Wireless

It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking.

Somewhat less common methods of achieving wireless communications involve other electromagnetic phenomena, such as light and magnetic or electric fields, or the use of sound.

In 1894, Guglielmo Marconi began developing a wireless telegraph system using radio waves, which had been known about since proof of their existence in 1888 by Heinrich Hertz, but discounted as a communication format since they seemed, at the time, to be a short-range phenomenon.

Marconi and Karl Ferdinand Braun were awarded the 1909 Nobel Prize for Physics for their contribution to this form of wireless telegraphy.

Millimetre wave communication was first investigated by Jagadish Chandra Bose during 1894–1896, when he reached an extremely high frequency of up to 60 GHz in his experiments.

VLC systems take advantage of light-emitting diodes (LEDs) which can be pulsed at very high speeds without a noticeable effect on the lighting output and human eye.

These systems typically use laser transmitters and offer a cost-effective protocol-transparent link with high data rates, i.e., 10 Gbit/s per wavelength, and provide a potential solution for the backhaul bottleneck.

Common examples of wireless equipment include:[19] AM and FM radios and other electronic devices make use of the electromagnetic spectrum.

In the absence of such control or alternative arrangements such as a privatized electromagnetic spectrum, chaos might result if, for example, airlines did not have specific frequencies to work under and an amateur radio operator was interfering with a pilot's ability to land an aircraft.

They can be used within the range of the mobile telephone site used to house the equipment required to transmit and receive the radio signals from these instruments.

Originally these units used bulky, highly local transceivers to mediate between a computer and a keyboard and mouse; however, more recent generations have used smaller, higher-performance devices.

[34] Concerns about the security of wireless keyboards arose at the end of 2007 when it was revealed that Microsoft's implementation of encryption in some of its 27 MHz models were highly insecure.

Energy can be transferred using either far-field methods that involve beaming power/lasers, radio or microwave transmissions, or near-field using electromagnetic induction.

The MBAN works by sending low-powered wireless signals to receivers that feed into nursing stations or monitoring sites.