Introduction to Wireless Communication

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written 5.4 years ago by

teamques10 ★ 68k

Wireless Communication is the fastest growing and most vibrant technological areas in the communication field. It is a method of transmitting information from one point to other, without using any connection like wires, cables or any physical medium.

Generally, in a communication system, information is transmitted from transmitter to receiver that are placed over a limited distance. With the help of wireless Communication, the transmitter and receiver can be placed anywhere between few meters (like a T.V. Remote Control) to few thousand kilometres (Satellite Communication).

The communication among devices is established by electromagnetic waves. The Frequency, Wavelength and various band names of Electromagnetic spectrum is as shown in Table 1.1:

Table 1: The Electromagnetic spectrum

f	$\lambda$	Band	Description
30 - 300Hz	$10^4-10^3$km	ELF	Extremly low frequency
300 - 3000Hz	$10^3-10^2$ km	VF	Voice frequency
3 - 30 KHz	$100-10$ km	VLF	Very low frequency
30 - 300 KHz	$10-1$ km	LF	Low frequency
0.3 - 3 MHz	$1-0.1$ km	MF	Medium frequency
3 - 30 MHz	$100-10$ m	HF	High frequency
30 - 300 MHz	$10-1$ m	VHF	Very High frequency
300 - 3000 MHz	$100-10$ cm	UHF	Ultra High frequency
3 - 30 GHz	$10-1$ cm	SHF	Super High frequency
30 - 300 GHz	$10-1$mm	EHF	Extremly High Frequency

Some of wireless technologies used in different bands are, Second Generation (2G) mobile technologies operating in the 800 MHz Band, Third Generation (3G) Mobile technologies operating in the 2000 MHz Band. Some of the short range wireless technologies like Bluetooth, Zigbee operate in the 2.4GHz Band.

All these frequency bands are not freely available. Most of the spectrum belongs to the licensed band and few bands are unlicensed. The technologies that use unlicensed spectrum are Bluetooth, Wi-Fi which use 2.4 GHz. Technologies that use licensed spectrum are GSM, CDMA One which use 800 MHz.

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