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The Evolution of the Cell Phone

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T
TANMOY GHOSH

Cell phone technology has evolved dramatically since its invention in 1843. By 1994, 16 million Americans subscribed to cellular services, growing to over 110 million subscribers today. Cell phones operate using cellular networks that divide cities into small cell sites, allowing frequency reuse and millions of simultaneous users. While early cell phones used analog signals, digital transmission methods now allow increased channel capacity. Bluetooth technology further enables wireless integration of devices like cell phones, computers, and GPS systems.

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The Evolution of the CellThe Evolution of the Cell Phone…Phone… ……and a little bit about Bluetoothand a little bit about Bluetooth 
Some facts to think about…Some facts to think about…  A mobile phone is designed to operate at a maximum power level ofA mobile phone is designed to operate at a maximum power level of 0.6 watts. A household microwave oven uses between 600 and0.6 watts. A household microwave oven uses between 600 and 1,100 watts.1,100 watts.  In 1994, 16 million Americans subscribed to cellular phone services.In 1994, 16 million Americans subscribed to cellular phone services. Today, more than 110 million Americans are subscribers. SomeToday, more than 110 million Americans are subscribers. Some experts predict that worldwide subscribership will reach 1.2 billionexperts predict that worldwide subscribership will reach 1.2 billion people by 2005.people by 2005.  In a 2005 University of Michigan study, 83 percent saidIn a 2005 University of Michigan study, 83 percent said cellcell phonesphones have made life easier, choosing it over the Internet (76 percent). Buthave made life easier, choosing it over the Internet (76 percent). But an additional 60 percent said they findan additional 60 percent said they find cellcell phones somewhatphones somewhat irritating when used in public.irritating when used in public.  The BBDO survey found that 75 percent ofThe BBDO survey found that 75 percent of cellcell phonephone owners hadowners had it turned on and within reach during their waking hours, 59 percentit turned on and within reach during their waking hours, 59 percent wouldn't think of lending theirwouldn't think of lending their cellcell phonephone to a friend for a day, 26to a friend for a day, 26 percent said it was more important to go home to retrieve apercent said it was more important to go home to retrieve a cellcell phonephone than a wallet.than a wallet.
History of the Cellular PhoneHistory of the Cellular Phone  In 1843 a man by the name of Michael FaradayIn 1843 a man by the name of Michael Faraday studied to see if space could conduct electricity.studied to see if space could conduct electricity.  In the year of 1865, Doctor Mahlon Loomis wasIn the year of 1865, Doctor Mahlon Loomis was the first person to communicate through wirelessthe first person to communicate through wireless atmosphere.atmosphere.  He came up with the idea of transmitting andHe came up with the idea of transmitting and receiving messages through atmosphere as areceiving messages through atmosphere as a conductor.conductor.  In 1973 martin copper came up with Motorola.In 1973 martin copper came up with Motorola.  In 1977 the first cell phone was made inIn 1977 the first cell phone was made in Chicago.Chicago.  When it first came out 2000 people was given a freeWhen it first came out 2000 people was given a free trial.trial.
What exactly is a cell phone?What exactly is a cell phone?  One of the most interesting thingsOne of the most interesting things about a cell phone is that it isabout a cell phone is that it is actually a radio -- an extremelyactually a radio -- an extremely sophisticated radio, but a radiosophisticated radio, but a radio nonetheless.nonetheless.  The genius of the cellular systemThe genius of the cellular system is the division of a city into smallis the division of a city into small cells. This allows extensivecells. This allows extensive frequency reuse across a city, sofrequency reuse across a city, so that millions of people can usethat millions of people can use cell phones simultaneously.cell phones simultaneously.  In a typical analog cell-phoneIn a typical analog cell-phone system in the United States, thesystem in the United States, the cell-phone carrier receives aboutcell-phone carrier receives about 800800 frequencies to use across thefrequencies to use across the city.city.
Are you in my network?Are you in my network?
So why are they called “cellular”So why are they called “cellular” phones?phones?  A single cell in an analog system uses one-seventh ofA single cell in an analog system uses one-seventh of the available duplex voice channels. That is, each cell (ofthe available duplex voice channels. That is, each cell (of the seven on a hexagonal grid) is using one-seventh ofthe seven on a hexagonal grid) is using one-seventh of the available channels so it has a unique set ofthe available channels so it has a unique set of frequencies and there are no collisions:frequencies and there are no collisions:  A cell-phone carrier typically gets 832 radio frequencies to use inA cell-phone carrier typically gets 832 radio frequencies to use in a city.a city.  Each cell phone uses two frequencies per call -- a duplexEach cell phone uses two frequencies per call -- a duplex channel -- so there are typically 395 voice channels per carrier.channel -- so there are typically 395 voice channels per carrier. (The other 42 frequencies are used for control channels -- more(The other 42 frequencies are used for control channels -- more on this later.)on this later.)  Therefore, each cell has about 56 voice channels available.Therefore, each cell has about 56 voice channels available.  In other words, in any cell, 56 people can be talking on theirIn other words, in any cell, 56 people can be talking on their cell phone at one time.cell phone at one time.
Analog vs. DigitalAnalog vs. Digital  Analog cellularAnalog cellular systems aresystems are considered first-considered first- generation mobilegeneration mobile technology, or 1G.technology, or 1G.  Digital transmissionDigital transmission methods (2G), themethods (2G), the number of availablenumber of available channels increases.channels increases.  For example, a TDMA-For example, a TDMA- based digital systembased digital system can carry three timescan carry three times as many calls as anas many calls as an analog system, soanalog system, so each cell has abouteach cell has about 168 channels168 channels available.available.
The major components…The major components…  Cell phones have low-Cell phones have low- power transmitters inpower transmitters in them.them.  Many cell phonesMany cell phones have two signalhave two signal strengths: 0.6 wattsstrengths: 0.6 watts and 3 wattsand 3 watts  For comparison, mostFor comparison, most CB radios transmit atCB radios transmit at 4 watts.4 watts.
So how does it all work?So how does it all work?  When you first power up theWhen you first power up the phone, it listens for anphone, it listens for an SIDSID (system identification #)(system identification #)..  The control channel is aThe control channel is a special frequency that thespecial frequency that the phone and base station usephone and base station use to talk to one another aboutto talk to one another about things like call set-up andthings like call set-up and channel changing.channel changing.  If the phone cannot find anyIf the phone cannot find any control channels to listen to, itcontrol channels to listen to, it knows it isknows it is out of rangeout of range andand displays a "no service"displays a "no service" message.message.
So how does it all work?So how does it all work?  When it receives the SID, the phone compares it to theWhen it receives the SID, the phone compares it to the SID programmed into the phone.SID programmed into the phone.  The phone knows that the cell it is communicating with is part ofThe phone knows that the cell it is communicating with is part of its home system.its home system.  Along with the SID, the phone also transmits aAlong with the SID, the phone also transmits a registration request, and the MTSO (registration request, and the MTSO (Mobile TelephoneMobile Telephone Switching OfficeSwitching Office) keeps track of your phone's location) keeps track of your phone's location in a database -- this way, the MTSO knows which cellin a database -- this way, the MTSO knows which cell you are in when it wants to ring your phone.you are in when it wants to ring your phone.  The MTSO gets the call, and it tries to find you. It looksThe MTSO gets the call, and it tries to find you. It looks in its database to see which cell you are in.in its database to see which cell you are in.  The MTSO picks a frequency pair that your phone willThe MTSO picks a frequency pair that your phone will use in that cell to take the call.use in that cell to take the call.
Your cellular network…Your cellular network…
So what exactly is Bluetooth?So what exactly is Bluetooth?  There are lots of different ways that electronicThere are lots of different ways that electronic devices can connect to one another:devices can connect to one another:  Component cablesComponent cables  Electrical wiresElectrical wires  Ethernet cablesEthernet cables  WiFiWiFi  Infrared signalsInfrared signals  A Bluetooth connection is wireless andA Bluetooth connection is wireless and automatic, and it has a number of interestingautomatic, and it has a number of interesting features that can simplify our daily lives.features that can simplify our daily lives.
Benefits of Bluetooth…Benefits of Bluetooth…  Bluetooth takes small-area networking to theBluetooth takes small-area networking to the next level by removing the need for usernext level by removing the need for user intervention and keeping transmission powerintervention and keeping transmission power extremely low to save battery power.extremely low to save battery power.  Bluetooth is essentially a networking standardBluetooth is essentially a networking standard that works at two levels:that works at two levels:  Provides agreement at the physical level -- BluetoothProvides agreement at the physical level -- Bluetooth is a radio frequency standard.is a radio frequency standard.  Provides agreement at the protocol levelProvides agreement at the protocol level
Think about this…Think about this…  You're on your Bluetooth-enabled cell phone, standing outside theYou're on your Bluetooth-enabled cell phone, standing outside the door to your house. You tell the person on the other end of the linedoor to your house. You tell the person on the other end of the line to call you back in five minutes so you can get in the house and putto call you back in five minutes so you can get in the house and put your stuff away. As soon as you walk in the house, the map youyour stuff away. As soon as you walk in the house, the map you received on your cell phone from your car's Bluetooth-enabled GPSreceived on your cell phone from your car's Bluetooth-enabled GPS system is automatically sent to your Bluetooth-enabled computer,system is automatically sent to your Bluetooth-enabled computer, because your cell phone picked up a Bluetooth signal from your PCbecause your cell phone picked up a Bluetooth signal from your PC and automatically sent the data you designated for transfer. .and automatically sent the data you designated for transfer. .
Can you hear me now?Can you hear me now?  So lets review:So lets review:  Cell phones technology was actually invented inCell phones technology was actually invented in 1843.1843.  Cell phones are used by 110 million people in the USCell phones are used by 110 million people in the US today.today.  The term “cellular” came from the type of radioThe term “cellular” came from the type of radio network which is used for cell phones tonetwork which is used for cell phones to communicate.communicate.  Older cell phones used analog signals, while today’sOlder cell phones used analog signals, while today’s cell phones use digital signals.cell phones use digital signals.  Bluetooth technology helps to integrate all forms ofBluetooth technology helps to integrate all forms of communication technology from your cell phone tocommunication technology from your cell phone to your television.your television.

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The Evolution of the Cell Phone

  • 1. The Evolution of the CellThe Evolution of the Cell Phone…Phone… ……and a little bit about Bluetoothand a little bit about Bluetooth 
  • 2. Some facts to think about…Some facts to think about…  A mobile phone is designed to operate at a maximum power level ofA mobile phone is designed to operate at a maximum power level of 0.6 watts. A household microwave oven uses between 600 and0.6 watts. A household microwave oven uses between 600 and 1,100 watts.1,100 watts.  In 1994, 16 million Americans subscribed to cellular phone services.In 1994, 16 million Americans subscribed to cellular phone services. Today, more than 110 million Americans are subscribers. SomeToday, more than 110 million Americans are subscribers. Some experts predict that worldwide subscribership will reach 1.2 billionexperts predict that worldwide subscribership will reach 1.2 billion people by 2005.people by 2005.  In a 2005 University of Michigan study, 83 percent saidIn a 2005 University of Michigan study, 83 percent said cellcell phonesphones have made life easier, choosing it over the Internet (76 percent). Buthave made life easier, choosing it over the Internet (76 percent). But an additional 60 percent said they findan additional 60 percent said they find cellcell phones somewhatphones somewhat irritating when used in public.irritating when used in public.  The BBDO survey found that 75 percent ofThe BBDO survey found that 75 percent of cellcell phonephone owners hadowners had it turned on and within reach during their waking hours, 59 percentit turned on and within reach during their waking hours, 59 percent wouldn't think of lending theirwouldn't think of lending their cellcell phonephone to a friend for a day, 26to a friend for a day, 26 percent said it was more important to go home to retrieve apercent said it was more important to go home to retrieve a cellcell phonephone than a wallet.than a wallet.
  • 3. History of the Cellular PhoneHistory of the Cellular Phone  In 1843 a man by the name of Michael FaradayIn 1843 a man by the name of Michael Faraday studied to see if space could conduct electricity.studied to see if space could conduct electricity.  In the year of 1865, Doctor Mahlon Loomis wasIn the year of 1865, Doctor Mahlon Loomis was the first person to communicate through wirelessthe first person to communicate through wireless atmosphere.atmosphere.  He came up with the idea of transmitting andHe came up with the idea of transmitting and receiving messages through atmosphere as areceiving messages through atmosphere as a conductor.conductor.  In 1973 martin copper came up with Motorola.In 1973 martin copper came up with Motorola.  In 1977 the first cell phone was made inIn 1977 the first cell phone was made in Chicago.Chicago.  When it first came out 2000 people was given a freeWhen it first came out 2000 people was given a free trial.trial.
  • 4. What exactly is a cell phone?What exactly is a cell phone?  One of the most interesting thingsOne of the most interesting things about a cell phone is that it isabout a cell phone is that it is actually a radio -- an extremelyactually a radio -- an extremely sophisticated radio, but a radiosophisticated radio, but a radio nonetheless.nonetheless.  The genius of the cellular systemThe genius of the cellular system is the division of a city into smallis the division of a city into small cells. This allows extensivecells. This allows extensive frequency reuse across a city, sofrequency reuse across a city, so that millions of people can usethat millions of people can use cell phones simultaneously.cell phones simultaneously.  In a typical analog cell-phoneIn a typical analog cell-phone system in the United States, thesystem in the United States, the cell-phone carrier receives aboutcell-phone carrier receives about 800800 frequencies to use across thefrequencies to use across the city.city.
  • 5. Are you in my network?Are you in my network?
  • 6. So why are they called “cellular”So why are they called “cellular” phones?phones?  A single cell in an analog system uses one-seventh ofA single cell in an analog system uses one-seventh of the available duplex voice channels. That is, each cell (ofthe available duplex voice channels. That is, each cell (of the seven on a hexagonal grid) is using one-seventh ofthe seven on a hexagonal grid) is using one-seventh of the available channels so it has a unique set ofthe available channels so it has a unique set of frequencies and there are no collisions:frequencies and there are no collisions:  A cell-phone carrier typically gets 832 radio frequencies to use inA cell-phone carrier typically gets 832 radio frequencies to use in a city.a city.  Each cell phone uses two frequencies per call -- a duplexEach cell phone uses two frequencies per call -- a duplex channel -- so there are typically 395 voice channels per carrier.channel -- so there are typically 395 voice channels per carrier. (The other 42 frequencies are used for control channels -- more(The other 42 frequencies are used for control channels -- more on this later.)on this later.)  Therefore, each cell has about 56 voice channels available.Therefore, each cell has about 56 voice channels available.  In other words, in any cell, 56 people can be talking on theirIn other words, in any cell, 56 people can be talking on their cell phone at one time.cell phone at one time.
  • 7. Analog vs. DigitalAnalog vs. Digital  Analog cellularAnalog cellular systems aresystems are considered first-considered first- generation mobilegeneration mobile technology, or 1G.technology, or 1G.  Digital transmissionDigital transmission methods (2G), themethods (2G), the number of availablenumber of available channels increases.channels increases.  For example, a TDMA-For example, a TDMA- based digital systembased digital system can carry three timescan carry three times as many calls as anas many calls as an analog system, soanalog system, so each cell has abouteach cell has about 168 channels168 channels available.available.
  • 8. The major components…The major components…  Cell phones have low-Cell phones have low- power transmitters inpower transmitters in them.them.  Many cell phonesMany cell phones have two signalhave two signal strengths: 0.6 wattsstrengths: 0.6 watts and 3 wattsand 3 watts  For comparison, mostFor comparison, most CB radios transmit atCB radios transmit at 4 watts.4 watts.
  • 9. So how does it all work?So how does it all work?  When you first power up theWhen you first power up the phone, it listens for anphone, it listens for an SIDSID (system identification #)(system identification #)..  The control channel is aThe control channel is a special frequency that thespecial frequency that the phone and base station usephone and base station use to talk to one another aboutto talk to one another about things like call set-up andthings like call set-up and channel changing.channel changing.  If the phone cannot find anyIf the phone cannot find any control channels to listen to, itcontrol channels to listen to, it knows it isknows it is out of rangeout of range andand displays a "no service"displays a "no service" message.message.
  • 10. So how does it all work?So how does it all work?  When it receives the SID, the phone compares it to theWhen it receives the SID, the phone compares it to the SID programmed into the phone.SID programmed into the phone.  The phone knows that the cell it is communicating with is part ofThe phone knows that the cell it is communicating with is part of its home system.its home system.  Along with the SID, the phone also transmits aAlong with the SID, the phone also transmits a registration request, and the MTSO (registration request, and the MTSO (Mobile TelephoneMobile Telephone Switching OfficeSwitching Office) keeps track of your phone's location) keeps track of your phone's location in a database -- this way, the MTSO knows which cellin a database -- this way, the MTSO knows which cell you are in when it wants to ring your phone.you are in when it wants to ring your phone.  The MTSO gets the call, and it tries to find you. It looksThe MTSO gets the call, and it tries to find you. It looks in its database to see which cell you are in.in its database to see which cell you are in.  The MTSO picks a frequency pair that your phone willThe MTSO picks a frequency pair that your phone will use in that cell to take the call.use in that cell to take the call.
  • 11. Your cellular network…Your cellular network…
  • 12. So what exactly is Bluetooth?So what exactly is Bluetooth?  There are lots of different ways that electronicThere are lots of different ways that electronic devices can connect to one another:devices can connect to one another:  Component cablesComponent cables  Electrical wiresElectrical wires  Ethernet cablesEthernet cables  WiFiWiFi  Infrared signalsInfrared signals  A Bluetooth connection is wireless andA Bluetooth connection is wireless and automatic, and it has a number of interestingautomatic, and it has a number of interesting features that can simplify our daily lives.features that can simplify our daily lives.
  • 13. Benefits of Bluetooth…Benefits of Bluetooth…  Bluetooth takes small-area networking to theBluetooth takes small-area networking to the next level by removing the need for usernext level by removing the need for user intervention and keeping transmission powerintervention and keeping transmission power extremely low to save battery power.extremely low to save battery power.  Bluetooth is essentially a networking standardBluetooth is essentially a networking standard that works at two levels:that works at two levels:  Provides agreement at the physical level -- BluetoothProvides agreement at the physical level -- Bluetooth is a radio frequency standard.is a radio frequency standard.  Provides agreement at the protocol levelProvides agreement at the protocol level
  • 14. Think about this…Think about this…  You're on your Bluetooth-enabled cell phone, standing outside theYou're on your Bluetooth-enabled cell phone, standing outside the door to your house. You tell the person on the other end of the linedoor to your house. You tell the person on the other end of the line to call you back in five minutes so you can get in the house and putto call you back in five minutes so you can get in the house and put your stuff away. As soon as you walk in the house, the map youyour stuff away. As soon as you walk in the house, the map you received on your cell phone from your car's Bluetooth-enabled GPSreceived on your cell phone from your car's Bluetooth-enabled GPS system is automatically sent to your Bluetooth-enabled computer,system is automatically sent to your Bluetooth-enabled computer, because your cell phone picked up a Bluetooth signal from your PCbecause your cell phone picked up a Bluetooth signal from your PC and automatically sent the data you designated for transfer. .and automatically sent the data you designated for transfer. .
  • 15. Can you hear me now?Can you hear me now?  So lets review:So lets review:  Cell phones technology was actually invented inCell phones technology was actually invented in 1843.1843.  Cell phones are used by 110 million people in the USCell phones are used by 110 million people in the US today.today.  The term “cellular” came from the type of radioThe term “cellular” came from the type of radio network which is used for cell phones tonetwork which is used for cell phones to communicate.communicate.  Older cell phones used analog signals, while today’sOlder cell phones used analog signals, while today’s cell phones use digital signals.cell phones use digital signals.  Bluetooth technology helps to integrate all forms ofBluetooth technology helps to integrate all forms of communication technology from your cell phone tocommunication technology from your cell phone to your television.your television.