Recommended
More Related Content
Similar to lecture_1.pdf
Similar to lecture_1.pdf (20)
Recently uploaded
Recently uploaded (20)
lecture_1.pdf
- 1. Page 1 LOGO Introductory Lecture Instructor Engr. Dr. Farzana Kulsoom Assistant Professor TED TE-306 Wireless Communication and RF planning (2 + 0)
- 2. Page 2 LOGO Recommended Textbooks 1) Wireless Communications , Andrea Goldsmith 2) Theodore Rappaport, Wireless Communications: Principles and Practice, Second Edition, Prentice Hall, 2003 ISBN: 3) Wireless communication & networks by William Stallings
- 3. Page 3 LOGO Electromagnetic waves and communication
- 4. Page 4 LOGO Wireless Communication • Transmitting voice and data using electromagnetic waves • Electromagnetic waves • Travel at speed of light (c = 3x108 m/s) • Has a frequency (f) and wavelength (l) c = f l • Higher frequency means higher energy and short wavelength • The higher the energy the more penetrating is the radiation
- 5. Page 5 LOGO Electromagnetic Spectrum 104 102 100 10-2 10-4 10-6 10-8 10-10 10-12 10-14 10-16 104 106 108 1010 1012 1014 1016 1018 1020 1022 1024 IR UV X-Rays Cosmic Rays Radio Spectrum 1MHz ==100m 100MHz ==1m 10GHz ==1cm Micro wave Visible light f(Hz) λ (m) 1) Radio Waves: These are long wavelength, small frequency waves; AM, FM, TV, Radar, Microwave. 2) Infrared : Emit by all objects at room temp, usually used in TV remote. 3) Visibile Light: This is the spectrum range for which our eyes are sensitive, they can sense colors.
- 6. Page 6 LOGO Uses 4) Ultra-Violent : Have short wavelength and frequency than visible light. Freq after this has more energy and dangerous to humans. 5) X-rays : Given off by stars naturally. Used In medical applications. 6) Gamma-Rays: Most energetic and shortest wave , given off by radio active elements and stars https://www.youtube.com/watch?v=cfXzwh3KadE
- 7. Page 7 LOGO Elements of Wireless system The information from transmitter to receiver is carried over a well defined frequency band over a certain medium or channel, like air, water or a substance. Signal gets faded over distance attenuated because of multiple paths and Reflection, Diffraction
- 8. Page 8 LOGO Communication mode • Simplex :When the signal is sent in one direction. • This is called simplex transmission, For example keyboard and monitor. • Half duplex mode, the signal is sent in both directions, but one at a time. walkie-talkie • Full duplex mode. both parties can communicate with each other simultaneously, mobile phones network
- 9. Page 9 LOGO Duplex Communication - FDD FDD: Frequency Division Duplex Frequency-division duplexing (FDD) which is a method for establishing a full duplex communication link that uses two different radio frequencies for transmitter and receiver operation. Base Station B Mobile Terminal M Forward Channel Reverse Channel Forward Channel and Reverse Channel use different frequency Bands. Complex to install----pairs of frequencies are required Low latency----- as no time switching is required Training overhead problem in 5G forward channel
- 10. Page 10 LOGO Duplex Communication - TDD TDD: Time Division Duplex • TDD is a method for emulating full-duplex communication over a half-duplex communication link. • Base Station B Mobile Terminal M Same frequency is used. The channel is divided into time slots. Mobile station and base station transmits on the time slots alternately. • High Latency because of switching • Spectral efficient • Pilot contamination problem in 5 G M B M B M B
- 11. Page 11 LOGO What is Mobility Initially Internet and Telephone Networks is designed assuming the user terminals are static • No change of location during a call/connection • A user terminals accesses the network always from a fixed location Mobility and portability – Portability means changing point of attachment to the network offline – Mobility means changing point of attachment to the network online
- 12. Page 12 LOGO Degrees of Mobility • Walking Users------------low mobility • Low speed • Small roaming area • Usually uses high-bandwith/low-latency access • Vehicles ------------high mobility • High speeds • Large roaming area • Usually uses low-bandwidth/high-latency access • Uses sophisticated terminal equipment (cell phones)
- 13. Page 13 LOGO Wireless/Mobile Networking • Ubiquitous Computing – Connectivity Anywhere, anytime computing and communication • You don’t have to go to the lab to work on your lab computer. – Pushing the computers more into background • Focus on the task and life, not on the computer smart home • Use computers seamlessly to help you and to make your life more easier. – Computers should be location aware • Adapt to the current location, discover services
- 14. Page 14 LOGO Some Example Applications of Ubiquitous Computing • You walk into your office and your computer automatically authenticates you through your active badge and logs you into the Unix system • You go to a foreign building and your PDA automatically discovers the closest public printer where you can print your schedule and give to your friend
- 15. Page 15 LOGO More Examples You walk into a Conference room or a shopping Mall with your PDA and your PDA is smart enough to collect and filter the public profiles of other people that are passing nearby Of course other people should also have smart PDAs. The cows in a village are equipped with GPS and GPRS devices and they are monitored from a central location on a digital map No need for a person to guide and feed them You can find countless examples
- 16. Page 16 LOGO What is PCS • Personal Communication Services – A wide variety of network services that includes wireless access and personal mobility services – Provided through a small terminal – Enables communication at any time, at any place, and in any form. • The market for such services is tremendously big – Think of cell-phone market
- 17. THANK YOU