802.11 Wireless Networking Protocols Explained

By: Daniel Imbellino
Updated: Feb 28, 2013

WiFi, or “Wireless Fidelity”, is a descriptive acronym for describing the use and implementation of 802.11 wireless local area networking protocols (WLAN). There are several main types of 802.11 (as defined by the Institute of electrical and electronics engineers) standards, also known as A/B/G/N networking protocols. If you connect to your internet at home using a wireless network, or connect to a WiFi network at say a coffee shop, or airport, you have undoubtedly used 802.11 Technology. The 802.11 protocols define a working set of standards for vendors of wireless networking equipment to abide by in order to help ensure interoperability among devices from different vendors, as described by the IEEE.

Some of the 802.11 Networking Protocols:
802.11 A: 54Mb/s at 5GHz
802.11 B: 11Mb/s at 2.4GHz Compatible with 802.11G and 802.11N protocols
802.11 G: 54Mb/s at 2.4GHz
802.11 N: Up to 1Gb/s can run at 2.4GHz or 5GHz

802.11 N makes use of MIMO technology (multiple input multiple output) that uses multiple antennas to achieve greater throughput that its predecessors. Manufacturers don’t always adhere to 802.11 standards when designing their devices. Many 802.11 networking devices employ proprietary technology to enhance reception and throughput of data transfer.

Wireless Local Area Networking devices use frequencies in the microwave range as a medium to encapsulate data onto. Data is enclosed in what is known as an “electro-magnetic carrier signal.” Microwaves are electro-magnetic radio frequencies that travel through the air, and in many cases matter. What is a frequency? Frequency is how many times a particular action is performed over a given period of time. Frequency is measured in “Hertz”, named after the famous German physicist Heinrich Hertz. One Hertz is also known as “one cycle per second.” If an action took place 900 times per second, we could say it functions at 900hz.

802.11 wireless networking transceivers (transmitter/receiver) Function in the 2.4GHz, and 5GHz frequencies ranges. Giga in the sense of computers and networking literally means “billion.” Giga refers to something that should be represented on a large scale. So, 2.4GHz means 2.4 billion, and in the sense of wireless networking, it means 2.4 billion complete cycles per second of an electro-magnetic waveform. We could also say that a wireless transmitter produces thru an antenna, 2.4 billion complete electro-magnetic waveforms per second, radiating away from the antenna source. We could also call this, 2.4 billion oscillations per second of a given waveform.

In the case of electro-magnetic frequencies, the higher the frequency, the shorter the wavelength of the corresponding wave. In turn, the lower the given frequency of a waveform, the longer the corresponding wavelength will be. This is analogous to say, hearing the bass of music from a distance, while not hearing the treble. This is because the high frequency sounds have shorter wavelengths than the low frequency sounds.

The 2.4GHz frequency, also part of the 3rd generation of wireless networking media, also known as “3G”, has a fairly good ability for its signals to penetrate through objects. On the other hand, higher frequency signals such as the 802.11A standard, which uses the 5GHz frequency spectrum, cannot penetrate through obstacles as well because of their shorter wavelengths. This is also a major complication with the newer 4th Generation (4G) devices today, such as smart phones, etc. Millions of consumers complained about how their new iphone, or other smart phone kept constantly dropping signals, sporadically. This is because 4th Generation wireless devices use frequencies that are much higher than their 2.4GHz counterparts, and therefore have much shorter wavelengths. Shorter wavelengths of electro-magnetic waves have less energy to dissipate as they travel through objects, regardless of the strength of the transmitting device or antenna. The telecommunication Co’s quickly figured out they were going to need a lot more power coming from their transmitting base stations. This is what happens when you don’t properly test a technology before implementing it, as in the case of 4G as a whole.

Electromagnetic waves travel at the speed of light, or so does their potential energy. We can use this value, say the speed of light measured in meters per second, to find the wavelength of a 2.4 GHz frequency. The speed of light is 299,792,458 M/s. We can divide this value by our given frequency (2.4GHz), to get our wavelength:

0.122 meters, or about 2.8 Inches. This would be the length of a 2.4 GHz frequency.

Wavelength in meters = The speed of light / the frequency in question as measured in meters.

299,792,458/2.4GHz

Likewise, we can find the frequency if we know the wavelength. Just divide the speed of light by the wavelength to figure out the frequency.

299,792,458/0.122meters = 2.45

We can also convert from centimeters to inches by multiplying centimeters by 0.3937 to get inches.

Most 802.11 transmitting devices use the 2.45GHz WLAN frequency range. The problem with this is that many other household devices also use these frequency ranges. Microwaves, cordless phones, and some walkie talkies operate in the same range. Simply running your microwave or using a cordless phone while surfing the internet through an 802.11 wireless network can cause your connection to drop entirely. Also, 802.11 wireless networking signals are subject to other issues caused by electro magnetic and radio frequency interference. Electric motors, alternators, etc, can all cause interference in 802.11 wireless signals. You can help circumvent this issue by switching between alternate 2.45GHz frequency channels.

Some of the 2.45GHz frequency channels:
1 2.3995 GHz – 2.4245 GHz
2 2.4045 GHz – 2.4295 GHz
3 2.4095 GHz – 2.4345 GHz
4 2.4145 GHz – 2.4395 GHz
5 2.4195 GHz – 2.4445 GHz
6 2.4245 GHz – 2.4495 GHz
7 2.4295 GHz – 2.4545 GHz
8 2.4345 GHz – 2.4595 GHz
9 2.4395 GHz – 2.4645 GHz
10 2.4445 GHz – 2.4695 GHz
11 2.4495 GHz – 2.4745 GHz
12 2.4545 GHz – 2.4795 GHz
13 2.4595 GHz – 2.4845 GHz

Switching between various fine tuned frequencies in the 2.4GHz frequency range can help to keep signals from alternate devices from overlapping or interfering with each other. Most cordless phones today now operate at the 5GHz frequency or above, but microwaves continue to be an issue with 802.11 networking today. You would need to access your wireless router, or devices, administrative page in order to switch between channels, while most cordless phones let you do this with the touch of a single button.