WiFi definition
WiFi technology (IEEE802.11) can be broadly categorised to IEEE802.11 a/b/g/n/ac. Each is an improvement in transmission speed and/or signal range from the previous, although these days only ‘G’ and ‘N’ are used.
The standard G versions of networking devices have an optimal transmission speed of 54 Mbps with an indoor range of approximately 40 m whereas the N versions have a theoretical maximum speed of 300 Mbps (practical of approximately 150 Mbps and above) with an indoor range in the region of 70 m.
In addition to this, N variations offer the choice of two frequency ranges; 2.4 GHz or 5 GHz. The higher frequency has no impact on the range but offers a potentially less polluted frequency to help reduce crosstalk noise.
Both the G and the N devices utilise the same channel capabilities but these vary regionally. In Europe (including UK) a channel system of 1-13 is used whereas in the US the system uses 1-11. Both use the same frequency ranges resulting in an approximate frequency void of 16.5 MHz at the end of the 2.4 GHz range.
Japan utilise a different system still, expanding the 2.4 GHz range beyond the acceptable ISM guidelines by 10.5 MHz to allow for an additional 14th channel with 11 MHz of non-interference from other channels (see Figure below) [80], [81], [82].
Image. 22MHz channel allocations for WiFi 2.4GHz frequencies, with curvatures implying affinities for intra-channel frequency selection.
The figure above shows the affinities for the frequency selection within each 22 MHz channel and the overlap between channel frequencies. The same would be seen for 40 MHz channels with the obvious exception that there would be twice the amount of overlap between channels, leaving fewer isolated channels. The solid lines show the 3 channels in the US 11 channel system that do not encroach on each other’s range at all. Each WiFi access point will secure its own channel and use that channel for all communications. Multiple channels will not be utilised by one access point other than during overlap.
WiFi communication protocols are Internet Protocol (IP) based where the destination address is in packet headers allowing large amounts of data to be transmitted through a network of nodes at high speed. This means that on any WiFi network a central control node (network coordinator) will allocate all IP’s in the network on discovery allowing for any packets to be addressed and routed to a connected device [82].
This article was created by --BRE. It was taken from The future of electricity in domestic buildings, a review, by Andrew Williams, published in November 2014.
NB The term 'WiFi' was coined by the Wi-Fi Alliance as shorthand for wireless local area network (WLAN) products based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards. It did not specifically 'stand for' anything. It has popularly been adopted to mean Wireless Fidelity but this is not correct.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Bluetooth.
- CAT5.
- Ethernet
- Extranet
- Glossary of electrical terms.
- ICT and Automation (ICTA) Scoping Study Report.
- In-building wireless.
- Information and communications technology.
- Internet of things.
- Internet of things in commercial buildings.
- Local area network.
- Smart buildings.
- Smart cities.
- Smart technology.
- The future of electricity in domestic buildings.
- WiMax.
- WiredScore.
- ZigBee.
[edit] External references
- [80] E. G. Villegas, E. López-Aguilera, R. Vidal and J. Paradells. Effect of adjacent-channel interference in IEEE 802.11 WLANs. Cognitive Radio Oriented Wireless Networks and Communications, Orlando, 2007.
- [81] Butler J. Wireless Networking in the Developing World, Copenhagen: Creative Commons, 2013.
- [82] Institute of Electrical and Electronics Engineering, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. IEEE Standards, 2012.
Featured articles and news
HSE simplified advice for installers of stone worktops
After company fined for repeatedly failing to protect workers.
Co-located with 10th year of UK Construction Week.
How orchards can influence planning and development.
Time for knapping, no time for napping
Decorative split stone square patterns in facades.
A practical guide to the use of flint in design and architecture.
Designing for neurodiversity: driving change for the better
Accessible inclusive design translated into reality.
RIBA detailed response to Grenfell Inquiry Phase 2 report
Briefing notes following its initial 4 September response.
Approved Document B: Fire Safety from March
Current and future changes with historical documentation.
A New Year, a new look for BSRIA
As phase 1 of the BSRIA Living Laboratory is completed.
A must-attend event for the architecture industry.
Caroline Gumble to step down as CIOB CEO in 2025
After transformative tenure take on a leadership role within the engineering sector.
RIDDOR and the provisional statistics for 2023 / 2024
Work related deaths; over 50 percent from construction and 50 percent recorded as fall from height.
Solar PV company fined for health and safety failure
Work at height not properly planned and failure to take suitable steps to prevent a fall.
The term value when assessing the viability of developments
Consultation on the compulsory purchase process, compensation reforms and potential removal of hope value.
Trees are part of the history of how places have developed.
Comments
WiFi does not stand for Wireless Fidelity. It is not an acronym. It is a term to define the ieee 802.11 standard.
WiFi was coined by the Wi-Fi Alliance as shorthand for wireless local area network (WLAN) products based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards. It did not specifically 'stand for' anything. It has popularly been adopted to mean Wireless Fidelity but this is not correct.