1. Chapter 16 Other Wireless Networks 16.# 1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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2. The IEEE 802.16 Worldwide Interoperability for Microwave Access.
WiMAX
The IEEE Worldwide Interoperability for Microwave Access.
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3. WiMAX provides the last mile of broadband wireless connectivity.
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4. WiMAX
WiMAX provides wireless access up to 50Km for fixed stations, 15Km for mobile stations
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5. Sprint and Clearwire have deployed the WiMAX technology .
Sprint will retire the service in 2015 in favor of LTE
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6. It has been successful in Russia, Pakistan, and Mongolia.
WiMAX
It has been successful in Russia, Pakistan, and Mongolia.
Available to about 30million people in 27 cities worldwide.
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7. WiMAX frequency band is from 2-66GHz and has bandwidth up to 75Mbps.
Actual field tests show bandwidth comparable to DSL service (5-10Mbps).
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8. Figure 16.1: Fixed WiMAX
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9. Figure 16.2: Mobile WiMAX
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10. LTE
Long Term Evolution
Marketed as 4G LTE.
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11. Service was first established in Dec 2009 (Europe),
LTE
Long Term Evolution
Service was first established in Dec 2009 (Europe),
2011 in North America.
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12. LTE supports roaming internet access from mobile phones.
LTE supports Voice over IP.
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13. Vocabulary
MSC = mobile switching center, searches for phones by paging until found.
Handoff = transferring a call between cells.
Roaming = agreements between providers to help complete calls.
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14. 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.
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15. A service provider must be able to: locate and track a caller,
Cellular Telephony
A service provider must be able to:
locate and track a caller,
assign a channel to the call,
and transfer the channel from base station to base station as the caller moves out of range.
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16. Figure 16.6: Cellular system
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17. Figure 16.7: Frequency reuse patterns
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18. First Generation (1G)
Cellular telephony is now in its fourth generation. The first generation was designed for voice communication using analog signals.
AMPS was the first generation cellular technology in North America. (Advanced Mobile Phone Service)
AMPS has a reuse factor of 7.
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19. 1G Cell math 25 MHz bandwidth 30 KHz per channel 832 channels
42 channels used for control
1/7 of the channels per cell
112 simultaneous calls per cell.
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20. Figure 16.8: Cellular bands for AMPS
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21. Second Generation (2G)
To provide higher-quality (less noise-prone) mobile voice communications, the second generation of the cellular phone network was developed.
1G is for analog service
2G supports digital service
Three major systems evolved in the second generation: D-AMPS, GSM, and IS-95.
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22. 2G D-AMPS Combined TDMA → QPSK → and FDMA.
Trios of calls are interleaved in TDMA frames before being converted to an analog signal on one channel. Has about 3 times the call capacity of 1G-AMPS.
D-AMPS has a cell reuse factor of 7.
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23. 2G-GSM The Global System for Mobile service was developed in Europe.
GSM has a cell reuse factor of 4
TDMA → GMSK → and FDMA
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24. 2G-GSM Capacity 8 calls per TDMA channel 25-MHz of bandwidth
200 KHz per channel
124 channels
About 31 channels per cell.
No more than 248 calls per cell.
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25. Figure 616.11: GSM bands (Global System for Mobile Service)
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26. Figure : GSM
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27. 2G IS-95
Interim Standard 95 used throughout North America for 2G service.
Uses GPS to synchronize base stations.
Has a cell reuse factor of 1.
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28. 2G IS-95 Station to phone CDMA → QPSK → FDMA
Phone to station DSSSS → QPSK → FDMA
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29. 2G IS-95 25 MHz band 1.228 MHz per channel 20 channels per cell
64 calls per channel using CDMA
1280 calls per cell
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30. Figure 16.14: IS-95 forward transmission
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31. Figure 16.15: IS-95 reverse transmission
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32. Third Generation (3G)
The third generation of cellular telephony refers to a combination of technologies that provide both digital data and voice communication.
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33. Third Generation (3G)
Using a small portable device, a person is able to talk to anyone else in the world with a voice quality similar to that of the existing land line telephone network.
A person can download and watch a movie, download and listen to music, surf the Internet or play games, have a video conference, etc.
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34. 3G 3G calls for, … 2 Mbps stationary bandwidth
144 to 384 Kbps moving bandwidth
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35. 3G-CDMA vs 3G-TDMA CDMA providers TDMA providers Verizon AT&T
Sprint T-Mobile
MetroPCS
Cricket
US Cellular
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36. Fourth Generation (4G)
The fourth generation of cellular telephony is expected to be a complete evolution in wireless communications. 4G-LTE appears to be the current trend.
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37. 4G 1 Gbps stationary bandwidth 100 Mbps moving bandwidth
CDMA → 64-QAM → IFDMA or OFDMA
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38. Satellite Network
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.
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39. Figure 16.17: Satellite orbits
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40. Figure 16.18: Satellite orbit altitudes
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41. Figure 16.19: Satellites in geostationary orbit
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42. Geostationary Orbit C = 2pi(35700km + 6300)
Speed = C / 24 hrs ~ 11,000km/hr
Example: weather satellite, satellite TV.
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43. MEO Satellites
Medium-Earth-orbit (MEO) satellites are positioned between the two Van Allen belts. A satellite at this orbit takes approximately 6 to 8 hours to circle the Earth.
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44. Figure 16.20: Orbits for global positioning system (GPS) satellites
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45. MEO Satellites: GPS GPS employs 24 satellites
Trilateration: 3 satellite positions are used to locate any point on the earths surface.
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46. Figure 16.21: Trilateration on a plane
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47. Figure 16.22: LEO satellite system
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48. LEO Satellites Periods range from 90min to 120min to circle the earth.
LEO is preferred for phone service due to less delay compared to MEO or GEO satellites.
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49. LEO Satellites
Globalstar – 48 satellites divided into 6 polar orbits. 8 satellites per orbit.
Iridium – 66 satellites divided into 6 polar orbits. 11 satellites per orbit. Used by DoD.
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