Chapter 16 Other Wireless Networks Copyright The Mc

Chapter 16 Other Wireless Networks Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display.

16 -1 Wi. MAX The IEEE 802. 16 Worldwide Interoperability for Microwave Access. 16. 2

16 -1 Wi. MAX provides the last mile of broadband wireless connectivity. 16. 3

16 -1 Wi. MAX provides wireless access up to 50 Km for fixed stations, 15 Km for mobile stations 16. 4

16 -1 Wi. MAX Sprint and Clearwire have deployed the Wi. MAX technology. Sprint will retire the service in 2015 in favor of LTE 16. 5

16 -1 Wi. MAX It has been successful in Russia, Pakistan, and Mongolia. Available to about 30 million people in 27 cities worldwide. 16. 6

16 -1 Wi. MAX frequency band is from 2 -66 GHz and has bandwidth up to 75 Mbps. Actual field tests show bandwidth comparable to DSL service (5 -10 Mbps). 16. 7

Figure 16. 1: Fixed Wi. MAX 16. 8

Figure 16. 2: Mobile Wi. MAX 16. 9

16 -1. 2 LTE Long Term Evolution Marketed as 4 G LTE. 16. 10

16 -1. 2 LTE Long Term Evolution Service was first established in Dec 2009 (Europe), 2011 in North America. 16. 11

16 -1. 2 LTE supports roaming internet access from mobile phones. LTE supports Voice over IP. 16. 12

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.

16 -2 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. 16. 14

16 -2 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. ● 16. 15

Figure 16. 6: Cellular system 16. 16

Figure 16. 7: Frequency reuse patterns 16. 17

16. 2. 2 First Generation (1 G) 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. 16. 18

1 G 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.

Figure 16. 8: Cellular bands for AMPS 16. 20

16. 2. 3 Second Generation (2 G) To provide higher-quality (less noise-prone) mobile voice communications, the second generation of the cellular phone network was developed. 1 G is for analog service 2 G supports digital service Three major systems evolved in the second generation: D-AMPS, GSM, and IS-95. 16. 21

2 G 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 1 G-AMPS. D-AMPS has a cell reuse factor of 7.

2 G-GSM The Global System for Mobile service was developed in Europe. GSM has a cell reuse factor of 4 TDMA → GMSK → and FDMA

2 G-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.

Figure 616. 11: GSM bands (Global System for Mobile Service) 16. 25

Figure 16. 12: GSM 16. 26

2 G IS-95 Interim Standard 95 used throughout North America for 2 G service. Uses GPS to synchronize base stations. Has a cell reuse factor of 1.

2 G IS-95 Station to phone CDMA → QPSK → FDMA Phone to station DSSSS → QPSK → FDMA

2 G IS-95 25 MHz band 1. 228 MHz per channel 20 channels per cell 64 calls per channel using CDMA 1280 calls per cell

Figure 16. 14: IS-95 forward transmission 16. 30

Figure 16. 15: IS-95 reverse transmission 16. 31

16. 2. 4 Third Generation (3 G) The third generation of cellular telephony refers to a combination of technologies that provide both digital data and voice communication. 16. 32

16. 2. 4 Third Generation (3 G) 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. 16. 33

3 G 3 G calls for, … 2 Mbps stationary bandwidth 144 to 384 Kbps moving bandwidth

3 G-CDMA vs 3 G-TDMA CDMA providers Verizon Sprint Metro. PCS Cricket US Cellular TDMA providers AT&T T-Mobile

16. 2. 5 Fourth Generation (4 G) The fourth generation of cellular telephony is expected to be a complete evolution in wireless communications. 4 G-LTE appears to be the current trend. 16. 36

4 G 1 Gbps stationary bandwidth 100 Mbps moving bandwidth CDMA → 64 -QAM → IFDMA or OFDMA

16 -3 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. 16. 38

Figure 16. 17: Satellite orbits 16. 39

Figure 16. 18: Satellite orbit altitudes 16. 40

Figure 16. 19: Satellites in geostationary orbit 16. 41

Geostationary Orbit C = 2 pi(35700 km + 6300) Speed = C / 24 hrs ~ 11, 000 km/hr Example: weather satellite, satellite TV.

16. 3. 3 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. 16. 43

Figure 16. 20: Orbits for global positioning system (GPS) satellites 16. 44

MEO Satellites: GPS employs 24 satellites Trilateration: 3 satellite positions are used to locate any point on the earths surface.

Figure 16. 21: Trilateration on a plane 16. 46

Figure 16. 22: LEO satellite system 16. 47

LEO Satellites Periods range from 90 min to 120 min to circle the earth. LEO is preferred for phone service due to less delay compared to MEO or GEO satellites.

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 Do. D.