The lingo
Wi-Fi is a wireless communication technique for transmitting and receiving information.
![Be warned: Hackers can easily tap into your personal information on weak security software.](/web/20170203183248im_/http://www.smh.com.au/content/dam/images/g/u/4/k/r/0/image.related.articleLeadwide.620x349.gu4krl.png/1486091285916.jpg)
There are set specifications used to implement wireless communication. These are established by the Institute of Electrical and Electronics Engineers, which currently uses 802.11 to transmit data, similar to the way a radio station would use a particular bandwidth to connect with listeners.
The alliance of engineers coined the term Wi-Fi (Wireless Fidelity) to replace the more cumbersome Wireless Local Area Network (WLAN).
![Compatability is the key to powerful Wi-Fi.](/web/20170203183248im_/http://www.smh.com.au/content/dam/images/g/u/4/k/p/k/image.related.articleLeadwide.620x349.gu4krl.png/1486091285916.jpg)
Up to date, and current
The radio frequency which is used to transmit and receive information comes via an Alternative Current (AC). This means the electric current changes direction periodically, instead of a Direct Current (DC), which flows only in one direction.
To establish a wireless connection, an alternative current passes through an antenna of a Wi-Fi enabled device, such as a mobile phone, laptop or tablet.
The current then generates an electromagnetic field which communicates with the antenna of another Wi-Fi enabled device. This is the Wi-Fi signal, and to work effectively, the electromagnetic fields carrying the information which is being transmitted must overlap between two antennae, as shown in the diagram below.
![Electromagnetic signals need to overlap for Wi-Fi to function properly.](/web/20170203183248im_/http://www.smh.com.au/content/dam/images/g/u/4/l/4/6/image.related.articleLeadNarrow.300x0.gu4krl.png/1486091285916.jpg)
For example, while you're having a meal at McDonald's, you turned on your Wi-Fi, triggering the antenna on your laptop to communicate with the antenna attached to the free McDonald's Wi-Fi.
Types of antenna
Based on a pattern of radiation which is generated by the electromagnetic pulse, an antenna can be of two types: directional and omnidirectional. Both of antennae transmit and receive digital information, but the distance and quality of coverage varies.
The directional antenna receives its signal from one specific direction. The benefits of this are that it can be focus specifically on one place, or direction, in need of service, and that it covers a longer distance.
On the flipside, an omnidirectional antenna has a 360-degree horizontal radiation pattern so it functions in all directions, albeit over a lesser distance than directional antennas.
Quality of frequency
Wi-Fi uses either a 2.4 GHz or 5 GHz frequency, which are unlicensed bands allocated by International Telecommunication Union.
There are several variations of Wi-Fi standard which are represented by adding a small letter after the number 802.11 – not dissimilar to the way diamonds are graded. Some popular variants of Wi-Fi are 802.11b, 802.11g, 802.11n and 802.11ac. Each of them vary in data speed, distance they cover, frequency band and the data encoding technique they use.
The latest versions of Wi-Fi communication protocols (802.11n, 802.11ac) use the Multiple in Multiple out (MIMO) communication technique. This supports a number of antennae which work together to cover longer distances and provide faster network speed.
It's improving, but only if they match
To work, all antennae being used in the communication process need to be compatible. That is, they need to use the same frequency band and data encoding techniques.
For example, let's consider two radio stations 92.7 FM and 102.3 AM. The frequency is represented by the numbers, and the FM/AM band represents the coding technique. If you don't tune your radio correctly, you won't hear the music. Wi-Fi works in a similar way, only the frequency and technique are pre-determined by the device you are using.
Security techniques
Wi-Fi uses a number of security techniques – Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), WPA2-PSK (Pre-Shared Key), WPA2-TKIP (Temporal Key Integrity Protocol) and WPA-EAP (Extensible Authentication Protocol), to name a few.
Each of them is a form of "security primitive" used by Wi-Fi providers to protect users and their privacy. Some of these security primitives (WEP and WPA-TKIP, for example) are weak. They can easily be compromised or hacked, even by non-security experts.
Caution when setting up
To connect to a Wi-Fi connection for first time, users need to follow steps:
- Turn on the Wi-Fi connection via settings on your device to see which Wi-Fi is available. Those which can be accessed will be displayed based on their SSID (Service Set Identifier) name.
- Select an appropriate Wi-Fi name from the displayed list. It will then show security settings of the Wi-Fi and will ask you to enter login details.
- You should be cautious. If your selected Wi-Fi connection is not asking for a password when you are connecting to it for first time, it might be a hoax/rogue Wi-Fi access point. In other words, an intruder may have set it up to steal your sensitive information and use it for malicious purposes.
There are over 3 million adult Australian internet users going online with Wi-Fi hotspots. It is technically difficult to count total number of Wi-Fi connections in Australia but according to research and analysis of Australian Communications and Media Authority (ACMA), rural and regional areas of Australia suffer from a lack of hotspot availability.
- Dr Biplob Ray is a lecturer in Information and Communication Technology at Central Queensland's School of Engineering and Technology.