Page 12 - Basics of Electrical, Electronic and Communication

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16.5 Navigational aids and systems . . . . . . . . . . . . . 315

17 Advanced communication Systems 317
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 317
17.2 Microwave communication . . . . . . . . . . . . . . . 317
17.2.1 Microwave frequency bands . . . . . . . . . . 318
17.2.2 Microwave communication system . . . . . . . 318
17.2.3 Advantages of microwave communication . . . 320
17.3 Satellite communication . . . . . . . . . . . . . . . . 321
17.4 Optical communication . . . . . . . . . . . . . . . . . 323
17.4.1 Fiber-optic technology . . . . . . . . . . . . . 324
17.4.2 Total internal reflection . . . . . . . . . . . . . 324
17.4.3 Snell’s law . . . . . . . . . . . . . . . . . . . 325
17.4.4 Light transmission through an optical fiber . . 327
17.4.5 Numerical aperture . . . . . . . . . . . . . . . 327
17.4.6 Optical fiber communication system . . . . . . 328
17.5 Cellular communications . . . . . . . . . . . . . . . . 329
17.5.1 Principles of cellular networks . . . . . . . . . 330
17.5.2 Frequency reuse . . . . . . . . . . . . . . . . 331
17.5.3 Operation of cellular system . . . . . . . . . . 333
17.5.4 Hand off . . . . . . . . . . . . . . . . . . . . 335
17.5.5 Roaming . . . . . . . . . . . . . . . . . . . . 336
17.5.6 Improving capacity in cellular system . . . . . 337
17.6 Global system for mobile communications . . . . . . . 337
17.6.1 GSM services . . . . . . . . . . . . . . . . . . 338
17.6.2 Architecture of the GSM network . . . . . . . 338
17.6.3 Code Division Multiple Access (CDMA) . . . 341
17.6.4 Comparison of GSM and CDMA . . . . . . . 342
17.7 General packet Radio Service (GPRS) . . . . . . . . . 343
17.7.1 Features of GPRS . . . . . . . . . . . . . . . . 343
17.7.2 GPRS services . . . . . . . . . . . . . . . . . 343
17.7.3 GPRS applications . . . . . . . . . . . . . . . 344

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