Wireless communication

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Introduction

The term wireless refers to the communication or transmission of information over a distance without requiring wires, cables, or any other electrical conductors. Wireless communication is one of the important mediums of transmission of data or information to other devices. The Communication is set and the information is transmitted through the air, without requiring any cables, by using electromagnetic waves like radio frequencies, infrared, satellite, etc., in a wireless communication technology network.

Different types of signals are used in communication between the devices for wireless transmission of data. The following are the different electromagnetic signals used depending on their wavelength and frequency. Electromagnetic wave

  • Extension: What is wavelength and frequency? Electromagnetic waves are measured using frequency. What is frequency?

The wavelength and frequency are shown in the following figure. Wavelength

  • Extension: What is radio? Radio Wave

Types of Wireless Data Transmission

  • Radio Frequency Transmission
  • Infrared Transmission
  • Microwave Transmission
  • Lightwave Transmission

    Radio Frequency Transmission

    Radio Frequency (RF) is a form of electromagnetic transmission used in wireless communication. RF signals are easily generated, ranging 3kHz to 300GHz. These are used in wireless communication because of their property to penetrate through objects and travel long distances.

Signal transmission and reception is via Antenna. Antenna Drawbacks

  • These are frequency-dependent
  • These have a relatively low bandwidth for data transmission. Examples

Infrared Transmission

Infrared radiations are electromagnetic radiations with longer wavelengths than visible light. These are usually used for short-range communications. These signals do not pass through solid objects.

Infrared is a media transmission system that transmits data signals through light-emitting diodes (LEDs) or Lasers. Infrared is electromagnetic energy at a wavelength that is longer than that of red light. The information cannot be traveled through obstacles in an infrared system but can be inhibited by light. One type of infrared is the point-to-point system in which transmission is possible between two points limited to a range and line of sight.

The signal frequency to transmit in a point-to-point system is 100 GHz to 1,000 terahertz (THz), and the speed ranges from 100 Kbps to 16 Mbps. Another method of transmission of infrared includes the broadcast system – and, in this method, reflective material or a transmission unit amplifies and retransmits a data signal to several other units. The normal frequency of an infrared broadcast system is 100 GHz to 1,000 THz with a limited speed of 1 Mbps.

  • Extension: Frequency and speed?

Example: Television remote control

Microwave Transmission

Microwaves are the form of electromagnetic transmission used in wireless communication systems. The wavelength of microwaves ranges from one meter to one millimeter. The frequency varies from 300MHz to 300GHz. These are widely used for long-distance communications and are relatively less expensive.

Microwave is an effective type of wireless data transmission that transfers information using two separate methods. One method which is used to transmit data through the wireless media of a microwave is the satellite method that transmits information via a satellite that orbits 22,300 miles above the Earth. Stations on the ground send and receive data signals to and from the satellite with a frequency ranging from 11 GHz to 14 GHz and with a transmission speed of 1 Mbps to 10 Mbps. Another method is a terrestrial method, in which two microwave towers with a clear line of sight between them are used ensuring no obstacles to disrupt that line of sight. For the purpose of privacy, it is used often. The frequency of data transmission for terrestrial systems is typically 4 GHz to 6 GHz or 21 GHz to 23 GHz, and the speed is usually 1 megabit per second (Mbps) to 10 Mbps.

Drawbacks

  • The microwave does not pass through buildings.
  • Bad weather affects signal transmission.
  • These are frequency-dependent.

Lightwave Transmission

Light is electromagnetic radiation with a wavelength ranging between infrared radiations and ultraviolet radiations. The wavelength ranges from 430 to 750THz. These are unguided optical signals such as lasers and are unidirectional.

Drawbacks

  • These signals cannot penetrate through rain and fog.
  • The laser beam gets easily diverted by air.

Types of Wireless Communication Technologies

  • Radio and Television Broadcasting
  • Radar Communication
  • Satellite communication
  • Cellular Communication
  • Global Positioning System
  • WiFi
  • Bluetooth
  • Radio Frequency Identification

Radio

Mostly radio broadcasts sound through the air as radio waves. Radio has a transmitter that transmits the data in the form of radio signals to the receiver antenna.

Cellular

Satellite

Wi-Fi

These networks are limited in range due to the low power transmission, allowing the user to connect only in close proximity.

Bluetooth Technology

Cell phones are connected to hands-free earpieces, wireless keyboards, mouse and mike to laptops with the help of Bluetooth as it transmits information from one device to other devices.

Features

  • Bluetooth technology uses radio waves to communicate between devices. Most of these radio waves have a range of 15-50 feet.
  • According to the official Bluetooth website, Bluetooth uses a low-power signal with a maximum range of 50 feet with sufficient speed to enable the transmission of data.
  • The pairing process identifies and connects any two devices to each other. It also prevents interference from other non-paired Bluetooth devices in the area.
  • It uses maximum power only when it is required, thus preserving battery life.

ZigBee

ZigBee is a wireless communication standard designed to address the unique needs of low-power, low-cost wireless sensor, and control networks. ZigBee can be used almost anywhere, as it is easy to implement and requires little power to operate. Zigbee has been developed looking into the needs of the communication of data with a simple structure like the data from the sensors.

Features

  • ZigBee devices are designed for low-power consumption.
  • ZigBee is used in Commercial Applications like sensing and monitoring applications.
  • ZigBee uses very low power and extremely long device battery life.
  • ZigBee gives the flexibility to do more with reliable wireless performance and battery operation.

Reference:

[1] Different Types of Wireless Communication Technologies

[2] Wireless principles : RF or radio frequency , Hertz explained in simple terms

[3] EM spectrum: radio wave, infrared, visible light, ultraviolet, X and Gamma ray