computer science

South African wireless community networks

South African wireless community networks is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand South African wireless community networks rather than just read about it. In short: South African wireless community networks are wireless networks that allow members to talk, send messages, share files and play games independent of the commercial landline and mobile telephone networks. Most of them use WiFi technology and many are wireless mesh networks.

Key takeaways

South African wireless community networks belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect South African wireless community networks to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of South African wireless community networks from memory before moving on to harder problems.

Reference excerpt

South African wireless community networks are wireless networks that allow members to talk, send messages, share files and play games independent of the commercial landline and mobile telephone networks. Most of them use WiFi technology and many are wireless mesh networks. A wireless community network may connect to the public switched telephone network and/or the Internet, but there are various restrictions on connectivity in South Africa. Wireless community networks are particularly useful in areas where commercial telecommunications services are unavailable or unaffordable. Wireless User Groups (WUGs) in South African cities build up infrastructure and applications, as well as training members in wireless technology skills. Therefore, WUGs provide a fertile ground for new technology and applications that may have large social benefits in informal communities and rural areas of South Africa and neighboring countries.

Background: South African Telecommunications Environment South Africa has the best developed and most modern telephone system in Africa. There are almost 110 combined fixed-line and cellular telephones per 100 persons. There are 5.1 million Internet users. The network is 99.9% digital. The fixed-line monopoly of Telkom SA, a listed company in which the government is the largest shareholder, expired with the licensing of Neotel as South Africa's second national operator, starting operations in November 2007. Neotel is licensed to provide the entire range of telecoms services with the exception of full mobility. Neotel is expanding their network fast, but so far is concentrating on urban areas. The South African mobile communications market is growing fast. The country's three cellular network operators (Vodacom, MTN and Cell C) have over 39-million subscribers, or nearly 80% of the population. However, although there are now over one million broadband subscribers, mostly using ADSL or HSDPA, bandwidth remains relatively limited and expensive. Major cities such as Cape Town, Durban, Johannesburg and Pretoria have launched public-private initiatives to build their own broadband networks to provide cheaper voice and data services. For example, the city of Tshwane, which includes Pretoria, is testing delivery of broadband Internet and voice services on their new metro-wide fibre-optic network using wireless hot spots to provide ADSL access. In the meantime, the high cost of broadband access has stimulated development of Wireless User Groups. The WUGS are not allowed to sell internet connectivity, since they are non-commercial community networks. Although non-profit and operating in the license-exempt spectrums, their legal status is not clear. In October 2007, JAWUG requested clarification on whether it required a radio frequency spectrum and/or ECNS license for its activities. Telkom provides relatively poor voice and internet service in underdeveloped rural areas of South Africa, although it is investigating ways to improve service using wireless technology. The Independent Communications Authority of South Africa has licensed several small telecoms firms to operate regional networks in remote, under-served areas of the country. Bokone Telecoms in Polokwane and Amathole Telecoms in the Eastern Cape are experimenting with WiMAX technology to provide service. However, due to relatively high costs and low revenue potential, these initiatives are moving slowly. There is room for more innovative approaches. Currently, VoIP (Voice over Internet Protocol) service is allowed only in areas where less than five percent of the population have access to a telephone, and WiFi is restricted to use by individuals or organisations within the confines of their own premises. The argument is that low-cost or free VoIP over WiFi would destroy the incentive for commercial network providers to upgrade rural networks. However, several commentators consider that this policy is counter-productive. As discussed later, many wireless community networks deliberately ignore the restrictions.

Sample City-Based Wireless Community Networks

Most cities in South Africa have one or more non-profit groups collaborating in running Wireless User Groups. Descriptions of a sample are given below, with information derived from their web sites.

Johannesburg WUG (JAWUG) Jawug is located in Johannesburg, the largest city in South Africa. Jawug, founded in 2002 by Kieran Murphy, Justin Jonker, Ross Clarke and Steven Carter, was the first wireless user group in South Africa, starting as an experimental network between four students, then quickly expanding into a much larger network by interconnecting several separate wireless mesh networks. Jawug is not an ISP. Its network is used purely for non-commercial and educational purposes. Jawug is regularly used for experimental deployment of new technologies. There are currently four links which interconnect the Jawug network with PTAWUG, the Wireless User Group in Pretoria, to the north of Johannesburg. Jawug and PTAWUG work together closely - Jawug helped to get PTAWUG off the ground. Jawug also gives technical assistance to new wireless users groups like Port Elizabeth Wireless Users Group (PEWUG). A core team of members manage all routing and highsite maintenance. Regular wugmeets are held to discuss network issues and future plans. Jawug has a membership base of approximately 300 locations, and is constantly expanding.

Pretoria WUG (PTAWUG)

The Pretoria WUG was founded on 28 July 2007. The PTAWUG constitution guarantees openness, free participation and equality to all members of the Wireless User Group. PTAWUG is exclusively funded by donations from the community. Volunteers conduct highsite installation and maintenance in their spare time. PTAWUG is the 5th largest wireless network organization in the world with about 600 member connections (7 October 2009). To avoid rental costs, all highsites are on privately owned properties, mostly in high areas with a good line of sight to the surrounding areas. The network has a number of towers, with the other highsites located on tall buildings or at private residences in strategic places. The Pretoria Wireless Project is another community based network in the city, which has been connected to the Pretoria WUG network as of 3 February 2008.

Cape Town Wireless User Group (CTWUG)

… excerpt ends here. Continue reading the full article.

Illustrations

CTWUG Logo

Worked examples

Example 1 — a first encounter with South African wireless community networks

Start with the simplest possible case. Write down what South African wireless community networks claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to South African wireless community networks before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about South African wireless community networks ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of South African wireless community networks

In research: South African wireless community networks appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses South African wireless community networks in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: South African wireless community networks is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mesh networking, Telecommunications in South Africa, so understanding it makes those chapters shorter.
In everyday life: Look for South African wireless community networks outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study South African wireless community networks in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what South African wireless community networks means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain South African wireless community networks out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is South African wireless community networks in simple terms?

Why does South African wireless community networks matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study South African wireless community networks?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on South African wireless community networks.