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Lecture Wireless and mobile computing – Chapter 1: Introduce

The following will be discussed in this chapter: What is wireless communication? Types of wireless communication, multiservice point-to-multipoint wireless network, electromagnetic radiation spectrum, wavelength of some technologies, types of electromagnetic carriers,. | Wireless and Mobile Computing Sajjad Ali Mushtaq What is Wireless Communication ? Transmitting voice, data, video and other services data using electromagnetic waves in open space (atmosphere) Electromagnetic waves Travel at speed of light (c = 3x108 m/s) Has a frequency (f) and wavelength (λ) c = f x λ Where c = wave speed Higher frequency means higher energy The higher the energy the more penetrating are the radiations Types of Wireless Communication Celullar Wireless computer network Radio service Multiservice Point-to-Multipoint Wireless Network Electromagnetic Radiation Spectrum The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Wavelength of Some Technologies GSM Phones: frequency ~= 900 Mhz wavelength ~= 33cm PCS Phones frequency ~= 1.8 Ghz wavelength ~= 17.5 cm Bluetooth: frequency ~= 2.4Gz wavelength ~= 12.5cm Wireless Media Standards Types of Electromagnetic Carriers When the distance between the sender and receiver is short (e.g. TV box and a remote control) infrared waves are used For long range distances between sender and receiver (e.g. TV broadcasting and cellular service) both microwaves and radio waves are used radio waves are ideal when large areas need to be covered and obstacles exist in the transmission path microwaves are good when large areas need to be covered and no obstacles exist in the transmission path Wireless Applications (Services) Advantages and Disadvantages of Wireless Communication advantages: mobility a wireless communication network is a solution in areas where cables are impossible to install (e.g. hazardous areas, long distances etc.) easier to maintain disadvantages: has security vulnerabilities high costs for setting the infrastructure unlike . | Wireless and Mobile Computing Sajjad Ali Mushtaq What is Wireless Communication ? Transmitting voice, data, video and other services data using electromagnetic waves in open space (atmosphere) Electromagnetic waves Travel at speed of light (c = 3x108 m/s) Has a frequency (f) and wavelength (λ) c = f x λ Where c = wave speed Higher frequency means higher energy The higher the energy the more penetrating are the radiations Types of Wireless Communication Celullar Wireless computer network Radio service Multiservice Point-to-Multipoint Wireless Network Electromagnetic Radiation Spectrum The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Wavelength of Some Technologies GSM Phones: frequency ~= 900 Mhz wavelength ~= 33cm PCS .