Cellular and Wireless A Perspective

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Cellular and Wireless A Perspective
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Back to the 1940s
Mid 40s mobile telephony began

• Where are our video watch phones?
• There were many reasons for this delay but the
  most important ones were...
• technology
• cautiousness
• federal regulation

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The Impediments

• Technological Problems
• We must be able to reuse frequencies
• Had to wait until low cost microprocessors and
  digital switching became available
• Caution
• The Bell System moved hesitatingly
• Anything ATT produced had to work reliably and
  had to make economic sense, Wireless did not
  offer much in the way of a potential customer
  base due to the limit of available frequencies.
• Federal Regulation
• Frequency availability was in turn controlled by
  the Federal Communications Commission
• Delayed Cellular radio in America by at least 10
  years.
• However, in Europe and Japan, where governments
  did not regulate their state run telephone
  companies, mobile wireless came no sooner.

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MTS

• 1946 MTS (Mobile Telephone Service)
• First American commercial mobile radio-telephone
  service to private customers
• Operated on six channels in the 150 MHz band
  with a 60 kHz channel spacing.
• Operation
• One party talked at a time
• You pushed a handset button to talk, then
  released the button to listen (half-duplex)
• Caller searched manually for an unused frequency
  before placing a call.

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Early Mobile Radio Humor - circa 1948
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Mobile Phones before the Transistor
Transistor Invented 1948
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Mobile Phones after the Transistor
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Late 1950s

• 1958 IC Invention
• Jack Kilby invented the integrated circuit at
  Texas Instruments.
• Kilby's invention revolutionized the electronics
  industry.
• Almost every electronic device we take for
  granted today has been made possible by the IC.
• Allotment of 800MHz band
• Also in 1958 the Bell System petitioned the FCC
  to grant 75 MHz worth of spectrum to
  radio-telephones in the 800 MHz band.
• The FCC had not yet allowed any channels below
  500MHz -not enough continuous spectrum to develop
  an efficient radio system.
• FCC sat on this proposal for ten years and only
  considered it in 1968 when demand became
  overwhelming

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Mid 1960s

• IMTS - Improved Telephone Service
• In 1964 the Bell System began introducing
  Improved Mobile Telephone Service or IMTS
• Replacement for the badly aging Mobile Telephone
  System.
• The IMTS field test was in Harrisburg,
  Pennsylvania, from 1962-1964.
• Operation
• Full-duplex
• Allowed direct dialing,
• Automatic channel selection
• Reduced bandwidth to 25-30 kHz.
• There are actually still IMTS/MTS systems in
  existence in North America today. The last of
  these - those run by Bell/Aliant Telecom in
  Newfoundland, Canada are slated for de-commission
  in August of 2002, thereby ending a long history
  of this technology.

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Science Fiction Jumps Aboard
Don Adams - the Shoe Phone
The BatPhone - not so mobile
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Late 60s
Formation of Nokio In 1967 the Nokia group was
formed by consolidating two companies the
Finnish Rubber Works and the Finnish Cable Works.
Finnish Cable Works had an electronics division
which Nokia expanded to include semi-conductor
research. These early 1970s studies readied Nokia
to develop digital landline telephone switches.
The first commercial cellular radio system In
January, 1969 the Bell System made commercial
cellular radio operational by employing frequency
reuse for the first time - aboard a train, using
payphones. The system was called the Metroliner.
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Early 70s
1971 - First microprocessor
1973 -Martin Cooper The Father of the
(handheld) Cell Phone
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Mid 70s
More Frequency Allotments On May 1, 1974 the
F.C.C. decides to open an additional 115
megahertz of spectrum, 2300 channel's worth, for
future cellular telephone use. Cellular looms
ahead, although no one knows when FCC approval
will permit its commercial rollout.
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Late 70s

• May 1978 First Analog Cellular system
• The Bahrain Telephone Company
• First time in the world that individuals started
  using what we think of as traditional, mobile
  cellular radio.
• The two cell system had 250 subscribers, 20
  channels in the 400Mhz
• Used all Matsushita equipment. (Panasonic is the
  name of Matsushita in the United States.)
• Gibson Cable and Wireless, now Global Crossing,
  installed the equipment.

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Late 70s - continued

• July, 1978 AMPS
• Advanced Mobile Phone Service or AMPS started
  operating in North America.
• ATT Baby
• Ten cells covering 21,000 square miles made up
  the Chicago system
• Began using 90 Bell System employees.
• December 20th, 1978, a market trial began with
  paying customers who leased the car mounted
  telephones - known as the "service test".
• Used the newly allocated 800 MHz band.

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Worldwide and US AMPS

• Worldwide commercial AMPS deployment followed
  quickly after its installment in US
• An 88 cell system in Tokyo began in December,
  1979, using Matsushita and NEC equipment.
• The first North American system in Mexico City,
  a one cell affair, started in August, 1981.
• United States cellular development did not keep
  up - Fully commercial systems were still not
  allowed, despite the fact that paying customers
  were permitted under the service test.
• The Bell System's impending breakup and a new
  FCC competition requirement delayed cellular once
  again.
• The Federal Communication Commission's 1981
  regulations required the Bell System or a
  regional operating company, such as Bell
  Atlantic, to have competition in every cellular
  market.

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Early 80s

• 1983 DSP by Texas Instruments introduced their
  single chip digital signal processor, operating
  at over five million operations a second.
• European Development
• 1981 European NMT (Nordic Mobile Telephone
  System)
• The first multinational cellular system
• Operated in Denmark, Sweden, Finland, and Norway
  
• Used the 450 MHz range
• In 1985 Great Britain started using the Total
  Access
• Communications System or TACS at 900 MHz.
• West Germany used C-Netz
• France used Radiocom 2000
• Italy used RTMI/RTMS

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European and US in the 80s
Europe had nine analog incompatible radio
telephone systems Plans were afoot during the
early 1980s, however, to create a single European
wide digital mobile service with advanced
features and easy roaming. Meanwhile - North
America continues with Analog North American
groups concentrated on building out their robust
but increasingly fraud-plagued and featureless
analog network.
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The Rise of GSM

• Europe decided to start a new technology in a new
  radio band.
• Cellular-structured and Fully digital
• Patterned after ISDN, hoping to make a wireless
  counterpart to it
• The new service was called GSM.
• The European Telecommunication Standards
  Institute or ETSI (external link) took
  responsibility for developing GSM.
• In 1990 the first recommendations were
  published.
• Pre-dating American PCS
• Specs were published in 1991
• United Kingdom asked for and got a GSM plan for
  higher frequencies.
• Digital Cellular System (DCS1800) works at
  1.8GHz
• More frequencies than available on the
  continent.

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Late 80s in North America

• North American cellular becomes standardized as
  network growth and complexity accelerated.
• In 1988 the analog networking cellular standard
  called TIA-IS-41 was published.
• IS-41 seeks to unify how network elements
  operate the way various databases and mobile
  switches communicate with each other and with the
  regular landline telephone network.
• Despite ownership or location, all cellular
  systems across America need to act as one larger
  system. In this way roamers can travel from
  system to system
• This Interim Standard is still evolving.

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North America Goes Digital

• 1990 North American carriers faced the question
  -- how do we increase capacity? -- do we pick an
  analog or digital method? The answer was digital.
  
• In March, 1990 the North American cellular
  network incorporated the IS-54B standard
• The first North American dual mode digital
  cellular standard.
• This standard won over Motorola's Narrowband
  AMPS or NAMPS - an analog scheme that increased
  capacity by cutting down voice channels from
  30KHz to 10KHz.
• IS-54 on the other hand increased capacity by
  digital means sampling, digitizing, and then
  multiplexing conversations, a technique called
  TDMA or time division multiple access.
• This method separates calls by time, placing
  parts of individual conversations on the same
  frequency, one after the next.
• It tripled call capacity

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IS-54
Using IS-54, a cellular carrier could convert any
of its systems' analog voice channels to digital.
A dual mode phone uses digital channels where
available and defaults to regular AMPS where they
are not. IS-54 was, in fact, backward
compatible with analog cellular and indeed
happily co-exists on the same radio channels as
AMPS. No analog customers were left behind
they simply couldn't access IS-54's new features.
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AMPS Still Alive
Advanced Mobile Phone Service remains a contender
to GSM and PCS, although its market share is now
decreasing. The best known AMPS systems are in
the US and Canada, but AMPS is also a de facto
standard throughout Mexico, Central and South
America, very common in the Pacific Rim and also
found in Africa and the remains of the USSR. In
summary, AMPS is on every continent except Europe
and Antarctica. Today, more than half the
cellular phones in the world operate according to
AMPS standards. From its humble beginnings,
AMPS has grown from its roots as an 800MHz analog
standard, to accommodate TDMA and CDMA digital
technology, narrowband (FDMA) analog operation
(NAMPS).
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By the Early 90s
By 1990s Cellular telephone deployment is now
world wide, but development remains concentrated
in three areas Scandinavia, the United States,
and Japan. Telecom deregulation is occurring
across the globe and the private market is
offering a wide variety of wireless
services. The leading technology in America is
now IS-54 while GSM dominates in Europe and many
other countries. Japan goes a slightly
different direction, with Japanese Digital
Cellular (or Personal Digital Cellular) in 1991
and the Personal Handyphone System in 1995. These
early digital schemes all use time division
multiple access (TDMA).
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By the Mid 90s
1993 American cellular was again running out of
capacity, despite a wide movement to IS-54.
Subscribers grew from one and a half million
customers in 1988 to more than thirteen million
subscribers in 1993. 1994 Qualcomm, Inc.
proposed a cellular system and standard based on
spread spectrum technology to increase capacity.
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IS-95 - Spread Spectrum CDMA

• Uses the AMPS protocol as a default, but in
  normal operation operates quite differently than
  analog cellular or the more advanced IS-54.
• Built on an earlier proposal, this code-division
  multiple access (CDMA) based system would be all
  digital and promised 10 to 20 times the capacity
  of existing analog cellular systems.
• IS-95 did work well, however the dramatic
  increase in capacity never proved out.
• There was enough increase, however, for CDMA
  based systems to become the transmission method
  of choice for new installations over TDMA.

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The Birth of PCS

• Existing cellular bands had no more room.
• By the mid-1990s even more wireless channels were
  needed in America.
• A new block of frequencies, much higher in the
  radio spectrum, was licensed for wireless use.
• FCC began auctioning spectrum in the newly
  designated PCS band, from December 5, 1994 to
  January 14, 1997.
• New set of FCC Rules
• Several carriers were licensed in each
  metropolitan area. The FCC at first thought this
  new competition to conventional cellular would
  lower rates overall.
• While competition was stimulated, lower prices
  did not occur.
• In many areas conventional cellular is now
  cheaper than PCS.

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The Birth of PCS

• PCS or Personal Communication Services
• All digital
• Use TDMA routines (IS-136)
• Also uses CDMA (Code Division Multiple Access)
  (IS-95)
• Most notable offerings
• European GSM, brought to America at a higher
  frequency and sometimes dubbed PCS1900. It uses
  TDMA.
• IS-136 - The evolution of IS-54. Came into being
  shortly after these new spectrum blocks were
  opened up.
• Today some carriers use both 900 MHz and 1900 MHz
  spectrum in a single area, putting a mobile call
  on whatever band is best at the time.

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The Major Contenders
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Toward the Future
Demand for new mobile wireless services seems
unlimited, especially with the mobile internet
upon us. Existing voice-oriented systems will
continue to be updated. New systems such as 3G
will arrive in America once additional spectrum
is cleared for their use. These new services will
combine data and voice, treating transmission in
a different way. Packet switching is a
fundamental, elemental change between how
wireless was delivered in the past and how it
will be presented in the future.
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Toward the Future - Packet Switching

• Circuit Switching
• Circuit switching dominates the public switched
  telephone network (PSTN). The circuit stays the
  same throughout the call - dedicated to your
  call.
• Conventional cellular radio and landline
  telephony use circuit switching.
• Packet Switching
• Packet Switching shares the bandwidth between
  users - like the Internet. When one caller
  becomes silent, another can use the bandwidth.
• Made possible since data and voice share the
  network.
• Wireless services like Cellular Digital Packet
  Data (CDPD), by contrast, employ packet
  switching.
• Wireless services now developing such as General
  Packet Radio Service (GRPS), Bluetooth, and 3G,
  will use packet switching as well.

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Wireless Subscribers Worldwide