1. Chapter 10, Wireless Communications Technologies: Part 2
Outline Introduction 10.2 Wireless Access Technologies
Frequency Division Multiple Access (FDMA) Time Division Multiple Access (TDMA) Code Division Multiple Access (CDMA)
First Generation Technology (1G) and AMPS 10.4 Second Generation Technologies (2G) Personal Communications Services (PCS) Global System for Mobile Communications (GSM) CdmaOne TDMA Technology Family Orthogonal Frequency Division Multiplexing (OFDM) G & Third Generation (3G) Technologies High Speed Circuit-Switched Data (HSCSD) General Packet Radio Service (GPRS) Enhanced Data Rates for Global Evolution (EDGE) CDMA Wideband Code Division Multiple Access (W-CDMA)

2. Chapter 10, Wireless Communications Technologies: Part 2
Outline Wireless Platforms and Programming Languages Handheld Devices Markup Languages (HDML) WAP & WML Compact HTML (cHTML) & I-mode Java & Java 2 Micro Edition (J2ME) XML & XHTML EPOC Binary Run Time Environment for Wireless (BREW) 10.7 SyncML Initative 10.8 Future of Wireless Technologies
Internet and World Wide Web Resources

3. 10.1 Introduction Wireless communications challenges
Standardization
Security
Cost of development
Wireless technology generations
1G, 2G, 2.5G, 3G, 4G
Wireless technologies
AMPS, PCS, GSM, FDMA, CDMA and TDMA
Programming languages and platforms for wireless
WAP, J2ME, cHTML, XML, XHTML

4. 10.2 Wireless Access Technologies
Access technologies are used to control and establish how communications take place as well as define guidelines for network development
Three key access technologies
Frequency Division Multiple Access (FDMA)
Time Division Multiple Access (TDMA)
Code Division Multiple Access (CDMA)

5. 10.2.1 Frequency Division Multiple Access (FDMA)
One of the first access technologies developed for communications networks
FDMA assigns each communications transmission to different frequency slots or channels.

6. 10.2.1 Frequency Division Multiple Access (FDMA)
Frequency slots are divided into uplinks (channels that handle transmissions from users to base stations) and downlinks (transmissions from base stations to users)
FDMA searches the available frequency slots and assigns a channel to a user for the duration of the uplink or downlink session.
No other users can use a channel that is already assigned until the transmission is complete
FDMA encounters interference problems, inefficiency and transmission interruptions.

7. 10.2.2 Time Division Multiple Access (TDMA)
Used worldwide with GSM, CDMA and other popular network technologies
TDMA takes multiple calls and assigns each call to a different time slot on the same radio frequency

8. 10.2.2 Time Division Multiple Access (TDMA)
Two technologies are used by TDMA
Frequency-Division Duplex (FDD)
Time-Division Duplex (TDD)
TDD
Uses on frequency band for all stations
Each station assigned a time slot on the band
FDD
Uses two separate frequency bands
Each station is assigned two time slots (one for receiving signals and one for sending signals)
Time slots are staggered

9. 10.2.3 Code Division Multiple Access (CDMA)
One of the more popular standards in the U.S. and internationally
Uses spread-spectrum technology
Breaks up signals and spreads them over their entire bandwidth
Increases capacity up to 3 times that of any other digital system and 20 times that of an analog one
Uses packet-switched data transmissions
Data is sent and received over a network in groups called packets
Packets can be sent on one channel and received on another

10. 10.2.3 Code Division Multiple Access (CDMA)
Advantages of CDMA
Less power to transmit signals which increases talk time and battery life
Interference and background noise are reduced
Require fewer cell cites thus reducing network construction time as compared to wireline and other wireless networks

11. 10.3 First Generation Technology (1G) and AMPS
First-generation technology uses analog signals: wave-like radio transmissions
Wave sent to base where broken down and routed
When destination determined, signal recreated and sent
Quality threatened by recreation errors
Advanced Mobile Phone Service
Used in areas without digital coverage
Backup in case of digital system failure
Coverage
Cells surround base station, base only communicates with users in cell
When user switches cells, bases handoff signal

12. 10.2 First Generation Technology (1G) and AMPS
An analog signal before and after being processed at the base station.

13. 10.4 Second Generation Technologies (2G)
Second Generation technologies most widely used today and will be primary support for future generations

14. 10.4.1 Personal Communications Services (PCS)
2G digital signals
Binary coding: digital signal form, based on sequence of 0s and 1s
Error rate greatly reduced from analog
Personal Communications Service (PCS)
One of first US digital services
Uses cells and base stations
Cells broken into microcells (picocells)
Creates better network coverage and reduces interference

15. 10.4.1 Personal Communications Services (PCS)
PCS types
Narrowband PCS
2-way paging, credit card verification, location services, GPS and voice and text paging
Broadband PCS
Portable computer communications
GSM is form of PCS network
Sprint PCS
Driven by CDMA technology
Internet access through cell phones
Can use phone as modem for laptop

16. 10.4.1 Personal Communications Services (PCS)
Digital signal transmission and reproduction.
A cell that is divided into microcells for
PCS communications

17. 10.4.2 Global System for Mobile Communications (GSM)
Global System for Mobile Communications: digital communications network
More calls on same frequency and faster data speeds
Roaming technology: complete communication from anywhere in world
Providers establish roaming areas: higher cost for users when outside home area
GSM offers SMS service
GSM accepted as standard in Europe and Asia

18. CdmaOne
CdmaOne: technologies and standards associated with CDMA
Telecommunications Industry Association (TIA) and International Telecommunications Union (ITU) regulate standards
Part of the IS-95 Standards group
CDMA is building block for 2.5G and 3G networks

19. 10.4.4 TDMA Technology Family
TDMA is used with other technologies like FDMA and CDMA
First digital system that transitioned from AMPS to the digital age is D-AMPS
Based on a combinations of FDMA and TDMA
Also known as TDMA IS-136
TDMA systems are used worldwide in areas including Latin America and the Middle East

20. 10.4.5 Orthogonal Frequency Division Multiplexing (OFDM)
Orthogonal Frequency Division Multiplexing: first used by military, now commercial
Frequency division multiplexing: gives each channel its own frequency
Compact signals use less spectrum
Support both data and voice
Uses multiple carrier waves to transmit signals, limiting interference and delay
Wideband OFDM (W-OFDM): development of 3G and 4G technologies using OFDM

21. 10.5 2.5G & Third Generation (3G) Technologies
2.5G Technology: intermediate step between 2G and 3G
3G Technology: seven times faster than 56kps modem
Factors behind growth of these technologies
Spectrum allocation
Infrastructure development
Standardization

22. 10.5.1 High Speed Circuit-Switched Data (HSCSD)
2.5G technology
Alternative to packet-switched data
An upgrade to GSM

23. 10.5.2 General Packet Radio Service (GPRS)
Enhances GSM networks
2.5G technology
Packet data traffic channels (PDCHs)
Transmit data packets (like SMS)
Always on connectivity

24. 10.5.3 Enhanced Data Rates for Global Evolution (EDGE)
Transmission speed of 384kbps (3G)
Always on connectivity
Built over existing networks
Leads to bandwidth and channel allocation limitations
Data only transmissions and voice technologies

25. CDMA2000
2.5G alternative
CDMA2000 is family of technology types
CDMA 1xMC Similar to EDGE
1xMC upgrades voice and data capacity
CDMA 1xEV
Separates voice and data into two separate channels
1xEV-DO: data only transmissions
1xEV-DV: expands DO to handle voice
CDMA 3xMC
Upgrade 1xMC to 3G networks
Similar to UMTS – voice and data

26. CDMA2000
Drawback to CDMA2000
Competing companies develop different versions within CDMA2000 family
No standardization
CDMA2000 is in direct competition with W-CDMA

27. 10.5.5 Wideband Code Division Multiple Access (W-CDMA)
3G CDMA technology
ITU’s Universal Mobile Telecommunications System standard and new frequency spectrum
W-CDMA supports circuit-switched and packet-switched data
All transmissions use same frequency
Determines signal’s speed and path individually
Developed by NTT DoCoMo
Uses single wave transmissions
Short-bursts instead of continuous
Occupy channels briefly

28. 10.6 Wireless Platforms & Programming Languages
No unifying standard
Protocols, platforms and languages are important developmental/implementation tools

29. 10.6.1 Handheld Devices Markup Language (HDML)
One of first languages for handheld devices
Similar to HTML
Evolved into WAP and WML
HDML no longer manufactured, but still present in many devices

30. 10.6.2 WAP and WML Wireless Access Protocol (WAP)
Set of protocols enabling communication between different wireless devices
Intended for phones, pagers and other handhelds
Wireless Markup Language (WML)
Creates web content for wireless devices, based on XML
Microbrowsers: access web via wireless internet
WML supports WAP
Deck: a WML document made up of cards
Image support and telephone support through telephony tags

31. 10.6.2 WAP and WML WAP limitations WAP communications
Security breaches and unreliability
Limited bandwidth
Can’t handle multimedia and overloaded easily
WAP communications
WAP-enabled mobile device
WAP gateway
Web server
WAP Communications Architecture. (Courtesy of Jason Manger, WAPuSeek)

32. 10.6.3 Compact HTML (cHTML) & i-mode
i-mode: popular service in Japan for voice, text, graphics and web-browsing
Uses cHTML, subset of HTML
NTT DoCoMo has over 30,000 cHTML pages on own servers – eliminates translation

33. 10.6.4 Java and Java 2 Micro Edition (J2ME)
Java: one of most widely used programming languages
Java 2 Micro Edition (J2ME): programming platform for mobile devices
Facilitates development of applications on wireless devices
Compensates for WAP’s drawbacks

34. 10.6.5 XML & XHTML XML: an open technology for data exchange
XML documents contain data, applications decide how data is displayed
Markup languages created with XML
XHTML
XHTML Basic
VoiceXML
WBXML
Markup documents
Tags mark and describe data
Documents are highly portable
Human and machine readable

35. 10.6.5 XML & XHTML XHTML Markup language identifies page’s elements
Equipped to represent complex data on wireless internet
Strict syntax and well-formed code

36. 10.6.6 EPOC EPOC: a platform for next generation wireless devices
Supports phone and PDA for 2.5G and possibly 3G technologies
Supports C++, Java, WAP and the internet; TCP/IP protocols, GSM, Bluetooth and infrared
Ericsson R380 phone which uses the EPOC operating system. (Courtesy of Ericsson)

37. 10.6.7 Binary Runtime Environment for Wireless (BREW)
Qualcomm’s platform enables applications accessible by variety of wireless devices
Ease of use and development – lower costs and production times
Many possible applications
Navigation
E-wallets
Games
Music

38. 10.7 SyncML Initiative Synchronization SyncML Initiative
Sharing information in multiple areas among non-compatible devices
SyncML Initiative
Formed by 8 companies to develop standard protocol for information exchange regardless of time, place or device
Remote synchronization: application used by two devices at same time
Works with fixed, infrared, cable or Bluetooth wireless technology networks
Divides synchronization areas into client-side and server-side
SyncML based on WBXML version of XML

39. 10.7 SyncML Initiative

40. 10.8 Future of Wireless Technologies
Advances in transmission speed and types of information
3G standards, technologies and protocols in development
Possibly 4G technologies by 2010
Multimedia communications will be dominant transmission type of future