Huawei WCDMA System Overview Course

7/25/2019 Huawei WCDMA System Overview Course

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WCDMA System Overview Internal use only

2014-10-28 HUAWEI Confidential Page1-1, Total12

Chapter 1 WCDMA System Overview

1.1 Development of Mobile Communications

Up till now the modern mobile communication has experienced two generations andevolved into the third generation that is ongoing with pre-commercialization. Manymanufacturers have already carried out their commercial trials in Europe and Asia.

The first generation is the analog cellular mobile communication network in the timeperiod from the middle of 1970s to the middle of 1980s. The most important

breakthrough in this period is the concept of cellular networks put forward by the BellLabs in the 1970s, as compared to the former mobile communication systems. Thecellular network system is based on cells to implement frequency reuse and thusgreatly enhances the system capacity.

The typical examples of the first generation mobile communication systems are theAMPS system and the later enhanced TACS of USA, the NMT and the NTT. The AMPS(Advanced Mobile Phone System) uses the 800 MHz band of the analog cellulartransmission system and it is widely applied in North America, South America andsome Circum-Pacific countries. The TACS (Total Access Communication System) usesthe 900 MHz band and includes two versions: ETACS (Enhanced TACS) in Europe andNTACS (Narrowband TACS) in Japan. It is widely applied in Britain, Japan and some

Asian countries.

The main feature of the first generation mobile communication systems is that they usethe frequency reuse technology, adopt analog modulation for voice signals and providean analog subscriber channel every other 30 kHz/25 kHz. However, their defects arealso obvious:

1) Low utilization of the frequency spectrum2) Limited types of services3) No high-speed data services

4) Poor confidentiality and high vulnerability to interception and numberembezzlement

5) High equipment cost

6) Large volume and big weight

To solve these fundamental technical defects of the analog systems, the digital mobile

communication technologies emerged and the second generation mobilecommunication systems represented by GSM and IS-95 came into being in the middleof 1980s. The typical examples of the second generation cellular mobilecommunication systems are the DAMPS of USA, the IS-95 and the European GSMsystem.

The GSM (Global System for Mobile Communications) is originated from Europe.Designed as the TDMA standard for mobile digital cellular communications, it supportsthe 64 kbps data rate and can interconnect with the ISDN. It uses the 900 MHz bandwhile the DCS1800 system uses the 1800 MHz band. The GSM system uses the FDDand TDMA modes and each carrier supports eight channels with the signal bandwidthof 200 kHz.


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The DAMPS (Digital Advanced Mobile Phone System) is also called the IS-54 (NorthAmerica Digital Cellular System). Using the 800 MHz bandwidth, it is the earlier of the

two North America digital cellular standards and specifies the use of the TDMA mode.The IS-95 standard is another digital cellular standard of North America. Using the 800MHz or 1900 MHz band, it specifies the use of the CDMA mode and has alreadybecome the first choice among the technologies of American PCS (PersonalCommunication System) networks.

Since the 2G mobile communication systems focus on the transmission of voice andlow-speed data services, the 2.5G mobile communication systems emerged in 1996 toaddress the medium-rate data transmission needs. These systems include GPRS andIS-95B.

The CDMA system has a very large capacity that is equivalent to ten or even twentytimes that of the analog systems. It also has good compatibility with the analog systems.

Currently some countries and regions such as USA, Korea and Hong Kong have putthe CDMA system into operation to provide services for subscribers. As thenarrowband CDMA technologies come into maturity at a time later than the GSMtechnologies, their application far lags behind the GSM ones and currently they haveonly found large-scale commercial applications in North America, Korea and China.The major services of mobile communications are currently still voice services andlow-speed data services. With the development of networks, data and multimediacommunications have also witnessed rapid development; therefore, the target of the3G mobile communication is to implement broadband multimedia communication.

The 3G mobile communication systems are a kind of communication system that canprovide multiple kinds of high quality multimedia services and implement globalseamless coverage and global roaming. They are compatible with the fixed networks

and can implement any kind of communication at any time and any place with portableterminals.

Put forward in 1985 by the ITU (International Telecommunication Union), the 3G mobilecommunication system was called the FPLMTS (Future Public Land MobileTelecommunication System) and was later renamed as IMT-2000 (International MobileTelecommunication-2000). The major systems include WCDMA, cdma2000 andUWC-136. On November 5, 1999, the 18

th conference of ITU-R TG8/1 passed the

Recommended Specification of Radio Interfaces of IMT-2000 and the TD-SCDMAtechnologies put forward by China were incorporated into the IMT-2000 CDMA TDDpart of the technical specification. This showed that the work of the TG8/1 in formulatingthe technical specifications of radio interfaces in 3G mobile communication systemshad basically come into an end and the development and application of the 3G mobilecommunication systems would enter a new and essential phase.

1.1.1 Standardization Organizations

The standardization of 3G mobile communication systems are in fact pushed forwardand implemented by two standardization organizations: 3GPP (3rd Generation PartnerProject) and 3GPP2.

Established in December 1998, the 3GPP is composed of the European ETSI, theJapanese ARIB, the Korean TTA and the American T1. It adopts the WCDMAtechnologies of Europe and Japan to construct a new radio access network andsmoothly evolves a core switching network from the existing GSM mobile switchingnetwork to provide more diversified services. The UTRA (Universal Terrestrial Radio

Access) is used as the radio interface standard.


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In January 1999, the 3GPP2 composed of the American TIA, the Japanese ARIB andthe Korean TTA also formally came into being. The cdma2000 and UWC-136

technologies are applied for radio access and the cdma2000 technologies adopt theQualcomm patents to a large extent. ANSI/IS-41 is used for the core network.

One formal member of the above two standardization organizations is the ChinaWireless Telecommunications Standard Group (CWTS) and two Chinese companies(Huawei and Datang) are two independent members of the 3GPP organization.

1.1.2 3G Evolution Policies

In general, the evolution policies formulated by 3GPP and 3GPP2 are progressive. Thishas the following benefits:

Guaranteeing the existing investment and operators benefits

Facilitating the smooth transition of the existing technologies

From the perspective of development, the process of evolution from the existing 2Gmobile communication systems to the IMT-2000 is a vital issue. It relates to the reuse ofthe existing networks (the construction of new networks should not be the optimalsolution) and the development of multiple 2G digital network systems towards the samestandard.

1. Policies of evolution from GSM to WCDMA

The policies of evolution from GSM to WCDMA should be as follows: The present GSM HSCSD (High Speed Circuit Switched Data at the rates from 14.4 kbps to 64 kbps) GPRS (General Packet Radio Service at the rate of 144 kbps) Smooth seamlessevolution from the network service coverage ultimately to IMT-2000 WCDMA (DS).

1) HSCSD: High Speed Circuit Switched Data

HSCSD is a feature to allocate multiple full-rate voice channels to the HSCSD structure.Its purpose is to provide the mixture of multiple services at different air interfacesubscriber rates with the single physical layer structure. Its benefits lie in the higherdata rates (up to 64 kbps; the maximum data rate depends on the manufacturers) and

the use of the existing GSM data technologies by slightly modifying the GSM system.

2) GPRS: General Packet Radio Service

The major benefits of GPRS are as follows:

Standard radio packet switching Internet/Intranet access applicable to all theplaces of GSM coverage

Variable peak data rate that ranges from several bits per second to 171.2 kbps

(the maximum data rate depends on the manufacturers)

Charging by the actual data volume: This charging method enables thesubscribers to pay the cost of the actual data volume transmitted while remainingonline all the days

Support for the existing services and new application services Packetization over the radio interfaces to optimize the sharing of radio resources Packet switching technology to optimize the sharing of network resources Capability of extension to the future radio protocols

Based on the existing GSM part, the packet switching GPRS network architecture hasthe new network function part:

3) WCDMA: Wideband Code Division Multi Access

The WCDMA has become a new mature technology aiming at the UMTS/IMT-2000. It

can satisfy all the requirements listed by the ITU to provide very effective high-speed


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data services and high quality voice and image services. In the process of evolutionfrom GSM to WCDMA, only the core network part is smoothly evolved. As the change

of the air interface is revolutionary, so is the evolution of the radio access network part.

2. Policies of evolution from IS-95 to cdma2000

After the IS-95A (at the rates of 9.6/14.4 kbps) is evolved to the IS-95B (at the rate of115.2 kbps) and ultimately to cdma2000 1X, the system can provide higher capacityand a higher data rate (144kbps) and can support the burst mode as well as addingnew supplemental channels. The cdma2000 1X EV with enhanced technologies canprovide higher performances.

The IS-95B is different from the IS-95A in that multiple channels can be bound in theIS-95B system. These two are basically the same in essence can they can coexist inthe same carrier. In contrast, the cdma2000 1X has greater improvements and its

system equipment can support 1X terminals and IS-95A/B terminals simultaneously.Therefore, these three systems (IS-95A/IS-95B/1X) can coexist in the same carrier. Forthe cdma2000 system, the gradual replacement method can be applied in the transitionfrom 2G systems to 3G systems. In other words, one carrier of the 2G systems can becompressed to become a 3G carrier to provide the services of medium and higher ratesto the subscribers. As the 3G systems have more and more subscribers, the number ofcarriers used in the 2G systems can be gradually reduced while more carriers can beadded to the 3G systems. Through this kind of smooth upgrading, the networkoperators can not only provide various latest serves to the subscribers but also wellprotect the investment of the existing equipment.

In the process of evolution to the 3G systems, the evolution of such wireless equipmentas BTS and BSC deserves special attention. The protection of operators investmenthas been fully taken into account in the formulation of the cdma2000 standard and

many radio indices of the 3G systems are the same as in the 2G systems. From thepoint of view of the BTS, the radio parts such as antenna, RF filters and poweramplifiers are all reusable while the baseband signal processing part needs to bereplaced.

There are currently two branches in the evolution to the cdma2000 1X EV: 1) Thecdma2000 1X EV-DO that only supports data services; and 2) the cdma2000 1X EV-DVthat supports both data services and voice services. For the cdma2000 1X EV-DO thatonly supports data services, the HDR put forward by Qualcomm has been determined;while for the cdma2000 1X EV-DV that supports both data services and voice services,there are several proposals at present (one of them is the LAS-CDMA technologysubmitted by China) and these are presently in the process of review.

3. Policies of evolution from DAMPS to UWC-136

The first step of evolution from IS-136 (DAMPS) to UWC-136 is to implement theGPRS-136 and the second step is to implement UWC-136 (Universal WirelessCommunications). The EDGE-based technologies have been decided for UWCC andTIA TR-45.3, this means that the GPRS network architecture will be used to support the136+ high-speed data transmission. The GPRS-136 is the official name of the 136+packet switched data service and its high-layer protocols (L3 protocols and above) arefully the same as those of the GPRS system, considering the economical aspect of theimplementation. It provides the same capacity as the GPRS of GSM and its subscriberscan have access to two forms of data networks: IP and X.25. Its major purpose is toreduce the technical difference between TIA/EIA-136 and GSM GPRS so that thesubscribers can roam between GPRS-136 and GSM GPRS networks. One of the

policies for the American TIA to develop the 3G systems is to implement convergence


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of the 3G systems with the GSM system that also uses the TDMA access mode. This isquite beneficial for the economics of global roaming and products and it also

implements the coordination protocol between UWCC and ETSI. Whats moreimportant, it enables the TDMA to player a more important role in the 3G systems.

1.2 Types and Differences of 3G Systems

1.2.1 Origin of the Multiple Systems

Currently the 3G research work of ITU is mainly undertaken by 3GPP and 3GPP2. Thegoal of ITU in terms of 3G is to establish the ITM-2000 family and implement globalroaming between different 3G systems.

Family concept

1) Network part

In one intermediate meeting of ITU-T SG11 in March 1997, the ITM-2000 FamilyConcept put forward in Europe was passed. This concept was based on the existingnetworks and involved at least two major standards: GSM MAP and IS-41.

2) Radio interface part

In the ITU-R TG8/1 meeting in September 1997, the discussion on the radio interfacefamily concept started. In a special meeting of TG8/1 in January 1998, the concept ofsuite was put forward and applied and this put the family concept out of use. Thismeans that there may be more than one radio interface standard but the concept ofmore than one standard is not yet accepted, rather, these different standards are

expected to ultimately form a unified standard.

The following two factors have caused various technical differences:

1) Relationship with 2G

The network part must be compatible with 2G, that is, the 3G networks are graduallyevolved from the 2G networks. There are two major 2G core networks: GSM MAP andIS-41.

Radio interfaces: The American IS-95 CDMA and IS-136 TDMA operators emphasizeon the backward compatibility (evolutional) while the European GSM and JapanesePDC operators emphasize on the backward incompatibility of the radio interface(revolutionary).

The correspondence between the core networks and the radio interfaces is shown inFigure 1-1 below:


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IS-41 core network

IS-136

UWC-136

IS-95 CDMA

cdma2000

PDC core network PDC

Core networks 2G/3Gaccess networks

GSM core network

GSM

W-CDMA

TD-SCDMA

Figure 1-1Correspondence between the core network and the radio access network interface

3) The important role of frequency spectrum on technical selection

In terms of frequency spectrum, the key issue is that the ITM-2000 frequenciesallocated by ITU have already been applied to the PCS service in USA. Because theUSA requires the sharing of frequency spectrum with 2G systems, the backwardcompatibility of the radio interfaces is especially emphasized and technically the USArequires gradual evolution. In contrast, most of the other countries have new IMT-2000frequency bands that feature very large flexibility. Whats more, the intellectual propertyrights play a very significant role, for example, Qualcomm has its own patentdeclaration. Competition is also a major factor to contribute to the technical differences.

1.2.2 RTT Technical Proposal

The eighth research group of ITU-R, i.e. the TG8/1 Task Group is responsible forpromoting the assessment and merge of IMT-2000 Radio Transmission Technology(RTT). Up till September 1998, there have been up to 16 RTT proposals including theMSS (Mobile Satellite Service). They all come from 16 RTT assessment groups ofIMT-2000 and are listed as follows:

1) UTRA WCDMA (Europe)

2) DECT (Europe)

3) cdma2000 (USA)4) UWC-136 (USA)5) WIMS WCDMA (USA)

6) WCDMA/NA (USA)

7) WCDMA (Japan)8) TD-SCDMA (China)

9) Global CDMA (Synchronous, Korea)


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10) Global CDMA (Asynchronous, Korea)

11) LEO satellite system SAT-CDMA

12) ESA wideband satellite system SW-CDMA13) CDMA/TDMA hybrid bandwidth satellite system SW-CTDMA

14) ICO RTT15) INMARSAT satellite system Horizons16) Iridium LLC satellite system INX

Among these proposals, the first ten are RTT proposals for the IMT-2000 terrestrialsystem and the last six reflect the efforts of incorporating the MSS (Mobile Satellite

Service) into the IMT-2000.

These proposals reflect the concern of many countries as to the future mode ofIMT-2000 and their basic wishes to exercise effective influence. However, as viewedfrom the market basis, backward compatibility and overall features, the UTRA WCDMAof ETSI and the cdma2000 of USA are the most competitive; therefore, the key to the

merge of RTT lies in the progress of effectively merging these two proposals.

1.2.3 Technical Merge

IMT-2000 includes both the Terrestrial Mobile Service (TMS) and the Mobile SatelliteService (MSS). The suggestion of one globally uniform and better-merged 3G mobilecommunication standard is conducive to whether operators, manufacturers,subscribers and policy planning & management bodies, so it is warmly welcomed by allcountries in the world.

As far the sixteen RTT candidate schemes are concerned, the ultimate result ofmerging terrestrial mobile communications will bring the biggest competitiveness to theWCDMA (DS) of ETSI and the cdma2000 of USA TIA in terms of the FDD mode; whilefor the TDD mode, the TD-CDMA put forward by ETSI UTRA and the D-SCDMA putforward by China CATT will be the major objects of further integration. At the end ofMarch 1999, Ericsson and Qualcomm reached a series of agreements on the IPR andthis act cleared way the obstacles from intellectual property rights for promoting aglobal CDMA standard. At the end of May 1999, the Operator Harmonization Group(OHG) composed of 31 global major operators and 11 major manufacturers put forwarda merge proposal of the IMT-2000. This proposal played a positive role in promoting theunification of the major parameters (chip rate, pilot structure, core network protocolbased on GSM-MAP and ANSI-41). All the participants unanimously agreed that thechip rate should be 3.84Mcps for FDD-DS-CDMA and 3.6864Mcps for FDD-MC-CDMA,which is also called FDD-cdma2000-(MC). In June 1999, the 17th meeting of TG8/1was held in Beijing. In this meeting, a framework agreement was reached on

Recommendations Rec, IMT and RSPC of the technical specifications of radiointerfaces. 3GPP, 3GPP2 and the Standards Development Organizations (SDOs) wereencouraged to support the above OHG proposal and TG8/1 Task Group was appointedto carry out more detailed work of the MSS proposal.

The 18th meeting of ITU TG8/1 was held in Helsinki, Finland in November 1999, andthe Recommended Specification of Radio Interfaces of IMT-2000 was adopted. Thismeant that the TG8/1's work in formulating the technical specifications of radiointerfaces in the 3G mobile communication systems had basically come to an end andthe development and application of 3G mobile communication systems would enter theessential phase. TD-SCDMA, WCDMA and cdma2000 were determined as theultimate three technical systems.


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1.2.4 Comparison Among the Three Major Technical Systems

1. WCDMA

Formulated by the European standardization organization 3GPP, WCDMA is widelysupported by the global standardization organizations, equipment manufacturers,component suppliers and operators. It will become one of the mainstream future 3Gsystems.

The core network evolves on the basis of and can thus be compatible with the existingGSM/GPRS networks.

It can be based on the TDM, ATM and IP technologies to evolve towards the all-IPnetwork architecture.

Logically, the core network comprises two parts: The circuit domain and the packetdomain to complete the circuit-switched services and the packet-switched servicesrespectively.

Based on the ATM technology, the UTRAN uniformly processes voice and packetservices and evolves towards the IP network architecture.

MAP and GPRS tunneling technologies are the core of the mobility managementmechanism in the WCDMA system.

The air interface adopts the WCDMA technologies with the signal bandwidth of 5 MHzand the chip rate of 3.84 Mcps. It uses the AMR voice encoding scheme and supportsthe synchronous/asynchronous Node B operation mode. Besides, the following modesare applied in the WCDMA system: Uplink/downlink closed loop power control plus

outer loop power control; open loop (STTD & TSTD) and closed loop (FBTD) transmitdiversity; pilot-assisted coherent demodulation; convolutional coding and Turbo coding;QPSK modulation in both the uplink and the downlink.

2. cdma2000 system

The cdma2000 system is a 3G standard put forward on the basis of the IS-95 standard.Its standardization work is currently undertaken by 3GPP2.

Circuit Switched (CS) domain: Adapted from the 2G IS95 CDMA network, the circuitdomain has introduced a service platform based on the WIN infrastructure.

Packet Switched (PS) domain: A packet network based on the Mobile IP technology.

Radio Access Network (RAN): Based on the ATM switch platform, it provides abundantadaptation layer interfaces.

The air interface adopts the cdma2000 technologies and is compatible with the IS95.

The signal bandwidth is N1.25MHz (N = 1, 3, 6, 9, 12) and the chip rate is

N1.2288Mcps. It uses the 8K/13K QCELP or 8K EVRC voice coding mode and itsBTS needs to run in the GPS/GLONESS synchronous mode. The following modes areapplied in the cdma2000 system: Uplink/downlink closed loop power control plus outerloop power control; OTD and STS transmit diversion in the forward direction to improvethe anti-fading capacity of channels and the signal quality of the forward channels;pilot-assisted coherent modulation in the reverse direction to improve the demodulationperformance; convolutional coding and Turbo coding; BPSK in the uplink and QPSK inthe downlink.


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3. TD-SCDMA system

The TD-SCDMA standard is put forward by the Chinese Wireless TelecommunicationStandard (CWTS) Group and now it has been merged into the specifications related tothe WCDMA-TDD of 3GPP.

The core network evolves on the basis of and can thus be compatible with the existingGSM/GPRS networks.

It can be based on the TDM, ATM and IP technologies to evolve towards the all-IPnetwork architecture.

Logically, the core network comprises two parts: The circuit domain and the packetdomain to complete the circuit-switched services and the packet-switched services

respectively.

Based on the ATM technology, the UTRAN uniformly processes voice and packetservices and evolves towards the IP network architecture.

MAP and GPRS tunneling technologies are the core of the mobility managementmechanism in the WCDMA system.

The air interface adopts the TD-SCDMA mode.

The TD-SCDMA features 3S: Smart antenna, Synchronous CDMA and Software radio.

The key technologies used in TD-SCDMA include Intelligent Antenna + Joint Detection,Multi-slot CDMA + DS-CDMA, Synchronous CDMA, Channel Coding/Decoding andInterleaving (the same as in 3GPP) and Baton Handover.

A comparison of the above three systems is given in the table below.

Table 1-1Comparison among the three major technical systems

System

WCDMA cdma2000 TD-SCDMA

Using countries Europe and Japan USA and Korea China

Inheritance from

GSM Narrowband CDMA

GSM

Synchronous mode

Asynchronous/synchronous

Synchronous

Synchronous

Chip rate

3.84Mcps

N1.2288Mcps 1.28Mcps

Signal bandwidth

5MHz N1.25MHz 1.6MHz

Air interface

WCDMA cdma2000 compatible with IS-95

TD-SCDMA

Core network GSM MAP ANSI-41 GSM MAP

1.3 3G Frequency Spectrum

ITU has allocated 230 MHz frequency for the 3G mobile communication systemIMT-2000: 1885 MHz ~ 2025MHz in the uplink and 2110v~ 2200 MHz in the downlink.Of them, the frequency range of 1980 MHz ~ 2010 MHz (uplink) and that of 2170 MHz~ 2200 MHz (downlink) are used for mobile satellite services. As the uplink and thedownlink bands are asymmetrical, the use of dual-frequency FDD mode or thesingle-frequency TDD mode may be considered. This plan was passed in WRC92 andnew additional bands were approved on the basis of the WRC-92 in the WRC2000conference in the year 2000: 806 MHz ~ 960 MHz, 1710 MHz ~ 1885 MHz and 2500

MHz ~ 2690 MHz, as shown in Figure 1-2 below.


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1850 1900 1950 2000 2050 2100 2150 2200 2250

Reserve

IMT 2000GSM 1800 DECT MSS

MSSIMT 2000PHS MSSIMT 2000

IMT 2000

MSSIMT 2000IMT 2000

IMT 2000

MSSIMT 2000

MSS

A D B EF A B C MSS

MSS MSS

GSM 1800, PCS

D FEB BC

ITU identifications

Europe

China

Japan,Korea (w/o PHS)

North America

1700 1750 1800950 1000800 850 900

IMT 2000IMT 2000

GSM

Cellular

PDC

Cellular

P C SMSS

GSM

Previous IMT-2000 terrestrial bands

New IMT-2000 terrestrial bands

Figure 1-2Frequency spectrum allocation of WRC-2000

The European Union (EU) also attached great importance to 3G mobile communicationsystems and the European Telecommunications Standards Institute (ETSI) started theresearch work of 3G mobile communication standardization as early as over ten yearsago and it established a UMTS (Universal Mobile Telecommunication System) Forumthat was composed of operators, equipment manufacturers and telecommunicationmanagement organizations. In 1995, the technical proposal for frequency spectrumdivision was submitted formally to the ITU.

In Europe, the allocation of frequency spectrum is as follows: 1900 MHz ~ 1980MHz,2010 MHz ~ 2025MHz and 2110 MHz ~ 2170MHz, totaling 155 MHz.

The situation in North America is rather complex, as shown in Figure 1-2. The 1850MHz ~ 1990 MHz band among the 3G low bands has already allocated for PCS useand it has been divided into two 15 MHz and two 5 MHz bands. Since the PCS servicehas already occupied the frequency spectrum of IMT-2000, the uplink band of theadjusted IMT-2000 even needs to be shared together with the downlink band of PCS.This kind of arrange is not suitable for the high-transmit and low-receive configurationsof ordinary base stations.

In Japan, the frequency band of 1893.5 MHz ~ 1919.6 MHz has already been allocatedfor PHS use and the 3G bands totaling 135 MHz (2 60 MHz + 15 MHz) are stillavailable: 1920 MHz ~ 1980MHz, 2110 MHz ~ 2170 MHz, 2010 MHz ~ 2025 MHz). At

present, Japan is endeavoring to clear the conflicts with the frequencies for 3G mobilecommunications.

Korea has the same allocated frequency as in ITU Recommendations, i.e., 170 MHz.

The WCDMA FDD mode uses the following frequency spectrum (bands other thanthose specified by 3GPP may also be used): Uplink 1920 MHz ~ 1980 MHz anddownlink 2110 MHz ~ 2170 MHz. Each carrier frequency has the 5M band and theduplex spacing is 190 MHz. In America, the used frequency spectrum is 1850 MHz ~1910 MHz in the uplink and 1930 MHz ~ 1990 MHz in the downlink and the duplexspacing is 80 MHz.

The frequency spectrum used by the WCDMA TDD mode (including the high bit ratesand the low bit rates) is as follows (bands other than those specified by 3GPP may also

be used):


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1) Uplink 1900 ~ 1920MHz and 2010 ~ 2025MHz

2) America: Uplink 1850 MHz ~ 1910 MHz and downlink 1930 MHz ~ 1990 MHz.

3) America: 1910 MHz ~ 1930 MHz in both the uplink and the downlink

In special cases (such as the boundary area of two countries), the TDD mode and theFDD mode may coexist in the same frequency band and 3GPP TSG RAN WG4 iscurrently researching this situation.

There is only the FDD mode in the cdma2000 system and currently there are a total ofseven band classes, of which Band Class 6 is the 1920 MHz ~1980 MHz/2110 MHz ~2180 MHz band stipulated in IMT-2000.

In China, according to the present radio frequency division, mobile services, fixedservices and spatial services are using the 1700 MHz ~ 2300 MHz band, which iscurrently serving plenty of microwave communication systems and a certain number of

wireless location devices. In December 1996, the State Radio Regulatory Committee ofP. R. China re-planned and adjusted some terrestrial radio service frequencies of 2GHz to adapt to the needs of cellular mobile communication development and radioaccess. However, the frequency spectrum still conflicts with the 3G mobilecommunication systems, that is, the 1.9 MHz band for public cellular mobilecommunications and the radio access band have both taken up some of the IMT-2000bands.

Therefore, the 3G mobile communication systems have to share the limited frequencyresources with the existing radio communication systems. With the development oftechnologies and services, the planning and adjustment of IMT-2000 bands must bewell done to stimulate the operators, scientific research organizations/institutions,manufacturers and other bodies to actively develop the 3G mobile communication

systems, so as to meet both the short-term and the long-term frequency spectrumneeds in China mobile communication development.

The occupation of the IMT-2000 frequency spectrum in China is illustrated in thefollowing figure.

1850 1900 1950 2000 2050 2100 2150 2200 2250

ITU

1850 1900 1950 2000 2050 2100 2150 2200 2250

1880 MHz 1980 MHz

1885 MHz 2025 MHz

2010 MHz

IMT 2000

2170 MHz

IMT 2000

2110 M Hz 2170 M Hz

MSS MSS

China MSSMSS MSSFDDFDD

1920 MHz

TDD TDD

1850 1900 1950 2000 2050 2100 2150 2200 2250

ITU

1850 1900 1950 2000 2050 2100 2150 2200 2250

1880 MHz 1980 MHz

1885 MHz 2025 MHz

2010 MHz

IMT 2000

2170 MHz

IMT 2000

2110 M Hz 2170 M Hz

MSS MSS

China MSSMSS MSSFDDFDD

1920 MHz

TDD TDD

Figure 1-3Occupation of the IMT-2000 frequency spectrum in China


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The bands allocated for IMT-2000 in China are listed below:

1) Basic operating bands

FDD mode: 1920 MHz ~ 1980MHz/2110 MHz ~ 2170 MHz

TDD mode: 1880 MHz ~ 1920 MHz/2010 MHz ~ 2025 MHz

2) Supplementary operating bands

FDD mode: 1755 MHz ~ 1785 MHz/1850 MHz ~ 1880 MHz

TDD mode: 2300 MHz ~ 2400 MHz, shared together with the wireless location services;both are major services and the sharing standard is to be specially formulated.

3) Operating band for satellite mobile communication systems

1980 MHz ~ 2010 MHz/2170 MHz ~ 2200 MHz.


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WCDMA Services Internal use onlyl


Chapter 2 WCDMA Services

2.1 Overview

Compatible with abundant services and applications of GSM and GPRS, the WCDMAsystem has an open integrated service platform to provide a wide prospect for various3G services. This chapter introduces the categories and features of 3G services, andpresents several typical types of services and their implementation methods, so thatthe readers may gain a general understanding of 3G services.

2.1.1 Categories of 3G Services

Basic telecom services, including voice service, emergency call service and SMS.

Supplementary services, the same as the supplementary services defined inGSM.

Bearer services, including circuit bearer service and packet bearer service. Intelligent service, an intelligent network service based on CAMEL mechanism

inherited from the GSM system. Location services, services related to location information, such as charging by

area, mobile yellow page and emergency locating. Multimedia services, including circuit real-time multimedia service, packet

real-time multimedia service and non real-time store-and-transfer multimedia

message service.The above services are roughly classified. Actually these services may overlap. Forexample, charging by area is not only a location service, but also an intelligent service.

2.1.2 Features of 3G Services

3G (WCDMA) services are inherited from 2G (GSM) services. In a new architecture,new service capabilities are generated, and more service types are available. Servicecharacteristics vary greatly, so each service features differently. Generally, there arefeatures as follows:

The real-time services such as voice service generally have the QoS requirement. Compatible backward with all the services provided by GSM.

The concept of multimedia service is introduced.

2.2 Details of Typical 3G Services

2.2.1 CAMEL Phase 3 Intelligent Service

CAMEL Phase 2 is implemented in GSM, mainly providing the prepaid service. CAMELPhase 3 needs to be implemented in UMTS. Phase 2 supports services such as CS,USSD (Unstructured Supplementary Service Data), SS (Supplementary Service) andCF (Call Forwarding). On this base, Phase 3 has added support for GPRS, SMS, MM

and LCS (optional).


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Service category:

CAMEL control service of basic circuit switch calls: It implements authentication

and accounting of voice calls. CAMEL control service of GPRS: It implements authentication and accounting of

GPRS bearers. CAMEL control service of SMS: It implements authentication, accounting and

transfer of SMS. CAMEL control service of USSD.

CAMEL control service of mobility management.

CAMEL control service of location information.

2.2.2 Location Services

It is widely accepted in the industry that the LCS has a promising market and

commercial prospect. LCS has been commercialized in GSM and GPRS networks inChina and other countries. In the 3G field, because of improvement of locationprecision and application of the open system structure, LCS is very attractive. It maybecome one of the main killer services in 3G. There are the following types of LCS:

Public security service

In the United States, October 1, 2001 started the provisioning of the EnhancedEmergency Services. The FCC (Federal Communications Commission) stipulated thatwireless operators should provide an estimated value of longitude and latitude of thecaller. The precision should be within 125 meters (67% of the estimated value) or lowerthan the result by root mean square. Mainly driven by national laws, this kind of serviceis provided by operators for the public interest. It is available without users application.To operators, it is a non-profitable service but can promote operators image. And thisservice is an inevitable development result of mobile communication technologies.

Besides emergency calls, there is also vehicle rescues: If a vehicle is broken on theroad, a fault locating automatic report is available. If there is an accident, the detectiondevice will detect it and auto report the related information such as location of theaccident.

Location Based Charging

Specific user charging: Some location areas (LAs) can be set as discount areas. Inthese LAs, calling and answering will be discounted.

Close location charging: If the caller and the called are in the same LA or close LAs,they will get a discount.

Specific area charging: If one or both of the caller and called are in a specific location,

such as shopping area, a discount will be given. It is to encourage the user to enter thisarea.

Enhanced Call Routing (ECR)

The ECR enables users calls to be routed to the nearest service point according tothelocation. The user can implement corresponding tasks with specific access numbers.For example, the user can input 427 to have access to the nearest gas station. Thisservice is available for chain companies, such as Caltex and KFC. The companies canapply for specific access numbers or preferential access number that will be preferredfor access among the counterparts (such as gas stations). To bank services, the usercan get the latest bank information or ATM information through ECR.

Location Based Information Services


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Get the subscriberlocation information

Return the subscriberlocation information

The information about the nearbyrestaurant is returned and it can be in the

form of graphics or text

Query The nearby restaurant

Location Server

SP Web Server

PORTAL

Location Server

Radio network

SP Web Server

PORTAL

Figure 2-1Location Based Information Services

Figure 2-1 shows the location-based information service that enables the user to getthe specific location-based information. Following are examples of service applications:

City sightseeing: Providing direction navigation between touring sites, or indicatingtouring sites nearby, and finding the nearest hotel, bank, airport, bus station orrelaxation place.

Location-based content broadcast: It can deliver messages to users in a specific area.It is mainly used in advertisement services, for example, delivering advertisements tousers in or near a shopping center to attract customers. It can also filter users. Forexample, the administration of a port can deliver dispatch messages to the staff withinthe port area. In addition, activities schedules can also be delivered to tourists in thesightseeing area.

Mobile yellow page

Mobile yellow page is similar to ECR. It provides contact information of the nearest

service point according to users needs. For example, the customer can input an entryrestaurant or more conditions such as Chinese food and within 3 kilometers tosearch. The output result can be phone numbers or addresses.

Network Enhancing Services

This service is still yet to be defined. At present lawful interception service is available.Lawful interception is the ability to intercept Content of Communication (CC) andIntercept Related Information (IRI) of an MS by the 3G system for Law Enforcement

Agency (LEA). The mobile target can be local subscribers, or subscribers roaming fromother 3G systems, or roaming subscribers that can use the 3G system from othermobile networks, such as GSM subscribers.


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2.2.3 Multimedia Service

In 3G, distributed multimedia service is the first to be developed. With a little bandwidth,voice service is the first to be developed, especially with the wide use ofhigh-compression-ratio MP3. The first application of video service is unidirectionalvideo application based on low bit rate and small image MPEG4 mode, such as

real-time advertising service, or movie clips.

Details of service types:

Circuit real-time multimedia service: The implementation of multimedia service inthe circuit domain mainly uses H.324/M protocol.

Packet real-time multimedia service

Multimedia service in the packet domain is mainly implemented via the SIP protocol.The major applications include 384 Kbps Video On Demand (VOD) and mobile

teleconference. An example of VOD service is illustrated inFigure 2-2. Non real-time multimedia message service

This service is called MMS (Multimedia Message Service), a natural development ofSMS. Technically speaking, SMS delivers text format messages through signaling, onlyable to deliver or receive text-only messages with a capacity of a little bit more than onehundred bytes. MMS, with rich service supporting capabilities, can delivermulti-functional message containing text, images, video, audio and data.

Platform

PortalWAP GW

Huawei OSS

WIN- CDMA

GPRS/ WCDMA

GGSN

WWWserver

WSRAS server

Router

QuidwayQuidwayTMTM

S2402S2402

QuidwayQuidwayTMTM

S2402S2402

IntranetApplication

server DB

WS

Still one hour beforeboarding, so I can see a

movie with my 3G MS

Figure 2-2Example of VOD service


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2.2.4 Other Typical Services

1. PUSH Service

PUSH service is kind of push technology. It means the network side (mainly the websites) initially pushes messages to subscribers, such as weather broadcast, stockinformation, news, adverting service, traffic information and other customized

messages.

To the research and discussion of PUSH service, 3GPP proposes series ofimplementation schemes. These schemes include: PUSH service implemented byusing network-initiated PDP context activation process; PUSH service implemented byusing network-initiated PDP context activation process triggered by DNS query; PUSHservice implemented by using SMS; PUSH service implemented by using on line forever, PUSH service implemented based on the SIP protocol, and PUSH service using

the HTTP protocol.

2. PORTAL service

PORTAL service is a kind of service based on PUSH service.

When the user accesses the Internet, the network will push portal pages. To thenetwork operators, they can get advertising fees from the pages. To the subscribers,they can access the Internet in a foolproof way, and get public information such asweather, traffic and stock for free.

To enhance this service, mobile subscribers can click the page to select each ISP, oraccess an enterprise network without fussy inputs.

2.3 Brief Introduction to the Implementation ofTypical 3G Services

2.3.1 CAMEL Phase 3 Intelligent Service

To introduce the intelligent network into the mobile communication system, theEuropean Telecommunications Standards Institute (ETSI) defined CAMEL in GsmPhase 2+ in 1997 to provide subscribers with service consistency unrelated to thespecific service network. The CAMEL feature is not a supplementary service but anetwork feature. Even the subscriber is not in the HPLMN (Home public land mobile

network), the CAMEL feature can be a means of helping network operators provide thesubscriber with the specific service.

The network structure of CAMEL Phase3 is shown in Figure 2-3. Several functionentities are added into the GSM network: GsmSSF (Service Switching Function),GsmSRF (Specialized Resource Function) and GsmSCF (Service Control Function).CAP Phase3 protocol interface is employed between GsmSCF and GsmSSF, andbetween GsmSCF and GsmSRF. While an internal protocol interface is used betweenMSC and GsmSRF, the others use MAP Phase3 interfaces.

The equipment designed specially for GsmSCF implementation is called the SCP, forGsmSSF implementation the SSP, and for GsmSRF implementation the IP.


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HLR

GMSC

gsmSCF

MSC

Forwarded leg

MSIncoming line

Visited NetworkInterrogating Network

Home Network

gsmSSFVLR

Roaming leg

CAPCAP

MAP

MAP MAP

gsmSSF

gsmSRFHome/Interrogating/Visited Network

CAP

MO call - Outgoing leg(or Forwarding leg)

MAP

Figure 2-3Network structure of CAMEL Phase3

CAMEL mainly embodies the separation of switching and services. The fundamentalidea is as follows: The switch only implements the basic call connection function, butthe control of all intelligent services is implemented by another network layer, i.e., theintelligent network. Of them, the Service Switching Function (SSF) implements the

switching function, reports various events during the call to the Service ControlFunction (SCF) and possibly suspends the call, waiting for further instruction of SCF.The triggering points of these events are called the Detection Points (DPs). SCFimplements the service logic control function. The essential of the CAMEL mechanismis a control mechanism between SCF and SSF.

2.3.2 LCS

Figure 2-4 shows the network structure of LCS implementation. Here, whenMSC/SGSN supports LCS, new interfaces to various network entities are added: TheLg interface between MSC/SGSN and GMLC, the Lh interface between GMLC andHLR, and the Lc interface between GMLC and gsmSCF.


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UENode B

(LMU

Type B)

HLR

Gateway

MLC

External

LCS client

LeLg

Lg

Lh

Gateway

MLC

Other PLMN

LMU

Type A

Uu

IuIub

gsmSCF

Lc

CBC

Note 1)

IuBC

3G-

SGSN

3G-

MSC/VLR

RNCNode B

(LMU

Type B)

Iur

Iub

SRNC(SMLC

functio-

nality)

Figure 2-4Network structure of LCS

The functions of the LCS system are described as follows:

LCS Client

LCS Client is the source of sending location requests, and uses the location result toimplement related services based on location. There are four kinds of clients accordingto the LCS Client functions.

1) Value-added LCS Clients - Using LCS to support variousvalue-added services, they may include UEs or no specificUEs.

2) PLMN operator LCS Clients - Using LCS to enhance orsupport some tasks related to O&M, such as supplementaryservice, IN related service, bearer service andtelecommunication service.

3) Emergency services LCS Clients - Using LCS enhance thesupport of emergency calls from the subscribers.

4) Lawful Interception LCS Clients - Using LCS to implementvarious legal requests and acceptance services.

GMLC (Gateway Mobile Location Center)

GMLC is a gateway device in the network connecting to the external LCS Client. Aftergetting related location request messages through the Le interface, it is responsible forHLR addressing, and delivering the location requests to the SGSN through the Lginterface. GMLC is also responsible for delivering related location results to relatedLCS Clients, or convents the results into local coordinate information upon request.

MSC/SGSN/VLR

MSC/SGSN/VLR mainly implements the coding/decoding of related locationinformation, version negotiation and processing of related signaling protocolinformation. In addition, it provides interface functions of related signaling tracing,

maintenance and management. MSC/SGSN/VLR needs to implement the main


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processing and control of location procedure, and user privacy protection, and providescharging information according to the processing.

HLRHLR stores the subscription data related to LCS, and provides the MSC number of thelocated subscriber.

Target UE

The Target UE (also referred as MS) is a target mobile phone located. The networkneeds to locate the current or last location of the mobile subscriber according to thelocation request. Generally, the target MS is the object to be located. But for MO-LR(Mobile Originated-Location Request), the target MS is the MS that initiates the locationrequest.

RNC

In 3G networks, RNC implements the specific locating testing and calculation in LCS

implementation.

RNC

SGSN/SGSN Server

MSC/MSC Server

GMLC

HLR

LCS client

Lg

Lh

Le

RNC

Figure 2-5Example of LCS procedure

The external client requests the location information of a target UE/MS from GMLC (or

non real-time location information request).1) GMLC checks the ID of the client and the requested service,

and then gets UE/MS identification from the requestinformation.

2) GMLC delivers a message to HLR/HSS to query the addressof SGSN or MSC/MSC Server. Upon receipt of the neededaddress, GMLC will deliver a location request to SGSN.

3) If GMLC belongs to another PLMN, SGSN needs to checkwhether the LCS request is allowed. Then SGSN will checkwhether the request can be initiated according to thesubscription information of the target UE/MS. If any item fails,SGSN will directly return a failure response. If the check ispassed, the SGSN then delivers a location request to RAN.


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4) If RAN stores location information that meets therequirements of SGSN, it returns a location report to SGSN.Otherwise, RAN needs to initiate a special locationprocessing message with the used location method. RANreturns a location information report that SGSN hasestimated.

5) SGSN returns the estimated location information andacquisition time to GMLC.

6) GMLC returns the location information to the LCS Client.GMLC records the LCS Client CDR and the CDR of SGSNinter-network cooperation.

2.3.3 MMS Service

MMS can run in different types of networks. The terminals can be used in 2G and 3G

networks. The MMS Environment (MMSE) includes all necessary service units, such astransfer, storage and notification functions. These service units can be in one network,or in different networks.Figure 2-6 illustrates the structure of the MMS system.

MMS User Agent

MMS User Agent

Roaming MMS User Agent

2G Mobile

Network

A

3G Mobile

Network

A

Internet/IP

Network

Mobile

Network

B

Mailbox

Wired Email Client

User DB

Message Store

MMS Server

MMS Relay

(Profile/ hlr )

MMSE

Figure 2-6MMS system structure

NMS User Agent: As the MMS functional part of the user terminal equipment, it must beable to support the MMS capability.

MMS Server: As the core part, it receives, notifies, dispatches, sends and forwards themultimedia messages. Equivalent to a control center, it dispatches different services. Inone MMSE there may be multiple MMS Servers, e.g. MMS Server, E-Mail Server, SMSServer and FAX Server.

MMS Relay: Acting as a bridge between the MMS User Agent and the MMS Server, iteliminates the difference between different servers and between different networks.

MMS User DB: Composed of the MMS Subscription Database, the MMS ProfileDatabase and the HLR, it enables users to flexibly customize services as they wish.


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In terms of physical entities, the MMS Server, the MMS Relay and the MMS User DBcan be integrated to form a Multimedia Messaging Service Center (MMSC). In this way,the MMSC exists as an independent entity and can be directly superimposed on theexisting GPRS network.

In practice, different manufacturers may adopt different networking modes based ontheir own comprehension of the protocols. Next we will introduce a WAP-basednetworking mode in the GPRS network. In this mode, the WAP gateway is addedbetween the MMSC and the wireless network to implement the interconnectionbetween these two. Figure 2-7 lists the implementation flow of the multimedia

messaging service.

MSC/VLR/HLR

SMSC

GGSN1

SGSN1 SGSN2

BTS1

BSC1

BTS2

BSC2

GPRS backbone network

MMSC

WAP GW

Email

Server

SMTP

Arrow 1

IP network

Figure 2-7MMS service flow

1) The MS activates the MMS service and sends a message tothe MMSC via BTS, BSC, SGSN, GGSN and WAP Gatewayin turn.

2) The MMSC distributes the message according to theterminal type and sends a short message notification to theMS via the SMSC if the type of terminal is an MS.

3) Upon receipt of the notification, the called accesses theMMSC via the GPRS network and the WAP Gateway, so asto distribute the MMS short message.

4) If the subscriber does not get the message within thespecified time limit, the MMSC forwards the message to themailbox system.


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WCDMA System Structure Internal use only


Chapter 3 WCDMA System Structure

3.1 Overview

The UMTS (Universal Mobile Telecommunications System) is the third generationmobile telecommunication system by using the WCDMA air interface technology,usually called the WCDMA telecommunication system. It adopts a structure similar tothe second generation mobile telecommunication system, including the RAN (Radio

Access Network) and the CN (Core Network). The RAN is used to process all theradio-related functions, while the CN is used to process all voice calls and dataconnections within the UMTS system, and implements the function of external networkswitching and routing. Logically, the CN is divided into the CS (Circuit Switched)Domain and the PS (Packet Switched) Domain. UTRAN, CN and UE (User Equipment)together constitute the whole UMTS system, the structure of which is shown inFigure3-1.

3G PS

MSC VLR GMSC gsmSSF3G CS PSTN

SGSN,GGSN

UTRAN

Service applicationdomainHLR, SCP

AN 3G CN External networkUE

Internet

Figure 3-1UMTS system structure

From the point of view of the 3GPP R99 standard, the UE and the UTRAN (UMTSTerrestrial Radio Access Network) are composed of new protocols, and the design isbased on WCDMA radio technologies. However, the CN adopts the definition of

GSM/GPRS, so it not only can implement smooth transition of the network, but also canimplement global roaming at the initial phase of 3G network construction.

3.1.1 Composition of the UMTS Network System

The composition of the UMTS network is shown inFigure 3-2.


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Uu lu

USIM

ME

Cu

Node B

Node B

Node B

Node BRNC

RNC

lub lur

MSC/

VLR GMSC

SGSN GGSN

HLR

PLMN PSTN

ISDN,etc

INTERNET

External NetworksCNUTRANUE

Figure 3-2Composition of the UMTS network system

As shownFigure 3-2,the UMTS network system includes the following parts:

1. UE (User Equipment)

As the user terminal equipment, the UE exchanges data with network equipmentthrough the Uu interface, and provides such kinds of services within CS and PSdomains as common voice, data communication, mobile multi-media and Internetapplication (For example, E-mail, WWW browse and FTP).

UE includes the two parts below:

ME (Mobile Equipment): Providing application and services.

USIM (UMTS Subscriber Module): Providing subscriber identification.

2. UTRAN (UMTS Terrestrial Radio Access Network)

UTRAN is divided into Node B and RNC (Radio Network Controller).

Node B

Node B is the base station of the WCDMA system (i.e. radio transceiver), and itinterconnects with RNC via the standard Iub interface and processes the physical layerprotocols of the Uu interface. Its main functions include spreading/de-spreading,modulation/demodulation, channel coding/decoding, and conversion betweenbaseband signals and RF signals.

RNC (Radio Network Controller)

RNC (Radio Network Controller) implements such functions as connectionestablishment and release, handover, macro diversity and the management andcontrol of radio resources. The details are given as follows:

1) Provides the system information broadcast and system access control functions2) Provides such mobility management functions as handover and RNC transition

3) Provides radio resource management and control functions such as macrodiversity combination, power control and radio bearer allocation

3. CN (Core Network)

CN (Core Network) is responsible for connecting other networks as well ascommunicating and managing UEs. The core network equipment of different protocolversions in the WCDMA system differ. Generally, the R99 core network is divided into

the CS domain and the PS domain. The R4 core network is the same as the R99 core


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network, but in the R4 core network, the MSC function of R99 CS is implemented by thetwo separate entities: MSC Server and MGW. The R5 core network is the same as theR4 core network except that R5 has been added with an IP multi-media domain.

The R99 core network has the following function entities:

1) MSC/VLR

MSC/VLR is a functional node of the CS domain in the WCDMA core network. Itconnects with UTRAN via the Iu-CS interface, with external networks (such as PSTNand ISDN) via the PSTN/ISDN interface, with HLR/AUC via the C/D interface, withMSC/VLR, GMSC or SMC via the E interface, with SCP via the CAP interface, and withSGSN via the Gs interface. Its main functions are call control, mobility management,

authentication and ciphering of the CS domain.

2) GMSC

GMSC is the gateway node between the CS domain of the WCDMA mobile networkand external networks, and it is an optional functional node. It connects with external

networks (PSTN, ISDN and other PLMN) through the PSTN/ISDN interface, connectswith HLR through the C interface and connects with SCP through the CAP interface. Itimplements the routing function of incoming calls in the VMSC function andinter-network settlement function of such external networks as fixed networks.

3) SGSN

SGSN (Serving GPRS Support Node) is a functional node of the PS domain in theWCDMA core network. It connects with UTRAN through the Iu-PS interface, withGGSN through the Gn/Gp interface, with HLR/AUC through the Gr interface, withMSC/VLR through the Gs interface, with SCP through the CAP interface, with SMCthrough the Gd interface, with CG through the Ga interface and with SGSN interfacethrough the Gn/Gp interface. And its main functions are route forwarding, mobilitymanagement, authentication and ciphering of the PS domain.

4) GGSN

GGSN (Gateway GPRS Supporting Node) is a functional node of the PS domain in theWCDMA core network. It connects with SGSN through the Gn/Gp interface and withexternal data networks (Internet/Intranet) through the Gi interface. It provides therouting and encapsulation of data packets between the WCDMA mobile network andthe external data networks. Its major functions are to provide interfaces to external IPpacket networks. It needs to provide the gateway function for UE to access externalpacket networks. From the point of view of external networks, GGSN looks as if it werea router of all user IP networks in the addressable WCDMA mobile network, and itneeds to exchange routing information with external networks.

5) HLR

HLR (Home Location Register) is a functional node shared by the CS and PS domains

in the WCDMA core network. It connects with MSC/VLR or GMSC through the Cinterface, with SGSN through the Gr interface, and with GGSN through the Gc interface.

And its main functions are to store subscription information for subscribers, support

new services and provide the enhanced authentication function.

3.2 Basic Structure of UTRAN

The structure of UTRAN is shown inFigure 3-3:

UTRAN includes one or several Radio Network Subsystems (RNSs). A RNS iscomposed of one RNC and one or several Node Bs. The Iu interface is used betweenRNC and CN while the Iub interface is adopted between RNC and Node B. WithinUTRAN, RNCs connect with one another through the Iur interface. The Iur interface


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can connect RNCs via the direct physical connections among them or connect themthrough the transport network. RNC is used to allocate and control the radio resourcesof the connected or related Node B. However, Node B serves to convert the data flows

between the Iub interface and the Uu interface, and at the same time, it alsoparticipates in part of radio resource management.

RNS

RNC

RNS

RNC

CN

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub

PSCS

Figure 3-3UTRAN structure

3.2.1 System Interfaces

UTRAN has the following main interfaces:

1. Cu interface

The Cu interface is the electrical interface between the USIM card and ME, and itadopts the standard interface.

2. Uu interface

The Uu interface is the radio interface of WCDMA. UE accesses the fixed network ofthe UMTS system through the Uu interface, so we can say the Uu interface is the most

important open interface in the UMTS system.

3. Iur interface

The Iur interface is the interface connecting RNCs. It is specific to the UMTS system formobility management of UEs in RAN. For example, when different RNCs perform softhandover, all UE data are transmitted from the working RNC to the candidate RNCthrough the open standard Iur interface.

4. Iub interface

The Iub interface is an open standard interface connecting Node B and RNC. It allowsRNC to connect to NodeB from another equipment manufacturer.


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5. Iu interface

The Iu interface is the interface between UTRAN and CN. Similar to the A interface and

the Gb interface in the GSM system, it is also an open standard interface. It allowsdifferent vendors UTRAN and CN to connect together,and can be divided into the

Iu-CS interface and the Iu-PS interface.

3.2.2 Basic Protocol Structure of UTRAN Interfaces

The protocol structure of UTRAN interfaces is designed according to a universalprotocol model. The principle of design is that logically the layer and the plane shouldbe independent. If necessary, you can modify a part of the protocol structure withoutmodifying other parts, as shown inFigure 3-4.

ApplicationProtocol

DataStream(s)

ALCAP(s)

TransportNetwork

Layer

Physical Layer

SignallingBearer(s)

TransportUser

NetworkPlane

Control Plane User Plane

TransportUser

NetworkPlane

Transport NetworkControl Plane

RadioNetwork

Layer

SignallingBearer(s)

DataBearer(s)

Figure 3-4Universal protocol model of UTRAN interfaces

Horizontally, the protocol structure contains the radio network layer and the transportnetwork layer. All protocols related to UTRAN are contained in the radio network layer.The transport network layer is the standard transmission technique adopted by UTRAN,and it has nothing to do with the specific functions of UTRAN.

Vertically, it contains the control plane and the user plane.

The control plane contains application protocols (RANAP in the Iu interface, RNSAP inthe Iur interface and NBAP in the Iub interface) and signaling bearers to transmit theseapplication protocols. Application protocols are used to build the bearers to UEs (Forexample, radio access bearer in the Iu interface, radio links in the Iur and Iubinterfaces). These signaling bearers of these application protocols can be the same asor can differ from those of the Access Link Control Application Protocol (ALCAP), and

they are established through O&M.


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The user plane contains data flows and data bearers to carry these data flows. Allinformation (such as voice and data) received or sent by UEs is transmitted through theuser plane. The transport network control plane is located between the control plane

and the user plane, and it is just in the transport layer, so it does not contain anyinformation about the radio network control plane. It contains ALCAP and the signalingbearer required by ALCAP. ALCAP establishes the transport bearer for the user plane.By adopting the transport network control plane, the application protocolimplementation of the radio network plane can be independent from the techniqueselected for the data bearer of the user plane.

In the transport network, the transport bearer of the data plane in the user plane is builtin such a way: Application protocols in the control plane conduct signaling processingfirst, which triggers the establishment of data bearer in the data plane through ALCAP.However, not all types of data bearers should be established through ALCAP. Withoutsignaling processing of ALCAP, the transport network control plane is not needed, sothe pre-configured data bearer should be used instead. The signaling bearer of ALCAP

can be the same as or can differ from that of the application protocol. Usually, theALCAP signaling bearer is established through O&M operations.

The data bearer of the user plane and the signaling bearer of the application protocolboth belong to the user plane of the transport network. In real-time operations, the databearer of the transport network user plane is controlled directly by the transport networkcontrol plane. However, the control operation required for establishing the signalingbearer of the application protocol belongs to O&M operations.

In conclusion, UTRAN obeys the following principles:

1) The signaling plane is separated from the data plane.

2) UTRAN/CN functions are separate from the transport layer, that is, the radionetwork layer does not depend on the specific transmission technique.

3) Macro diversity (FDD Only) is processed totally by UTRAN.

4) The mobility management of RRC connections is processed totally by UTRAN.

3.2.3 Functions Implemented by UTRAN

1) Functions related to overall system access control

Admission control Congestion control system information broadcast2) Functions related to security and confidentiality Encryption/decryption of radio channels Protection of message integrity3) Functions related to mobility

Handover

SRNS relocation4) Functions related to radio resource management and control Radio resource configuration and operation Radio environment survey Macro diversity control (FDD) Connection and release of radio bearers (RB control) Allocation and cancellation of radio bearers Dynamic channel allocation (TDD) Radio protocol function RF power control RF power setting5) Timing advance setting (TDD)

6) Radio channel coding


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7) Radio channel decoding8) Channel coding control9) Initial (random) access detection and processing

10) CN distribution of NAS messages

3.2.4 RNC (Radio Network Controller)

RNC is used to control the radio resources of UTRAN. Usually, it connects with the CSdomain (MSC), the PS domain (SGSN) and the broadcast domain (BC, not indicated inthe figure) through the Iu interface. The RRC protocol between UE and UTRANterminates here. Logically, RNC corresponds to the Base Station Controller (BSC) inthe GSM network.

The RNC used to control Node B is called the Controlling Radio Network Controller(CRNC) of Node B, which is responsible for managing the radio resources of the cellunder its control.

If more than one RNS is used to connect a UE with UTRAN, all the relevant RNSs canbe divided into the following types:

Serving RNS (SRNS): Managing the radio connection between UE and UTRAN, Itcorresponds to the termination point of this UEs Iu interface (Uu interface). Allbasic radio resource management is implemented by SRNC in SRNS, for example,mapping the radio access bearer parameters to the parameters of transportchannels, cell handover and open loop power control. A UE connected withUTRAN should have one and only one SRNC.

Drift RNS (DRNS): Any RNS except the SRNS used by UE is called the DRNS. Itscorresponding RNC is DRNC. A subscriber can have none, one or severalDRNSs.

Usually, the actual RNC contains all functions of CRNC, SRNC and DRNC.

3.2.5 Node B

Node B is the base station (i.e. radio transceiver) of the WCDMA system, and itinterconnects with RNC through the standard Iub interface to process the physical layerprotocols of the Uu interface. Its main functions include: Spreading/de-spreading,modulation/demodulation, channel coding/decoding, and conversion betweenbaseband signals and RF signals. Meanwhile, it implements such radio resourcemanagement functions as inner loop power control. Logically, it corresponds to theBase Transceiver Station (BTS) in the GSM network.

3.3 Basic Structure of the Core Network

Logically, CN is divided into the circuit switched domain (CS domain), the packetswitched domain (PS domain) and the broadcast domain (BC domain). The CS domainequipment provides circuit service for subscribers, or provides the entities for relatedsignaling connections. Specifically, it covers the following entities: MSC, GMSC, VLRand IWF. The PS domain provides packet data services for subscribers, including thefollowing specific entities: SGSN and GGSN. Other equipment, for example, HLR (orHSS), AuC and EIR are shared by the CS domain and the PS domain.

The overall structure of the WCDMA network is defined in 3GPP TS 23.002.Now, thereare the following three versions:

R99

3GPP TS 23.002


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R4 3GPP TS 23.002

R5 3GPP TS 23.002

Note:

R means Release.

3GPP began to formulate 3G specifications at the end of 1998 and beginning of 1999.As scheduled, the R99 version would be completed at the end of 1999, but in fact it wasnot completed until March, 2000. After R99, the version was no longer named by theyear. At the same time, the functions of R2000 are implemented by the following twophases: R4 and R5. In principle, the R99 specification is a subset of the R4specification set. If R99 is added with new features, it will be upgraded to R4. Similarly,the R4 specification set is a subset of the R5 specification set. If R4 is added with newfeatures, it will be upgraded to R5.

For the above three versions, the specific equipment of the PS domain does notchange, but only their protocols are upgraded and optimized. The CS domain and GSMnetwork of the R99 version do not fundamentally change. In the R4 network, MSC asthe CS domain of the CN is divided into the MSC Server and the MGW, at the sametime, a SGW is added, and HLR can be replaced by HSS (not explicitly specified in thespecification). In the R5 network, the end-to-end VOIP is supported and the corenetwork adopts plentiful new function entities, which have thus changed the original callprocedures. With IMS (IP Multimedia Subsystem), the network can use HSS instead ofHLR.

3.3.1 Structure and Interfaces of the R99 Network

To guarantee the investment benefits of operators, the design of R99 network structurehas considered fully the 2G/3G compatibility, so as to support the smooth transition ofGSM/GPRS/3G. Therefore, the CS domain and the PS domain are parallel in the

network. The R99 core network includes the equipment such as MSC/VLR, IWF,

SGSN, GGSN, HLR/AuC and EIR. To support 3G services, the corresponding

interface protocols are added to some equipment and the original interface protocolsare improved.

Figure 3-5 shows the basic network structure of PLMN (including the CS domain andthe PS domain). All function entities in the figure can be regarded as independentphysical devices.


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BSS

BSC

RNS

RNC

CN

Node B Node B

A IuPS

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Bold lines indicate the interfaces to support user services while slim lines indicate the interfaces to support signaling

Figure 3-5Structure of the R99 network

In R99, the function entities of the CS domain include MSC, VLR and others. Accordingto the different connection modes, an operator can set MSC as GMSC, SM-GMSC orSM-IWMSC. To implement internetworking, IWF (usually working with MSC) isconfigured in the system.

Besides the above function entities, the specific function entities of the PS domaininclude SGSN and GGSN to provide packet data services for subscribers. HLR, AuCand EIR are the common devices shared by the CS domain and the PS domain.


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The main function entities of R99 include:

1) Mobile Switching Center (MSC)

MSC is specific to the CS domain to connect the radio systems (including BSS andRNS) and the fixed network. It implements all functions of CS calls, for example,controlling call proceeding, managing the communication services of MS within thisnetwork or other networks (PSTN/ISDN/PSPDN and other mobile networks), andproviding charging information.

2) Visitor Location Register (VLR)

VLR is also specific to the CS domain. It stores the information of the registeredsubscribers that enter the control area, so as to provide necessary data of callconnection of mobile subscribers. When an MS roams to a new VLR area, this VLR willinitiate the location registration procedure to HLR and get the necessary subscriberdata; however, when the MS leaves this control area, the subscriber data should bedeleted. Therefore, VLR can be regarded as a dynamic database.

A VLR can manage several MSCs, but usually in implementation, MSC and VLR arecombined.

3) Home Location Register (HLR)

HLR is a device shared by the CS domain and the PS domain, responsible formanaging the database system of mobile subscribers. PLMN can contain one or moreHLRs, and the detailed configuration mode is determined by subscriber quantity,system capacity and network structure. All mobile subscriber data of the home locationarea, for example, identity flags, location information and subscribed services, arestored in the HLR.

When a subscriber roams, HLR receives the new location information and requests theprevious VLR to delete all data of the subscriber. When a subscriber is called, HLR will

provide the routing information.4) Authentication Center (AuC)

AuC is a device shared by the CS domain and the PS domain to store the entity ofsubscriber authentication algorithm and ciphering key. AuC sends authentication andciphering data to VLR, MSC and SGSN through HLR, to ensure the legality andsecurity of communication. Each AuC associates with the corresponding HLR, and itcommunicates with others only through this HLR. Usually, AuC and HLR are combinedin the same physical entity.

5) Equipment Identification Register (EIR)

EIR is a device shared by the CS domain and the PS domain. It stores the InternationalMobile Equipment Identity (IMEI) of mobile devices used by the system. The mobiledevices are divided into three levels: white, gray and black, and they are stored in the

corresponding lists respectively. Nowadays, the EIR is not yet used in China.

A minimized EIR can only contain the smallest white list (the device is in the whitelevel).

6) Gateway MSC (GMSC)

SMSC is the specific device of CS domain. GMSC, As the interface between thesystem and other public communication networks, has the function of querying locationinformation. When an MS is called, if the network cannot be sure to which HLR thesubscriber belongs, it should query the HLR through GMSC, and then forwards the call

to the current registered MSC of the MS.

Specifically, operators can decide which MSCs (e.g. part of MSCs or all MSCs) can betaken as GMSCs,.

7) Serving GPRS Support Node (SGSN)


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SGSN is a piece of equipment specific to the PS domain, and it provides the connectionbetween CN and BSS/RNS of the radio access system. In CN, SGSN andGGSN/GMSC/HLR/EIR/SCP have the corresponding interfaces. SGSN implements

the mobility management and session management of packet data services. Itmanages the mobile and communication services of each MS within the mobilenetwork, and provides the charging information.

8) Gateway GPRS Supporting Node (GGSN)

GGSN is also a piece of equipment specific to the PS domain. As the interface betweenthe mobile communication system and other public data networks, it has the function ofquerying location information. When an MS is called, first the data is transmitted toGGSN, then GGSN queries the current location information from HLR and forwards thecall to the current registered SGSN. GGSN also provides the charging interface.

The interface protocols of the R99 core network are shown inTable 3-1.

Table 3-1Interface names and meanings of the R99 core network

Interface name Connection entity Signaling and protocol

A MSC-BSC BSSAP

Iu-CS MSC-RNS RANAP

B MSC-VLR

C MSC-HLR MAP

D VLR-HLR MAP

E MSC-MSC MAP

F MSC-EIR MAP

G VLR-VLR MAP

Gs MSC-SGSN BSSAP+

H HLR-AuC

MSC-PSTN/ISDN/PSPDN TUP/ISUPGa GSN-CG GTP'

Gb SGSN-BSC BSSGP

Gc GGSN-HLR MAP

Gd SGSN-SMS-GMSC/IWMSC MAP

Ge SGSN-SCP CAP

Gf SGSN-EIR MAP

Gi GGSN-PDN TCP/IP

Gp GSN-GSN (Inter PLMN) GTP

Gn GSN-GSN (Intra PLMN) GTP

Gr SGSN-HLR MAP

Iu-PS SGSN-RNC RANAP

3.3.2 Structure and Interface of the R4 Network

Figure 3-6 shows the basic network structure of the PLMN in R4 version. All functionentities in the figure can be regarded as independent physical devices. The standardsof Nb, Mc and Nc interfaces are included in 23.205 and 29 series of technicalspecifications.

In actual application, some functions may be combined into the same physical entity,such as MSC/VLR and HLR/AuC, to make some interfaces become internal interfaces.


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BSS

BSC

RNS

RNC

CN

ode B ode B

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Bold lines indicate the interfaces to support user services whi le slim lines indicate the interfaces to support signaling

Figure 3-6Structure of the R4 network

Note:

(G) MSC Server and MGW can be integrated into a single physical entity - (G) MSC.

In R4 version, the function entities (SGSN and GGSN) of the PS domain remainunchanged and so do the external interfaces. The function entities of the CS domainstill contain the following devices: MSC, VLR, HLR, AuC, EIR and so on, and theinterrelation between them does not change yet. To meet the development requirement


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of all-IP networks, the entities of the CS domain in R4 version have the followingchanges:

1. When necessary, the MSC can be divided into two different entities: MSC Server(for processing signaling only) and Circuit Switched Media Gateway (CS-MGW forprocessing subscriber data) to implement the MSC function together. Thecorresponding GMSC is also divided into GMSC Server and CS-MGW.

1) MSC Server

The MSC Server is composed of the call control module and the mobility controlmodule to process calls of the CS domain. It terminates and converts the user-networksignaling into the network-network signaling. It can also contain VLR to process service

data of mobile subscribers and the related CAMEL data.

The MSC Server can control part of call status about the connection control module ofthe CS-MGW media channel through interfaces

2) Circuit Switched Media Gateway (CS-MGW)

CS-MGW is the transmission termination point of PSTN/PLMN, and it connects withCN and UTRAN through the Iu interface. It may be the termination point of either thebearer channel from the CS network or the media flow from the packet network (suchas RTP flow in IP networks). On the Iu interface, CS-MGW can support mediaconversion, bearer control and payload processing (for example, multi-media digitalsignal codec, echo cancellation and conference bridge), and also can support differentIu options of CS services (based on AAL2/ATM or RTP/UDP/IP).

CS-MGW:

Connecting with MSC server and GMSC server to control resources Owning and using such resources as echo canceller Can be equipped with a multimedia digital signal codec

CS-MGW may have necessary resources to support UMTS/GSM transport media.Furthermore, it can require the H.248 tailor to support multimedia digital signal codecand framing protocol.

The bearer control module and payload processing capability of CS-MGW can be usedto support such mobility functions as SRNS reallocation/handover and locationservices. Nowadays, it is expected that the H.248 standard mechanism can be used tosupport these functions.

3) GMSC Server

The GMSC Server is composed of the call control module and the mobility controlmodule of GMSC.

2. HLR can be updated to become a Home Subscriber Server (HSS). For details,please refer to the R5 network introduction.

3. In R4, a new entity has been added: Signaling Gateway (SGW)

There are two kinds of singalling transport methods: TDM based tradictional SS7 andIP based siganlling transport network SIGTRAN.

A siganlling gateway is needed to convert the transport layer protocol (i.e. betweenSigtran SCTP/IP and SS7 MTP) when two equipments communicate using differentsignalling transport method. The SGW does not interpret the application layer (e.g.MAP, CAP, BICC, ISUP) messages but may have to interpret the underlying SCCP orSCTP layer to ensure proper routing of the signaling.

In R4 networks, some interface protocols are also added, as shown inTable 3-2.


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Table 3-2Names and meanings of external interfaces in R4 CN

Interface name Connection entity Signaling and protocol

A MSC-BSC BSSAPIu-CS MSC-RNS RANAP

B MSC-VLR

C MSC-HLR MAP

D VLR-HLR MAP

E MSC-MSC MAP

F MSC-EIR MAP

G VLR-VLR MAP

Gs MSC-SGSN BSSAP+

H HLR-AuC

MSC-PSTN/ISDN/PSPDN TUP/ISUP

Ga SGSN-CG GTP'

Gb SGSN-BSC BSSGP

Gc GGSN-HLR MAPGd SGSN-SM-GMSC/IWMSC MAP

Ge SGSN-SCP CAP

Gf SGSN-EIR MAP

Gi GGSN-PDN TCP/IP

Gp GSN-GSN (Inter PLMN) GTP

Gn GSN-GSN (Intra PLMN) GTP

Gr SGSN-HLR MAP

Iu-PS SGSN-RNC RANAP

Mc (G) MSC Server-CS-MGW H.248

Nc MSC Server-GMSC Server BICC/ ISUP/TUP

Nb CS-MGW-CS-MGW

Mh HSS-R-SGW


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3.3.3 Structure and Interface of the R5 Network

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