A PRESENTATION ON VOCATIONAL TRAINING IN BSNL

2 3-Jul-16 GSM (Global System For Mobile Communication) The Global System for Mobile communications (GSM: originally from Groupe Spécial Mobile ) is the most popular standard for mobile phones in the world. GSM service is used by over 2 billion people across more than 212 countries and territories.GSM works by providing a dedicated radio channel to the mobile device when and only when the device is in operation.mobile phones billion

3 3-Jul-16 KEY FEATURES OF GSM 1.Higher digital voice quality and low cost alternatives. In order to make calls such as the Short Message Service (SMS).Short Message Service (SMS) 2.Roaming services Cellular standards GSM allows network operators to offer roaming services which mean subscribers can use their phones all over the world.Roamingroaming 3.Digital call quality GSM differs significantly from its predecessors in that both signaling and speech channels are Digital call quality.Digital call quality

4 3-Jul-16 GSM NETWORKS The Mobile Station (MS) The Base Station Subsystem (BSS)Base Station Subsystem The Network and Switching Subsystem (NSS)Network and Switching Subsystem The Operation and Support Subsystem (OSS)

5 3-Jul-16 GSM FUNCTIONS Transmission Radio Resources Management (RR) Mobility Management (MM) Communication Management (CM) Operation, Administration and Maintenance (OAM)

6 3-Jul-16 DISADVANTAGES OF GSM The available radio channel speed of 9.6kbps while reasonable for voice is severely limiting for the sending and receiving of data Lack of bandwidth provides major obstacles when trying to implement multimedia on mobile devices. For example, streaming audio on a portable device would need a bandwidth of 128kbps to provide near CD quality using MP3 compression. This is the over the 13 times the bandwidth provided by GSM. Streaming video demands an even higher bandwidth than this so it too is unviable using GSM networks. When used for applications such as credit card verification this wait becomes unacceptable, as the user is normally unwilling to have to wait so long for basic services.

7 3-Jul-16 1G – First Generation 1G (or 1-G) is short for first-generation wireless telephone technology, cell phones. These are the analog cell phone standards that were introduced in the 1980s and continued until being replaced by 2G digital cell phones. The main difference between two succeeding mobile telephone systems, 1G and 2G, is that the radio signals that 1G networks use are analog, while 2G networks are digital. wirelesstelephonetechnologycell phones 1980s2G

8 3-Jul-16 2G 2G systems were developed as the requirement for mobile communications grew. There characteristics included the use of digital signaling across the air interface, roaming, security and the ability to carry data as well as speech. The main differentiator to previous mobile telephone systems, retrospectively dubbed 1G, is that the radio signals that 1G networks use are analog, while 2G networks are digital.1Ganalog digital 2.5G The requirement for mobile data services, fuelled by the growth of the internet, was the driver for the development of enhanced data services known as 2.5G. These include HSCSD (High Speed Circuit Switched Data), 14.4Kbps GSM Data, and GPRS.3G - Third Generation

9 3-Jul-16 3G Third-generation The services associated with 3G include wide-area wireless voice telephony and broadband wireless data, all in a mobile environment. In marketing 3G services, video telephone has often been suggested as the killer application for 3G.video telephonekiller application The most significant feature offered by third generation (3G) mobile technologies are Capacity Radio Spectrum

10 3-Jul-16 ADVANTAGES OF GPRS Instant access to data as if connected to an office LAN Charging based on amount of data transferred (not the time connected) Higher transmission speeds

11 3-Jul-16 Principle of Mobile Communication Multiple Access methodology The technique of dynamically sharing the finite limited radio spectrum by multiple users is called Multiple Access Technique. Generally there are three different types of multiple access technologies. They are:- 1.Frequency Division Multiple Access (FDMA) 2.Time Division Multiple Access (TDMA) 3.Code Division multiple Access (CDMA)

12 3-Jul-16 CODE DIVISION MULTIPLE ACCESS(CDMA) Code Division Multiple Access (CDMA) is cellular technology regarded as the digital second generation system, bases on Direct Sequence Spread – Spectrum techniques for multiplexing, that provides an alternative to TDMA (Time Division Multiple Access) for second – generation cellular networks. At present time the latest version of CDMA are also Developed, like CDMA (3G), CDMAOne and WCDMA etc.

13 3-Jul-16 KEY FEATURES OF CDMA A multiple access scheme for digital radio, to send voice, data, and signaling data (such as a dialed telephone number) between mobile phones and cell sites.digital radiosignalingmobile phonescell sites It is a mobile digital radio technology that transmits streams of bits and whose channels are divided using codes (PN sequences).digital radiobits channelsPN sequences

14 3-Jul-16 ADVANTAGES OF CDMA OVER GPRS Larger Capacity Vocoder and variable data rates Less (Optimum) Power per cell Seamless Hand-off No Frequency Planning High Tolerance to Interference Multiple Diversity Capacity Considerations

Changing Scenario

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