Unit-1_Mobile and Wireless Communication.pptx

WIRELESS COMMUNICATION

1. Modern Wireless Communication System (21EC0103T ) Unit-1 DR. AARTI Sharma Assistant professor Department of Ece SRM IST, Delhi ncr campus 1

2. Course outcome of Unit-2 At the end of this unit student will learn to analyze transmission of various wireless communication system. 2

3. Contents Wireless Communication Multiple Access Techniques Cellphone Generation – 1G, 2G, 3G and 4G. 4G Transmission Fundamentals 3

4. Wireless Communication Transmitting and Receiving voice and data using electromagnetic waves in space. Freedom from wires Less installation cost 4

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6. Frequency Spectrum 6

7. Need of Wireless Communication Freedom from Wires Global Coverage Stay Connected Flexibility 7

8. Challenges in Wireless Communication Efficient Hardware Efficient use of Radio Spectrum Integrated Service Connecting and Coverage 8

9. Multiple Access Techniques Multiple access technique allow many mobile user to share a finite amount of radio spectrum. The sharing of spectrum is required to achieve high capacity by simultaneously allocating the bandwidth. 9

10. Frequency Division Multiple Access (FDMA) 10

11. Time Division Multiple Access (TDMA) 11

12. Code Division Multiple Access (CDMA) In CDMA every user is allowed at all the time and all frequencies band for communication but they have to share a particular code. 12

13. Cellular Network – Evolution (1G) G – Generation – Generally refers to the change in the nature of system, speed, technology and frequency. First Generation (1G) First generation system is an analog system developed in mid 1980’s. 13

14. First Generation (1G) 1G uses analog modulation. Mostly FM modulation techniques are used in 1G. 1G is used for voice services. FDMA Multiple Access techniques are used. Confined to national boundaries. Speed is up to 2.4Kbps. 14

15. Second Generation (2G) 2G is digital system introduced in late 1980’s. Developed for voice communication. Digital Modulation techniques are used in 2G. TDMA and CDMA multiple access techniques are used. Provides data rate up to 9.6 kbps. 15

16. Limitations of 2G Developed for voice communication. Unsuitable for data traffic. Not suitable for internet services (Packet Switching). 16

17. 2.5 G The effort to remove limitations of 2G resulted in 2.5 G. Digital System Voice + Low data rates (Circuit Switching + Packet Switching) Internet access through GPRS. 17

18. Third Generation (3G) Third generation was introduced in 2000. Simultaneous voice+ High speed data. Multimegabit internet access. Voice activated calls. Multimedia Transmission Example is WCDMA 18

19. Fourth Generation (4G) Introduced in late 2000. IP based network system. Main objective is to provide high speed, high quality and voice over internet protocal ( voip ). Having speed of 10Mbps. LTE and WiMax (Wireless Interoperability for microwave access) are 4G technology. 19

20. Summary 20

21. Time Domain Concepts In the time domain, voltage or current is expressed as a function of time as illustrated in Figure. 21

22. Signals can also be represented by a magnitude and phase as a function of frequency. Signals that repeat periodically in time are represented by a line spectrum as illustrated in Fig. The line spectrum has a DC component at 0 Hz, a fundamental component at 1/T, and harmonics at n/T (where n is an integer). 22

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