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WiFi Standards

 What is Wifi?

WiFi stands for Wireless Fidelity. It is based on the IEEE 802.11 family of standards and is mainly a local area networking (LAN) technology designed to provide in-building broadband coverage.

Nowadays, WiFi has become the de facto standard for last mile broadband connectivity in homes, offices, and public hotspot locations. Systems can typically provide a coverage range of only about 1,000 feet from the access point.

Wifi Standards

The 802.11 standard is defined through several specifications of WLANs. It defines an over-the-air interface between a wireless client and a base station or between two wireless clients.


802.11b


• 802.11b was approved in 1999.

• It uses the same 2.4 GHz frequency as the original 802.11 standard.

• It supports a maximum theoretical rate of 11 Mbps and has a range up to 150 feet.

• 802.11b components are cheap, but the standard has the slowest maximum speed of all the 802.11 standards.

• And since 802.11b operates in the 2.4 GHz, home appliances or other 2.4 GHz Wi-Fi networks can cause interference.


802.11a


• It was released at the same time as 802.11b.

• It introduced a more complex technique, known as OFDM (orthogonal frequency division multiplexing) for generating the wireless signal.

• 802.11a offers a few advantages over 802.11b: it operates in the less crowded 5 GHz frequency band, making it less prone to interference.

• Its bandwidth is much higher than 802.11b, with a theoretical max of 54 Mbps.

• Users probably haven’t encountered many 802.11a devices or routers in the market. This is because 802.11b devices were cheaper and became more popular in the consumer market.

• 802.11a was mainly used in business applications.


802.11g

• 802.11g was approved in 2003.

• The 802.11g standard uses the same OFDM technology introduced with 802.11a. Like 802.11a, it supports a maximum theoretical rate of 54 Mbps.

• It operates in the crowded 2.4 GHz like 802.11b

• It has same interference issues like 802.11b

• 802.11g is backward compatible with 802.11b devices: an 802.11b device can connect to an 802.11g access point (but at 802.11b speeds).

• It supports good Wi-Fi speeds and coverage. At the same time, consumer wireless routers were getting better, with higher power and better coverage than earlier generations


802.11n (Wifi-4)


• 802.11n was approved in 2009.

• With the 802.11n standard, Wi-Fi became even faster and more reliable.

• It supports a maximum theoretical transfer rate of 300 Mbps (and can reach up to 450 Mbps when using three antennae).

• 802.11n uses MIMO (Multiple Input Multiple Output) where multiple transmitters/receivers operate simultaneously at one or both ends of the link.

• This provides a significant increase in data without needing a higher bandwidth or transmit power. 802.11n operates in both the 2.4 GHz and 5 GHz bands.

• When you hear wireless LAN vendors use the term “dual-band”, it refers to being able to deliver data across these two frequencies.


802.11ac (Wifi-5)


• It was introduced in 2014

• 802.11ac supercharges Wi-Fi, with speeds ranging from 433 Mbps all the way up to several Gigabits per second.

• To achieve this high speed performance, 802.11ac works exclusively in the 5 GHz band, supports up to eight spatial streams (compared with 802.11n’s four streams), doubles the channel width up to 80 MHz

• It uses a technology called beamforming. With beamforming, the antennae basically transmit the radio signals so they’re directed at a specific device.

• Another significant advancement with 802.11ac is multi-user (MU-MIMO). While MIMO directs multiple streams to a single client, MU-MIMO can direct the spatial streams to multiple clients simultaneously.

• While MU-MIMO doesn’t increase the speed to any single client, it can increase the overall data throughput of the entire network.


802.11ax (Wifi-6)


• It is known as High Efficiency WLAN

• 802.11ax aims to improve the performance in WLAN deployments in dense scenarios, such as sports stadiums and airports.

• It is still operating in the 2.4GHz and 5GHz spectrum.

• The group is targeting at least a 4X improvement in throughput compared to 802.11n and 802.11ac., through more efficient spectrum utilization.

• Approval is estimated to be in July 2019.

• 802.11ax is significantly faster.

• For example, if one assumes the speed is increased by 4x with 160 MHz channels, the speed of a single 802.11ax stream will be 3.5Gbps. The equivalent 802.11ac connection will be 866 Mbps. A 4×4 MIMO environment would result in a total capacity of about 14 Gbps


Can all Wifi standards communicate with each other?

Two devices using the same Wi-Fi standard can communicate without issues or restriction.

When you try to connect two devices that use different, potentially incompatible standards, issues will arise.

• In recent times, your router and devices using 802.11ac can communicate well.

• Devices that use 802.11b, g, and n can all communicate with an ac router.

• 802.11a cannot communicate with 802.11b devices, and vice versa.

The original 1997 standard (now known as 802.11 legacy) is now outdated, while the a and b standards are nearing the end of their lifespan

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