Microwaves and Radio waves are used to transmit binary data. The binary data is represented by pulses of electromagnetic frequency.
WiFi and Bluetooth are the most common protocols for transmitting data wirelessly, however newer protocols have appeared in recent times such as Thread and Zigbee which have become popular in low power home automation. These protocols set the rules for how data is sent and received by devices.
The main benefit of using wireless connections is the convinenece of not having to be tethered by a cable.
Limitations of Wireless Connections
While wireless connections are convienent there are many limitations:
- Range: While a wired connection can carry a signal at least 100m over CAT 5 / CAT 6 and much further over fibre-optic cables, the most common methods of wireless networking have shorter ranges. WiFi has a limit of 30m and lower power protocols like Bluetooth has an even shorter range.
- Bandwidth: More recent versions of WiFi boast bandwidth figures greater than that of wired connections, however in reality the amount of bandwidth available is much lower and less than that of a wired connection in almost all situations.
- Interference: Wireless connections are suseptable to interference from other wireless connections and frequencies in the imediate area. This interference may require error correction or that data packets to be resent. The more common frequencies such as 2.4GHz that is used by WiFi and Bluetooth experience interference from Microwave ovens and baby monitors which also make use of 2.4GHz frequencies.
- Absorption, Reflection and Refraction: Wireless signals can be absorped, reflected and refracted when they come into contact with different physcal materials. This can result limited range and areas of buildings where devices cannot connect to the network.
Wirless Local Area Networks (WLAN)
WLANs make use of Wireless Access Points (WAP) – these are devices which allow wireless devices to join a LAN using WiFi.
At home your WAP is integrated into a multi-function devices commonly referred to as the "router”.
In commercial settings a WAP is a separate device. In larger buildings a network may have many WAPs in order to provide wider wireless network coverage.
Other forms of Wireless Connections
While WiFi and Bluetooth are the most widely known forms of Wireless Connections, there are a range of other technologies we use in our daily lives.
- RFID (Radio Frequency Identification): A short form of wireless communication (usually >10cm). This technology is often used in ID cards to open electronically locked doors and with contactless debit and credit cards. RFID is unidirectional with data being read off the RFID chip.
- NFC (Near Field Communication): Similar to RFID, however data can be sent bi-directionally and at faster rates. NFC can be used to share data between devices at short distances (again, usually > 10cm). NFC is used in mobile contactless payments: the terminal sends data to the smartphones NFC chip, and if authenticated by the user on the device the payment details are sent to the payment terminal.
- Zigbee: A 2.4GHz radio protocol used in smart home hardware to connect devices. Zigbee can be used to create mesh networks which allows devices to pass data on for devices which may be further away from the base station.
