4G Mobile Network [601572]

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4G Mobile Network

Student: [anonimizat]: 341 C5

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Contents

Introduction ………………………….. ………………………….. ………………………….. ………………………….. … 3
GSM technology ………………………….. ………………………….. ………………………….. ………………………. 3
GSM system architecture ………………………….. ………………………….. ………………………….. …………. 4
Peculiarities of 4G network ………………………….. ………………………….. ………………………….. ………. 8
Features: ………………………….. ………………………….. ………………………….. ………………………….. ……………. 8
IMT-Advanced regulations ………………………….. ………………………….. ………………………….. ………………. 9
IPv6 support ………………………….. ………………………….. ………………………….. ………………………….. …….. 10
4G Network coding and interference approa ch ………………………….. ………………………….. ……………… 10
Attenuation of 4G network signals ………………………….. ………………………….. ………………………….. ….. 10
How fast is 4G network as compared to its predecessor, 3G network? ………………………….. ………….. 11
Comparison: 3G vs. 4G ………………………….. ………………………….. ………………………….. ………….. 14
Main performance of 3G and 4G ………………………….. ………………………….. ………………………….. …….. 16
Justifying the shift to 4G ………………………….. ………………………….. ………………………….. ………………… 16
REFERENCES: ………………………….. ………………………….. ………………………….. …………………….. 17

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Introduction

In 1982, the CEPT (European Conference of Postal and Telecommunications
Administrations ) created the GSM (Groupe Spécial Mobile in its original name ) in order to
develop a standard in the mobile phone system able to be used in Europe . In 1987 , 13 European
countries signed an agreement for the development of a single mobile phone system .
The first stage of GSM specifications was issued in 1990 , with the first GSM network
released in Finland in 1991.

GSM technology

In the GSM (Global System for Mobile Communications ), a subscription is separated by
the terminal used . In the old radio -phone networks , the number a subscriber could be called at
used to be stored in a terminal equipment and physically interpreted in such equipment . In the
GSM network, terminals are simplified, they have no configuration and are thus unusable . It is
necessary to associate them with a smart card called a SIM card, namely Subscriber Identity
Module . It stores all the features of a subscription and also stores the user characteristics (list of
abbreviated numbers , personal access password , the last number dialed etc.) and radio equipment
characteris tics (the features of the latest ne twork for connection etc.).
If a user changes the equipment without changing the SIM card or the geographic
location , the operation is completely transparent to the network. It always sees the same user
with the same characteristics.

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GSM system architecture

What is a GSM network made up of?

The structure of a GSM network is quite complicated . Basically, there are three main elements:
Base Station Subsystem ( BSS), Network and Switching Subsystem ( NSS) and GPRS Core
Network . The Base Station Subsystem is the component that allows mobile phones to connect to
a mobile phone exchange . It consists of the GSM stations that we see everywhere nowadays
which are called Base Transceiver Stations ( BTS) , as well as the station control units (BSC ).
GSM stations are usually endowed with unidirectional antennas . The coverage area around a
station/GSM cell is radially divided into sectors of whom each is assigned with one or two
antennas . One common type of sectorization is the clover with three sectors of 120° each.

Structure of a GSM
network

A station control unit (BSC) usually controls tens or hundreds of antennas, directi ng traffic to
the NSS. There are several regional BSC’s in a GSM network which concentrate the
connections in a particular area and forward them to the MSC , a component of the NSS. The

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BSC is regarded as the most robust component of a GSM network, being equipped with
redundant systems meant to ensure the ongoing operation of the network.
Network Switching Subsystem (NSS) is the component of a GSM network similar to the phone
exchange of a fixed network. It performs management of the network communications and
provides interconnectivity with other mobile or fixed networks. The most important component
of the NSS is Mobile Switching Center (MSC). It is responsible mainly for forwarding the calls
and SMS’s. Additionally, via the MSC, a user in the GSM network can contact a user in a fixed
network. GPRS or General Packet Radio Service is a mobile phone service for data
transmission based on the truncation of data flows into packets . GPRS Core Network , the third
component of a GSM network, is resp onsible for the management of such data service.

Structure of a GSM network – simplified version

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Background of 4G networks and their predecessors

GSM cell systems of mobile communication s have been developed in four distinct generations
so far :

The First Generation ( 1G) was designed to provide a single service – voice . This included
systems such as NMT , AMPS , TACS etc. and emerged in 1980. They were analogue signal
processing systems operating in 800-900 MHz or 450MHz bands . At present, first generation
systems are in the end of their “careers” and removed from operation in many countries where
they used to work.

The Second Generation (2G): originally designed to provide voice services while having a
limited capacity for data transmission services at relatively low speed . They are digital signal
processing systems , operating in 900 MHz and 1800 MHz bands . Examples of such systems are
GSM , D-AMPS etc. The first GSM systems were brought into operation in 1991. 2G systems are
currently at the “peak” of their progress . Three development stages in the 2G evolution can be
highlighted: 1, 2, and 2+. In the 2+ stage, GSM offers the possibility to increase the speed of
data transmission via the introduction of special procedures such as HSCSD and GPRS. Thus, by
using the transmission with data pack ets via the GPRS method , data transmission speed can be
up to 172 kbit/s (as compared to the speed of 14.4 kbit/s provided in the 1 development stage ).
This makes it possible for the development of multimedia transmissions.

The Third Generation (3G): provides enhanced transmission speeds of up to 2 Mbit/s (up to 8
Mbit/s in some versions) and shows multiple opportunities for quality multimedia services and
operation in different environments. They are digital signal processing systems operating in a 2
GHz band . Examples of such systems are WCDMA and TD/CDMA , both in the European
version for the UTRA interface , WCDMA in the Japanese version , CDMA2000 (USA ) etc.
Worldwide, 3G is designated as IMT-2000, too and the version developed in Europe is called
UMTS . Bringing into operation the first 3G systems took place in 2001 -2002 , therefore being in
their early evolution. 2G systems underlie the growth of the 3G. Thus, the GSM in the 2 and 2+
versions are gradually integrated in the 3G, with the UTRA development starting just from the

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GSM interface . Currently, the best possible compatibility among various 3G systems is
attempted.

The Fourth Generation (4G) is a huge difference as compared to the 3G . Speed increases
from 7.2 Mbps or 21.3 Mbps in large cities to 100 and even 300 Mbps. Lagging decreases
significantly, namely connections are faster and servers respond to requests immediately. Pages
load faster, whether one transfers 2 kB or 2 MB.
800, 900, 180 0, 2100 and 2600 MHz bands are generic names. They are like a brand. Nobody
emits exactly only on 2600 MHz, but each operator has some channels that may be somewhere
between 10 and 30 MHz around 2600 MHz. For example, in Germany the 2600 MHz band
actually refers to the 2500 -2690 MHz band where the networks of four different operators work.
In Romania, channels in these generic bands have been acquired. The blocks acquired by the
phone operators in Romania had 10 Mhz band width in the 800 band, 12.5 MHz in t he 900, two
of 10, 15 and 30 in the 1800 Mhz and so on. Not significant to users, but only counting for
operators, as that has some impact according to how busy the network may be at one point.

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Peculiarities of 4G network

4G is a marketing term used by service providers to describe the “fourth generation” of wireless
services. More precisely, technology offers speeds of four to ten times higher than those offered
by 3G networks.
There are two main technologies that underlie the 4G: WiMax and Long Term Evolution (LTE).
WiMax is a standard developed by the IEEE (Institute of Electrical and Electronics Engineers).
The development of the LTE standard is the responsibility of the 3GPP, an industry supporting
the providers that use GSM, the current tech nology for cell communication. Both WiMax and
LTE rely on advanced antenna technologies for improving signal reception and performance,
based on different types of wireless spectrum.
The main feature of the 4G is the user control in terms of the services t hey can manage according
to the service packet they have subscribed for. The user has the freedom to select the desired
service, with a desired quality index, at an affordable price, anywhere and anytime.

Features:

 Transmission techniques on a physica l layer are the following :

– MIMO: To achieve ultra high spectral efficiency via spatial processing , including MIMO
multi -antennas and multi -users;
– Frequency -domain -equalization to module the multi -carrier (OFDM) in the downlink or a
single transport operator called single -carrier frequency (SC -FDE) in the uplink: in order
to operate the frequency of a selected channel without a complex equalization;
– Static multiplexing frequency domain state, for example OFDMA or FDMA in the
uplink : the bit rate is variable by assigning different sub-channels for different users in
terms of the functions in the respective channel ;
– Turbo principle of error -correcting codes : to minimize the SNR needed in the reception ;

 Channel -dependent scheduling: to allow the use of time varying channels;

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 Network adjustment: adaptive modulation and error correction nodes ;
 Mobile IP used for mobility;
 Femtocells based on IP ( home nodes connected to Internet broadband infrastructure ).

IMT -Advanced regulations

4G networks must comply with IMT -Advanced regulations (International Mobile
Telecommunications Advanced):

– They must have a peak data rate of about 100 Mbit/s for mobility;
– They must use and share the dynamic resources of the network to support multiple simultaneous
users per cell;
– 5-20 MHz frequency bands (40 MHz optionally );
– Peak spectral efficiency of 15 bit/s/Hz in the downlink , 6.75 bit/s/Hz in the uplink (1 Gbit/s in
the downlink should be able to operate on a bandwidth of <67 MHz );
– Spectral efficiency of the system must be up to 3bit/s/Hz/ cell in the downlink and 2.25 bit/s/Hz/
the one inside a room.

In the Summit on International Telecommunication Union ( ITU) when the 4G technology was
officially proposed/released , two technological standards underlying it were shown : standardized
LTE Advanced of 3GPP and IEEE standardized of 802.16m.

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IPv6 support
Unlike the 3G which is based on two parallel infrastructures consisting of switched circuits , the
4G relies only on packet switching . This requires data transmission with low l agging . In the
context of 4G networks , IPv6 is essential to bear a large number of wireless devices . By
increasing the number of available IP addresses , IPv6 removes the need for Network Address
Translation ( NAT), a method of distributing a limited number of addresses from a larger group
of devices.

4G Network coding and interfe rence approach
In 4G networks , in theory, the DPC -Dirty Paper Coding is used . The results of such coding apply
to a channel subject to interferences only if the interferences are known to the transmitter :
R=s+i+n,
where s is the signal information, i refers to interferences, and n is noise.
The capacity that can be achieved when such type of coding is used is log2 (1+Ps/Pn), namely
the same capacity as if interferences were not present. Not to be mistaken for the pre -cancellation
of interferences .
DPC -Dirty Paper Coding uses the following operating principle : it selects a codebook (a set of
words transmitted ) according to the interference.

Attenuation of 4G network signals

Attenuating sig nals in 4G networks is mainly directly proportional to the square of the operation
frequency . For example, if the transmission frequency doubles , 4 times more signal is lost .
However, a low frequency allows the penetration of materials that normally attenuate a signal ,
thus, inside a modern concrete building a low frequency signal is preferred in order to reach a
proper coverage.

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Global plan of 4G network implementation

As far as the global plan of 4G network implementation is concerned, GSMA Intelligence
predicts that the number of 4G -LTE connections in the world will exceed one billion by 2017.
By 2017, it is expected that LTE will be one of the 8 connections of more than 8 billion in total
projected for that time. In the end of 2013, LTE accounted for ap proximately 176 million
connections . Almost 500 LTE networks will be in operation in about 128 countries , nearly
double the number of functional LTE networks at the moment.

How fast is 4G network as compared to its predecessor, 3G network?

3G network ( or the “Third Generation”) is a standard released in Japan in 2001. In mid 2010,
most networks in the United States were 3G. This standard was a significant improvement over
its predecessor , the 2G, providing much higher rates for data transfers. Yet, the difference
between 4G and 3G is weakly emphasized for now. In order to illustrate the difference, analysts
use a parallel with standard television vs. HD television.
3G 4G
Amount of transferred data Up to 3.1 Mbps with an
average speed between 0.5
and 1.5 Mbps Currently between 2 and 12 Mbps
(Telstra network in Austria bears
speeds of up to 40 Mbps), but
with an estimated potential of
100 to 300 Mbps
Maximum upload rate 5 Mbps 500 Mbps
Maximum download rate 100 Mbps 1 Gbps
Transfer mode Packet shift Shift of packets/messages
Network architecture Wide cell areas Integration with WLAN and
WAN
Services and applications CDMA 2000, UMTS, EDGE Winmax2 and LTE -Advance
Forward Error
Correction(FEC) Use of Turbo codes Concatenated codes for error
correction
Frequency band 1.8-2.5 GHz 2-8 GHz

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Comparison of 1G, 2G, 2.5G, 3G standards:

Generation Definition Speed Technology Period
of time Specifications
1G Analogue 14.4 Kbps
(peak) AMPS,NMT,TACS 1970 –
1980 Wireless phones
during the 1G period
were used only for
voice
communications.
2G Digital
Narrow band
circuit data 9.6/14.4
Kbps TDMA,CDMA 1990 to
2000 Multiplexing helps
reach 2G performance
and multiple users can
access the same
channel . Phones begin
to be used for data
traffic.
2.5G Packet Data 171.2
Kbps(peak)
GPRS 2001 –
2004 The Internet becomes
popular during this
standard, so data
traffic becomes
important, too .
Multimedia services
and streaming start to
show their existence. 20-40
Kbps

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3G Digital
Broadband
Packet Data 3.1 Mbps
(peak) CDMA 2000
2004 –
2005 3G provides much
more advanced
multimedia support
and streaming . In 3G,
universal access and
portability on several
types of devices are
an important
advantage . 500-700
Kbps (1xRTT, EVDO)
UMTS, EDGE
3.5G Packet Data 14.4 Mbps
(peak) HSPA 2006 –
2010 3.5G bears higher
speeds in order to
meet users’ demands.
1-3 Mbps
4G Digital
Broadband
Packet 100-300
Mbps
(peak) WiMax

now 4G speeds are much
higher to meet the
demand for data
transfer of various
services . They bear
HD streaming . New
smartphones emerge.
Portability in 4G has
increased. World -wide
roaming becomes
more affordable. All IP 3-5 Mbps LTE
Very high
throughput 100 Mbps
(Wi-Fi) Wi-Fi

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Comparison: 3G vs . 4G

Both the 3G network and its p redecessor, the 2G, have been designed primarily for voice and
secondly for data traffic . The 4G standard is primarily meant for data traffic, providing users
with faster access via portable devices . For example , video streaming works much faster and has
a much higher resolution via a 4G network . Similarly, video conferencing and online games
work with much better transfer rates via 4G data transmission.
In everyday life, the speeds experienced by users depend on much more factors than the 3G or
4G transmission protocol . This protocol refers to the communication between the device and the
antenna to get the signal from, so practically it is just one piece of the communication puzzle .
Data transfer speeds are mostly influenced by factors such as :
 The number of GSM towers nearby
 How many users use those towers simultaneously
 The bandwidth provided by those towers to connect to the Internet or to a telephone operator
network .
3G is at present the most reliable connection method when it comes to mobile phones . 4G is the
successor of the 3G standard , with the differences between the two standards’ archit ectures
shown in the pictures below :

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The main difference between 3G and 4G is abandoning the switching of circuits once the new
technology has been adopted . 3G technology uses a hybrid pattern of circuit switching and
packet change . Circuit switching is an old technique used in the telephone system for a long
time. The disadvantage of this technology is the following: resources are blocked while the
connection is active. The exchange of packets is a common technology in computer networks
and now it ha s been introduced in the mobile phone along with the 4G standard . Via this
technology , resources are locked while something is transmitted with their help . The
effectiveness of such a method allows the 4G providing company to carry multiple conversations
among various devices on the same bandwidth . Thus, the 4G standard no longer uses circuit
switching , not even for audio or video calls. All information is transferred in the form of packets.
3G technology is currently used to a large extent, whereas the 4G begins to show its presence.
An important aspect as the difference between the two is the technologies that the two standards
are compatible with. Although many companies haste to announce that their networks are the 4G
type, in reality they do not meet the standard itself. Here one refers to technologies such as LTE,
WiMax , UMB , often referred to as Pre-4G or3.9G standards.
The main reason that has caused this change is the same that has generated the need for evolution
from 2G to 3G and so on, namely t he users’ desire for increased speed and increasingly higher
data volume. The fact that physically speaking speed could not be increased further at this point
has generated a different approach : changing from circuit switching to packet transfer . One
should wait and see what the future holds , as one can only make suppositions on this issue .

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Main performance of 3G and 4G
3G (including 2G+) 4G
Key conditions underlying
architecture Voice transmission and data,
increasing emphasis on data Convergence of data and voice
transmissions over IP
Network architecture Cell based on large areas Hybrid integration of WLAN
and large area networks
Frequency band By country , in the
1800 -2400 MHz domain 2-8 GHz frequency bands and
even higher
Transmission speed Up to 2 Mbit/s , typically 384
Kbit/s
for mobile environment
20 – 100 Mbit/s for mobile
environment
RF channel bandwidth 5 – 20 MHz Of 100 MHz

Justifying the shift to 4G
Moving to 4G is a natural step , the same taken in the transition from 2.5G to 3G . The need for
higher speed and higher data volume has made researchers find a solution, by adapting the
mechanism used by PC’s, packet transmission, in mobile data transmission.

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REFERENCES:

 History of 4G networks and their predecessors:
o www.techradar.com
o Martin Sauter –“From GSM to LTE”

 GSM system architecture: http://www.go4it.ro/telefoane -mobile/retelele -gsm-pe-intelesul –
tuturor -3291414/

 Comparison 3G vs . 4G:
o www.diffen.com
o www.ripublication.com
o www.descopera.ro
o www.hit.ro

 How fast is 4G compared to 3G:
o www.pcmag.com
o www.teqlog.com

 Peculiarities of 4G network:
o www.cnet.com
o www.descopera.ro
o http://www.lteworld.org/