Prepared By
Greg Andersen - E-Mail:
andersen@cpsc.ucalgary.ca
Guy Bailie - E-Mail:
bailie@cpsc.ucalgary.ca
Kent Jarvie - E-Mail:
jarvie@cpsc.ucalgary.ca
Mike Mccarthy - E-Mail:
mccarthy@cpsc.ucalgary.ca
Last update: April 10, 1996
Some people believe that the purest vision of a Broadband Network is an integrated all fibre, all digital, two-way. high speed network over one super-pipe.
This includes everything from the Plain Old Telephone System (POTS) to On-Demand Interactive Video. All connected to one terminal in your house.
There are two qualifications that need to be met for a network to be counted as broadband. They are:
Here is a quick look at the possible transfer rate of fibre optic cable:
1) High Bandwidth Capacity
2) Two-way communications capability
The following terms will be defined:
IDN
- Integrated Digital Network
In other words: A predetermined method in which layers in a network talk to each other.
A fibre the thickness of a human hair can deliver 32,000 simultaneous conversations. This can be compared to twisted pair, which can only transmit 12 simultaneous conversations.
There are many applications of broadband networks. Some of them are:
| Application | Example |
|---|---|
| Multimedia Activites | |
| Video On Demand | Ordering a Movie |
| Medical Imaging | |
| Color Facsimile | |
| High Speed File Transfer | |
| Distance Learning | On-Line and Distance Learning |
| Molecular Modeling | Lab for Molecular Modeling |
| Animation | The Simpsons |
| Video Conferencing | Further Information |
| Desktop Publishing | |
| CAD/CAM | |
| Home Shopping and Banking | Home Banking/Home Shopping Screen Phone |
| Virtual Reality | Virtual Reality and VRTIF |
Eventually, the largest demand for broadband services will be generated by Video-On-Demand. This refers to a feature where a potential viewer requests a certain sequence of video and that sequence is instantly transferred to the user. The sequence can be a movie, a television show, a video sequence that is part of a multimedia presentation, a lecture, or any other type of video presentation.
Most cable tv companies have the capability to offer this kind of service today eg., in the form of pay-tv. Some cable companies are installing systems with some 500 channels, enough for a variety of offerings. Practically all current cable tv systems transmit information from a head to the individual users, but the cable networks cannot transmit information back to the head. The heads receive tv programs over dedicated lines. There are no switches in the distribution system.
Seeing a large market, the telephone companies want to generate tv programs and other video information for their customers. Currently, this is not permitted in the US, but the US congress, the FCC, and the courts are beginning to lift the prohibitions for the telephone companies to generate tv programs. If and when this happens, the tv companies will need broadband cables to each customer. This represents an investment on the order of hundreds of billions of dollars. Once broadband links are installed to homes and offices, many other uses for them will materialize.
A true VOD system, as opposed to Pay-Per-View, or Near Video on Demand, is enormously complicated in terms of delivery software. VOD has to be able to send the same movie to thousands of people at different times while providing the standard VCR controls that we have all grown accustomed to. VOD is a virtual VCR with fast forward, fast reverse, pause, etc. Thousands and thousands of file pointers have to be updated every second.
At the receiving end, there is a digital set-top box which decodes the compressed video signal and sends it to the television or teleputer (telephone /television/computer) that it is connected to. Designing set-top boxes is a highly competitive industry right now and also a highly technical one. So technical in fact, that they are more complicated than a PC, and more expensive. Set-top boxes cost about 2000 dollars, and industry forecasts determine that they will have to drop down to about 150 to 200 dollars before VOD becomes economically practical.
Distance Learning
[Apps Table]
The current trend is to have the classroom come to the student rather than have the students come to the classroom. This increases the efficiency of the teachers and reduces the students traveling time.
A student will have the option to use a canned lecture at his/her leisure or to participate in a live lecture, a kind of conference call.
This type of lecture is not new technology in fact in the late 1950's and early 1960's teachers would conduct widely broadcast classes over the television. However the "dull Talking-head" medium was not the best production method. But as we seen advances like Video conferencing we move from a one-way communication link to an interactive two-way link.
Several governmental and private entities are exploring the building of broadband networks for distance learning and other applications.
We have already discussed many of the advantages and disadvantages to this type of learning, in Richard Shanks "Engines for Education" and through classroom discussions,
Video Conferencing
[Apps Table]
Video Conferencing has been in use for over 30 years now, but with limited success. Video Conferencing has evolved from specially equipped conference rooms to small desktop units, mainly, videophones. Perhaps the most notable attraction to video conferencing, is the money companies can save in travel expenses. No longer do people have to sit physically face to face in order to engage in a meeting. In order to have a true, real time meeting, teleconferencing must be used via broadband communications.
The latest compression technology allows users to substantially decrease the size of video files, which in turn, decreases the required bandwidth or frame rate. In fact, broadband links are not required, if you reduce the frame rate enough. However, the video quality improves with a higher transmission bandwidth.
Today, video conferencing is used in a wide variety of professions. Some of the tasks which video conferencing is helping to make easier are:
When conducting a video conferencing session, here are some good suggestions to help make the experience more successful:
Home Shopping and Banking
[Apps Table]
Home shopping implies that a user can sit in his/her home or office with catalogs an promotion material and place orders for merchandise and services. Similarly, home banking refers to a situation where user can transfer funds, obtain statements, and conduct other bank business from a PC.
Obviously, the computer cannot yet dispense cash or accept deposits. Simple cases of home shopping and banking can be handled by transmitting low speed text files and thus do not require broadband facilities. However, we can expect vendors to want to display color pictures, as well as audio on the screen of the potential customer. In such cases, broadband will be required.
At present birdirection broadband communictaion is not readily available and we are forced to use serial connections. Much of the work is done locally on the users PC to shorten the on-line time. In other words the client simply connects, retrieves their information and disconnects and then can go through the information at their leisure.
However good some people may think this is, there are others who are reluctant to adopt this technology. Many people are skeptical of doing there banking completely by computer, they like to physically perform ttransactions through a bank teller.
Similarily many people are hesitant of placing a grocery order over the computer, and even more hesitant of giving a vise number of the computer. Not only is the security an issue but many people bank and shop for strictly social reasons. They are able to get out and interact with others. This may eventually phase out but it is hard to have people change.
The main obstacle in providing a broadband service to the public is naturally cost. Currently, the installation of a T1 line can range from 1500 to 3000 dollars depending on your house location and the type of optoelectritic components you wish to install. The two industries which will likely be the providers of the service are the telephone and cables companies. Each has a distinct advantage.
Telephone Companies have a great networking and routing ability, but unfortunately they use twisted pair wire which does not have the bandwidth to provide broadband services. Cable Companies on the other hand, use coax cable in their network which has a much larger bandwidth which can provide a limited number of broadband services. Unfortunately their networks are passive, one way, and do not have the networking and routing abilities of the telephone companies.
Developments by Rogers Comm. have pushed the development of Canadian broadband communication beyond that of the US. Their vision is to interconnect local broadband cable communication with other narrowband telecommunication on both the local and national level, This will give Rogers the ability to bypass local telecommunication companies and offers customers many more services. For example Cellular phone communication can be routed through Rogers fibre optic trunks to provide customers with cross country service.
Rogers communication has also been involved in a service called CableLink-school which provides over 600 schools with broadband services such as on-line Canadian Encyclopedia and access to a classroom edition of The Globe and Mail. Plans are also in the works to provide Cablelink-Work and Cablelink-Home.
Other smaller telecommunication companies provide specialized services. Stentor for example provides a broadband link for video conferencing between The SkyDome in Toronto and L.A. The cost of this service is not cheap though, considering a one hour transmission costs roughly 1500 dollars.
Here are some Sites worth taking a look at:
McGraw Hill., 1991.
Prentice-Hall Inc., 1988.
Addison-Wesly., 1992.
