Wireless Communications

1
Wireless Communications
It is dangerous to put limits on wireless.
Guglielmo Marconi, 1932 Nobel Prize
Winner Inventor of Radio
2
History

• Wired Communications
• 1834 ? Gauss and Weber build telegraph system in
  Germany
• 1844 ? Morse connects Baltimore and Washington
  by telegraph
• 1858 ? First transatlantic telegraph cable laid
• 1876 ? Alexander Bell demonstrates telephone
• 1911 ? New York can telephone Denver
• 1918 ? First telephone carrier system with
  multi-plexing
• 1945 ? First digital computer (ENIAC)
• 1956 ? First transatlantic telephone cable
• 1965 ? First packet switched computer network
  (ARPANET)
• 1981 ? IBM personal computer
• 1995 ? World Wide Web
• 1998 ? Internet usage expands exponentially

3
History

• Wireless Communications ? Not so new
• 1899 ? Marconi sends first radio message across
  Atlantic
• 1905 ? Hulsmeyer detects ships with radar
• 1927 ? US Europe telephones linked by HF radio
• 1934 ? AM mobile police radios for public safety
  widely used
• 1935 ? Armstrong demonstrates FM radio system
• 1940 ? First microwave radar
• 1965 ? First commercial communication satellite
• 1968 ? ATT proposes cellular phone system to FCC
• 1983 ? FCC allocates spectrum for analog cellular
  service (AMPS)
• 1990 ? GSM digital cellular service introduced in
  Europe
• 1995 ? FCC auctions new PCS licenses in U.S. for
  digital services
• 1998 ? 40 million cellular phone users in U.S.
  (20 of adults)
• 2002 ? 62 of U.S. adults own a cell phone

4
Cell Phone Useage
1990 ? 8 million worldwide users 2002 ? 700
million worldwide users 2005 ? 2.2 Billion 2010
? 4.6 Billion 2015 ? 6.8 Billion! 97 of World
Population!!
5
Frequencies

• RF Radio Frequencies
• 1 MHz to 1 GHz
• general classification, not absolute
• 50 MHz to 1 GHz
• more widely used definition
• Microwave Frequencies
• 1 GHz to 300 GHz ? general
• 1 GHz to 100 GHz ? more widely used
• Trend towards use of higher frequencies
• Greater signal bandwidth (BW)
• Max. BW ? 10 of fc
• More users and/or higher data rates
• More difficult to design !! ? more
• Propagation distance ? as frequency ?

6
Wireless Applications

• Mature
• Appliances
• Garage door opener
• Car alarms
• TV/VCR remote
• Cordless phones
• Communications
• Fixed microwave (point-to-point or LOS) ? nearly
  20,000 in U.S.!
• Satellite to fixed ground stations (TV, phone,
  defense, etc.)
• Paging
• 1st generation (1G) analog cellular ? AMPS (FM)
• 2nd generation (2G) digital cellular ? IS-95,
  IS-136, GSM
• 3rd generation (3G) digital cellular ? UMTS,
  CDMA2000
• WLAN Wireless Local Area Networks (WiFi)

7
Wireless Applications

• Still Developing
• Mobile computers/email (3G/4G)
• Wireless Local Loop (WLL)
• Local phone service via wireless connection
• Very prominent in non-industrialized nations
• Cheaper to install than wired lines
• Local competition from long-distance carriers in
  U.S.!
• Satellite to mobile ground units ? Land Mobile
  Satellite (LMS)
• Constellation of 66 satellites in orbit (plus
  spares)
• Motorola/Iridium ? Bankrupt in 2001! (now Iridium
  Communications)
• 4G Digital Cellular/PCS ? LTE
• PCS Personal Communication Services

8
Wireless Applications

• Long-term trends in mobile communications driven
  by
• 1) Technology
• Integrated Circuits (ICs) ? cheaper, smaller,
  faster, etc.
• RF/microwave circuit fabrication ? higher
  frequencies (MMICs)
• Digital Signal Processing (DSP) chips
• Customized for specific applications (e.g. ASICs)
• Baseband signal processing
• Coding, modulation, encryption, equalization,
  etc.
• 2) Governments (e.g. FCC)
• Spectrum allocation
• Public use vs. from auctions
• Regulations
• International standards

9
U.S. Mobile Radio Spectrum
PCS
PCS
AMPS
AMPS
Fig. 11.23 pg. 592
PCS
PCS
Reallocated to PCS
802.11b Wi-Fi
802.11a Wi-Fi
10
U.S. Mobile Radio Spectrum

• SMR Bands ? Specialized Mobile Radio
• Three 20 MHz bands from 800?900 MHz
• Large number of private licenses nationwide
• Paging/messaging
• Voice dispatch ? taxi, P/F/A
• Data (UPS/Fedex)
• Extended SMR
• Nextel/Motorola partnership ? bought by Sprint
• Purchased SMR licenses all over the country
• Nationwide coverage providing digital
  cellular/data service

11
U.S. Mobile Radio Spectrum

• ISM Bands ? Industrial/Scientific/Medical
• 902?928 MHz and 2400?2484 MHz
• Unlicensed garbage bands
• Anyone can develop application as long as FCC
  guidelines are met
• Spread spectrum modulation must be used
• Tx power level lt 1 W
• Remote meter reading
• Wireless medical monitors
• Digital cordless telephones
• 802.11b IEEE WLAN standard _at_ 2.4 GHz

12
U.S. Mobile Radio Spectrum

• 1st Generation (1G) Cellular Telephone
• AMPS Advanced Mobile Phone System
• 824?849 MHz
• Reverse Channel Xmit from mobile to base station
  (fixed)
• 869?894 MHz
• Forward Channel Xmit from base station to mobile
• FCC mandated duopoly in Major Trading Areas
  (MTAs)
• MTA 51 largest U.S. cities
• Two providers/MTA
• e.g. Cellular One Southwestern Bell Mobile in
  K.C.
• All MTA providers have upgraded to 2G/3G systems
• 1G AMPS still used only sparsely in rural areas

13
U.S. Mobile Radio Spectrum

• Digital PCS Band
• 1.85?1.99 GHz
• FCC Spectrum Auctions 1998 2000 ? 10
  Billion!!
• 1st time spectrum sold for in U.S.
• A B blocks for MTAs
• Duopoly like AMPS
• C, D, E, F blocks ? Basic Trading Areas (BTAs)
• BTA 492 large rural areas (includes MTAs!)
• 2nd Generation (2G) digital cellular phone
  service PCS
• PCS messaging, caller ID, voice mail, email,
  data, etc.
• Compete with analog cellular and SMR services
  combined

14
U.S. Mobile Radio Spectrum

• 3rd Generation (3G) Cellular Telephone
• ATT (HSPA)
• 850 1900 MHz (AMPS PCS)
• Verizon (CDMA)
• 800 1900 MHz (AMPS PCS)
• T-Mobile (HSPA)
• 1700 MHz (forward link) 2100 MHz (reverse link)
• Sprint (CDMA)
• 850 MHz 1800 MHz (AMPS PCS)
• New 4G network 2.5 - 2.7 GHz (reallocated from
  MMDS)

15
U.S. Mobile Radio Spectrum

• Analog Broadcast TV Frequencies ? recent
  reallocation
• Broadcast TV channels 52-69 relinquished in the
  switchover to digital
• 700 800 MHz
• Split into 5 blocks (A-E) by FCC for 3G/4G use
• Auctioned by FCC for 19.6 billion
• Block A (12 MHz)
• 698 704 728 734 MHz
• Block B (12 MHz)
• 704 710 734 740 MHz
• Block C (22 MHz)
• 746 757 776 787 MHz
• Block D (6 MHz)
• 758 763 788 793 MHz
• Block E (10 MHz)
• 722 728 MHz

16
U.S. Mobile Radio Spectrum

• UNII ? Unlicensed National Information
  Infrastructure
• Allocated in 1997 for public use applications
• 5.15?5.35 GHz 5.725?5.825 GHz
• 300 MHZ of available spectrum
• WLL, wireless internet access, and WLAN
  applications
• 802.11a IEEE WLAN standard
• Only spectrum in U.S. with enough BW to support
  very high data rate services (gt 50 Mbps)
• High speed WLAN
• Wireless ATM
• Campus or building applications
• High frequency ? poor signal propagation
  geographic coverage
• Will NOT support cellular phone applications