Wireless

Wireless communication, often just called "wireless," is a way to send information from one place to another without using wires or cables. Instead, it uses things like radio waves. These waves can travel short distances, like a few meters for something like a wireless computer mouse, or incredibly far distances, even millions of kilometers for communication with spacecraft.

Many everyday tools and gadgets use wireless technology. This includes cellphones, wireless networking like Wi-Fi, Bluetooth for connecting devices close by, GPS for finding locations, garage door openers, headsets, and more. Wireless technology makes it possible to have portable and mobile communication without being tied down by cords.

The word "wireless" has been used in different ways over time. It was first used around 1890 for early radio technology, called "wireless telegraphy." Later, the term "radio" took over. But in the 1980s and 1990s, "wireless" came back to describe digital devices that could talk to each other without wires, like mobile phones and Wi-Fi. This is how we most use the term today.

Wireless communication allows services that would be hard or impossible with wires, such as mobile phones and communication between planets. It's an important part of the telecommunications industry, making it easier for people to connect and share information over both short and long distances.

History

See also: History of telecommunication

Photophone

Main article: Photophone

In 1880, Alexander Graham Bell and Charles Sumner Tainter created the photophone, a device that could send sound using a beam of light. However, it needed sunlight and a clear view between the sender and receiver, which made it hard to use in real life. It took many years before these ideas were used in military communications and later in fiber-optic communications.

Electric wireless technology

Early wireless

In the late 1800s, people tried many ways to send messages without wires, like using electric currents through water or the ground. Thomas Edison even made a system to send messages from a moving train. These early methods had some uses, like helping trains during a big snowstorm or sending messages in World War I, but they were not very successful.

Radio waves

Main article: History of radio

In 1894, Guglielmo Marconi started working on a way to send messages using radio waves, which were discovered by Heinrich Hertz. Marconi’s system could send signals much farther than people thought possible. He and Karl Ferdinand Braun won the 1909 Nobel Prize for Physics for this work.

In 1898, Nikola Tesla showed the first boat that could be controlled with radio waves at Madison Square Garden. The small boat could move, turn, and light up using signals from a box. Some people thought it might be magic or controlled by a hidden animal, but it was all radio waves.

Jagadish Chandra Bose also worked with very high-frequency radio waves in the mid-1890s and made important discoveries about detecting radio signals.

Wireless revolution

The big change to wireless technology started in the 1990s. Digital wireless networks changed how we live, leading to many new devices like cell phones, mobile telephony, and computer networks that work without wires. This shift was possible because of big advances in technology, allowing more people to send voice, text, images, and streaming media over wireless connections.

Modes

Wireless communications can happen in different ways.

Radio

Main article: Radio communication

Further information: Microwave transmission

Radio and microwave communication send information by changing parts of waves in space. A device creates these waves using changing electric currents in an antenna. The waves travel until they reach another antenna, which turns them back into the original information.

Wireless optical

Free-space optical (long-range)

Main article: Free-space optical communication

Free-space optical communication uses light traveling through the air or space to send data without wires. This is helpful when connecting places with wires is too expensive or hard. For example, it connects buildings in a city or is used in devices like remote controls and some WiFi alternatives.

Sonic

Sonic communication, especially using high-pitched sounds, can send and receive information over short distances.

Electromagnetic induction

Electromagnetic induction is good for short-range communication and power transfer. It is used in medical devices like pacemakers and for small tags called RFID.

Services

Wireless technology is used in many everyday devices. Some common examples include remote controls that use infrared or ultrasonic waves, two-way radios for families and professionals, and amateur radio for hobbyists.

Other devices include marine radios for boats, airband and navigation equipment for pilots, cell phones for portable communication, GPS for finding locations, and cordless computer accessories like mice, keyboards, and headphones. Satellite television also uses wireless signals to bring multiple TV channels to viewers from satellites in space.

Electromagnetic spectrum

See also: Spectrum management

AM and FM radios and other electronic devices use something called the electromagnetic spectrum. The parts of this spectrum that can be used for communication, called the radio spectrum, are like a shared resource. Groups like the American Federal Communications Commission, Ofcom in the United Kingdom, the international ITU-R, and the European ETSI help decide who can use which frequencies for what. This prevents problems, like an amateur radio operator interfering with an airplane’s communication during landing. Wireless communication uses frequencies from 9 kHz up to 300 GHz.

Applications

Mobile telephones

One of the best-known examples of wireless technology is the mobile phone, also called a cellular phone. These phones use radio waves from special towers to let people make calls from many places around the world.

Data communications

Wireless Internet lets devices like computers, tablets, and phones connect to the Internet without wires. Wi-Fi is a common way to do this at homes, offices, and public places. It works like a local network that helps devices talk to each other and to the Internet.

Cellular data service is another way, offering Internet access from cell towers. Over time, this service has gotten faster, from older technologies to today’s 5G networks.

Wireless data communications help devices talk over long distances, provide backup links if normal connections fail, and make it easier to connect devices in places where wires are hard to use.

Peripherals

Computers can also connect things like keyboards and mice without wires, using Wi-Fi or special radio signals. These connections can work up to about 10 feet, but walls or other things can sometimes make the signal weaker.

Energy transfer

Wireless energy transfer is a way to send power to devices without using wires. This can be done using radio waves or special close-range methods. In 2015, scientists showed they could use Wi-Fi signals to power small cameras.

Medical technologies

New wireless tools can help watch over health by checking things like blood pressure and heart rate. These tools send signals to special receivers, which can then show the information to nurses or doctors. This helps keep people safe without the risks of wires.

Categories of implementations, devices, and standards

Wireless technology has many different types and uses. Some common ones include:

• Cellular networks: 0G, 1G, 2G, 3G, 4G, 5G, 6G
• Cordless telephony: DECT (Digital Enhanced Cordless Telecommunications)
• Land Mobile Radio or Professional Mobile Radio: TETRA, P25, OpenSky, EDACS, DMR, dPMR
• List of emerging technologies
• Radio station in accordance with ITU RR (article 1.61)
• Radiocommunication service in accordance with ITU RR (article 1.19)
• Radio communication system
• Short-range point-to-point communication: Wireless microphones, Remote controls, IrDA, RFID (Radio Frequency Identification), TransferJet, Wireless USB, DSRC (Dedicated Short Range Communications), EnOcean, Near Field Communication
• Wireless sensor networks: Zigbee, EnOcean; Personal area networks, Bluetooth, TransferJet, Ultra-wideband (UWB from WiMedia Alliance).
• Wireless networks: Wireless LAN (WLAN), (IEEE 802.11 branded as Wi-Fi and HiperLAN), Wireless Metropolitan Area Networks (WMAN) and (LMDS, WiMAX, and HiperMAN)