IEEE have released a set of standards that specify on how transmission in wireless networking happens. The base version of the standard (known as 802.11) was published in 1997, and since then many amendments have followed. Some of the commonly used wireless standards include 802.11a, 802.11b, 802.11g, 802.11n, and 802.11ac, where each standard was released to improve on the existing ones.
These versions provide wireless connectivity in the form of wireless local area networks (WLANs) in both homes and offices premises.
802.11b was an extension of the base standard 802.11 which was released in 1999. 802.11b uses the 2.4 GHz – 2.5 GHz frequency band and supports data transfer rate of 11 Mbps. 802.11b was quickly adopted by manufacturers owing to the low cost of producing devices at this frequency band.
However, this frequency band is prone to high interference from other appliances which operate in the same band such as Bluetooth devices and microwave ovens.
Pros of 802.11b :
- 802.11g has a low cost of manufacturing
- Provides a good signal range
- Not easily obstructed.
Cons of 802.11b
- Bandwidth is too small (11 Mbps).
- Interference with home appliances that work on the same frequency.
802.11a was developed around the same time as 802.11a. 802.11a supports a bandwidth of 54 Mbps, which is much faster than 802.11b. 802.11a used a frequency band of 5 GHz.
By operating at this frequency, interference with other household wireless devices can be avoided. However, a higher frequency meant that signal had trouble penetrating walls and other obstructive objects.
It also shortened the range of the signal. Usage of high frequency also increased the cost of development of networking hardware which limited the use of 802.11a in big enterprises.
Pros of 802.11a
- Fast speed (54Mbps)
- Less interference with other household appliances (due to use of regulated frequency band)
Cons of 802.11a
- Signal gets obstructed by brick walls
- A low range of signal
- The high cost of hardware
This standard was an improvement on the previous standard as it combined the best components of both 802.11a and 802.11b. It used the same frequency band as 802.11b (2.4 GHz – 2.5 GHz) thus reducing cost, providing large signal coverage and allowing the signal to penetrate walls.
To improve on speed, it uses the modulation technique used by 802.11a called orthogonal frequency-division multiplexing (OFDM). OFDM manipulated digital signal by splitting a single data stream into separate narrowband channels. 802.11g reached a maximum speed of 54 Mbps.
Pros of 802.11g
- Fast speed (54 Mbps)
- Good signal range
- Less obstruction by walls
Cons of 802.11g
- Hardware costs more than 802.11b
- Interference with household appliances
802.11n (also known as Wireless N) was officially released in 2009, although many manufacturers started building devices using its specification in 2006 itself. It was designed as an improvement over 802.11g regarding bandwidth support.
This was done by adopting MIMO (multiple input and multiple outputs) technologies which use multiple antennas for sending and receiving signals instead of one.
The specification in 802.11g was able to increase maximum speed to 600 Mbps with higher bandwidth. 802.11n can operate on multiple frequency bands, 2.4 GHz, and 5.8 GHz and has backward compatibility with 802.11a/b/g.
Pros of 802.11n
- Very fast maximum speed (600 Mbps)
- Better signal range than 802.11g
- Improvement in interference with household appliances
Cons of 802.11n
- Hardware costs more than 802.11g
- Use of multiple channels may cause interference with nearby 802.11b/g networks
802.11ac is the latest generation of IEEE standards. 802.11ac has improved on the previous standards regarding bandwidth. 802.11ac used dual-band wireless technology.
It can support connections using the 5GHz frequency band. 802.11ac supports a maximum speed of 1.3 Gbps when using three streams. This is the first specification have reached the 1 Gb mark and is also called the Gigabit Wi-Fi.
Pros of 802.11ac
- Supports data transfer rate of 1.3 Gbps
- Backward compatibility with 802.11b/g/n
- Highly beneficial in a network with a large number of users.
Cons of 802.11ac
- To attain the higher speed of the specification, both the router and device should support 802.11ac standard.
- Many clients still don’t support 802.11ac.
- The cost of new devices is very high
- There can be interference with other 802.11n/ac devices.