08-02-2013, 02:22 PM
Presentation on GSM & CDMA Network
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IN cellular services there are two main complementary network technologies, global system for mobile communication (GSM) and code division multiple access (CDMA).
What is GSM ? :
What is GSM ? Global System for Mobile (GSM) is a second generation cellular standard developed to cater voice services and data delivery using digital modulation
What IS GSM :
What IS GSM The full form of GSM is Global system for Mobile Communication. GSM is one of the most famous working standards for mobile phones all over the world. Over two billion people use the GSM services across 212 countries and territories in the world. The utility of GSM makes national and international roaming very simple and easy between mobile phone operators, which enable users to use their cell phone in various parts of the world.
History Of GSM :
History Of GSM : Developed by Group Spéciale Mobile (founded 1982) : Aim : to replace the incompatible analog system
First GSM Launched :
First GSM Launched 18years ago: the first produced GSM phone , Nokia launched the world's first commercially available GSM digital phone, the Nokia 1011, the model number coming from the launch date: 10 November 1992. Nokia's 1011: GSM first The 475g 1011 was rather heavier than today's slimline models. A lot of the weight came from the unit's nickel-cadmium rechargeable battery, which yielded a low - by today's standards - talk time of just 90 minutes. It could stay operational for 12 hours in stand-by mode. The 195 x 60 x 45mm handset could hold 99 phone numbers and the names of their owners, any of which could be displayed on the 1011's two-line screen. There was no colour, no camera, no Bluetooth, no memory card slot and the handset had to have an extendible antenna. But it did introduce one innovation that phone owners now use without a second thought: text messaging.
GSM System Architecture-I :
GSM System Architecture-I Mobile Station (MS) Mobile Equipment (ME) Subscriber Identity Module (SIM) Base Station Subsystem (BSS) Base Transceiver Station (BTS) Base Station Controller (BSC) Network Switching Subsystem(NSS) Mobile Switching Center (MSC) Home Location Register (HLR) Visitor Location Register (VLR) Authentication Center (AUC) Equipment Identity Register (EIR)
System ArchitectureMobile Station (MS) :
System ArchitectureMobile Station (MS) The Mobile Station is made up of two entities: Mobile Equipment (ME) 2. Subscriber Identity Module (SIM)
History And Development Of CDMA :
History And Development Of CDMA CDMA (Code Division Multiple Assess) is first used in military based communication technology used during World War II by English allies to Stop German attempts to decode transmissions A Company named Qualcomm created communications chips and designs for CDMA technology and later claimed patents on the technology. Claude Shannon and Robert Pierce had provided CDMA framework in 1949.
How CDMA works :
How CDMA works 1 Frequency division multiple access (FDMA) 2.Time division multiple access (TDMA) 3.Code division multiple access (CDMA) Thus CDMA is one access technology which cell phones uses to transmit and receive data.. That is FDMA puts each call on a separate frequency and TDMA assigns each call a certain portion of time on a designated frequency for the above mentioned purpose. But CDMA gives a unique code to each call and spreads it over the available frequencies. All these are multiple access systems because more than one user can use the specified At a Time
Code Division Multiple Access Principles :
Code Division Multiple Access Principles Many voice channels share the same frequency band No timeslots; all channel uses the same frequency simultaneously all the time Channels are differentiated by its code Signaling uses a dedicated frequency band
What is Multiple Access? :
What is Multiple Access? Since the beginning of telephony and radio, system operators have tried to squeeze the maximum amount of traffic over each circuit Each pair of users enjoys a dedicated, private circuit through the transmission medium, unaware that the other users exist. Multiple Access: Simultaneous private use of a transmission medium by multiple, independent users.