Wi-Fi

Wi-Fi is a wireless communications standard that is used to connect devices in a local area network to each other and/or to the internet. Typical uses include connecting printers and digital cameras to desktop PC’s, laptops or smartphones or connecting video games consoles, PC’s, smartphones or laptops and many other types of modern electronics devices to the internet. It is also used in public locations to enable users to connect to the internet via a Wi-Fi hotspot. Initially Wi-Fi was used mainly for data communications but now mobile phone users are able to make and take calls over Wi-Fi, thus minimising the problem of poor mobile phone signal coverage and dropped calls. Wi-Fi uses the 2.4 and 5 Ghz frequency range to communicate. The initial standards, 802.11a/b/g have been superseded with more recent standards, 802.11n (Wi‑Fi 4) 802.11ac (Wi‑Fi 5) and 802.11ax (Wi‑Fi 6). These newer standards have improved on previous versions, having faster transmission speeds, better propegation characteristics, being less prone to inteference as well as being more secure. Typical distances are 46 metres (150 feet) indoors in ideal conditions.

Wi-Fi 6 (802.11ax)

Wi-Fi 6 is the latest release of the 802.11 wireless standard. It is capable of sending data at much faster speeds, has greater capacity, is more secure and enables end devices attached to the network to have much longer battery life. Two initial releases of the standard were rejected by the IEEE committee in 2016 and 2017, before finally, in July 2018, over 80% of the members voted to pass Draft 3.0. The official release of the standard is scheduled to take place in December 2019.

Speed

In lab tests Wi-Fi 6 could travel at speeds of 9.6 Gbps. That’s up from 3.5 Gbps on Wi-Fi 5. This speed would never be used or needed in real world situations. For example the typical download speed in the US is 72 Mbps. However this speed could be shared out among multiple devices thus meaning higher speeds for each device. This is a major advantage, the fact that an 802.11ax network can handle multiple devices without any drop off in performance. To achieve faster speeds Wi-Fi 6 uses MU-MIMO and OFDMA. MU-MIMO or “multi-user, multiple input, multiple output,” is currently being used in routers and devices, but Wi-Fi 6 upgrades it. Using MU-MIMO enables a router to communicate with multiple devices at the same time, rather than broadcasting to each devce one by one. Currently MU-MIMO allows routers to communicate with four end devices at a time. Wi-Fi 6 will allow routers to communicate with up to eight. OFDMA, which stands for “orthogonal frequency division multiple access,” allows one transmission to deliver data to multiple devices at once.

Improved Battery Life

The Wi-fi 6 standard enables the end devices to schedule and plan transmission times with the router in their network. The end devices will not have to be awake all the time thus saving battery life. This technology is more suitable for small devices such as sensors on water meters etc. However it will not improve the performance of the router when connected to the internet

Security

Wi-Fi has introduced a new security protocol called WPA3. This protocol makes it more difficult for hackers to hack into networks by guessing passwords, even if they do manage to hack in to a network the protocol makes it harder to decipher and understand data. Current devices and routers support WPA3, however this is optional. Manufacturers of Wi-Fi 6 enabled devices must have the WPA3 security features installed by default otherwise these devices will not be certified for use in any application.

802.11xx Network Setup

Wi-Fi networks are set up in two ways  – Infrastructure and Ad-hoc mode.

Infrastructure mode:

In infrastructure mode a wireless network is joined to a wired Ethernet network while still supporting connections to wireless clients. At least one access point is required. The access point and all the wireless clients on the LAN are configured to use the same network name, i.e SSID. The access point is connected to the wired network via a cable. This enables the wireless clients access to the Internet or printers etc. Additional access points can be added to the network to increase its reach and support more wireless clients.

The advantages of this type of network include scalability and centralised security. The disadvantage is the additional cost of buying more access point hardware.

Wi-fi Infrastructure mode

Wi-fi infrastructure mode set-up

Ad-hoc Mode

In Ad Hoc mode wireless devices connect directly to each other. They find another device within range and communicate with each other in a peer to peer manner. A centralised access point or router is not required in the network.

To set up an ad-hoc wireless network, each wireless adapter must be configured for ad-hoc mode rather thaninfrastructure mode. All wireless adapters in the network must use the same channel and SSID.

Ad-hoc networks work well where there are small groups of devices close together and connected to each other. Performance suffers as the number of devices grows and large ad-hoc networks are more difficult to manage. Ad-hoc networks cannot connect to wired local area network or to the Internet without installing a special-purpose gateway.

Ad hoc mode is used when building a small all wireless network and has the advantage of not being as expensive as infrastructure mode. Ad hoc networks are used as a temporary setup if infrastructure mode hardware (access points or routers) stop functioning.

Wi-fi Adhoc network

A typical Wi-fi ad-hoc network

Wi-fi in industry:

Wi-fi networks are gaining popularity in industrial applications. The standard is easily understood and the cost of modules has reduced significantly. Many embedded modules are now available with real-time operating systems (RTOS) and a built in serial port interface that allows a wireless connection to many devices, e.g an E.C.G monitor while needing only a basic understanding of wireless communications. We supply embedded and boxed Wi-fi hardware manufactured by Digi International. This is high quality, long life hardware that comes with excellent functionality and customisation options. Please contact us for more details.