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Mobile communication

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sourabh kant
sourabh kant

1. The document discusses 1G and 2G mobile communication technologies. 1G used analog FDMA technology for voice calls only, while 2G introduced digital TDMA and CDMA to support voice, data, and multimedia on mobile networks. 2. 1G speeds ranged from 28-56kbps while 2G networks supported speeds up to 115kbps. Digital encoding in 2G also made networks more spectrum efficient and enabled features like SMS and internet access. 3. The document provides details on GSM, CDMA, and GPRS as the main 2G standards and discusses frequency reuse techniques like cell sectoring to reduce interference in mobile networks.

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PRESENTED BY:- SOURABH KANT
 ANALOG communication  1G Frequency Division Multiple Access (FDMA)  DIGITAL communication  2G, 3g, 4g… Time Division Multiple Access (TDMA) & Code Division Multiple Access (CDMA)
 Communication is done wirelessly by using FDMA technique between Base Stations(BS) & Mobile Stations(MS).  It only supports voice communication.  Although 1G & 2G systems uses digital signaling to connect the radio towers (Base Stations) to the rest of the telephone system, the voice during a call is encoded to digital signals (TDM & CDM) in 2G, whereas voice in 1G is only modulated to higher frequency (i.e. FM), typically at 150 MHz and up.  1G speeds vary between 28k modem(28kbit/s) and 56k modem(56kbit/s).  Example : AMPS (Advanced Mobile Phone System) used in the North America and Australia.
 uses separate frequencies, or "channels", for each conversation (FDMA). It therefore required large bandwidth for a large number of users.  the Base station could flexibly assign channels to handsets based on signal strength, allowing the same frequency to be re-used in various locations without interference. This allows a larger number of phones to be supported over a geographical area.  Disadvantage (compared to Digital systems): 1. very sensitive to noise and static. 2. no protection against call theft. 3. Only supports voice communication
 Communication is done wirelessly by using TDMA or CDMA technique between Base Stations(BS) & Mobile Stations(MS). Thus, digital systems are significantly more efficient on the spectrum, allowing for far greater mobile phone penetration levels.  It supports voice, data, and multimedia communication. Thus, data processing became possible and SMS, MMS, Internet Access, VoIP, Fax, etc. existed.  Digital voice data can be compressed and multiplexed much more effectively than analog voice encodings. Thus, Less power used by BS and MS, and small & cheap BS /MS equipments existed.  After 2G, newer technologies 2.5G, 2.75G, 3G, 4G, etc. are now launched which has increased the speed of data transfer from 56 kbit/s up to 115 kbit/s and more, as the need for speed is increasing day by day.
 2G technologies can be divided into TDMA-based and CDMA- based standards depending on the type of multiplexing used. The main 2G standards are: 1. GSM (TDMA-based), originally from Europe but used in almost all countries. 2. Over 60 GSM operators are also using CDMA2000 in the 450 MHz frequency band (CDMA450). 3. IS-95 or CDMA-One (CDMA-based, commonly referred as simply CDMA in the US), used in the Americas and parts of Asia. 4. GPRS (General Packet Radio Service), used for WAP, MMS, internet service. It is sometimes called 2.5G 5. EDGE (Enhanced GPRS) is also a GPRS with increased speed. It is sometimes called 2.75G
Mobile communication
Mobile communication
Forward link is from BS to MS Downward link is from MS to BS  There are two types of Logical channels: 1. control channels, and 2. traffic channels.  Control channels are less and are used for sending beacon signals, page signals, control information, SMS and orders. MS users share this channel.  Traffic channels are used for transmitting the voice signals at the time of conversation, and it is individually given to each MS user by BS
 Same frequency band used in a cell can be used by in another cell at far distance D from the cell of radius R.  This increases the efficiency available bandwidth.  Reuse Distance D=R√3N (N= no. of cells in a cluster)  Common hex cell clusters are of 1, 3, 4, 7, 9, 12, 13, 16 cells.
Cell Sectoring by Directional Antennas The Base transceiver station, or BTS, contains transceivers (the equipment for transmitting and receiving radio signals), antennas, and a tower. Directional BTS has more then one antennas on its tower which covers different sectors of cell areas. This is cell sectoring. This reduces the interference of the same frequency signals coming from adjacent BTS, in frequency reuse pattern.
Mobile communication

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Mobile communication

  • 2.  ANALOG communication  1G Frequency Division Multiple Access (FDMA)  DIGITAL communication  2G, 3g, 4g… Time Division Multiple Access (TDMA) & Code Division Multiple Access (CDMA)
  • 3.  Communication is done wirelessly by using FDMA technique between Base Stations(BS) & Mobile Stations(MS).  It only supports voice communication.  Although 1G & 2G systems uses digital signaling to connect the radio towers (Base Stations) to the rest of the telephone system, the voice during a call is encoded to digital signals (TDM & CDM) in 2G, whereas voice in 1G is only modulated to higher frequency (i.e. FM), typically at 150 MHz and up.  1G speeds vary between 28k modem(28kbit/s) and 56k modem(56kbit/s).  Example : AMPS (Advanced Mobile Phone System) used in the North America and Australia.
  • 4.  uses separate frequencies, or "channels", for each conversation (FDMA). It therefore required large bandwidth for a large number of users.  the Base station could flexibly assign channels to handsets based on signal strength, allowing the same frequency to be re-used in various locations without interference. This allows a larger number of phones to be supported over a geographical area.  Disadvantage (compared to Digital systems): 1. very sensitive to noise and static. 2. no protection against call theft. 3. Only supports voice communication
  • 5.  Communication is done wirelessly by using TDMA or CDMA technique between Base Stations(BS) & Mobile Stations(MS). Thus, digital systems are significantly more efficient on the spectrum, allowing for far greater mobile phone penetration levels.  It supports voice, data, and multimedia communication. Thus, data processing became possible and SMS, MMS, Internet Access, VoIP, Fax, etc. existed.  Digital voice data can be compressed and multiplexed much more effectively than analog voice encodings. Thus, Less power used by BS and MS, and small & cheap BS /MS equipments existed.  After 2G, newer technologies 2.5G, 2.75G, 3G, 4G, etc. are now launched which has increased the speed of data transfer from 56 kbit/s up to 115 kbit/s and more, as the need for speed is increasing day by day.
  • 6.  2G technologies can be divided into TDMA-based and CDMA- based standards depending on the type of multiplexing used. The main 2G standards are: 1. GSM (TDMA-based), originally from Europe but used in almost all countries. 2. Over 60 GSM operators are also using CDMA2000 in the 450 MHz frequency band (CDMA450). 3. IS-95 or CDMA-One (CDMA-based, commonly referred as simply CDMA in the US), used in the Americas and parts of Asia. 4. GPRS (General Packet Radio Service), used for WAP, MMS, internet service. It is sometimes called 2.5G 5. EDGE (Enhanced GPRS) is also a GPRS with increased speed. It is sometimes called 2.75G
  • 9. Forward link is from BS to MS Downward link is from MS to BS  There are two types of Logical channels: 1. control channels, and 2. traffic channels.  Control channels are less and are used for sending beacon signals, page signals, control information, SMS and orders. MS users share this channel.  Traffic channels are used for transmitting the voice signals at the time of conversation, and it is individually given to each MS user by BS
  • 10.  Same frequency band used in a cell can be used by in another cell at far distance D from the cell of radius R.  This increases the efficiency available bandwidth.  Reuse Distance D=R√3N (N= no. of cells in a cluster)  Common hex cell clusters are of 1, 3, 4, 7, 9, 12, 13, 16 cells.
  • 11. Cell Sectoring by Directional Antennas The Base transceiver station, or BTS, contains transceivers (the equipment for transmitting and receiving radio signals), antennas, and a tower. Directional BTS has more then one antennas on its tower which covers different sectors of cell areas. This is cell sectoring. This reduces the interference of the same frequency signals coming from adjacent BTS, in frequency reuse pattern.