low-Earth-orbit (LEO). Geostationary satellites orbit at an altitude of 36,000 kilometers (km) above the equator — the only orbit that allows the satellite to maintain a fixed position in relation to Earth. At this height, communications through a GEO entail a minimum round-trip transmission latency — end-to-end delay — of at least one-half second. This means that GEOs can never provide fiber-like delays.

This GEO latency is the source of the annoying delay in many intercontinental phone calls, impeding understanding and distorting the personal nuances of speech. What can be an inconvenience on voice transmissions, however, can be untenable for real-time applications such as videoconferencing as well as many standard data protocols — especially for the protocols underlying the Internet. By comparison, Teledesic’s LEO satellites will orbit at 1,375 km, or 25 times closer to Earth than GEO satellites.

One of the fundamental principles of the Internet is the notion of all applications moving onto a common network platform — an open network based on common standards and protocols. The idea of stand-alone, proprietary networks or application-specific networks is fast disappearing. All applications will move over the same networks using the same protocols. In these packet-switched networks — where voice, video and data are all just packets of digitized bits — it is not practical to separate out applications that can tolerate delay from those that cannot. As a result, the network should be designed for the most demanding application. The Teledesic Network is designed to provide end-to-end quality of service that enables global enterprise networking, meeting the demands of the Internet of the future.

Distributed vs. Centralized Architecture
Just as networks on the ground have evolved from centralized systems built around a single mainframe computer to distributed networks of interconnected PCs, space-based satellite networks are evolving from centralized networks relying on a single geostationary satellite to distributed networks of interconnected low-Earth-orbit satellites. In geostationary systems, any single satellite loss or failure is catastrophic to the system. To reduce this contingency to acceptable levels, reliability must be engineered far along toward the point of diminishing returns where further gains in reliability are achieved only at a very high cost.

With a distributed network, like the Teledesic Network, reliability can be built into the network rather than the individual unit, reducing the complexity and cost of the individual satellites and enabling more streamlined, automated manufacturing processes and associated design enhancements. In its distributed architecture, dynamic routing, and robust scalability, the Teledesic Network emulates the most famous distributed network, the Internet, while adding the benefits of real-time capability and location-insensitive access.

Low-Earth-Orbit Satellite Systems
The evolution from geostationary to low-Earth-orbit (LEO) satellites has resulted in a number of proposed global satellite systems, which can be grouped into three distinct types. These LEO systems can best be distinguished by reference to their terrestrial counterparts: paging, cellular and fiber.

System Type	Little LEO	Big LEO	Broadband LEO
Example	Orbcomm, VITA	Iridium, Globalstar, ICO	Teledesic
Terrestrial Counterpart	Paging	Cellular	Fiber
Frequency	<1 GHz	1 - 3 GHz	30/20 GHz

The Big LEOs, for example, provide premium-priced, narrowband mobile voice service, whereas Teledesic provides primarily fixed, broadband connections at costs comparable to urban wireline service. Just as cellular and fiber are generally not considered to be competitive, the only thing Teledesic really has in common with the Big LEOs is the use of low-Earth-orbit satellites.

The Market for Teledesic
The convergence of computing and communications is causing all things one associates with a high standard of living — from education and health care to economic development and public services — to become dependent on an ever-increasing flow of information. In highly urbanized areas, this demand for information is being satisfied by the high-bandwidth and high-quality connections of fiber optics. Increasingly, institutions and individuals are utilizing broadband connections for Internet access, computer networking, aggregation and trunking of voice lines, and telecommuting. But step out of the cities, and these fiber-like telecommunications services become prohibitively expensive or are simply unavailable at any price. In some cases, islands of broadband access are available but without a guaranteed, end-to-end quality of service to interconnect a far-flung enterprise and enable seamless worldwide communication.

Teledesic will help remove location as an obstacle to effective communication. With the Teledesic Network, enterprises will have the power to interconnect everyone throughout their extended organization — every branch office, every distributor, every supplier, every customer — improving performance and expanding operations through shared information and better coordinated action. Students everywhere will have access to resources undreamed of by a previous generation of scholars. And governments worldwide will be able to extend the reach of essential public services.

Because Teledesic satellites move in relation to the Earth, Teledesic provides the same quality and capacity of service to all parts of the globe. In this sense, Teledesic’s Internet-in-the-Sky^TM network is an inherently egalitarian technology. On Day One of service, Teledesic will help transform the economics of telecommunications to enable universal access to the Internet and the Information Age.