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Introduction to Mobile Communications. TCOM 552, Lecture #1 Hung Nguyen, Ph.D. 28 August, 2006. Chapter 10: Cellular Wireless Networks. Cellular wireless network design issues First generation analog (traditional mobile telephony service) Second generation digital cellular networks

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introduction to mobile communications

Introduction to Mobile Communications

TCOM 552, Lecture #1

Hung Nguyen, Ph.D.

28 August, 2006

chapter 10 cellular wireless networks
Chapter 10: Cellular Wireless Networks
  • Cellular wireless network design issues
  • First generation analog (traditional mobile telephony service)
  • Second generation digital cellular networks
    • Time-division multiple access (TDMA)
    • Code-division multiple access (CDMA)
  • Third generation networks

Hung Nguyen, TCOM 552, Fall 2006

chapter 2 transmission fundamentals
Chapter 2: Transmission Fundamentals
  • Basic overview of transmission topics
  • Data communications concepts
    • Includes techniques of analog and digital data transmission
  • Channel capacity
  • Transmission media
  • Multiplexing

Hung Nguyen, TCOM 552, Fall 2006

chapter 6 signal encoding techniques
Chapter 6: Signal Encoding Techniques
  • Wireless transmission
    • Analog and digital data
    • Analog and digital signals

Hung Nguyen, TCOM 552, Fall 2006

chapter 5 antennas and propagation
Chapter 5: Antennas and Propagation
  • Principles of radio and microwave
    • Antenna performance
    • Wireless transmission modes
    • Fading

Hung Nguyen, TCOM 552, Fall 2006

chapter 8 coding and error control
Chapter 8: Coding and Error Control
  • Forward error correction (FEC)
  • Using redundancy for error detection
  • Automatic repeat request (ARQ) techniques

Hung Nguyen, TCOM 552, Fall 2006

chapter 7 spread spectrum
Chapter 7: Spread Spectrum
  • Frequency hopping
  • Direct sequence spread spectrum
  • Code division multiple access (CDMA)

Hung Nguyen, TCOM 552, Fall 2006

chapter 10 cellular wireless networks8
Chapter 10: Cellular Wireless Networks
  • Cellular wireless network design issues
  • First generation analog (traditional mobile telephony service)
  • Second generation digital cellular networks
    • Time-division multiple access (TDMA)
    • Code-division multiple access (CDMA)
  • Third generation networks

Hung Nguyen, TCOM 552, Fall 2006

chapter 13 wireless lan technology
Chapter 13: Wireless LAN Technology
  • Overview of LANs and wireless LAN technology and applications
  • Transmission techniques of wireless LANs
    • Spread spectrum
    • Narrowband microwave
    • Infrared

Hung Nguyen, TCOM 552, Fall 2006

chapter 12 mobile ip and wireless access protocol
Chapter 12: Mobile IP and Wireless Access Protocol
  • Modifications to IP protocol to accommodate wireless access to Internet
  • Wireless Application Protocol (WAP)
    • Provides mobile users access to telephony and information services including Internet and Web
    • Includes wireless phones, pagers and personal digital assistants (PDAs)

Hung Nguyen, TCOM 552, Fall 2006

chapter 11 cordless systems and wireless local loop
Chapter 11: Cordless Systems and Wireless Local Loop
  • Cordless systems
  • Wireless local loop (WLL)
    • Sometimes called radio in the loop (RITL) or fixed wireless access (FWA)

Hung Nguyen, TCOM 552, Fall 2006

chapter 10 cellular wireless networks12
Chapter 10: Cellular Wireless Networks
  • Cellular wireless network design issues
  • First generation analog (traditional mobile telephony service)
  • Second generation digital cellular networks
    • Time-division multiple access (TDMA)
    • Code-division multiple access (CDMA)
  • Third generation networks

Hung Nguyen, TCOM 552, Fall 2006

wireless comes of age
Wireless Comes of Age
  • Marconi invented the wireless telegraph in 1896
    • Communication by encoding alphanumeric characters in analog electromagnetic signal
    • Sent telegraphic signals across the Atlantic Ocean
  • Communications satellites launched in 1960s
  • Before 1980’s: wireless technology usage
    • Radio, television, communication satellites, paging
  • More recently
    • Cellular services started in early 1980’s in the US
    • Wireless data at low rates available in the 1990’s (e.g., ARDIS, Bell South), higher data rates underway
    • WLAN came of age in late 1990’s, WiFi hotspots

Hung Nguyen, TCOM 552, Fall 2006

cellular pcs evolution
Cellular/PCS Evolution
  • Bell Labs proposes cellular in 1968
  • First cellular system begins operation in early 1980’s using analog (AMPS) system, by ATT -- First Generation systems (1G) --’Cellular’
    • These are called cellular systems, in the 800 and 900 MHz range mostly. Large, bulky phones
  • Digital system using TDMA starts early 1990’s (2G)
    • Both in 800 and 900 MHz, and around 1800 and 1900 MHz
    • These, along with GSM and CDMA below, labeled PCS, when in the 1800 and 1900 MHz range

Hung Nguyen, TCOM 552, Fall 2006

cellular pcs evolution cont d
Cellular/PCS Evolution (Cont’d)
  • European GSM starts operation early 1990’s (2G)
    • Similar frequency range as TDMA but not exactly--- US and Europe usually differ
    • GSM used nearly worldwide, more users than US standards -- in US Voicestream uses it
  • First CDMA operation 1996-1997 -- Qualcomm holds ‘key’ patents (2G)
    • Used by half of 2G systems in US, S. Korea, parts of Latin America
  • First (very) limited 3G operation in Japan in May 2001- Wideband CDMA
    • Worldwide (semi) standardization agreed to in 1999, for data rate services to 2 Mbps
    • Frequency allocation around 1800 MHz in most of world, US just set 90 MHz
  • 2.5G, in the form of GPRS (GSM/TDMA) and 1XRTT (IS-95) out in 02
    • Some pictures, higher data rates

Hung Nguyen, TCOM 552, Fall 2006

mobile comms anywhere anytime
Mobile Comms -- Anywhere/Anytime
  • Personal Communications -- Inexpensive use of cellular and wireless to communicate anywhere, anytime --- Personal: for individual use
    • Cellular in 1983 was expensive, PCS in 90’s it became cheap, commonplace
    • Terms: Wireless, Mobile, PCS, etc
  • Comms for access to people (voice) and information (data, services)
  • Essential Requirements
    • Mobility >>> untethered >>> wireless
    • Mobility also meant having access to the network (the PSTN) -- will get you anywhere
    • Personal (e.g., not just corporate) >>> cheap small terminals, cheap services

Hung Nguyen, TCOM 552, Fall 2006

mobile comms anywhere anytime cont d
Mobile Comms -- Anywhere/Anytime (cont’d)
  • Essential Ingredients
    • Infrastructure (Comms systems and networks)
    • User terminals (for personal use)
    • Standards (multiple systems need to interoperate)
    • Spectrum (availability and use)
    • Services (over the infrastructure) --- From voice to smart phones to data -- value added
    • Subscribers (enough to make it financially attractive)

Hung Nguyen, TCOM 552, Fall 2006

categories of mobility
CATEGORIES OF MOBILITY

Mobile

Untethered

Portable

Transportable

In Building

Wireless

LAN

Hung Nguyen, TCOM 552, Fall 2006

wireless examples
Wireless Examples
  • Mobile wireless systems
    • Cellular/PCS (Personal Communications Systems)
  • Terrestrial microwave transmission
  • Satellite transmission
  • Broadcast radio and TV
  • Fixed wireless
  • WLAN
  • Paging
  • Wireless Data
    • Including email/Web/News/Video on personal units

Hung Nguyen, TCOM 552, Fall 2006

limitations and issues in wireless technologies
Limitations and Issues in Wireless Technologies
  • Political and economic limitations affect wireless technologies
    • Spectrum limitations, infrastructure costs, standards, politics and policies
  • Spectrum is limited, best portions allocated, expensive --- legal/political
    • 3G US spectrum a problem, 90 MHz to be reallocated from DOD/MDS (asked for more)
    • NextWave bought for $5B, bankrupt, FCC sold spectrum for $16B, lost in court, still in litigation, asked to be relieved of debt burden
  • Expensive infrastructure (15K base stations) needed for national coverage

Hung Nguyen, TCOM 552, Fall 2006

limitations and issues in wireless technologies cont d
Limitations and Issues in Wireless Technologies (cont’d)
  • Standards evolve slowly, require international consensus, and involve multiple incompatible variants --- seamless roaming is not always possible
  • Telecom infrastructure and industry are important national policy issues
  • Current wireless woes: low market valuations due to very competitive cellular market, debt burdens, too many carriers, expensive/limited spectrum, wireless data build up is expensive and unprofitable
  • Technical
    • Wireless propagation is error prone and forces complex radio equipment
    • Small devices for mobility, hard on technology and battery

Hung Nguyen, TCOM 552, Fall 2006

mobile telephone internet users
Mobile Telephone & Internet Users

Millions

Mobile Telephone

Users

Internet Users

Source: Ericsson Radio Systems, Inc.

Year

BUT: SLOWED DOWN, OVERHYPED, AND ARPU IS DOWN

Hung Nguyen, TCOM 552, Fall 2006

slide24

137,458,902 currentU.S. Wireless Subscribers

Aug. 24, 2002, 2AM, per CTIA

From CTIA site

http://www.wow-com.com

/industry/stats/surveys/

NOTE: Subscribers, Cell Sites, ARPU

Hung Nguyen, TCOM 552, Fall 2006

slide25

From CTIA web site

Hung Nguyen, TCOM 552, Fall 2006

slide26

From CTIA web site

Hung Nguyen, TCOM 552, Fall 2006

slide27

From CTIA web site

Hung Nguyen, TCOM 552, Fall 2006

other wireless status data
Other Wireless Status Data
  • Wireless companies market cap
    • March 2000 --- $794B
    • March 2001 --- $265B
  • Wireless industry layoffs, Dec.2000-Jan2002: 352,000
  • Wireless subscribers still growing, but slower
    • Sales in one year period expected at 540 million handsets down to less than 400 million, globally
  • DOCOMO (Japan) continues to add subscribers, including iMode (Internet) accounts -- ARPU is $71.86, much higher than in US
  • China to have 132 million wireless users by the end of2001, a gain of 46.4 million over a year before, 2nd to the US, Europe about 100 million -- Asia Pacific biggest growth area

Hung Nguyen, TCOM 552, Fall 2006

nokia 3g concept phone where cellular might be going
Nokia 3G Concept Phone---Where Cellular Might Be Going---

Nokia concept phone, from

http://www.3g-generation.com/index.htm

Hung Nguyen, TCOM 552, Fall 2006

mobile wireless data services
Mobile Wireless Data Services
  • Mobile messaging, two way paging, email/news
    • e.g., Motorola 2-way, Blackberry RIM, other specialized services
  • Mobile cell-phone-based data
    • Currently on WAP enabled phones (messaging, news, sports, wireless Internet promise)
    • iMode in Japan --- better/faster, growing use
    • SMS based on GSM in Europe --- messaging
    • Coming: GPRS-based and 1xRTT-based services to few 10’s Kbps -- wireless Internet, email, pictures, etc
    • Later higher with EDGE, and to 2 Mbps with 3G (Europe Japan first, later in US) -- 3G will do all services above plus voice and video simultaneously
  • WLAN -- WiFi spreading like a virus, many public AP’s
    • Some say it will do VOIP, go mobile/wide-area, do away with 3G

Hung Nguyen, TCOM 552, Fall 2006

slide31

Public WLAN Service: Mobile Operators Must not Miss the Boat (#IN020286MD)

Hung Nguyen, TCOM 552, Fall 2006

broadband wireless technology
Broadband Wireless Technology
  • Higher data rates obtainable with mobile broadband wireless technology
    • Broadband = more than messaging or paging or voice
    • Fixed broadband wireless --- to home/office, Internet
    • But mobile applications more difficult --- GPRS 1st
  • Shares same advantages of all wireless services: convenience and reduced cost
    • Service can be deployed faster than other fixed service
    • No cost of cable plant
  • But so far not a commercial success (some exceptions), service is spotty for wireless data

Hung Nguyen, TCOM 552, Fall 2006

why is wireless different
Why Is Wireless Different?
  • Why is there a ‘send’ or ‘call’ button on a cell phone?
  • Why can’t you make a cell phone call from some places?
  • Why does a cell connection break up sometimes?
  • Why does a cell phone battery last less time than a pager battery?
  • Why are cell phone calls becoming cheaper?

Hung Nguyen, TCOM 552, Fall 2006

cellular system overview
Cellular System Overview

Hung Nguyen, TCOM 552, Fall 2006

why is mobile wireless difficult
Why is Mobile Wireless Difficult?
  • Coverage limitations (blank spots in coverage, shielding in buildings, shadowing)
  • Signal losses and fading, due to propagation, blockage, and multipath, while still or while moving (lower received signal power, causes bit errors, lower voice quality, can fade out)
  • Call blocking, due to having no available channel (number of channels in a cell, busy hours, busy spots)
  • Small user terminals desired, battery (talktime, ontime, and lifetime)
  • Infrastructure (base stations and switches) needs to be built up and connected to phone network --- expensive
  • Spectrum needs to be acquired --- expensive

Hung Nguyen, TCOM 552, Fall 2006

slide36

From iec.org

Hung Nguyen, TCOM 552, Fall 2006

slide37
Hung Nguyen, TCOM 552, Fall 2006

From Rappaport & Ref. there

wireless the technical good news
Wireless -- The Technical Good News
  • Radio propagation effects can be offset
    • Use of modulation, coding and processing techniques
      • Continuously improving techniques (e.g., smart antennas)
    • Coverage can be expanded and filled in with additional base stations (if there are enough customers to pay for it)
  • Battery power is sufficient because of highly power efficient techniques and power control in most units
    • Problems persist for higher data rates, such a 3G
  • Spectrum allocations do exist and additional spectrum is/will be auctioned off or allocated
  • Standards do exist and large areas allow roaming
  • Current infrastructure works OK for voice (mostly), data expansion underway

Hung Nguyen, TCOM 552, Fall 2006

typical cellular numbers
Typical Cellular Numbers
  • Base Station Transmitted Power: 10-100 watts (= 20 dBW = 50 dBm)
  • Base Station Antenna Gains: 10-17 dB (i.e., X10-50)
  • US: Base stations: about 100K --- Users: 130M
  • Voice Transmission BW or Data Rates:
    • Analog (FM): 25 or 30 KHz
    • Digital: 8-14 Kbps
  • 3 dB = X2; 10 dB = X10; 20 dB = X100; 30 dB = X1000; 100 dB = X10,000,000,000 (or 10^10 = 10 Billion)
  • Receiver Sensitivities: -100 to -117 dBm (dB below a milliwatt) (-100 dBm = 10^-10 mW) -- pretty good ah!!
  • Propagation Losses: 80-180 dB over 1-10 kms
  • US Cellular and PCS Frequencies: 824-894 MHz, and 1850-1990 MHz

Hung Nguyen, TCOM 552, Fall 2006

slide40

Source: Ericsson Radio Systems, Inc.

Hung Nguyen, TCOM 552, Fall 2006

books
Books
  • Stallings
    • Online resources at www.WilliamStallings.com/Wireless1e.html
    • Has signals and comms basics, comms technical topics on modulation, coding, spread spectrum, others
    • Has cellular and other wireless topics such as satellite and WLAN
    • Not deep into cellular/mobile topics, but good introduction for TCOM major
  • Rappaport
    • More technical than Stallings. Often used for EE major
    • Deeper into cellular and mobile and much more physical layer
    • A bit dry and a good reference for working engineer
  • Lee
    • Preceded Rappaport and provided mathematical and theoretical foundation for mobile communications

Hung Nguyen, TCOM 552, Fall 2006

some internet and web resources
Some Internet and Web Resources
  • Web page for Stallings Book
    • WilliamStallings.com/Wireless1e.html
      • Useful web sites, errata sheet, figures, tables, slides, internet mailing list, wireless courses
  • Wireless devices and items http://www.zdnet.com/special/filters/wireless/
  • Web proforum telecom, wireless and other simple tutorials http://www.iec.org/online/tutorials/
  • Washington area centric, telecom at http://www.washtech.com/news/telecom/
  • Qualcomm CDMA Technology Home Page at http://www.cdmatech.com/
  • Regulatory: FCC and ITU at www.fcc.gov and www.itu.int
  • Wireless News --- wirelessweek.com
  • CTIA --- http://www.wow-com.com/
  • More Complete Online References, next page

Hung Nguyen, TCOM 552, Fall 2006

online references cont d
Online References (cont’d)
  • http://comet.columbia.edu/cellularip/ Cellular IP protocol research
  • http://delson.org/wc/ 3G Wireless Conference
  • http://www.tiaonline.org/ Telecom Industry Association
  • http://www.thestandard.com/section/0,1970,813,00.html The Industry Standard, on Tech and Telecomm, Latest
  • http://www.openwave.com/ Makers of WAP wireless phone microbrowser
  • http://www.itu.int/home/index.html ITU page on IMT2000
  • http://www.3gpp2.org/ 3G Partnership consortia – 2 (1 was Europe, 2 US)
  • http://www.ietf.org/html.charters/wg-dir.htmlActive IETF Working Groups
  • http://www-daedalus.cs.berkeley.edu/ Berkeley wireless project
  • More Complete Online References, next page

Hung Nguyen, TCOM 552, Fall 2006

online references cont d44
Online References (cont’d)
  • http://www.ieee-wcnc.com/ IEEE Wireless Comms and Networking Conference
  • http://www.sss-mag.com/ Online spread spectrum and RF magazine
  • http://www.analysys.com/vlib/ Virtual library, telecomunications
  • Wireless Design Online (Review site in general – 'a vertical net marketplace for industry professionals') http://www.wirelessdesignonline.com/content/hubs/dir.asp?hub=news
  • http://www.iec.org/tutorials/cell_comm/index.html Tutorials, this one on cellular communications
  • http://www.washtech.com/news/telecom/ Washington Tech online, Latest
  • http://www.zdnet.com/enterprise/filters/resources/0,10227,6016597,00.html zdNet wireless resources
  • http://www.cdmatech.com/ Qualcomm CDMA Technology Home Page

Hung Nguyen, TCOM 552, Fall 2006