Volume 4, Number 3 July/August 1996
Researchers at the Center for Satellite and Hybrid Communication Networks (CSHCN), a NASA Commercial Space Center, have collaborated with Hughes Network Systems engineers in Germantown, Maryland, to develop a low-cost hybrid (terrestrial and satellite) network service that can deliver data from the Internet to the user at much faster rates.
Satellite technology makes it possible for DirecPC to provide nationwide service immediately, eliminating the need for incremental upgrades to the cable or telephone plants in each locality. According to Hughes representatives, users equipped with a 9,600-bps modem could experience a 40-fold increase in speed in receiving material using DirecPC.
DirecPC is a hybrid system consisting of a receive-only satellite dish coupled with a special SLIP telephone/modem connection. Increasing the rate at which users can receive information is desirable because most computer users, especially those in a home environment, want to consume much more information than they generate. A receive-only satellite terminal is considerably less expensive to manufacture and much easier to install than one that also transmits. Internet protocol encapsulation manipulates the transmission control protocol/internet protocol to route packets away from and back to the user asymmetrically.
"Our joint effort to develop inexpensive hybrid terminals that can provide a variety of services to the user and to foster hybrid communications is the most promising path to the National Information Infrastructure, both technically and financially," said Dr. John Baras, director of the Systems Engineering and Integration Laboratory and the CSHCN. "As the most direct demonstration of these capabilities we are developing a variety of tools that can extend Internet services through satellite broadcasting, while at the same time providing the end user with higher quality service."
DirecPC uses a device driver developed at the CSHCN that breaks the network link into two physical channels: the terrestrial dial-up that carries data from the terminal into the Internet and a receive-only satellite link that carries information from the Internet to the user. This system is aimed at supporting bandwidth-hungry Internet applications, such as Mosaic and FTP, and it works with the Internet without any modifications. In addition, it is compatible with any Intel 80386/486 or Pentium personal computer.
The driver was developed under the Broadcast Internet Access project at the CSHCN and is exclusively licensed to Hughes. The idea for the Broadcast Internet Access project was conceived from research conducted with the Advanced Communications Technology Satellite (ACTS), sponsored by the Office of Space Access and Technology. NASA developed the ACTS in concert with U.S. industry to test and prove advanced communications technologies and evaluate potential new telecommunications services.
A wireless broadcast mode of communication offers extraordinary efficiencies compared to wireline communications, even where the wireline service employs sophisticated packet-switching techniques. Traditional radio and television broadcasting has exploited the efficiencies of the broadcast mode for years using terrestrial radio frequencies. Newer satellites offer television and radio broadcasts from the vantage of a geosynchronous orbit in space. Hughes currently markets a satellite dish and television set top box called DirecTV designed on this basis. DirecTV provides 150 channels of digital television. This development is a first step toward a "broadband Internet."
DirecPC expands the scope of the evolution from terrestrial to satellite broadcast beyond radio and television to data services delivered to the remote personal computer. The Internet and numerous commercial online data services could benefit from this enhancement to satellite-based broadcasting. The system and resulting products can now be used to provide high-performance, affordable services in several areas, including linking elementary and high schools to digital libraries (with images), providing telemedicine and cooperative diagnosis systems, and linking news and business services. As a result, in April 1996, the CSHCN received a "large company" award from the State of Maryland at the Maryland Industrial Partnerships Awards for Excellence.
Hughes began commercial product development in 1994. By 1995, their new line of DirecPC products had sales over $5 million, with more than 1,000 units installed and an order backlog exceeding 20,000 units. They also had employed more than 50 people in new marketing, sales, operations, development and manufacturing jobs in Maryland.
Participants in this work were Douglas Dillon, Ilya Faenson and William Stanton of Hughes Network Systems, as well as Dr. Baras, Aaron Falk, Narin Suphasindhu, Vivek Arora and Tim Kirkwood of CSHCN. It was supported by the CSHCN, Hughes Network Systems and the State of Maryland under a cooperative industry-university contract from Maryland Industrial Partnerships. The Commercial Space Center program, a nonprofit consortia of industry, academia and government partners, was established by the Office of Space Access and Technology to foster the use of space for commercial products and services.
For more information about this project and the results and products, contact Dr. John Baras.
Phone: 301/405-6606, E-mail: baras@isr.umd.edu
Or contact Timothy Kirkwood. Phone: 301/405-7904, E-mail: timk@isr.umd
Please mention that you read about it in Innovation.
Curator: Joe Goldfus
