1. introduction to telecom

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Profile of a CustomerProfile Contains

Who does this connection belong to(Telephone Number &

PORT get Linked)

What is his/her telephone number

Can he/she make International calls

Can he/she make National calls

Does he/she have call waiting facility etc

Telephone exchange recognizes everything with the help of thePORT


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2011-10-3

When we say 'wireless phones' today, we are no longer talking about those cordless,

land line, home phone. Instead the term 'wireless' pertains to mobile of cellular

devices. With this great technology, there are no wires, no cords, no limit (well, just

for cellular signals, that is). Cellular signals are sent via radio waves so there is

obviously no need for wires and cables for it to operate.

The technological development that distinguished the First Generation mobile

phones from the previous generation was the use of multiple cell sites, and the ability

to transfer calls from one site to the next as the user travelled between cells during a

conversation. The first commercially automated cellular network (the 1G generation)
http://en.wikipedia.org/wiki/Handoffhttp://en.wikipedia.org/wiki/1Ghttp://en.wikipedia.org/wiki/1Ghttp://en.wikipedia.org/wiki/Handoff


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No wires between Handset & Telephone Exchange

In Wireless the connection is established through MSC(Mobile Switching Center)

Access Network has changed from Wireline to Wireless

Air(also called Free space) is the Interface between a Customer & the Core Network

or MSC

Roam Freely is the main purpose to go for a Mobile

At any point in time a subscriber is under the service area of a BTS(primary BTS)

also under the service area of MSC/BSC

As the subscriber moves, his/her serving BTS/BSC/MSC could change

Typically cluster are formed in a cellular network Cluster are adjacent BTS

coverage areas that are parented to a BSC/MSC

When a subscriber moves out of a cluster not only will the serving BTS change buteven the serving MSC may change

In short customer can ever move from one country to another country he/she may

also use service of that operator(when international roaming is introduced)


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As digital becomes more popular, it is likely that the existing analogue services

will be removed. In some cases this has already happened, where a

broadcaster has offered incentives to viewers to encourage them to switch to

digital. In other cases government policies have been introduced to encourage

or force the switchover process, especially with regard to terrestrial broadcasts


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Multiple Access Achieved by dividing the available

radio frequency spectrum, so that multiple users can

be given access at the same time.FDMA - Frequency Division Multiple Access

( eg: GSM each Frequency channel is 200KHz)

TDMA - Time Division Multiple Access

( eg: GSM each frequency channel is divided

into 8 timeslots)

CDMA - Code Division Multiple Access(eg: IS95- Each User data is coded with a

unique code)-

OFDMA-Orthognoal Frequency division

Multiple access


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A new generation of cellular standards has appeared approximately every tenth year

since 1G systems were introduced in 1981/1982. Each generation is characterized by

new frequency bands, higher data rates and non backwards compatible transmission

technology. The first release of the 3GPP Long Term Evolution (LTE) standard does not

completely fulfill the ITU 4G requirements called IMT-Advanced. First release LTE is

not backwards compatible with 3G, but is a pre-4G or 3.9G technology, however

sometimes branded "4G" by the service providers. WiMAX is another technology

verging on or marketed as 4G.the UMTS system, first offered in 2001, standardized by

3GPP, used primarily in Europe, Japan, China (however with a different radio

interface) and other regions predominated by GSM2G system infrastructure. The cell

phones are typically UMTS and GSM hybrids
http://en.wikipedia.org/wiki/1Ghttp://en.wikipedia.org/wiki/3GPP_Long_Term_Evolutionhttp://en.wikipedia.org/wiki/3.9Ghttp://en.wikipedia.org/wiki/WiMAXhttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/UMTShttp://en.wikipedia.org/wiki/3GPPhttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/2Ghttp://en.wikipedia.org/wiki/2Ghttp://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/3GPPhttp://en.wikipedia.org/wiki/UMTShttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/WiMAXhttp://en.wikipedia.org/wiki/3.9Ghttp://en.wikipedia.org/wiki/3GPP_Long_Term_Evolutionhttp://en.wikipedia.org/wiki/1G


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The GSM standard has been an advantage to both consumers, who may benefit from

the ability to roam and switch carriers without replacing phones, and also to network

operators, who can choose equipment from many GSM equipment vendors.[4] GSM

also pioneered low-cost implementation of the short message service (SMS), also

called text messaging, which has since been supported on other mobile phone

standards as well. The standard includes a worldwide emergency telephone number

feature.

Leverage technology to increase capacity

Speech compression; digital signal processing

Utilize/extend Intelligent Network concepts

Improve fraud prevention; Add new services

Wide diversity of 2G systems

IS-54/ IS-136 Digital AMPS; PDC (Japan)

DECT and PHS; iDENIS-95 CDMA (cdmaOne)

GSM
http://en.wikipedia.org/wiki/GSMhttp://en.wikipedia.org/wiki/Short_message_servicehttp://en.wikipedia.org/wiki/Emergency_telephone_numberhttp://en.wikipedia.org/wiki/Emergency_telephone_numberhttp://en.wikipedia.org/wiki/Short_message_servicehttp://en.wikipedia.org/wiki/GSM


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3G TechnologyGSM evolution: W-CDMA, HSDPA, HSPA, +

leverages GSMs dominant positionLegally mandated in Europe and elsewhere

Requires substantial new spectrum5 MHz each way (symmetric) at a minimum

Slow start (was behind CDMA 2000), but now the acceptedleader

Network effect built on GSMs >80% market shareSurely LTE will benefit in the same fashion

4G TechnologyOrthogonal Frequency Division Multiple Access

Supercedes CDMA used in all 3G variantsOFDMA = Orthogonal Frequency Division Multiplexing (OFDM) plus statisticalmultiplexing

Optimization of time, frequency & code multiplexingOFDM already deployed in 802.11a & 802.11g

Took Wi-Fi from 11 Mbps to 54 Mbps & beyond


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1. introduction to telecom

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