# K-12 School Computer Networking/Chapter 31
## 1. Definition and Popularity

In recent years, Wi-Fi becomes a new word in our e-dictionary. Every digital user knows more or less about “Wi-Fi”. But, what is the accurate definition of Wi-Fi? Let’s take a closer look of it.
Wi-Fi (Wireless Fidelity) is the name of a popular wireless networking technology that uses radio waves to provide wireless high-speed Internet and network connections. The Wi-Fi Alliance, the organization that owns the Wi-Fi (registered trademark) term specifically defines Wi-Fi as any "wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards."
Many applications and devices (especially palm devices) support Wi-Fi. These include video game consoles, home networks, PDAs, mobile phones, major operating systems, and other types of consumer electronics (e.g. laptop, notebook, and netbook). Any products that are tested and approved as "Wi-Fi Certified" (a registered trademark) by the Wi-Fi Alliance are certified as interoperable with each other, even if they are from different manufacturers.
Today, people use smart phone, laptop, netbook, and other palm devices which support Wi-Fi. The coverage of Wi-Fi is getting wider and wider in many countries. One may notice the sign “Wi-Fi” in luxury hotels, upscale residential areas, airports, some train stations, libraries, college campuses, bookstores, cafes, and some restaurants. It is so popular that it becomes a part of our daily life to use Wi-Fi.
What’s so good about Wi-Fi technology? Everything
It allows us to access to internet with high speed and low cost without any physical wire. Unlike Bluetooth and infrared technologies, Wi-Fi has much wider coverage and much higher transmission speed. Although it has much narrower radio range, it is still the best option for us to enjoy the access of internet without wire.
Many of us realize the benefit of having a Wi-Fi enabled device. One group of these people is adolescence. They enjoy to have smart phones, iPod Touch, and laptops/or netbooks. This brings up potential uses of Wi-Fi in K-12 schools especially middle and high schools.

## 2. Potential uses of Wi-Fi in schools

Today’s children are digital natives. Today’s adolescence love digital devices: iPhone, iPod Touch, smart phone, and laptop/netbook. With Wi-Fi service on school campus, students with Wi-Fi enabled devices could enjoy surfing on internet during school time. This will most likely to extend their time of practicing technology skills, as well as academic studying.
Technology to the Kid
Education technology most often focuses on bringing technology to the school and classroom. A Wi-Fi enabled laptop program brings technology to the kids. As the figure 1 below illustrates, Wi-Fi can connect the student studying at home to the school’s intranet and its content and instructional software. The school’s intranet is not the Internet with content inappropriate for students (pornography, gambling, etc). By limiting access to a private, school-managed intranet, students cannot be reached by online predators.
File:Sunding Figure2.jpg Figure 1 Wi-Fied school intranet content and instructional software
Affordability
One of the major attractions to Wi-Fi is its cost per subscriber. Table 1 below illustrates its cost relative to other technologies in terms of cost per home passed. This low cost per home passed brings it into the realm of possibilities for a school district to build its own private access network independent of commercial operators.
File:Wifi-table15.pdf
Table 1 Wi-Fi--the least expensive access technologies on the market
Government program
One-to-One computing program and One Laptop Per Child (OLPC) program have enhanced thousands of students’ technology skills as well as academic improvement.
Public school district receives in annual tax money per student (federal, state and local funding), some school district can equip each student with a Wi-Fi-enabled laptop extending the school intranet’s content and application to the student at home (an example: Henrico County school district of Virginia, http://www.henrico.k12.va.us/whyhcps/technology.html ). Also, nearly 90% of Lottery money collection flows to state government to support public schools financially. These enable a school district to deploy a Wi-Fi network linking student laptops to school intranet content and instructional software 7x24x365 for an estimated $1 per month per student or a one-time cost of about $40 (depending on population density).
A networked (commercial internet access) laptop or netbook might be standard issue for children of higher social-economic status (SES) and may one day be inevitable in American homes and classrooms. How far off is that day? Ten years or two years? It depends on ordinary people’s affordability. Below is the Figure 2 which shows the trend of Wi-Fi enabled laptop in US’s schools.
File:Sunding figure1.jpg Figure 2: Trend of one-on-one networked/Wi-Fi enabled laptops in US schools
Applications
Applications for instruction are the real power, the true value of the Wi-Fi network. A Wi-Fi network and one-to-one computing do little for a student’s instruction in and of themselves. The power of the network lies in the applications residing on the school’s intranet accessed by students via the Wi-Fi network and the one-to-one computing program.
A student armed with a Wi-Fi-enabled laptop loaded with interactive literacy instructional software would find their daily instruction greatly enhanced. One example would be an English language learner whose English vocabulary would be improved using sight-sound relationships made available via the laptop and software. At the high school level, a student studying for their American Tests (ACT) can improve their rate of reading and test taking skills via a series of practice tests offered by these software products. Another example might be a student who has missed a good deal of class due to family emergency can do “credit recovery” (NovaNet is one example).
Interactive software on a student’s Wi-Fi-enabled laptop enhances a student’s number sense. A number of software products offer math games that enable practice and development of number sense. At the high school level 3-D graphics are very helpful in understanding trigonometry, physics and biology.
Many students find it much easier to write on a computer than with pen and paper. As a result, students are more willing to experiment with their writings (thus writing more) and share drafts of their writings with their peers and teachers. The collaborative learning process is enhanced. The Wi-Fi-enabled laptop empowers a student to use email thread dialog to discuss materials with both the teacher and their peers. Student blogs encourage writing as a means of student expression. Some see a laptop and laptop applications (word processing, email, web pages, etc) as being ‘real life”, something they can use as everyday problem solving skills where as traditional pen and paper is seen as “non-real life”.
Some interesting Statistic Data
The Federal Communication Commission reports that broadband penetration in the US approaches 90% throughout most of the US area.
According to the data and the survey of Palm Beach County (Florida) school district (www.palmbeach.k12.fl.us ), • 48% said they would give up beer before giving up Wi-Fi; • Nearly 60% of the students surveyed said they wouldn't attend a school or a college that doesn't offer free Wi-Fi; • More than 50% of the students said they have checked MySpace or Facebook or sent or received email while using a laptop in class; • nearly 50% had sent an instant message to a friend; • 55% Students log in at coffee shops or restaurants, 47% in parks, 24% in their cars, in addition to libraries and laboratories; • 43% had reached Wi-Fi using a handheld device instead of a laptop or desktop; • Fully 90% believe Wi-Fi access is as essential to an education as a classroom or a computer;
Allocation of tax money to public schools ranges from $5,000 to $7,000 per student per year. That means to provide a Wi-Fi-enabled laptop to each child would cost less than 10% of that district’s annual tax dollar per-student allocation;
ABI Research (www.abiresearch.com ) said Wi-Fi penetration should reach 99% of all campuses by year 2013;
The US Census Bureau enumerated the following numbers of school systems in the United States in year 2002 (published once every five years) • 13,506 school district governments • 178 state-dependent school systems • 1,330 local-dependent school systems • 1,196 education service agencies (agencies providing support services to public school systems) • 45 million students (K-12 grades) in US public schools as of October 2005
Conclusion
There is a huge Wi-Fi market in K-12 schools throughout 50 states; there is a big possibility to build up “wireless K-12”; there is a potential uses of Wi-Fi in schools. Let’s discuss the pros and cons of using Wi-Fi in schools.

## 3. Advantages and Challenges

Like any other new gismo, to use Wi-Fi technology in K-12 schools certainly has its advantages and challenges. The following a)—i) lists the most common (but not least) pros and cons.
Advantages
1). Easy to setup WLAN and lower cost
Wi-Fi allows local area networks (LANs) to be deployed without cables and wires for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
Wireless network adapters are now built into most laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in even more devices.
2). Convenient to use
With Wi-Fi service, students, faculty and staff can conveniently use their Wi-Fi enabled devices anywhere in the school campus during school time.
3). Enhance technology skills
The longer the students use computer and internet/intranet, the more digital skills they will learn.
4). Improve academic grade
Students who spend more time on school’s intranet usually get more information of their subjects, and most likely should be easier to do their homework. Therefore, improving of the grade is automatic.
Challenges
1). Channel Limitations
In order to have digital equity and to optimize the Wi-Fi technology to everyone in the world, each country has different spectrum assignments and operational limitations. For instance, U.S. uses channel 1, 6, 11, and Europe’s is: 1, 5, 9, and 13. General speaking, Most of Europe allows for an additional 2 channels beyond those permitted in the U.S. for the 2.4 GHz band. (1–13 vs. 1–11); Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect.
2). Short range
Wi-Fi wireless network ranges are vary, it depends on the type of the equipment, use of antenna, at an open environment or in a building that has many walls and furniture. The materials of the walls and floors could have great influence of signal transmission range. Wi-Fi is a low power radiation signal, and therefore it couldn’t go through metal, water and any other high density materials.
In a typical office, Wi-Fi network transmitting distance can be 75-150 ft. In an empty room/building or outdoor open area, it can reach to 1000ft or further; with a good antenna and an optimized position, it is possible to reach to 1000 ft or further. So, one should always watch the range while using a Wi-Fi device.
3). Speed decreasing by distance
Wi-Fi speed is decrease with the distance from the hub/device. The further, the slower. For instance, a build-in laptop Wi-Fi receiver’s speed could be 11Mbps within 100 ft. When one moves further than 100ft, the data speed will decline to 5.5Mbps, then to 2 Mbps，and finally to 1 Mbps. Because most DSL and Cable speeds are all lower than 1Mbps, Wi-Fi‘s is good enough to be accepted.
4). Radiation Instability
Wi-Fi radiation is not stable. It can be interrupted by internal or external causes in any minute. Suffering from the interrupting of online activities is one of the disadvantages with today’s Wi-Fi technology. It needs greatly improvement.
5). Threats to security
The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2), which began shipping in 2003, aims to solve this problem and is now available on most products. Wi-Fi Access Points typically default to an "open" (encryption-free) mode. Novice users’ benefit from a zero-configuration device that works out of the box, but this default is without any wireless security enabled, providing open wireless access to their LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI). Wi-Fi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network, unless another security method is used to secure the data, such as a VPN or a secure web page.
6). Wi-Fi and network abuse
Some digital-smart students may play tricks with their Wi-Fi enabled devices. They may break-in and attack the school’s network.
7). Traffic jam
It will be inevitable to stick on the traffic jam due to the large amount of Wi-Fi devices using in the school campus. To reduce the jam, school district need to increase the relevant budget in order to upgrade the equipment.
8). Interference with other appliances
Microwave, cordless phone, baby monitors, security cameras, Bluetooth devices, Heart rhythm device, (in some countries) Amateur radio, video senders are all operated in 2.4GHz spectrum, shared the band with Wi-Fi. That means, they can interfere each other. In most cases, they only slow down Wi-Fi’s speed without stopping its operating. To prevent interference, you can separate your devices which use the 2.4 GHz band from the Wi-Fi devices. Move them further from Wi-Fi equipment, or change Wi-Fi channel if applicable.
9). Channel pollution
Wi-Fi pollution, or an excessive number of access points in the area, especially on the same or neighbor channel, can prevent access and interfere with the use of other access points by others, caused by overlapping channels in the 802.11g/b spectrum, as well as with decreased signal-to-noise ratio (SNR) between access points. This can be a problem for a school that is located in high-density areas, such as large apartment complexes or office buildings with many Wi-Fi access points (Schools in Manhattan can be an example). General guidance to those who suffer these forms of interference or network crowding is to migrate to a Wi-Fi 5 GHz product, (802.11a, or the newer 802.11n if it has 5 GHz support) because the 5 GHz band is relatively unused, and there are many more channels available. This also requires users to set up the 5 GHz band to be the preferred network in the client and to configure each network band to a different name (SSID). It is also an issue when schools seek to provide large area coverage. This openness is also important to the success and widespread use of 2.4 GHz Wi-Fi.
10). Harmful radiation
Followed by more advanced technology, human being live in more high-density electromagnetic field. Wi-Fi’s radiation could cause some unknown diseases. It is estimated harmful for our hearth. Therefore, Wi-Fi devices are prohibited to sell and to use in some countries like Germany and China. An example of the policy is iPhone must disable its Wi-Fi function before imported to China.

## 4. Conclusion and Recommendations

This paper explains opportunities for Wi-Fi in schools. Wi-Fi is primarily a wireless and low cost effective means of extending the school district’s intranet-based content and applications to the student body beyond the school campus and outside of school hours equating to any time, anywhere instruction. Wi-Fi in school’s education is best explained via the “3 A’s” of Access (how Wi-Fi provides student network access); Affordability (how a school district can afford a district-wide network) and Applications (the real value of the network or how the Wi-Fi network will be applied to instruction).
There are a number of market drivers for Wi-Fi in schools including one-to-one computing programs, the desire to extend instruction beyond the classroom (i.e. “technology to the kid”), government mandates and funding. However, given the march of technology, the Wi-Fi-enabled laptop for school kids might be inevitable. Will the school district lead or follow?

## 5. REFERENCES:

1. Thane Terrill, 2006. Technology on a Shoestring. New York, NY: Teachers College Press
2. Online Wiki Book "K-12 School Computer Networking” http://en.wikibooks.org/wiki/K-12_School_Computer_Networking
3. WIKIPEDIA: http://en.wikipedia.org
4. Henrico County of Virginia public school district website: http://www.henrico.k12.va.us/whyhcps/technology.html
5. Palm Beach County (Florida) school district: http://www.palmbeach.k12.fl.us
6. The United States Census Bureau: http://www.census.gov
7. The Federal Communication Commission: http://www.fcc.gov
8. ABI Research company: http://www.abiresearch.com
9. Search Engine: http://www.baidu.com
10. Webpedia: http://www.webopedia.com