Licence exempt free space radio networks using Wireless Access Points (WAP's) and computers with the appropriate wireless network card.
Licence exempt systems
Licence exempt systems operate in frequency bands that do not require a licence for their use. Although such systems do not incur any ongoing licence fees there are still strict regulations governing usage, hardware specifications, aerial gain and power output.
- 802.11a is an 54MBps standard for Wireless Local Area Networks (WLANs) operating in the 5.4Ghz frequency band.
- 802.11b is an 11MBps standard for WLANs operating in the 2.4Ghz frequency band.
- 802.11g is a 54MBps standard for WLANs operating in the 2.4Ghz frequency band. 802.11g is backward compatible with 802.11b, so old radio equipment can still be used with newer 802.11g radios, albeit at the slower data rate.
- 802.11n is a draft 100Mbps standard for WLAN's likely to operate in the 5GHz band.
- 802.11e is a draft standard which can provide Quality of Service (QoS) for WLAN's .
- 802.16a is a draft specification (known as WiMAX) for wireless broadband operating on frequencies between 2-11GHz.
Effective Data Throughput
In practice the effective data throughput for wireless devices should be taken as approximately half the stated data rate due to control and encryption overheads. It should also be noted that the quoted data rate is for the system so if there are two wireless clients connected to one WAP/bridge the effective data throughput to each client will need to be further halved.
Wireless Access Point
A wireless network installation normally uses one or more WAP's which are dedicated stand-alone hardware with typically more powerful aerials. Normally a WAP will have a range of no more than 100m which will reduce rapidly if the signal has to pass through any walls particularly if they contain metal.
Site Survey
We have experienced engineers who can carry out site surveys to find out how many access points are likely to be needed and what sort of aerial would give the best coverage.
Power Over Ethernet
Power Over Ethernet (POE) as described by the 802.3af standard is a means by which power can be integrated onto existing cat5e/6 structured wiring. POE is very useful where WAP's are to be installed in hard to reach locations where installing an adjacent mains socket would be very costly.
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