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Wireless# Guide to Wireless Communications

Wireless# Guide to Wireless Communications. Chapter 10 Wireless Wide Area Networks. Objectives. Describe wireless wide area networks (WWANs) and how they are used Describe the applications that can be used on a digital cellular telephone Explain how cellular telephony functions

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Wireless# Guide to Wireless Communications

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  1. Wireless# Guide to Wireless Communications Chapter 10 Wireless Wide Area Networks

  2. Objectives • Describe wireless wide area networks (WWANs) and how they are used • Describe the applications that can be used on a digital cellular telephone • Explain how cellular telephony functions • List features of the various generations of cellular telephony • Discuss how satellite transmissions work Wireless# Guide to Wireless Communications

  3. Cellular Telephone Applications • Digital cellular telephones can be used to: • Browse the Internet • Send and receive short messages and e-mails • Participate in videoconferencing • Receive various sorts of information • Run a variety of business applications • Connect to corporate networks • Watch television or on-demand movies • Take and transmit pictures and short movies • Locate family members and employees using GPS Wireless# Guide to Wireless Communications

  4. Cellular Telephone Applications (continued) • Short Message Services (SMS) • One of the most widely used applications • Allows for the delivery of short, text-based messages between wireless devices • Messages are limited to about 160 characters • Applications • Person-to-person • Agent-to-person • Information broadcast services • Software configuration • Advertising Wireless# Guide to Wireless Communications

  5. How Cellular Telephony Works • Keys to cellular telephone networks • Cells • City cells measure approximately 10 square miles • At the center of each cell is a cell transmitter connected to a base station • Each base station is connected to a mobile telecommunications switching office (MTSO) • Link between the cellular network and the wired telephone world • Controls all transmitters and base stations Wireless# Guide to Wireless Communications

  6. How Cellular Telephony Works (continued) Wireless# Guide to Wireless Communications

  7. How Cellular Telephony Works (continued) • Keys to cellular telephone networks (continued) • Transmitters and cell phones operate at low power • Enables the signal to stay confined to the cell • Signal at a specific frequency does not go far beyond the cell area • Same frequency can be used in other cells at the same time • Except in adjacent cells • Cell phones have special codes Wireless# Guide to Wireless Communications

  8. How Cellular Telephony Works (continued) Wireless# Guide to Wireless Communications

  9. How Cellular Telephony Works (continued) Wireless# Guide to Wireless Communications

  10. How Cellular Telephony Works (continued) • When user moves within the same cell • Transmitter and base station for that cell handle all of the transmissions • As the user moves toward the next cell • A handoff process occurs • Roaming • User moves from one cellular network to another Wireless# Guide to Wireless Communications

  11. How Cellular Telephony Works (continued) Wireless# Guide to Wireless Communications

  12. How Cellular Telephony Works (continued) • Steps to receive a call • Cell phone listens for the SID being transmitted by the base station on the control channel • Phone compares SID with its programmed SID • If they match, phone is in a network owned by carrier • If SIDs do not match, phone is roaming • When a call comes in, MTSO locates the phone through the registration request • User can move to another cell • Phone and transmitter can change frequencies Wireless# Guide to Wireless Communications

  13. How Cellular Telephony Works (continued) Wireless# Guide to Wireless Communications

  14. Digital Cellular Telephony • Cellular telephones have been available since the early 1980s in the United States • Most industry experts outline several generations of cellular telephony Wireless# Guide to Wireless Communications

  15. First Generation Cellular Telephony • First Generation (1G) • Uses analog signals modulated using FM • Based on Advanced Mobile Phone Service (AMPS) • Operates in the 800-900 MHz frequency spectrum • Each channel is 30 KHz wide with a 45 KHz passband • There are 832 frequencies available • Uses Frequency Division Multiple Access (FDMA) • FDMA allocates a single cellular channel with two frequencies to one user at a time • 1G networks use circuit-switching technology Wireless# Guide to Wireless Communications

  16. First Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  17. First Generation Cellular Telephony (continued) • Circuit-switching technology • Makes a dedicated and direct physical connection • Between the caller and the recipient • Analog signals are prone to interference • Do not have the same quality as digital signals Wireless# Guide to Wireless Communications

  18. Second Generation Cellular Telephony • Second Generation (2G) • Transmits data between 9.6 Kbps and 14.4 Kbps • In the 800 MHz and 1.9 GHz frequencies • 2G networks are also circuit-switching • 2G systems use digital transmissions • Digital transmission benefits • Uses the frequency spectrum more efficiently • Over long distances, the quality of the voice transmission does not degrade • Difficult to decode and offer better security Wireless# Guide to Wireless Communications

  19. Second Generation Cellular Telephony (continued) • Second Generation (2G) (continued) • Digital transmission benefits (continued) • Digital transmissions use less transmitter power • Enables smaller and less expensive individual receivers and transmitters • Multiple access technologies • Time Division Multiple Access (TDMA) • CDMA • Global System for Mobile communications (GSM) • Uses a combination of FDMA and TDMA technologies Wireless# Guide to Wireless Communications

  20. Second Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  21. Second Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  22. 2.5 Generation Cellular Telephony • 2.5 Generation (2.5G) • Interim step between 2G and 3G • Operates at a maximum speed of 384 Kbps • 2.5G networks are packet-switched • Advantages of packet switching • Much more efficient • Can handle more transmissions over a given channel • Permits an always-on connection Wireless# Guide to Wireless Communications

  23. 2.5 Generation Cellular Telephony (continued) • 2.5G network technologies • General Packet Radio Service (GPRS) • For TDMA or GSM 2G networks • Uses eight time slots in a 200 KHz spectrum and four different coding techniques • Enhanced Data rates for GSM Evolution (EDGE) • Can transmit up to 384 Kbps • Based on a modulation technique called 8-PSK • CDMA2000 1xRTT • Operates on two 1.25 MHz-wide frequency channels • Supports 144 Kbps packet data transmission Wireless# Guide to Wireless Communications

  24. Third Generation Cellular Telephony • Third Generation (3G) • Intended to be a uniform and global standard for cellular wireless communication • Standard data rates • 144 Kbps for a mobile user • 386 Kbps for a slowly moving user • 2 Mbps for a stationary user • 3G network technologies • CDMA2000 1xEVDO • For 2.5G CDMA2000 1xRTT networks Wireless# Guide to Wireless Communications

  25. Third Generation Cellular Telephony (continued) • 3G network technologies (continued) • CDMA2000 1xEVDV will be the successor of CDMA2000 1xEVDO • Wideband CDMA (W-CDMA) • For 2.5G EDGE networks • High-Speed Downlink Packet Access (HSDPA) • Beyond W-CDMA • Uses a 5 MHz W-CDMA channel, variety of adaptive modulation, multiple in multiple out (MIMO) antennas, and hybrid automatic repeat request (HARQ) Wireless# Guide to Wireless Communications

  26. Third Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  27. Third Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  28. Third Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  29. Third Generation Cellular Telephony (continued) Wireless# Guide to Wireless Communications

  30. Client Software • Internet surfing or videoconferencing require client software • To operate on a wireless digital cellular device • Common types of clients • WAP • i-mode • Java • BREW Wireless# Guide to Wireless Communications

  31. Wireless Application Protocol (WAP and WAP Version 2) • Wireless Application Protocol (WAP) and WAP2 • Provide a standard way to transmit, format, and display Internet data • For devices such as cell phones • WAP was developed in 1997 • Enables devices to send and receive Internet text-only data • WAP cell phone runs a microbrowser • Uses Wireless Markup Language (WML) instead of HTML Wireless# Guide to Wireless Communications

  32. Wireless Application Protocol (WAP and WAP Version 2) (continued) Wireless# Guide to Wireless Communications

  33. Wireless Application Protocol (WAP and WAP Version 2) (continued) • WAP gateway (sometimes called WAP proxy) • Computer running special conversion software • Used to translate between WML and HTML • Many features of HTML are not supported in WML • Extensible Markup Language (XML) • Defined by the World Wide Web Consortium (W3C) • Uses tags to describe how an item should be displayed on the screen • WML document is called a deck • Contains one or more blocks, known as cards Wireless# Guide to Wireless Communications

  34. Wireless Application Protocol (WAP and WAP Version 2) (continued) Wireless# Guide to Wireless Communications

  35. Wireless Application Protocol (WAP and WAP Version 2) (continued) • WAP2 is based on XHTML (an extension of HTML version 4) • Displays graphics and multiple font styles on color screen equipped mobile devices • Includes a protocol stack that allows it to support TCP/IP directly • Defines a new profile, an extension of XML, specifically to support mobile devices • WAP2 is backward compatible with WAP version 1 Wireless# Guide to Wireless Communications

  36. i-Mode • i-mode • Internet access system • Owned by the Japanese corporation NTT DoCoMo • Based on compact HTML(cHTML) • A subset of HTML designed for mobile devices • cHTML has its own set of tags and attributes • i-mode users pay for the service • By the amount of information downloaded plus a service charge • WAP services are charged by the connection time Wireless# Guide to Wireless Communications

  37. Java • Java programming language • Developed by Sun Microsystems • Object-oriented language used for general-purpose business programming • As well as interactive Web sites • Java 2 Micro Edition (J2ME) • Subset of Java specifically developed for programming wireless devices • Enables a cellular phone to access remote applications and e-mail • As well as run programs on the cellular phone itself Wireless# Guide to Wireless Communications

  38. Binary Runtime Environment for Wireless (BREW) • BREW is a thin software environment • Very small program that resides on a wireless device • Capable of running applications that can be downloaded by the device on demand • BREW is compatible with Java, C, and C++ • BREW efficiently uses small amount of memory • Occupies only a small amount of flash memory • Dynamically allocates RAM for applications • BREW can be used with other applications Wireless# Guide to Wireless Communications

  39. Digital Cellular Challenges and Outlook • Users will benefit the most from digital cellular telephony • Once the industry settles on a single cellular standard Wireless# Guide to Wireless Communications

  40. Competing Technologies • There is no single road to 3G digital telephony • Europe standards • W-CDMA and HSDPA • China and South Korea standards • CDMA2000 1xEVDO • Japan standard • W-CDMA • United States standards • HSDPA and CDMA2000 1xEVDO Wireless# Guide to Wireless Communications

  41. Limited Spectrum • Spectrum • Single largest factor limiting the development of 3G • Although 3G can operate at almost any spectrum • Industry tries to use the same part of the spectrum for 3G communications around the world • 1.710 to 1.855 GHz and 2.520 to 2.670 GHz • U.S. Department of Defense currently uses the 1.7 GHz band for satellite control and military purposes Wireless# Guide to Wireless Communications

  42. Costs • High monthly service fees for data transmission • User cost for 3G pales in comparison to costs for the carriers to build entire 3G networks Wireless# Guide to Wireless Communications

  43. Other Wireless Options • Top speed for a 3G user is 10 Mbps downstream • 802.11g WLANs offer speeds of over 54 Mbps • Coverage area of a single WLAN is far less than a digital cellular network • Deploying multiple access points can create large areas of coverage • Higher power consumption and the large number of electronic components of 802.11g • Factors that have kept this technology from being implemented in cellular phone handsets Wireless# Guide to Wireless Communications

  44. Other Wireless Options (continued) • Impact of WiMAX • Two distinct kinds of WWAN set-up • 802.16-2004 and 802.16e • 802.16e WiMAX network can be overlaid on an existing cellular tower infrastructure • Provides mobile users with lower cost access to data at speeds equivalent to EVDO • 802.16-2004WiMAX • Provides Internet and cable TV access to rural areas and remote cities Wireless# Guide to Wireless Communications

  45. Satellite Broadband Wireless • Use of satellites for personal wireless communication is fairly recent • Satellite use falls into three broad categories • Satellites are used to acquire scientific data and perform research in space • Satellites look at Earth from space • Satellites include devices that are simply reflectors Wireless# Guide to Wireless Communications

  46. Satellite Broadband Wireless (continued) Wireless# Guide to Wireless Communications

  47. Satellite Transmissions • Satellites generally send and receive on one of four frequency bands • Frequency band affects the size of the antenna Wireless# Guide to Wireless Communications

  48. Satellite Transmissions (continued) Wireless# Guide to Wireless Communications

  49. Satellite Transmissions (continued) Wireless# Guide to Wireless Communications

  50. Satellite Transmissions (continued) • Class and Type of Service • Satellites can provide two classes of service • Consumer class service • Shares the available bandwidth between the users • Business class service • Offers dedicated channels with dedicated bandwidth • Types of connectivity • Point-to-point, point-to-multipoint, and multipoint-to-multipoint Wireless# Guide to Wireless Communications

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