2G 

(or 2-G) is short for second-generation wireless telephone technology. Second generation 2G cellular

telecom networks were commercially launched on the GSM standard in Finland by Radiolinja (now part
of Elisa Oyj) in 1991. Three primary benefits of 2G networks over their predecessors were that phone
conversations were digitally encrypted; 2G systems were significantly more efficient on the spectrum
allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile,
starting with SMS text messages.

After 2G was launched, the previous mobile telephone systems were retrospectively dubbed 1G. While
radio signals on 1G networks are analog, and on 2G networks are digital, both systems use digital
signaling to connect the radio towers (which listen to the handsets) to the rest of the telephone system.

2G has been superseded by newer technologies such as 2.5G, 2.75G, 3G, and 4G; however, 2G
networks are still used in many parts of the world.

2G technologies
2G technologies can be divided into TDMA-based and CDMA-based standards depending on the type
of multiplexing used. The main 2G standards are:

 GSM (TDMA-based), originally from Europe but used in almost all countries on all six inhabited
continents. Today accounts for over 80% of all subscribers around the world. Over 60 GSM operators
are also using CDMA2000 in the 450 MHz frequency band (CDMA450).[2]
 IS-95 aka cdma One (CDMA-based, commonly referred as simply CDMA in the US), used in the
Americas and parts of Asia. Today accounts for about 17% of all subscribers globally. Over a dozen
CDMA operators have migrated to GSM including operators in Mexico, India, Australia and South
Korea.
 PDC (TDMA-based), used exclusively in Japan
 iDEN (TDMA-based), proprietary network used by Nextel in the United States and TELUS mobile
in Canada
 IS-136 aka D-AMPS (TDMA-based, commonly referred as simply 'TDMA' in the US), was once
prevalent in the Americas but most have migrated to GSM.

2G services are frequently referred as Personal Communications Service, or PCS, in the United States.

Capacities, advantages, and disadvantages

Capacity
Using digital signals between the handsets and the towers increases system capacity in two key ways:
 Digital voice data can be compressed and multiplexed much more effectively than analog voice
encodings through the use of various codecs, allowing more calls to be packed into the same amount
of radio bandwidth.
 The digital systems were designed to emit less radio power from the handsets. This meant
that cells could be smaller, so more cells could be placed in the same amount of space. This was also
made possible by cell towers and related equipment getting less expensive.
Advantages

 The lower power emissions helped address health concerns.

 Going all-digital allowed for the introduction of digital data services, such as SMS and email.
 Greatly reduced fraud. With analog systems it was possible to have two or
more "cloned" handsets that had the same phone number.
 Enhanced privacy. A key digital advantage not often mentioned is that digital cellular calls are
much harder to eavesdrop on by use of radio scanners. While the security algorithms used have
proved not to be as secure as initially advertised, 2G phones are immensely more private than 1G
phones, which have no protection against eavesdropping.

Disadvantages

 In less populous areas, the weaker digital signal may not be sufficient to reach a cell tower. This
tends to be a particular problem on 2G systems deployed on higher frequencies, but is mostly not a
problem on 2G systems deployed on lower frequencies. National regulations differ greatly among
countries which dictate where 2G can be deployed.
 Analog has a smooth decay curve, digital a jagged steppy one. This can be both an advantage
and a disadvantage. Under good conditions, digital will sound better. Under slightly worse conditions,
analog will experience static, while digital has occasional dropouts. As conditions worsen, though,
digital will start to completely fail, by dropping calls or being unintelligible, while analog slowly gets
worse, generally holding a call longer and allowing at least a few words to get through.
 While digital calls tend to be free of static and background noise, the lossy compression used by
the codecs takes a toll; the range of sound that they convey is reduced. You'll hear less of the tonality
of someone's voice talking on a digital cellphone, but you will hear it more clearly.

Evolution
2G networks were built mainly for voice services and slow data transmission.
Some protocols, such as EDGE for GSM and 1x-RTT for CDMA2000, are defined as "3G" services
(because they are defined in IMT-2000 specification documents), but are considered by the general public
to be 2.5G services (or 2.75G which sounds even more sophisticated) because they are several times
slower than present-day 3G services.

2.5G (GPRS)
2.5G is a stepping stone between 2G and 3G cellular wireless technologies. The term "second and a half
generation" is used to describe 2G-systems that have implemented a packet switched domain in addition
to the circuit switched domain. It does not necessarily provide faster services because bundling of
timeslots is used for circuit switched data services (HSCSD) as well.

The first major step in the evolution of GSM networks to 3G occurred with the introduction of General
Packet Radio Service (GPRS). CDMA2000 networks similarly evolved through the introduction of 1xRTT.
The combination of these capabilities came to be known as 2.5G.

GPRS could provide data rates from 56 kbit/s up to 115 kbit/s. It can be used for services such as
Wireless Application Protocol (WAP) access, Multimedia Messaging Service (MMS), and for Internet
communication services such as email and World Wide Web access. GPRS data transfer is typically
charged per megabyte of traffic transferred, while data communication via traditional circuit switching is
billed per minute of connection time, independent of whether the user actually is utilizing the capacity or is
in an idle state.

1xRTT supports bi-directional (up and downlink) peak data rates up to 153.6 kbit/s, delivering an average
user data throughput of 80-100 kbit/s in commercial networks. It can also be used for WAP, SMS & MMS
services, as well as Internet access.

2.75G (EDGE)
GPRS networks evolved to EDGE networks with the introduction of 8PSK encoding. Enhanced Data rates
for GSM Evolution (EDGE), Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC) is a backward-
compatible digital mobile phone technology that allows improved data transmission rates, as an extension
on top of standard GSM. EDGE was deployed on GSM networks beginning in 2003--initially by Cingular
(now AT&T) in the United States.

EDGE is standardized by 3GPP as part of the GSM family and it is an upgrade that provides a potential
three-fold increase in capacity of GSM/GPRS networks. The specification achieves higher data-rates (up
to 236.8 kbit/s) by switching to more sophisticated methods of coding (8PSK), within existing GSM
timeslots.
The Union Minister of Telecommunications Mr. A. Raja, now being popularly known as
SPECTRUM Raja has become a famous personality overnight. The Spectrum Scandal which has
cost the government more than rupees 1 lakh crore is supposed to be the biggest scam the
country has ever seen.

The Ministry of Telecommunications held by Raja is in charge for the allocation of Spectrum to
the companies which offer mobile phone services in the country. In the year 2008, 2nd
generation (2G) Spectrum for GSM service providers was allotted to the private players. There
were a lot of controversies in the way Spectrum allocation took place by 2008 itself, now the
minister’s office is being raided by the CBI for further investigation.

The Minister claims that there is no truth in the allegations against him; he says that whatever
procedure was followed in the year 2001 has been adopted by him as well. But there were mere
50 lakh subscribers in the year 2001 compared to 37.5 crore mobile phone users by the end of
March 2008; there has been an exponential growth in the Mobile Market which is known to all
of us. The fact that the market has grown by leaps and bounds in between 2001 and 2008 is
unquestionable.

In the year 2001 the government was shouldering the responsibility to nurture the mobile
services market, therefore the Spectrum license was not auctioned then. Even the private players
in the industry would not have anticipated such a colossal growth in the mobile services market.
The Government was then in a position to motivate and attract private players to operate in the
mobile services space.

But that is not the case in 2008. Both domestic as well as MNC players consider investing in
Telecommunications extremely profitable. In this sort of a scenario if the government decides to
fix the same price, following the same procedure as it did in the year 2001 then it would be a
deliberate attempt to put too small a price for the 2G spectrum.

The Telecom Regulatory authority of India (TRAI) is a statutory body found by the government
of India in 1995 to avoid excessive government interference in pricing and policy. The TRAI had
advised the Telecom ministry to auction the Spectrum License in the years 2001, 2003, 2007
respectively. But the Telecom ministry held by Raja had completely neglected TRAI’s
recommendations and allotted the 2G spectrum license on first come first serve basis. More than
that fact, Mr. Mishra (TRAI - Head) in his letter dated 14th Jan 2008 to the Telecom Ministry
had clearly pointed out that the Ministry has ignored all the crucial recommendations of TRAI
and considered a few points for name sake.

The last date to submit applications for 2G spectrum was announced as 1st October 2007 by the
ministry as on 24th September. Later an artificial cut-off date, Sep 25, 2007, was created and
applications received between Sep 25 and Oct 1 were summarily rejected. (This in itself is a
clear violation of TRAI’s guidelines).

Datacom Solutions, Yestel, Shyam Telelink, Loop Telecom, Spice, Idea Cellular, Tata
Teleservice, Swan and Unitech were given license for 2G Spectrum. The total fee generated by
the government for selling license to the above 9 companies is 10, 772.68 crore.
Out of the companies mentioned above, the two companies Swan and Unitech do not have any
prior experience in the business of mobile phone, broadband or related services. Swan Telecom
has obtained Spectrum license to operate in 14 circles for an amount of 1537.01 crore while
Unitech has obtained license to operate in 22 circles by paying 1651 crore respectively.

Within a matter of six months these two companies have sold majority of their stake to foreign
companies. Swan Telecom had sold 45% of its shares for a whopping amount of 4050 Crore to a
company called Etisalat which is based out of UAE due to which the valuation of Swan Telecom
had increased to Rs. 9990.56 crore. Unitech had sold 60% of its stares to a Norway based
company Telenor for Rs. 6120 crore due to which the valuation of Unitech had increased to a
monstrous amount of 10, 731 crore. Just by leveraging their ability to acquire Spectrum license,
Swan and Unitech had made massive 700% return on their investment within a matter of six
months.

Raja’s ministry made Rs. 10,772.65 crore by selling 2G license to 9 companies whereas Swan
and Unitech just by selling half of their stake had proved the fact that their license is worth more
than 20,000 crore. If we consider the market value of these two companies, the Government by
selling license to these nine companies should have generated 70, 022.42 crore as license fee. In
that way our country has incurred a loss of over Rs. 60, 000 crore.

The Central Vigilance had written a letter to the Telecom Department stating the irregularities in
allocation of 2G Spectrum as on 15th of December 2008. It had clearly mentioned that it is
highly disappointed with the way 2G Spectrum was licensed. Even after that, Raja while
answering to a question in Parliament had told that 2G Spectrum was allotted on first come first
serve basis; he had also mentioned that neither TRAI nor the Vigilance had raised objections,
which is against truth.

TRAI head Mr. Mishra had clarified in an interview (December 2008) that nowhere in the
guidelines or recommendations of TRAI it had mentioned that Spectrum needs to be allotted on
first come first serve basis. The Chief of the Central Vigilance Mr. Prathyush Sinha had told in
an interview (April 2009) that it is evident that there have been severe irregularities in 2G
Spectrum allocation.

Despite all misshapes the Congress party, Prime Minister and the Finance Minister are trying to
hold up the Telecom Minister A. Raja due to political pressure from the DMK which is obvious.
In fact Raja has said on record that whatever he has done has been discussed and in consent with
the Prime Minister. This very fact is even more shocking than the scam in itself.

Dec 9 : A diary with incriminating information is believed to have been recovered during the
searches conducted by the Central Bureau of Investigation (CBI) at the residence of former
telecom minister A. Raja on Wednesday.

Sources said the diary has some data pertaining to the allocation of 2G spectrum among
other incriminating details. They said the agency would question Raja soon. CBI sleuths
spent hours in decoding the entries made in the diary which has names of some politicians
and corporate honchos, sources said.
Raja could not be contacted for his reaction despite repeated attempts.

Meanwhile, the CBI continued to question former department of telecom (DoT) officials and
a Chennai-based businessman whose premises were raided by the agency on Wednesday.

The CBI had also searched the premises of Raja's former personal secretary R.K. Chandolia,
then DoT secretary Siddhartha Behuria, former member of Telecom Commission K.
Sridhar, then deputy director general of Access Service Wing of DoT A.K. Srivastava and his
business partner and managing director of Chennai-based Greenhouse Exports Sadiqui
Batcha.

Raja was forced to resign as minister on November 14 in the wake of CAG's report that the
rates at which 2G spectrum was allotted resulted in a possible loss to the exchequer to the
tune of Rs 1.76 lakh crore. Besides being accused of undervaluing 2G spectrum, Raja has
also been blamed for circumventing the rules to favour companies that did not meet the
eligibility criteria for getting spectrum licences.

The CBI action comes close on the heels of Supreme Court coming down heavily on the
agency last month for failing to question Raja and the telecom secretary over the scam,
saying it was "beating around the bush". The CBI had registered a case on October 21, 2009
against unknown DoT officials and private people and companies for allegedly causing
massive loss to the exchequer.