# Wi-Fi

## Summary


Wi-Fi is a technology for wireless local area networking with devices based on the IEEE 802.11 standards. User Equipment (laptop/mobile) uses a wireless adapter to translate data into a radio signal and transmit that signal using an antenna. At the receiving end, a wireless router converts radio waves back into data and then sends it to the Internet using a physical connection. Wi-Fi networks either operate in infrastructure mode or ad hoc mode.

Wi-Fi networks typically operates in unlicensed 2.4, 5 and 60 GHz radio bands. Data rates up to 20 Gbps are possible in the 60 GHz band. Range of a Wi-Fi network varies anywhere from a few metres (point-to-multipoint) to many kilometres (point-to-point with directional antennas).

## Discussion

### What are the roles of IEEE and Wi-Fi Alliance in Wi-Fi Technology?

IEEE 802.11 is the Working Group of Institute of Electrical and Electronics Engineers (IEEE) that deals with Local Area Networks (LANs), and its main role is to develop technical specifications for WLAN implementation. 

The Wi-Fi Alliance was formed to ensure interoperability testing and certification for the rapidly emerging 802.11 world. This gives consumers the confidence a device from one vendor will work with another from another vendor, as long as they are Wi-Fi certified. It developed Wi-Fi Protected Access (WPA) in response to the poorer security of WEP. While, IEEE standards have technology-centric names, Wi-Fi Alliance has come up with more consumer-friendly naming. For example, IEEE 802.11ax is named Wi-Fi 6. 


### What's the difference between WiFi and WLAN?

WLAN (Wireless Local Area Network) is a LAN to which a user (Station) can connect through a wireless connection. However, Wi-Fi is a type of WLAN that adheres to IEEE 802.11x specifications. 


### What are the different existing 802.11x Standards?


| 802.11 protocol | Frequency (GHz) | Bandwidth (MHz) | Data Rate (Mbit/s) | Description |
| --- | --- | --- | --- | --- |
| 802.11a | 5 | 20 | 54 | Uses data link layer protocol and frame format as the original standard, but an OFDM-based air interface. |
| 802.11b | 2.4 | 22 | 11 | Uses same media access method defined in the original IEEE standard. |
| 802.11g | 2.4 | 20 | 54 | Uses OFDM-based transmission and operates at physical layer. |
| 802.11n | 2.4/5 | 20, 40 | 600 | Provides multiple-input multiple-output antennas. |
| 802.11ac | 5 | 20, 40, 80, 160 | 3467 | Release incrementally as Wave 1 and Wave 2. More spatial streams, higher-order modulation and the addition of multi-user MIMO. |
| 802.11ad | 60 | 2106 | 6757 | An amendment that defines a new physical layer to operate in the 60 GHz millimeter wave spectrum. |
| 802.11ax | 2.4/5 | 20, 40, 80, 80+80 | 9608 | Successor to 802.11ac meant to increase the efficiency of WLAN networks. |
| 802.11aj | 45/60 |  |  | A rebranding of 802.11ad for China. |
| 802.11ay | 60 | 8000 | 20000 | Extension of the existing 11ad, aimed at extending the throughput, range and use-cases. |


### Which are the types of Wi-Fi products available in market?

Wi-Fi products with a number of features are getting released on a regular basis. Here's a short list of Wi-Fi product types: 

    + **Wi-Fi Access Point (AP)** - Used to connect other devices in Wi-Fi Infrastructure mode. All User Equipment will get access to Internet via Access Point.
    + **Wi-Fi Analyzer** - To Test and diagnose wireless performance issues such as throughput, connectivity, device conflict and single multipath.
    + **Wi-Fi Autodoc** - Autodoc is foremost software to generate a comprehensive report from firewall configuration files.
    + **Wi-Fi Adapters** - Adapters permit various devices to connect with cable-less media to perform various type of external or internal interconnects as PC cards, USB, PCI etc.
    + **Wi-Fi Bar Code Scanner** - WiFi bar code scanner continues their workflow in retail and intended to read stock keeping unit by providing efficiency and simplicity.

### Could you explain infrastructure and ad hoc modes of operation?

Infrastructure mode is suitable for any permanent network that's intended to cover a wide area. Ad hoc mode is suitable for a temporary network where the devices are close to each other.

In infrastructure mode, Wi-Fi devices on this network communicate through single access point, which is generally called wireless router. For example, two laptops placed next to each other might connect to the same AP. They don't communicate directly. Instead, they’re communicating indirectly through the wireless access point. Infrastructure mode requires a central access point that all devices connect to. 

Ad-hoc mode is also known as **peer-to-peer mode**. Ad-hoc networks don’t require a centralized access point. Instead, devices on the wireless network connect directly to each other. 


### Is Wi-Fi a viable technology for IoT applications?

For IoT, wireless technologies commonly proposed include RFID, LoRa, Sigfox, NB-IoT, LTE-M, IEEE 802.15.4, BLE and Bluetooth Mesh. Wi-Fi is not suitable for battery-operated devices due to its higher power consumption. Where a power outlet is available, Wi-Fi can be used in smart homes, home appliances, digital signages, and security cameras. Wi-Fi 6 might cater to connected cars and retail IoT. 

The high data rates and low latency offered by Wi-Fi 5 and 6 make them suitable for vehicular services and applications heavy on media such as security cameras. 

For low-power long-range applications, **IEEE 802.11ah**, aka Wi-Fi HaLow, is the most suitable standard. It operates in sub-1 GHz band with a range of 1 km. It supports short bursty data transmission and scheduled sleep/wakeup. It's ideal for smart building applications (lighting, HVAC) and smart city applications (parking meters or garages). 

**IEEE 802.11p** is for vehicular applications. It aligns with FCC's Dedicated Short-Range Communications (DSRC). Applications seek to improve road safety and traffic management. It competes with LTE-V2V. 


### Could you share a list of top WLAN solution providers?

In 2019, some well-known WLAN solution providers included Aerohive Networks, Mojo Networks, Aruba Networks, Cisco Meraki, Ruckus Wireless, Datto Networking, Ubiquiti Networks, Mist Systems, Purple, Edgecore Networks, Cloud4Wi, and Eleven. The best of them provide cloud management, including the use of ML/AI. 

A report from IDC showed that in Q1-2019, about 47% of the enterprise market is with Cisco. This is followed by Aruba, Ubiquiti and Ruckus. 

## Milestones

1990

NCR Corporation creates *WaveLAN* as a wireless alternative to Ethernet and Token Ring computer networking. In 1991, AT&T acquires NCR. The same year WaveLAN becomes the starting point for the standardization of Wi-Fi. 

1996

Australian agency CSIRO's WLAN and its method of recovering data in multipath environments is granted a US patent. It's only in 1999 that the patent goes into the standard IEEE 802.11a. The technology is made available to implementers via non-exclusive licenses. In 2005, CSIRO files first worldwide family litigation. In 2012, it files suits against US carriers. Patent expires in 2013. 

Jun  
1997

IEEE publishes the first version of Wi-Fi standard, called **IEEE 802.11-1997**. It supports 2 Mbps in the 2.4 GHz band. 

1999

Some companies come together to form a global non-profit association to promote and facilitate Wi-Fi adoption and interworking, regardless of brand. This association is initially called *Wireless Ethernet Compatibility Alliance*. In 2000, it's renamed to **Wi-Fi Alliance**. The Alliance also announces **Wi-Fi®** as the formal name for the wireless technology. The term Wi-Fi was in commercial use as early as August 1999. It was a name coined by Interbrand who also designed the Wi-Fi logo. The Alliance announces a certification programme and the first certified devices come out in 2000. 

Sep  
1999

IEEE publishes two amendments, **IEEE 802.11a** (only 5 GHz band, 54 Mbps max) and **IEEE 802.11b** (only 2.4 GHz band, 11 Mbps max). Although 802.11a offers 54 Mbps, 802.11b offers better range, uses the same modulation as the original standard and leads to dropping prices due to wider adoption. However, in terms data rates Wi-Fi remains far slower than its wired counterparts, Fast Ethernet (100 Mbps, 1995) and Gigabit Ethernet (1Gbps, 1998). 

Jun  
2003

IEEE publishes the **IEEE 802.11g** standard that provides 54 Mbps data rate although it uses the same 2.4 GHz band as 802.11b. Thus, 802.11g devices can work with 802.11b devices. It uses OFDM as the modulation just as 802.11a. Soon dual-band 802.11a/b products become tri-band 802.11a/b/g. 

2004

TVs and smartphones get Wi-Fi certified and are launched in the market. **WPA2** is released to provide higher security. For the first time, Wi-Fi is offered to passengers on a commercial flight. 

Jan  
2008

NASA installs the first Wi-Fi device on the International Space Station. Two Netgear RangeMax 802.11b/g APs are installed, each giving 240 Mbps. In May 2016, the Wi-Fi network is extended to outside the space station. In 2019, Wi-Fi is integrated into a space suit, takes a space walk and streams HD video. 

Oct  
2009

IEEE publishes the **IEEE 802.11n** standard. Further amendments appear in later years: 802.11ac (December 2013) and 802.11ax (September 2019). 802.11ax can be seen as an evolution of 802.11ac. 

Dec  
2012

IEEE publishes the **IEEE 802.11ad** standard that allows operation in the 60 GHz band. It's derived from a WiGig specification completed by *Wireless Gigabit Alliance* in 2009. Since 2010, this alliance has been cooperating with Wi-Fi Alliance to promote WiGig. However, it's only in 2016 that Wi-Fi Alliance starts certifying WiGig products. The delay is mainly because vendors are reluctant to adopt a technology that has little infrastructure support. 

Oct  
2018

In an effort to simplify naming, Wi-Fi Alliance introduces **consumer-friendly generation names**. For example, 802.11ax is also known as Wi-Fi 6; 802.11ac as Wi-Fi 5; and 802.11n as Wi-Fi 4. In addition, UI visuals are defined to indicate which Wi-Fi standard is currently in use. Meanwhile in 2018, Wi-Fi certifications reach 45,000 and **WPA3** is released for higher security. 

2019

The 30 billionth Wi-Fi device is shipped. Wi-Fi adoption is accelerating given that the 10 billionth device was shipped in 2014 and the 20 billionth device was shipped only in 2017.