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With Tom Worthington FACS, Visiting Fellow, Department of Computer Science, Australian National University
Wireless broadband technologies, 8 May 2002
The Minister for Communications, Information Technology and the Arts, released terms of reference for an inquiry into wireless broadband technologies on 4 April 2002:
The Standing Committee, chaired by MHR Christopher Pyne, has been asked to conduct an inquiry into the current and potential use of wireless technologies (including wireless LAN, 3G, Bluetooth, LMDS and Wireless Local Loop) to provide broadband communications in Australia.
Broadband technology is widely considered to be a crucial driver in ensuring that Australia derives maximum economic and social benefit from the information economy. It is also clear, both here and overseas, that both fixed and mobile wireless technologies provide a real opportunity to offer affordable broadband solutions for residential and business users, competing strongly with DSL and cable based delivery systems.
From: WIRELESS BROADBAND TERMS OF REFERENCE, Media release 75/02, 4 April 2002
But what are wireless LAN, 3G, Bluetooth, LMDS and Wireless Local Loop and why are they important? How might be better than DSL and cable based delivery systems, and what are they? What is the nation's current broadband strategy? How broad is broadband? How much broadband can we afford? How necessary is it?
The Issues Around Canberra
The problem is that systems like Transact can't easily run cables in newer suburbs because there aren't power poles to hang them on. Also it is expensive to run cable out into the bush, where the customers are a long way apart. Instead we can use "Wireless Broadband", with radio waves carrying Internet data. There are an assortment of technologies, adapted from office networks, TV broadcasting and mobile telephones. No one is quite sure which is best, what it will cost or who should be allowed to use it, which is why there is an inquiry.
One technology with a lot of potenital is the wireless LAN. If you see someone at the ANU's Purple Pickle cafe with a laptop which has a strange bump sticking out the side, that is a wireless LAN card. A tiny radio transmitter in the card communicates with base stations in the computer science building across the road and from there to the Internet. A card costs about $300 and anyone can buy a couple and start communicating. These only work about 100 m, but if you use an antenna on your roof (similar to a TV antenna) the system will work about 30 km.
There are DIY networks springing up around Australia. A local computer store in a country town could put an antenna on their roof to service the surrounding region. The catch is that this service isn't fast enough for TV and the government will have nightmares about everyone setting up their own network.
Other technologies which the enquiry is looking at:
- 3G (eg UMTS, W-CDMA): These are beefed up mobile telephone systems. The catch is you have to buy a new more expensive mobile telephone (several thousand dollars) and at present the telephone companies are charging about a THOUSAND TIMES AS MUCH for using the Internet this way as for wired service. This service isn't fast enough for TV and would send you broke quickly anyway. ;-)
- BLUETOOTH: Designed for wireless headsets for mobile telephones and very short range (30 meters) communications. It is not clear why this was included in the broadband enquiry.
- LMDS, MMDS, WLL: These are assorted radio technologies developed for supplying first a telephone or TV and later Internet. You have a TV-like antenna on the roof and plug it into your phone, TV and/or computer. These are something the phone company installs, rather than a DIY activity like wireless LANs. The ANU is working on technology one called BushLAN designed to work 100 km and providing 100 kbps (about twice as good as a dial-up Internet service, but not good enough for pay TV). Technical details: Local multipoint distribution system (LMDS), Multipoint Microwave Distribution System (MMDS), wireless local loop (WLL)
- SATELLITE: You use an antenna similar to that for satellite TV. Several services are available in Australia, but this costs more than a terrestrial service.
The minister requested that the inquiry report by the end of the year. The report would be considered by the Broadband Advisory Group (BAG) and Government. The committee adopted the inquiry on 15 April 2002, so far there have been no submissions published, or public hearings scheduled and one media release has been issued.
The terms of reference of the committee are brief and clear, but there are major technical and political issues therein:
... inquire and report on the current and potential use of wireless technologies to provide broadband communication services in Australia, including regional Australia, having particular regard to the following:
- The current rollout of wireless broadband technologies in Australia and overseas including wireless LAN (using the 802.11 standard), 3G (eg UMTS, W-CDMA), bluetooth, LMDS, MMDS, wireless local loop (WLL) and satellite;
- The inter-relationship between the various types of wireless broadband technologies;
- The benefits and limitations on the use of wireless broadband technologies compared with cable and copper based broadband delivery platforms;
- The potential for wireless broadband technologies to provide a 'last mile' broadband solution, particularly in rural and regional areas, and to encourage the development and use of broadband content applications;
- The effect of the telecommunications regulatory regime, including spectrum regulation, on the development and use of wireless broadband technologies, in particular the Radiocommunications Act (1992) the Telecommunications Act (1997), and Parts XIB and XIC of the Trade Practices Act:
- Whether Government should make any changes to the telecommunications regulatory regime to ensure that Australia extracts the maximum economic and social benefits from the use of wireless broadband technologies; and
- Likely future national and international trends in the development and use of wireless broadband technologies.
From: Inquiry into Wireless Broadband Technologies, Standing Committee on Communications, Information Technology and the Arts, Parliament of Australia Web Site
There was previously a flurry of government broadband inquiries around 1994. The Internet was still seen as an experimental system for academics and the public debate was over the "information superhighway". Roger Clarke and I produced the Australian Computer Society submission, Vision for a Networked Nation: The Public Interest in Network Services, for the ASTEC Working Group on Research Data Networks; the Broadband Services Expert Group; the Bulletin Boards Task Force; and the Senate Standing Committee on Industry, Science, Technology, Transport, Communications and Infrastructure. The government adopted part of the title and some of the content for its policy:
- The Networked Nation, The Australian Science and Technology Council, 1994
- Networking Australia’s Future, Final report, Broadband Services Expert Group, 1994.
- Networking the Nation, DCITA, 2000
However, a rollout of duplicated cabling for analogue pay TV by Telstra and Optus sidetracked broadband implementation in Australia. This rollout did not extend beyond parts of the major capital cities. The cabling was was not designed for broadband data, but for TV with some telephone and data services.
For an overview of wireless technology see: The World Will Go Wireless
Some more recent Australian developments:
The operation of most digital communications in this band is defined by the IEEE802.11 standard and its successors. The use that was first promoted and which is still the major use of network interface cards (NICs) to IEEE802.11 is local area networking. In fact the radiated power produced by commercial NICs is sized appropriately for this use, in the range 35-50 mW. This provides acceptable indoor range, negligible biohazard, and allows many networks to coexist in the same channel without undue interference. The basic principle of the infrastructure mode (the most useful to examine) is for one NIC to be connected to a wired backbone LAN. This station is called the access point, and acts like a hub. All other stations logged on to the access point use the same channels and spreading sequence, and effectively communicate with the access point in a wireless LAN with total data capacity that may be up to 11 Mb/s. Data rates of 45 Mb/s have been announced...
Assume that a high bandwidth Internet link is available in a country town, to which a wireless access point is connected. The access point signal is taken to a nearby high point or mast. An antenna is connected, designed to produce a substantially horizontal radiation pattern, tailored in azimuth to the population area it is designed to serve. A bi-directional amplifier is used, to reach the maximum allowable EIRP (Effective Isotropic Radiated Power).
Subscribers to the ISP service must have line of sight to the access point antenna, though community sharing is quite possible. Each subscriber has an NIC and a highly directional antenna pointing towards the access point antenna, again within the ACA limits.
What will have been achieved is a possible 11 Mb/s service area of 5 km radius (assuming an antenna omnidirectional in azimuth), probably capable of supporting 50-70 broadband users with a reasonable fraction of this data rate at most times. Greater range is possible at lower rates, as shown in case study 2. These range extensions have been achieved over the indoor 100 m by eliminating problems in the radio path, providing highly directional antennas, and boosting the central power where highly directional antennas are not possible...
Take-up of ADSL in a Networking the Nation trial in Launceston resulted in only 180 subscribers (target of 2500 by mid 2002). The Commonwealth Government recently announced a subsidy to waive the $A189 connection fee and reduce the monthly fee to $A50.50 from $A89 [Mercury, 11-07-2001]. It would be interesting to see the effect of an equivalent subsidy ($A1.1M over two years) applied to wireless broadband in a similar city without broadband services...
The policies of the Commonwealth and of the political parties should provide incentives (parallel to the ADSL and other initiatives) for the establishment of wireless ISPs in regional Australia, as soon as possible. Community access centres should also be capable of managing such funds and services.
From: Broadband Internet Access in Regional Australia, Arthur Sale, Journal of Research and Pratice in Information Technology, Vol 33 Number 4, 2002.
The Internet has long outgrown its beginnings as a message system. It now hosts a multitude of video and audio applications. However, the current quality of real time delivery is insufficient for streaming media video. This paper examines what isneeded to improve this quality to acceptable levels by considering the issues involved for the Internet to support broadcast television.
However, for most users of the current Internet the quality of streaming media,particularly of streaming media video, is generally very poor. The pictures are small, the video isjerky and lossy, and servers repeatedly crash when asked to stream a single feed to many userssimultaneously...
The service can be supported as a result of evoluntary upgrades that are already being deployed for other commercial reasons.
From: Issues in the Deployment of Digital TV on the Internet, Chris Bennett, Journal of Research and Pratice in Information Technology, Vol 33 Number 4, 2002.
- In regional Australia the telephone infrastructure is unsuitable for both present day and future Internet service. Regional Australia includes hundreds of thousands of Australians living within ~100 kms of major regional town centres.
- Most network technologies rely on large population densities for a return on infrastructure investment. For remote services in regional Australia, a low cost infrastructure is required which can service a very low density of users.
- Low frequency VHF television can already provide high bandwidth (5 MHz), long distance (> 100 kms) reception not limited by ghosting induced data corruption.
- A 100 kbps long range VHF wireless data service would require < 100 Watts RF power at each wireless modem. There would be no large scale infrastructure.... VHF TV does not need expensive repeaters or satellites!
The Research School of Physical Sciences and Engineering (RSPhysSE) and the Faculty of Engineering and Information Science (FEIT) of the Australian National University (ANU) are developing a new wireless technology - the Bush Local Area Network (BushLAN).
Each LAN extends around a regional centre equipped with a base station to the Internet backbone. BushLAN allows a one hop route to connect remote users.
We are aiming for a minimum data rate of 100 kbps (higher data rates are feasible).
From: Why BushLAN?, Research School of Physical Sciences and Engineering, ANU, 2002
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Copyright © Tom Worthington 2001-2002.