tailieunhanh - Lecture Data communications and networks: Chapter 16 - Forouzan 

We discussed wireless LANs in chapter 14. Wireless technology is also used in cellular telephony and satellite networks. We discuss the former in this chapter as well as examples of channelization access methods (see Chapter 12). We also briefly discuss satellite networks, a technology that eventually will be linked to cellular telephony to access the Internet directly. | Chapter 16 Wireless WANs: Cellular Telephone and Satellite Networks Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 16. 16-1 CELLULAR TELEPHONY Cellular telephony is designed to provide communications between two moving units, called mobile stations (MSs), or between one mobile unit and one stationary unit, often called a land unit. Frequency-Reuse Principle Transmitting Receiving Roaming First Generation Second Generation Third Generation Topics discussed in this section: 16. Figure Cellular system 16. Figure Frequency reuse patterns 16. AMPS is an analog cellular phone system using FDMA. Note 16. Figure Cellular bands for AMPS 16. Figure AMPS reverse communication band 16. Figure Second-generation cellular phone systems 16. Figure D-AMPS 16. D-AMPS, or IS-136, is a digital cellular phone system using TDMA and FDMA. Note 16. Figure GSM bands 16. Figure GSM 16. Figure Multiframe components 16. GSM is a digital cellular phone system using TDMA and FDMA. Note 16. Figure IS-95 forward transmission 16. Figure IS-95 reverse transmission 16. IS-95 is a digital cellular phone system using CDMA/DSSS and FDMA. Note 16. The main goal of third-generation cellular telephony is to provide universal personal communication. Note 16. Figure IMT-2000 radio interfaces 16. 16-2 SATELLITE NETWORKS A satellite network is a combination of nodes, some of which are satellites, that provides communication from one point on the Earth to another. A node in the network can be a satellite, an Earth station, or an end-user terminal or telephone. Orbits Footprint Three Categories of Satellites GEO Satellites MEO Satellites LEO Satellites Topics discussed in this section: 16. Figure Satellite orbits 16. What is the period of the Moon, according to Kepler’s law? Example Here C is a constant . | Chapter 16 Wireless WANs: Cellular Telephone and Satellite Networks Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 16. 16-1 CELLULAR TELEPHONY Cellular telephony is designed to provide communications between two moving units, called mobile stations (MSs), or between one mobile unit and one stationary unit, often called a land unit. Frequency-Reuse Principle Transmitting Receiving Roaming First Generation Second Generation Third Generation Topics discussed in this section: 16. Figure Cellular system 16. Figure Frequency reuse patterns 16. AMPS is an analog cellular phone system using FDMA. Note 16. Figure Cellular bands for AMPS 16. Figure AMPS reverse communication band 16. Figure Second-generation cellular phone systems 16. Figure D-AMPS 16. D-AMPS, or IS-136, is a digital cellular phone system using TDMA and FDMA. Note 16. Figure GSM bands 16. Figure GSM