1. 3G System for Global Roaming

2. 3G System
The third generation (3G) cellular networks were developed with the aim of offering high speed data and multimedia connectivity to subscribers. The International Telecommunication Union (ITU) provides the standard known as, IMT-2000 (International Mobile Telecommmunications-2000 for 3G systems.
The aim of IMT-2000 is to harmonize worldwide 3G systems to provide Global Roaming.

3. A few technologies are able to fulfill the International Mobile Telecommunications (IMT-200) standards. The original members of the IMT-2000 family included the UMTS, CDMA2000, TD-CDMA, EDGE and DECT technologies.
Universal Mobile Telecommunications System (UMTS)
UMTS Terrestrial Radio Access (UTRA)
TD-SCDMA (Time Division-High Speed Circuit Switched Data)
EDGE (Enhanced Data Rates for GSM Evolution)
Digital Cordless Phones (DECT) like WiFi
TD-CDMA ↔ Time-division-Code division multiple access

4. Universal Wireless Communications, or UWC-136, is a proposed standard from the Universal Wireless Communication Consortium (UWCC)—a consortium of more than 85 telecommunications carriers and wireless product vendors—for a 3G (third-generation) wireless communication system.
UWC-136 is a pure Time Division Multiple Access (TDMA) technology that is designed to be backward compatible with the existing IS-136 TDMA digital cellular phone system defined by the ANSI-136 and IS-41 standards and still widely used in North America.

5. For IMT-2000 intended Data Rates Low 144 kbits/s satellite and rural outdoor, Medium 384 kbits/s urban outdoor, High 2048 kbits/s indoor and low range outdoor. The speed of the MS above 10 Kmph will loose data rate.

6. IMT-2000 Vision Common Spectrum worldwide (1.8-2.2GHz band)
Multiple radio environments (cellular, cordless, satellite, LANs)
Wide range of telecommunication services (voice, data, multimedia, Internet)
Global seamless roaming
Enhance security and performance
Integration of satellite and terrestrial system.

7. Evolution to 3G IS-95 GSM EDGE GPRS HSCSD IS-95B Cdma2000-1xRTT
IS-136 & PDC
GSM
EDGE
GPRS
HSCSD
IS-95B
Cdma2000-1xRTT
Cdma2000-1xEV,DV,DO
Cdma2000-3xRTT
W-CDMA
TD-SCDMA 2G 3G
2.5G
3GPP
3GPP2
(EV, DV, DO↔ Evolution, Data Voice, Data Optimized)
RTT ↔ Radio Transmission Technologies

8. GSM evolution to 3G HSCSD WCDMA GPRS EDGE
9.6kbps (one timeslot)
GSM Data
Also called CSD
General Packet Radio Services
Data rates up to ~ 115 kbps
Max: 8 timeslots used as any one time
Packet switched; resources not tied up all the time
GSM / GPRS core network re-used by WCDMA (3G)
GPRS
HSCSD
High Speed Circuit Switched Data
Dedicate up to 4 timeslots for data connection ~ 50 kbps
Good for real-time applications (better than GPRS)
Inefficient in a sense that ties up resources, even when nothing is sent
Not as popular as GPRS (many skipping HSCSD)
EDGE
Enhanced Data Rates for Global Evolution
Uses 8PSK modulation
3x improvement in data rate on short distances
Can fall back to GMSK for greater distances
Combine with GPRS (EGPRS) ~ 384 kbps
Can also be combined with HSCSD
WCDMA

9. 3G W-CDMA (UMTS)
Universal Mobile Telecommunications System (UMTS) is the generic name for 3G developed by the European Telecommunications Standards Institute (ETSI) based on the specifications of IMT-2000 developed by the International Telecommunications Union (ITU).
The technology is based on the GSM standard.
Developed and maintained by the 3GPP (3rd Generation Partnership Project ).
UMTS uses wideband code division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators.

10. Here user-information bits are spread over a wide bandwidth (much larger than the information signal bandwidth) by multiplying the user data with the spreading code. The chip (symbol rate) rate of the spreading sequence is 3.84 Mcps, which, in the WCDMA system deployment is used together with the 5 MHz carrier spacing.
The core network is Asynchronous Transfer Method (ATM) allows circuit switched transfer of data using packets. High speed data transfer – currently maximum 10 Gbps.

11. IPv6 Arguments are being pushed for the core network which would allow packets to be transferred directly from the internet to the device with no translation.
UMTS uses a pair of 5 MHz channels, one in the 1900 MHz range for uplink and one in the 2100 MHz range for downlink. The specific frequency bands originally defined by the UMTS standard are 1885–2025 MHz for uplink and 2110–2200 MHz for downlink.
Some of the key features include the support to two basic modes FDD and TDD, variable transmission rates, intercell asynchronous operation, adaptive power control, increased coverage and capacity, etc.

12. Scrambler Used for Data Encryption. Make call more secure.
Randomizes data. Prevents the transition of a long series of 1’s or 0’s

13. UMTS UMTS is the European vision of 3G.
UMTS is an upgrade from GSM via GPRS or EDGE.
The standardization work for UMTS is carried out by Third Generation Partnership Project (3GPP).
Data rates of UMTS are:
144 kbps for rural
384 kbps for urban outdoor
2048 kbps for indoor and low range outdoor
Virtual Home Environment (VHE)

14. UMTS System Architecture
A UMTS network consists of three interacting domains: Core Network (CN), UMTS Terrestrial Radio Access Network (UTRAN) and User Equipment (UE) or ME.
The 3G system terminal is called ‘‘UE’’ and it contains two separate parts: Mobile Equipment (ME) and the UMTS Service Identity Module (USIM). USIM contains member specific data and enables the authenticated entry of the subscriber into the network.

15. UMTS network architecture
GERAN: GSM EDGE Radio Access Network
The GERAN air interface is Um, whereas the UTRAN air interface is Uu
Radio Network Subsystem (RNS)
Radio Network Controllers (RNC)
Circuit switch domain
Packet switch domain
UMTS network architecture

16. This UMTS UE is capable of working in three modes: CS (circuit switched) mode, PS (packet switched) mode and CS/PS mode.
Serving GPRS Support Node (SGSN)
Gateway GPRS Support Node (GGSN)

17. Base Station is referred as Node-B and control equipment for Node-B's is called Radio Network Controller (RNC) as if the BSC of GSM.
The functions of Node-B are:
Air interface Transmission / Reception
Modulation / Demodulation
CDMA Physical Channel coding
Micro Diversity
Error Handing
Closed loop power control
The functions of RNC are: Radio Resource Control
Admission Control
Channel Allocation
Power Control Settings
Handover Control
Macro Diversity
Ciphering
Segmentation / Reassembly
Broadcast Signaling
Open Loop Power Control

18. Core Network (CN) :
The Core Network is divided in circuit switched and packet switched domains.
Some of the circuit switched elements are Mobile services Switching Centre (MSC), Visitor location register (VLR) and Gateway MSC.
Packet switched elements are Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). Some network elements, like EIR, HLR, VLR and AUC are shared by both domains.
To provide switching, routing and transit for user traffic. The basic CN architecture for UMTS is based on the GSM network with GPRS.

19. Serving GPRS Support Node (SGSN) interfaces the access network of MS and the Gateway GPRS Support Node (GGSN) connects UMTS core network with external packet network like Internet, X.25 or similar.
The Asynchronous Transfer Mode (ATM) is defined for UMTS core transmission. The ATM Adaptation Layer type 2 (AAL2) handles the circuit switched connection and the packet connection protocol AAL5 is designed for data delivery.

20. UMTS Network Architecture
Circuit Switch
Packet Switch
Replacing the existing GSM air interface is the final and most important step in the evolution of GSM to UMTS i.e. 3G. Recall that one of the criteria for a system to be IMT2000 compliant is that it implements an air interface standard defined by the ITU. In the case of UMTS, the communication over the air interface, or UMTS Terrestrial Radio Access (UTRA) as it is technically known, is achieved using W-CDMA and TD-CDMA. The access parts of the network, called the UMTS Terrestrial Radio Access Network (UTRAN), are based on ATM and it is here that the major changes in upgrading will occur, which of course will also be reflected on the handsets (figure 4).
There are four interfaces connecting the UTRAN internally or externally to other functional entities: Iu, Uu, Iub and Iur

22. Bodies Give Proposal for 3G
Two international bodies are established.
Third Generation Partnership Project (3GPP)
The Japanese standardization body ARIB (Association of Radio Industries and Business), Telecommunications Industry Association (TIA) of Korea, ESTI (European Telecommunication Standards Institute) of Europe proposed for WCDMA is based on DS-CDMA (direct sequence code division multiple access) technology.
Third Generation Partnership Project 2 (3GPP2),
A partnership consisting of five telecommunications standards bodies: CWTS in China, ARIB and TTC in Japan, TTA in Korea and TIA in North America proposed for CDMA-2000.

23. 3GPP North America T1 Europe ESTI China CWTS Japan ARIB/ TTC Korea TTA
T1→ANSI Committee
CWTS→ China Wireless Telecommunications Standard

24. 3GPP2 North America TIA China CWTS Japan ARIB/ TTC Korea TTA

25. 3G CDMA-2000
TIA of USA and TTA of Korea proposed 3G CDMA Code division multiple access 2000 is the natural evolution of IS-95 (cdmaOne).
It includes additional functionality that increases its spectral efficiency and data rate capability. CDMA (code division multiple access) is a mobile digital radio technology where channels are defined with codes (PN sequences).
CDMA permits many simultaneous transmitters on the same frequency channel.

26. CDMA2000 evolution to 3G IS-95B Uses multiple code channels
Data rates up to 64kbps
Many operators gone direct to 1xRTT
1xEV-DO
CDMA2000 1xEV-DO: (Evolution-Data Only)
1XEV-DO, also called 1XEV Phase One, is an enhancement that puts voice and data on separate channels in order to provide data delivery at 2.4 Mbps.
1xRTT
CDMA2000 1xRTT(Radio Transmission Technologies): single carrier RTT
First phase in CDMA2000 evolution
Easy co-existence with IS-95A air interface
Release 0 - max 144 kbps
Release A – max 384 kbps
Same core network as IS-95
CDMA IS-95A
IS-95A
14.4 kbps
Core network re-used in CDMA2000
1xEV-DV
CDMA2000
3xRTT
EV-DV, or 1XEV Phase Two promises data speeds ranging from 3 Mbps to 5 Mbps.
CDMA20003X evolution: speeds to 5Mbps (more than 3xRTT i.e. 3 times the standard 1.25 MHz )

27. Evolution to 3G – The Carrier’s Choice
Evolution of CDMA Networks
Evolution to 3G – The Carrier’s Choice
1995
1999
2000
2001
2002
Nearly Doubles Voice, 307k, RF backward compatible
Data only 2.4 Mbps
RF backward compatible
Voice, 14.4k
Voice, 64k
CDMA
CDMA2000 1x
IS-95A
CDMA2000 1xEV-DO
IS-95B
2003
2004

28. 3G TD-SCDMA
Time Division-Synchronous Code Division Multiple Access, or TD-SCDMA, is a 3G mobile telecommunications standard, being pursued in the People's Republic of China by the Chinese Academy of Telecommunications Technology (CATT).
This proposal was adopted by ITU as one of the 3G options in late TD-SCDMA is based on spread spectrum technology.

30. Three system parameters
Capacity
Coverage
Quality
Three system parameters coverage area of a cell, quality of voice and capacity of physical channel are interlinked. Enhancement of any parameter will degrade another two parameters. For example if coverage area of a cell is increased then delay difference of multipath propagation will also increase hence BER will be high. To keep the BER within tolerable range chip rate i.e. capacity of the channel has to be reduced or size of the cell must be lowered to reduce the delay difference of mulipath propagation.