Article on Radio Wireless Mobile Communication Technology

Introduction - Wireless communication , like their wired counterparts rely on the manipulation of electrical charge to enable communication between devices , however they use a specific type of signal known as radio frequency or RF . Following the demonstration by Marconi , led to the widespread use of radio waves for communication . Radio communication is hence the process in which radio waves are used as a carrier for transmitting and receiving intelligent information through atmosphere or deep space and sky (Poole , 2006 ,

. 8 . This article explains the fundamentals of radio communication starting from the basics

of radio signals , then going on to explain how radio waves can be used for communication . In the later part of the article , the popular cellular radio communication schemes are discussed

The nature of radio signals

What radio signals are

Radio Signals are electromagnetic waves , almost exactly similar to visible and infrared light except for their frequency and wavelength The frequency of radio waves is much lower than the visible and infrared light . And in consequence there wavelength is much longer (Poole , 2006 br

. 19 . This is because of the fact that the wavelength of a radiation is inversely proportional to its frequency this can be represented as below is the constant speed at which any electromagnetic wave travels equal to 3x108 m /s

How radio signals propagate over a wireless medium

Radio waves travel outwards much like waves in a water pond and become weaker as they travel longer distances . However , the distances covered by the radio waves are very large and are in fact the signals that scientist look for from the farthest galaxies to find the outer extremities of the universe . Since they are electromagnetic waves , radio signals do not need any medium in to propagate . Light waves , like radio waves travel , in straight lines and are subject to reflection refraction , diffraction , absorption and scattering . The entire radio spectrum is divided into very low , low , medium , high , very high , ultra high , super high and extremely high frequencies , and a group frequencies is called a band (Haslett , 2008 ,

. 87

Factors that adversely affect radio signal propagation

There are several factors that affect the radio transmission . At different frequencies some of these factors affect radio waves more than others . Many of the factors lead to attenuation , which means the weakening of a radio signal as it passes through the atmosphere . All the radio signals are attenuated as they pass through rain or any type of water in the air , such as cloud , snow sleet etc , but radio signals at higher frequencies are attenuated more than the radio signals at lower frequencies (Xiao , 2007 ,

. 352 . In addition to this radio communications are also affected by the ionosphere layer present in the earth 's atmosphere . This layer affects the radio waves due to the presence of a large number of electrons and other ions . This layer causes two major disturbances in the transmission of radio waves

Faraday Rotation - This phenomena is whereby the polarization plane of...