What is Wi-Fi(Wireless Fidelity)?

We all know about Wi-Fi, in our mobile, laptop everywhere Wi-Fi is supported. Wi-Fi is a wireless networking technology, by which we can access network or connect with other computers or mobile using a wireless medium. In Wi-Fi, data are transferred over radio frequencies in a circular range.

Wi-Fi (Wireless Fidelity) is a generic term that refers to the communication standard for the wireless network which works as Local Area Network to operate without using the cable and any types of wiring. It is known as WLAN. The communication standard is IEEE 802.11. Wi-Fi works using Physical Data Link Layer. Nowadays in all mobile computing devices such as laptops, mobile phones, also digital cameras, smart TVs has the support of Wi-Fi. The Wi-Fi connection established from the access point or base station to the client connection or any client to client connection within a specific range, the range depends on the router which provides the radio frequency through Wi-Fi. These frequencies operate on 2 types of bandwidth at present, 2.4 GHz and 5 GHz. All the modern laptops and mobiles are capable of use both the bandwidths, it depends on the Wi-Fi adapter which is inside the device to catch the Wi-Fi signal. 2.4 GHz is the default bandwidth supported by all the devices. 2.4 GHz can cover a big range of areas to spread Wi-Fi signal but the frequency is low, so in simple words, the speed of the internet is less and 5 GHz bandwidth is for a lower range of area but the frequency is high so the speed is very high.
Let’s say, if there is an internet connection of 60 MB/s bandwidth, then for 2.4 GHz bandwidth, it provides approx 30 to 45 MB/s of bandwidth connection and for 5 GHz bandwidth, it provides approx 50 to 57 MB/s bandwidth.

History:

The concept of Wi-Fi is very old but its implementation is not so old. At first ALOHA System is a wireless network system that is used to connect Hawaii island via a network in the year 1971. Where the protocol is used for this was ALOHA protocol and the network used packet transfer. Later it’s converted to IEEE 802.11 protocol.
Then in 1985, the Federal Communications Commission (FCC) released a new network for general uses which works on 900 Mhz, 2.4 GHz, and 5.8 GHz bandwidth. This is known as ISM band. Also, IBM introduced a Token Ring LAN network for connecting several computers, it can transfer data at 4 Mb/s speed. Then in 1988, a wireless cashier system was invented based on the Token Ring LAN network known as waveLAN, it operates at 900MHz or 2.4 GHz band and offers speeds of 1 to 2 Mbps. Then it was converted to IEEE 802.11LAN/MAN standards in 1989. ?Then in 1990, IEEE 802.11 Working Group for Wireless LANs is established by Vic Hayes, he was known as the “Father of Wi­Fi” .
Then in 1994 Dr. Alex Hills introduced a research project on the wireless network, which provided coverage of network to 7 buildings wirelessly.
Then in 1996 Commonwealth Scientific and Industrial Research Organization (CSIRO) introduced a wireless network based on the same protocol 802.11, later it was known as IEEE 802.11a standards.

Then after all this in 1997 the first version of Wi-Fi is released officially which is 802.11 and it can support a maximum of 2 Mb/s link speed. Then in 1999, the link speed is increased to 11 Mb/s over 2.4 GHz frequency band, this version is known as 802.11b
Then after a month, the IEEE 802.11a standard is approved officially, which provides up to 54 Mb/s link speed over 5 GHz band, but the signal range is weaker than 2.4 GHz band.
Then in 2003 the speed is increased in a new version, knows as 802.11g. The speed offers up to 54 to 108 Mb/s over 2.4 GHz.
After this two more versions were introduced that are, 802.11i and 802.11e. In 802.11i, the security mechanism was increased and in 802.11e, Voice over Wireless LAN and multimedia streaming are involved.
Then in 2009, 802.11n is developed, which supports both 2.4 GHz and 5 GHz radiofrequency. And these are used simultaneously by dual-band routers and can reach maximum speeds of 600 Mbps.
Then in 2014, a new version was introduced that offers a potential speed of 1733 Mb/s in the 5 GHz band. This version known as 802.11ac. Till now this is the latest version of Wi-Fi.

Applications of Wi-Fi :

Wi-Fi has many applications, it is used in all the sectors where a computer or any digital media is used, also for entertaining Wi-Fi is used. Some of the applications are mentioned below –



    Wi-Fi in our daily life :

  • Accessing Internet: Using Wi-Fi we can access the internet in any Wi-Fi-capable devices wirelessly.
  • We can stream or cast audio or video wirelessly in any device using Wi-Fi for our entertainment.
  • We can share files, data, etc between two or more computers or mobile phones using Wi-Fi, and the speed of the data transfer rate is also very high. Also, we can print any document using a Wi-Fi printer, this is very much useful nowadays.
  • We can use Wi-Fi as HOTSPOTS also, it points Wireless Internet access for a particular range of area. Using Hotspot the owner of the main network connection can offer temporary network access to Wi-Fi-capable devices so that the users can use the network without knowing anything about the main network connection. Wi-Fi adapters are mainly spreading radio signals using the owner network connection to provide hotspot.
  • Using the Wi-Fi or WLAN we can construct simple wireless connections from one point to another, knows as Point to point network. This can be useful to connect two locations which are difficult to reach by wire, such as two buildings of corporate business.
  • One more important application is VoWi-Fi, this is known as voice over Wi-Fi. Some years ago telecom companies are introduced VoLTE (Voice over Long-Term Evolution ). Nowadays they are introduced to VoWi-Fi, by which we can call anyone by using our home Wi-Fi network, only one thing is that the mobile needs to connect with the Wi-Fi. Then the voice is transferred using the Wi-Fi network instead of using the mobile SIM network, so the call quality is very good. Many mobile phones are already getting the support of VoWi-Fi.
  • Wi-Fi in offices: In an office, all the computers are interconnected using Wi-Fi. For Wi-Fi, there are no wiring complexities. Also, the speed of the network is good. For Wi-Fi, a project can be presented to all the members at a time in the form of an excel sheet, ppt, etc. For Wi-Fi, there is no network loss as in cable due to cable break.
  • Also using W-Fi a whole city can provide network connectivity by deploying routers at a specific area to access the internet. Already school, colleges or universities are providing network using Wi-Fi because of its flexibility.
  • Wi-Fi is use as a positioning systems also, by which we can detect the positions of Wi-Fi hotspots to identify a device location.

Types Wi-Fi:

Wi-Fi has several types or standards, which are discussed earlier, here just the name of the standards are defines,

Standards Year of Release Description
Wi-Fi-1 (802.11b) 1999 This version has link speed from 2Mb/s to 11 Mb/s over 2.4 Ghz frequency band
Wi-Fi-2 (802.11a) 1999 After a month of release previous version, 802.11a was released and it provide upto 54 Mb/s link speed over 5 Ghz band
Wi-Fi-3 (802.11g) 2003 In this version the speed was increased up to 54 to 108 Mb/s over 2.4 Ghz
802.11i 2004 This is same as 802.11g but only the security mechanism was increased in this version
802.11e 2004 This is also same as 802.11g, only Voice over Wireless LAN and multimedia streaming are involved
Wi-Fi-4 (802.11n) 2009 This version supports both 2.4 Ghz and 5 Ghz radio frequency and it offers up to 72 to 600 Mb/s speed
Wi-Fi-5 (802.11ac) 2014 It supports speed of 1733 Mb/s in 5 Ghz band

A new version will release in 2020 name as 802.11ax develop by Huawei, which can be supports maximum of 3.5 Gb/s. it will knows Wi-Fi 6.

How Wi-Fi works?

First of all Wi-Fi is a wireless technology for networking, so it uses Electromagnetic waves to transmit networks. We know that there are many divisions of Electromagnetic wave according to there frequency such as X-ray, Gamma-ray, radio wave, microwave, etc, in Wi-Fi, the radio frequency is used. For transmitting Wi-Fi signal there is 3 medium,

  • Base station network or a Ethernet(802.3) connection : It is the main host network from where the network connection being provide to the router.
  • Access point or router : it is a bridge between wired network and wireless network. It accepts a wired Ethernet connection and convert the wired connection to wireless connection and spread the connection as radio wave.
  • Accessing devices : It is our mobile, computer etc from where we use the Wi-Fi and surfing internet.

    accessing devices of wifi

    All the electronics devices read data in binary form, also router or our devices, here routers are provide radio waves and those waves are receive by our devices and read the waves in binary form. We all know how a wave looks like, upper pick of the wave is knows as 1 and lower pick of the wave is knows as 0 in binary. Like below:
    binary wave

Wi-Fi has some more terminologies:

  • SSID (Service Set Identifier) : It is a 32 character name which identifies the Wi-Fi network and differentiate one Wi-Fi to another Wi-Fi. All the devices are attempting to connect a particular SSID. Simply, SSID is the name of the wireless network.
  • WPA-PSK (Wi-Fi Protected Access- Pre-Shared Key) : It is a program developed by the Wi-Fi Alliance Authority to secure wireless networks with the use of Pre-Shared Key(PSK) authentication. WPA has 3 types, such as WPA. WPA2, WPA3. It is a way of encrypting the Wi-Fi signal to protect from the unwanted users.
  • Wi-Fi uses Ad-Hoc networks to transmit. It is a point to point network without any interface.

How signals are reached to our devices:

how wifi signals reached to our devices

Advantages of Wi-Fi

  • Tt is a flexible network connection, no wiring complexities. Can be access from any where in the Wi-Fi range.
  • it does not require regulatory approval for individual users.
  • It is salable, can be expanded with using Wi-Fi Extenders.
  • It can be set up in a easy and fast way. Just need to configure the SSID and Password.
  • Security in high in Wi-Fi network, its use WPA encryption to encrypt radio signals.
  • It is also lower in cost.
  • It also can provide Hotspots.
  • it supports roaming also.

Disadvantages of Wi-Fi

  • Power consumption is high while using Wi-Fi in any device which has a battery, such as mobile, laptops, etc.
  • Many times there may be some security problems happen even it has encryption. Such as many time known devices become unknown to the router, Wi-Fi can be hacked also.
  • Speed is lower than direct cable connection.
  • It has lower radiations like cell phones, so it can be harm humans.
  • Wi-Fi signals may be affected by climatic conditions like thunderstorm.
  • Unauthorized access to Wi-Fi can happen, because it does not has firewall.
  • To use Wi-Fi we need a router, which needs a power source, so at the time of power cut we cannot access the internet.

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3rd year student of Information Technology JADAVPUR UNIVERSITY

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