As computer technology has improved and evolved, wireless connections are rapidly becoming the primary connection method for all manner of computer components and devices. However, when someone says ‘wireless’ to us, most of us automatically first think of Wi-Fi, either in our home or with related hotspots.
As we probably already know, even if we’ve never given it too much thought, there are connections besides ‘Wi-fi’ and I’ll take a look at these here too.
|An example of Wireless Communications|
Radio Frequency (RF)
Radio networking communications are made possible through the use of RF waves in the 10 KHz to 1 GHz range, which are sent to wireless radio antennas. When these antennas transmit, they convert electrical energy into RF radio waves and, when they receive, they convert the RF waves into electrical energy.
In this form of wireless communication, low-frequency data or voice signals are transmitted through high-frequency radio waves by superimposing the data onto them.
Allocation of the RF Spectrum. The RF spectrum of radio waves are classified based on the frequency range in which they operate.
- 3 Hz – 30 Hz: Extremely Low Frequency (ELF)
- 30 Hz – 300 Hz: Super Low Frequency (SLF)
- 300 Hz – 3 KHz: Ultra Low Frequency (ULF)
- 4 KHz – 30 KHz: Very Low Frequency (VLF)
- 30 KHz – 300 KHz: Low Frequency (LF)
- 300 KHz – 3 MHz: Medium Frequency (MF)
- 3 MHz – 30 MHz: High Frequency (HF)
- 30 MHz – 300 MHz: Very High Frequency (VHF)
- 300 MHz – 3 GHz: Ultra High Frequency (UHF)
- 3 GHz – 30 GHz: Super High Frequency (SHF)
- 30 GHz – 300 GHz: Extremely High Frequency (EHF)
Bluetooth is a wireless communication technology that transmits data in low-power radio waves. Bluetooth enabled devices contain a tiny chip with a Bluetooth radio and software. Devices have to ‘pair’ with each other in order to communicate and exchange data. Bluetooth uses frequency-hopping spread spectrum technology to avoid interference, operating in the frequency range of 2.402 GHz to 2.483 GHz. Additionally, Bluetooth devices operate at very low power levels of approximately 1 milliwatt (1 mW)
|A Bluetooth Headset|
Bluetooth facilitates short range (up to about 30 feet) communication between computers, laptops, mobile telephones, gaming consoles and some gaming peripherals. Bluetooth communication devices are able to exchange both voice and data information.
|A Bluetooth ‘Dongle’|
It’s possible to connect a maximum of 8 bluetooth devices to each other at any one time and this form of connecting 2-8 devices is known as a piconet.
Near Field Communications (NFC)
NFC is a wireless communication technology that enables capable devices to establish a form of radio communication by bringing them into close proximity with each other, or by touching them. Typically, NFC enabled devices need to be within 10 cm of each other in order for the communication to take place. NFC is slower than a Blutooth connection and operates at 13.5 MHz. However, NFC consumes less power than Bluetooth and does not require pairing.
|NFC enabled phones – transmitter (bottom) and receiver (top)|
Presently, one of the most common uses for NFC is possibly contactless payments via credit card. Placing your card close to the ‘reader’ enables information to be exhanged and finances to be taken from your account.
|The ‘Contactless’ logo|
IR transmission differs from other types of wireless communication because both the transmitter and receiver need to be in a line of sight and have an unobstructed view of each other. However, IR signals can be bounced off of hard surfaces to reach the receiving device.
IR transmission sends signals via pulses of infrared light and is generally only used for short range transmission due to the above limitation. Typically, IR communication takes place in the near-infrared frequency range which is in the near visible region of the spectrum. Because of this, IR communication is also sometimes referred to as Optical Wireless Communication (OWC).
|The visible light spectrum|
IR electromagnetic waves have frequencies ranging from 300 GHz to 400 THz and have wavelengths that range from 1 mm to 750 nm. There are different IR sub-bands; far-infrared, mid-infrared and near-infrared, the latter visible to the naked human eye as red or violet light. Far-Infrared frequencies are not visible to the human eye but are radiated in the form of heat.
IR Technology is used in a variety of ways within the computing and telecommunication fields, the most common of which is to provide network connectivity in wireless personal area networks. In this situation, IR provides connectivity between a two computers or a computer and a handheld device. Some wireless devices such as wireless mice, keyboards and game controllers use IR communication, but the most common of these types is the television remote control.