7. Bibliography

Literature Review




Requirements for Literature Review

+ Get students to search for at least 5 sources related to their chosen topic meeting the following requirements:
(a) 3 x online articles (From Google or other search engines)
(b) 1 x Book or eBook (From National Libraries, Info-hub, purchased, owned or borrowed)
(c) 1 x Journal or eJournal (From National Library or Google Scholar)
If you need to buy any eBooks or eJournals, please send me a link by email to tan_hoe_teck@sst.edu.sg

+ All 5 sources must be evaluated to be a good source based on the checklist found here:

First Source (Website)

Wifi is an energy field that is transmitted as waves. The waves have a certain height, distance between them and travel at a certain speed. The distance between wifi waves is shorter than that of radio waves and longer than that of microwaves, giving wifi a unique transmission band that can't be interrupted by other signals. Wifi waves are about 3 to 5 inches from crest to crest. The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0. Chains of 1s and 0s that can be translated into the letters, numbers and codes that make up websites, email and other internet content. Typical wifi waves decrease in amplitude as they travel further from the source which is why the waves are larger to the right and smaller to the left.



Second Source (Website)

A wireless network uses radio waves , just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication. Here's what happens:
  1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
  2. A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.
The radios used for WiFi communication are very similar to the radios used for walkie-talkies, cell phones and other devices. They can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and convert the radio waves back into 1s and 0s. But WiFi radios have a few notable differences from other radios:
  1. They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is considerably higher than the frequencies used for cell phones, walkie-talkies and televisions. The higher frequency allows the signal to carry more data.
  2. They use 802.11 networking standards, which come in several flavors:
  3. 802.11a transmits at 5 GHz and can move up to 54 megabits of data per second. It also uses orthogonal frequency-division multiplexing (OFDM), a more efficient coding technique that splits that radio signal into several sub-signals before they reach a receiver. This greatly reduces interference.
  4. 802.11b is the slowest and least expensive standard. For a while, its cost made it popular, but now it's becoming less common as faster standards become less expensive. 802.11b transmits in the 2.4 GHz frequency band of the radio spectrum. It can handle up to 11 megabits of data per second, and it uses complementary code keying (CCK) modulation to improve speeds.
  5. 802.11g transmits at 2.4 GHz like 802.11b, but it's a lot faster -- it can handle up to 54 megabits of data per second. 802.11g is faster because it uses the same OFDM coding as 802.11a.
  6. 802.11n is the most widely available of the standards and is backward compatible with a, b and g. It significantly improved speed and range over its predecessors. For instance, although 802.11g theoretically moves 54 megabits of data per second, it only achieves real-world speeds of about 24 megabits of data per second because of network congestion. 802.11n, however, reportedly can achieve speeds as high as 140 megabits per second. 802.11n can transmit up to four streams of data, each at a maximum of 150 megabits per second, but most routers only allow for two or three streams.
  7. 802.11ac is the newest standard as of early 2013. It has yet to be widely adopted, and is still in draft form at the Institute of Electrical and Electronics Engineers (IEEE) , but devices that support it are already on the market. 802.11ac is backward compatible with 802.11n (and therefore the others, too), with n on the 2.4 GHz band and ac on the 5 GHz band. It is less prone to interference and far faster than its predecessors, pushing a maximum of 450 megabits per second on a single stream, although real-world speeds may be lower. Like 802.11n, it allows for transmission on multiple spatial streams -- up to eight, optionally. It is sometimes called 5G WiFi because of its frequency band, sometimes Gigabit WiFi because of its potential to exceed a gigabit per second on multiple streams and sometimes Very High Throughput (VHT) for the same reason.
  8. Other 802.11 standards focus on specific applications of wireless networks, like wide area networks (WANs) inside vehicles or technology that lets you move from one wireless network to another seamlessly.
  9. WiFi radios can transmit on any of three frequency bands. Or, they can "frequency hop" rapidly between the different bands. Frequency hopping helps reduce interference and lets multiple devices use the same wireless connection simultaneously.
  10. As long as they all have wireless adapters, several devices can use one router to connect to the Internet. This connection is convenient, virtually invisible and fairly reliable; however, if the router fails or if too many people try to use high-bandwidth applications at the same time, users can experience interference or lose their connections. Although newer, faster standards like 802.11ac could help with that.

Third Source(Website)
Radio Waves and Fields
Radio waves, such as those used to carry cell phone signals, are an example of electromagnetic radiation, moving electric fields that travel at the speed of light. An aluminum-foil barrier cancels the fields, so a radio wave cannot pass through it. A cell phone surrounded on all sides by foil receives no radio waves.
Two-Way Blocking
While the Faraday Cage formed by aluminum foil surrounding a cell phone keeps signals from reaching it, it also blocks signals coming from the cell phone. If you sat inside a Faraday Cage the size of a small room with a cell phone, you would not be able to make any calls because the cell tower would not receive your signal. You could communicate with a partner using walkie-talkies inside the cage, but not to anyone outside it.
Berrey, A. (n.d.). KNOCKING SOME SENSE INTO THE SMARTPHONE (1st ed., Vol. 1, pp. 1-46). Alan Berrey.f
Fourth Source (eJournal)
Tri-band WiFi
The utilization of tri-band WiFi gets new wireless solutions. By this network topology the data rate increased to 5Gbps. The aim of this solution is utilized in enterprise to get increased wireless speed, improved wireless access and increased network capacity by using the IEEE802.11ad or WiGig standard.
Advanced Enterprise WiFi
The new wireless technologies for enterprise environments in 2014 will change the trends of enterprise employees. The different ways will advance in coming years such as:

  • Adoption of 802.11ad which represents the upcoming change in the IEEE 802.11 protocol and increases the data speed into the Gigabit world.
  • Expansion of cloud for small and medium sized enterprises.
  • WiFi- based location analytics will help for different organization to improve the
  • customers and user WiFi experience, to increase business intelligence and to improving
  • the security policy.
  • BY using advance Hot Spot 2.0 and pass point open services.
  • To allow user to log in to the WiFi network by using their social credentials.
  • Fifth Source (eBook)
  • WiFi CERTIFIEDTM AC
    • The WiFi CERTIFIED 802.11ac can deliver data rate which is more than double of a 802.11n network.
    • It supports only the 5 GHz frequency, means signal has less range.
    • It supports multiple antennas that is MIMO(multiple input multiple output).
    • The important feature 802.11ac is beam forming that gets around the general 5 GHz
    • range problem. It States with 802.11ac the signal is propagate for broadcast directly from the access point(AP) to a certain device and back towards the AP.
  • Mohapatra, S., Choudhury, R., & Das, P. (2014). The Future Directions in Evolving Wi-Fi: Technologies, Applications and Services. International Journal of Next-Generation Networks IJNGN, 6(3), 13-22.
http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_11-4/ipj_11-4.pdf

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