Lec-20_Cellular_Networksx

fearlessquickΚινητά – Ασύρματες Τεχνολογίες

12 Δεκ 2013 (πριν από 3 χρόνια και 8 μήνες)

73 εμφανίσεις

Cellular Networks

Presented by: Ashok Kumar J


Supervised by: Tamer Nadeem

CS 752/852


Wireless and Mobile Networking

Introducing 4G


What is 4G?


Why is 4G so popular?


Is 4G going to be the next world standard?


How fast is 4G growing?


Who currently uses 4G?


US wireless carriers
AT&T, Sprint, T
-
Mobile
and Verizon are
already using 4G

Discussion Topics

1G


First Generation Telecommunication System


No data transmission at all


2G


Second Generation Telecommunication System

Limited data transmission which increased in 2.5G


4G


Fourth Generation Telecommunication System

Completely out of the group


4G Underlying Technologies

Different implementations of 4G by different constituents


LTE and
WiMAX

LTE is being preferred over WIMAX


1G

3G


Third Generation Telecommunication System

Fairly High data transmission speeds


2G

3G

4G

Differences

LTE


Analog Telecommunication Standard


FDMA


Transmission
Technique


Hand
-
off and frequency reuse


No data transmission only voice
transmission


First
commercially automated cellular network in
1979


Standards: AMPS, NMT, TACS, JTACS, C
-
450, Radiocom 2000 and RMTI

Drawbacks


Poor security due to lack of encryption



Many different standards being used in
different places


Limitation
on the number of calls that
could be made
simultaneously



1G


First Generation Mobile Telecommunication


Purely digital technology


TDMA, GSM, CDMA


operator technologies


Conversations
were digitally
encrypted


I
ntroduced
data services for mobile, starting with
SMS


Commercially
launched on the GSM
standard in Finland in 1991


Circuit
-
switched
data services (HSCSD
)


Greatly reduced fraud and discouraged cloned handsets


Operates from 800/900 or 1800/1900 MHz and bandwidth of 2G is 30
-
200 KHz

Drawbacks


Weak digital signal may not be sufficient
especially in higher frequencies



Increased dropouts


Very slow data transmission



2G


Second Generation Mobile Telecommunication

2.5G


Packet
-
switched domain in addition to the circuit
-
switched
domain


GPRS: The
first major step in the evolution of GSM networks to
3G


GPRS provides data rates of 56
-
114
kbps


CDMA
used CDMA2000 1XRTT


CDMA data
speeds of up
to peak
153
kbps and generally up to 60

100
kbps


GPRS


A
llows 2G and
3G
mobile
networks to transmit IP packets to
the Internet


Integrated
part of the GSM network switching
subsystem


GPRS core network
in
GSM and
WCDMA provides


Mobility
management


Session
management


Transport for Internet Protocol packet
services


Billing based on volume of data and lawful
interception



2G Transitional


2.5G, 2.75G

EDGE (has many versions)


Standardized by 3GPP as part of the GSM family


Easy upgrade to GPRS and is backward compatible


Pre
-
3G radio technology and is part of ITU's 3G
definition


Can
be used for any packet switched application,
like Internet connection


Throughput up to 236.8kbps for 4 timeslots, 473.6kbps for 8


Widely
used (
441
GSM/EDGE networks in
184 countries)


Updates are still being released (latest version of EDGE… almost 3G)


2.75G


Digital broadband packet access


UTMS(WCDMA), CDMA2000 1xEV
-
DO


operator technologies


Voice
telephone, mobile
Internet,
video calls and mobile
TV

in
a
mobile.


Offers
greater security than
2G


Supports up to 3.1mbps peak but general speed is 500
-
700kbps


3G was relatively slow to be adopted
globally


Uses different frequency spectrum than 2G


Operates at 2100MHz and bandwidth of 15
-
20MHz


Drawbacks


No proper backward compatibility


Need to replace most broadcast towers


No formal definition


carriers used their own

technologies to

implement 3G network


Expensive Construction and
maintenance


3
G


Third Generation Mobile Telecommunication

3G
Transitional


3.5G, 3.75G,
3.9G

HSPA(has many versions)


Amalgamation
of two mobile telephony
protocols


Improves
the performance of existing
UTMS protocols


Fairly high peak data downlink rates up to 3.6/ 7.2/ 14.4 mbps


Fairly high peak data uplink rates up to 5.76mbps


General speeds are in between 1
-
3mbps


Reducing
the production cost per
bit


Over 200 operator in more than 80 countries


Easy update to
existing 3G
networks.


Preferred
over
WiMAX
, which requires a dedicated network
infrastructure



Comparison of Generations 1G, 2G, 3G, 4G.

Generation

Definition

Throughput

Technologies

1G

Analog

14.4 kbps
(peak)

AMPS,NMT,TACS

2G

Digital

(Narrow band

Circuit Data
)

9.6/14.4 kbps
(peak)

TDMA, GSM,

CDMA

2G

Transitional

Packet Data

114
/236.8 kbps
(peak)

20
-
40 kbps

HSCSD, GPRS, EDGE

3G

Digital

broadband
packet data

3.1 mbps

(peak)

500
-
700 kbps

UTMS,


CDMA2000 1XRTT

3G

Transitional


>2mbps

3.6/7.2/14.4

mbps
(peak)

1
-
3 mbps

HSPA,

CDMA2000 EV
-
DO

4G

Digital

broadband
packet based


All IP (VOIP)

100


300 mbps
(peak)

3
-
12 mbps

LTE Advanced

WiMax

Advanced

HSPA+


All IP based secured packet switched network


Voice also transmitted over IP


Supports IPv6


Access schemes


OFDMA, SC
-
FDMA, MC
-
CDMA


Supports up to 100mbps downlink and 50mbps uplink.


Using MIMO, speed can be increased.


Technologies


LTE,
WiMAX
, Wi
-
Fi metro, HSPA+.


No formal specification


Operators making their own choices.


Verizon, Sprint, ATT, T
-
Mobile are offering.

4
G


Fourth Generation Mobile Telecommunication

4G (
Continued
)

Ressource: http
://4gwirelessjobs.com/
lte_wimax.htm

4G (
Continued
)

Ressource: http
://4gwirelessjobs.com/
lte_wimax.htm

LTE A
dvanced

(E
-
UTRAN)


Proposed by 3GPP based
on
UMTS/
HSPA.


OFDMA for uplink and downlink



Can be constructed using existing
3G network.


Backward compatible.


Downlink up to 100mbps and
uplink up to 50mbps.


Natural upgrade to GSM/UMTS
networks, can be using by CDMA
networks also.


Proposed by IEEE based on
WiMAX



OFDMA for downlink and SC
-
FDMA
for uplink.


Requires completely different
network.


Backward compatible.


Bit rates up to 40mbps.


Can be used by any

network.

W
i
MAX

A
dvanced

4G Technologies

Resource:
www.itechdiary.com
/compared
-
wimax
-
versus
-
lte4g.html

Resource: http
://1001
-
tricks.blogspot.com/2010/12/lifehacker
-
explains
-
4g
-
technology.html


Increased downlink and uplink peak data rates.


Scalable
bandwidth and flexible bandwidth.


Improved spectral efficiency


All IP network


A standard’s based interface that can support a multitude of user types.


LTE networks are intended to bridge the functional
data
exchange


gap


between


very

high

data

rate


fixed
wireless


Local


Area


Networks

(LAN)

and very high mobility cellular networks
.



Long Term Evolution
-

Advanced

Questions?