Sunday, December 6, 2015

Great 3G Basic Understanding

Here we just wan to showed you about 3G ( UMTS/WCMSA..HSDPA+ ) as below: 

To attain a general understanding of UMTS systems

GSM Evolution Towards UMTS
3g Standards
Code Division Multiple Access Technology
UMTS Network Elements and Architecture
UMTS Air Interface


** ** 
1st and 2nd Generation Cellular Systems Overview
3rd Generation Drivers and Standards
CDMA Mobile Technology Overview
UMTS Architecture Overview
UMTS Air Interface

People talk about mobile technology in terms of generations:
1st Generation or 1G
2nd Generation or 2G
2.5G
3rd Generation or 3G

*** 1st Generation 
1976+, though really the technology of the 1980’s
Analogue modulation
Frequency Division Multiple Access
Voice traffic only
No inter-network roaming possible
Insecure air interface
AMPS (Analogue Advanced Mobile Phone System)
North American Standard in cellular band (800MHz)
TACS (Total Access Communications System)
UK originated Standard based on AMPS in 900MHz band
NMT (Nordic Mobile Telephony System)
Scandinavian Standard in 450MHz and 900MHz bands
C-450
German Standard in 450MHz band
JTACS (Japanese Total Access Communications System)
Japanese Standard in 900MHz band

Macrocellular
High sites for coverage driven planning
Antennas above roof height
Frequency planning required
For networks with more cells than frequencies these must be planned
Large cell size
Order 30km
Handover
Mobile only ever connected to a single cell

*** 2nd Generation
1990’s
1st system to use Digital modulation
Voice and low rate circuit switched data
Same technology allows international roaming
Secure air interface
First networks in 1992
European developed standard, but with worldwide subscriber base
Different frequency bands
GSM450, GSM900, GSM1800, GSM1900
Largest 2nd Generation subscriber base
Frequency/Time Division Multiple Access

Macrocells and microcells
Capacity driven planning
Frequency planning required
Optional parameters requiring planning
Hierarchical Cell Structures
Frequency Hopping
Discontinuous Transmission
Power Control
Simple subscriber/traffic analysis
Capacity limited by number of TRX’s
Handover - yes
TDMA (D-AMPS)
North American TDMA/FDMA based standard based upon AMPS
Predominantly used in North and South America
ANSI-41 Core Network
Planning Similar to GSM

First networks in 1996
Derived from Qualcomm IS-95 air interface
Largely American subscriber base with some Asian networks
Code Division Multiple Access
The closest 2nd generation standard to many of the 3rd generation standards
ANSI-41 core network
Chip rate of 1.2288Mcps
Macrocells and microcells
Single Frequency
multiple frequencies for hotspots
Soft Handover (multiple connections between mobile and network)
Code Planning
Capacity Interference Limited

**** Who does IMT-2000 serve?

Integrating all the following users
fixed
cellular
cordless
professional mobile radio
paging
satellite
specialised (aeroplane, etc)



2002+
Digital modulation
Voice and high rate data
Multi technology roaming
Secure air interface
Standards
UMTS FDD (CDMA based)
UMTS TDD (CDMA based)
cdma2000 (CDMA based)
EDGE (TDMA based)


*** UMTS FDD
UMTS Frequency Division Duplexing Mode
Built onto enhanced GSM core network
Utilises:
QPSK modulation (Quadrature phase shift keying)
Multiple channel coding and bearer rates
Variable spreading factors and multi-code transmission
CDMA
FDD
Data up to rates of 2Mbps
UMTS Time Division Duplexing Mode
Built onto enhanced GSM core network
Utilises:
QPSK modulation
Multiple channel coding and bearer rates
CDMA
TDD
Data up to rates of 2Mbps
Will happen after UMTS FDD

*** CDMA 2000
Built onto ANSI - 41 core network
Utilises:
QPSK modulation
Multiple channel coding and bearer rates
CDMA
FDD
Multiple carriers on the downlink
allows compatibility with cdmaOne
Synchronous operation
Data up to rates of 2Mbps (typically less)






















































































































































































































































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