zxur 9000 umts (v4.11.10) system description

ZXUR 9000 UMTSRadio Network Controller

System Description

Version: V4.11.10

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Revision History

Revision No. Revision Date Revision Reason

R1.0 2011-07-28 First edition

Serial Number: SJ-20110704093556-003

Publishing Date: 2011-07-28(R1.0)

ContentsAbout This Manual ......................................................................................... I

Chapter 1 UMTS Network Architecture .................................................... 1-11.1 UMTS R99 Network Architecture......................................................................... 1-1

1.2 UMTS R4 Network Architecture........................................................................... 1-3

1.3 Network Architecture of Other Versions................................................................ 1-3

Chapter 2 UMTS Network Element Functions ........................................ 2-12.1 Functions of Major Core Network Elements.......................................................... 2-1

2.1.1 MSC Functions ........................................................................................ 2-1

2.1.2 VLR Functions ......................................................................................... 2-1

2.1.3 GMSC Functions...................................................................................... 2-1

2.1.4 SGSN Functions ...................................................................................... 2-2

2.1.5 GGSN Functions ...................................................................................... 2-2

2.1.6 HLR Functions ......................................................................................... 2-2

2.1.7 AuC Functions ......................................................................................... 2-2

2.1.8 EIR Functions .......................................................................................... 2-2

2.1.9 MSC Server Functions.............................................................................. 2-3

2.1.10 GMSC Server Functions ......................................................................... 2-3

2.1.11 MGW Functions...................................................................................... 2-3

2.2 Functions of Major RAN Elements ....................................................................... 2-3

2.2.1 RNC Functions......................................................................................... 2-3

2.2.2 Node B Functions..................................................................................... 2-3

Chapter 3 Interfaces in the UMTS ............................................................. 3-13.1 System Interfaces .............................................................................................. 3-1

3.2 Functions of Major Interfaces .............................................................................. 3-4

3.2.1 Radio Access Network Internal Interfaces .................................................. 3-4

3.2.2 RAN-CN Interface .................................................................................... 3-4

3.2.3 Core Network Internal Interfaces ............................................................... 3-5

3.2.4 Air Interface ............................................................................................. 3-7

Figures............................................................................................................. I

Tables ............................................................................................................ III

Glossary .........................................................................................................V

I

About This ManualPurpose

This manual describes the network architecture of UMTS, major network elements andinterfaces, aiming to help readers get familiar with the UMTS network.

Intended Audience

l System engineersl Planning engineers

What Is in This Manual

Chapter Summary

Chapter 1, UMTS Network Architecture Describes basic network architecture of UMTS

R99 and UMTS R4.

Chapter 2, UMTS Network Element Functions Describes the functions of major network

elements in the UMTS.

Chapter 3, Interfaces in the UMTS Describes the functions of major interfaces in the

UMTS.

I

Chapter 1UMTS Network ArchitectureTable of Contents

UMTS R99 Network Architecture................................................................................1-1UMTS R4 Network Architecture..................................................................................1-3Network Architecture of Other Versions ......................................................................1-3

1.1 UMTS R99 Network ArchitectureThe UMTS network has evolved from the GSM network. The UMTS R99 inherits the corenetwork architecture of the GSM system. The R99 system differs from the GSM system inthe air interface technology, which brings in a new radio access network using WCDMA.

UMTS R99 Network Architecture is illustrated in Figure 1-1.

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SJ-20110704093556-003|2011-07-28(R1.0) ZTE Proprietary and Confidential

ZXUR 9000 UMTS System Description

Figure 1-1 UMTS R99 Network Architecture

The core network of UMTS R99 is divided into the circuit-switched (CS) domain and thepacket-switched (PS) domain. The CS domain has evolved from the GSM Phase2+ circuitcore network. The network elements in the CS domain include the Mobile SwitchingCener (MSC), the Visitor Location Register (VLR), the Gateway Mobile Switching Center(GMSC). The PS domain has evolved from the GPRS core network. The PS-domainnetwork elements include the Serving GPRS Support Node (SGSN) and the GatewayGPRS Support Node (GGSN). Other elements, including the Home Location Register(HLR), the Authentication Center (AuC), and the Equipment Identity Register (EIR) areelements shared by both the CS and PS domains. The network elements in the RadioAccess Network (RAN) include the Radio Network Controller (RNC) and the WCDMAbase station (Node B).

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Chapter 1 UMTS Network Architecture

1.2 UMTS R4 Network ArchitectureThe UMTS architecture has changed in the CS domain from R99 to R4. According to theidea to separate call control from bearer and bearer control, the network element (G)MSCin the R99 CS domain has evolved to two elements in the R4 stage, that is, the MediaGateway (MGW) and the (G)MSC Server. The MSC Server implements call control, andthe MGW implements control on the transmission resources. The UMTS R4 NetworkArchitecture is illustrated in Figure 1-2.

Figure 1-2 UMTS R4 Network Architecture

1.3 Network Architecture of Other VersionsThemajor changes in other evolved 3GPP versions of UMTS standards are shown in Table1-1. For details, you can refer to relevant standards.

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Table 1-1 Network Architecture of Other Versions

Version Radio AccessNetwork

Core Network(CS) Core Network(PS)

R5 Introduced HSDPA and

broad-band AMR.

No major changes Introduced IMS.

Introduced IPv6.

R6 Introduced HSUPA and

MBMS.

No major changes IMS stage two

R7 Introduced HSPA+.

Introduced OFDM and

MIMO.

Simplified the network

architecture.


architecture.

R8 Introduced LTE. Simplified the network

architecture.


architecture.

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Chapter 2UMTS Network ElementFunctionsTable of Contents

Functions of Major Core Network Elements................................................................2-1Functions of Major RAN Elements..............................................................................2-3

2.1 Functions of Major Core Network Elements

2.1.1 MSC FunctionsThe Mobile Switching Center (MSC) is the core of the CS-domain network. It providesswitching functions, and implements functions such as paging access, channel allocation,call connection, traffic control, charging, and base station management. The MSC alsoprovides interfaces for other function entities in the system and the elements in fixednetworks (PSTN, ISDN, PDN). MSC works along with other network elements to fulfillmultiple functions, including location registration, inter-cell handover, automatic roaming,validity check, and channel handover.

2.1.2 VLR FunctionsThe Visitor Location Register (VLR) serves the mobile subscribers in its control area bystoring the information of registered subscribers who is currently in the area and providingthese subscribers with necessary conditions for establishing call connections. The VLRobtains necessary data of a subscriber from the corresponding Home Location Register(HLR) and stores the data temporarily. After leaving the area controlled by the VLR,the subscriber registers in another VLR, and the previous VLR deletes the data of thesubscriber. Therefore, the VLR can be regarded as a dynamic database of subscriberinformation.

2.1.3 GMSC FunctionsThe Gateway MSC (GMSC) connects the CS domain of the core network with externalPSTN entities. The GMSC provides physical connections for the PSTN and the CSdomain, and requests for a roaming number from the HLR when a fixed-line subscribercalls a mobile subscriber.

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2.1.4 SGSN FunctionsThe Serving GPRS Support Node (SGSN) is the core of the PS-domain network. It tracesthe location of the Mobile Stations (MS), performs security authentication and accesscontrol, and works together with the GGSN in establishing, maintaining, and deleting PDPconnections. In the 2G system, the SGSN connects to the General Packet Radio ServiceBase Station Subsystem (GPRS BSS) via the Gb interface. In the 3G system, the SGSNconnects to the Radio Network Subsystem (RNS) via the Iu interface.

2.1.5 GGSN FunctionsThe Gateway GPRS Support Node (GGSN) provides an interface that connects the PSdomain of the Core Network (CN) with external packet data networks. The GGSN alsoprovides necessary inter-network security mechanisms, such as firewall. To perform apacket session, the User Equipment (UE) needs to establish a PDP context with theGGSN.The PDP acts as a channel connecting the UE with external networks.

2.1.6 HLR FunctionsThe Home Locatin Register (HLR) is the data center of the system. It stores theinformation of all mobile subscribers registered in it, including their location, servicedata, and account management information. The HLR also provides realtime queryand modification of the location information, and implements various services relatedto subscriber mobility management in the mobile communications network, includinglocation update, call processing, and supplementary authentication services.

One HLR can control several mobile switching areas. It stores all important static data ofmobile subscribers, including the International Mobile Subscriber Identity (IMSI), accesscapability, subscriber type, and supplementary service data. Besides, the HLR also storesthe dynamic data of the subscribers' roaming area and provides the data for the MSC.

2.1.7 AuC FunctionsThen Authentication Center (AuC) performs the security management in the system. Itstores the authentication information and ciphered keys to ensure the information securityof mobile subscribers, and to prevent unauthorized access.

2.1.8 EIR FunctionsThe Equipment Identity Register (EIR) stores the International Mobile Equipment Identity(IMEI) of mobile phones. The white list, black list, and grey list respectively contain theIMEI numbers of authorized mobile phones, monitored faulty User Equipment (UE), andforbidden stolen UEs. In this way, operators can take immediate preventive measuresagainst abnormal UEs to ensure the uniqueness and security of the UEs in the network.

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Chapter 2 UMTS Network Element Functions

2.1.9 MSC Server FunctionsThe MSC server provides call control and mobility control specified in the R99 protocols.It controls mobile-originated and mobile-terminated CS calls, receives user-networksignaling messages, and transfers such messages to network-network signalingmessages. The MSC server also stores the mobile subscribers' service data and thedata related to CAMEL, and manages the media channel connections in the MGW viainterfaces to control call states.

2.1.10 GMSC Server FunctionsThe MSC server provides call control and mobility control specified in the R99 protocols.

2.1.11 MGW FunctionsThe Media Gateway (MGW) terminates the transmission in the PSTN/PLMN network.The MGW connects to the UTRAN via the Iu interface. The MGW can receive boththe bearer channel from the circuit-switched (CS) network and the media flow from thepacket-switched (PS) network. The MGW supports media conversion, bearer control,and payload processing at different Iu interfaces for CS services.

2.2 Functions of Major RAN Elements

2.2.1 RNC FunctionsRNC is the control center for the whole radio access network. It performs controlmanagement of radio resources.

l The RNC controls the access control, handover control, channel allocation, andestablishment of signaling connections for the calls of the UE. Besides, the RNC alsoforwards data and signaling between the UE and the core network.

l The RNC manages the physical-layer resources by controlling the Node B. The RNCalso performs data transmission with the Node B via the user plane of the Iub interface.

l The RNC communicates with another RNC over the Iur interface to transmit data,such as signaling and soft handover data.

l The RNC processes the paging messages from the core network, and sends differenttypes of paging messages to the UE according to the RRC state of the UE.

l The RNC connects to and communicates with the Operation and Maintenance Center(OMC) of the access network. The Node B communicates with the OMC via the RNC.

2.2.2 Node B FunctionsThe main function of the Node B is to manage physical-layer resources. The Node Bimplements the physical-layer functions of the air interfaces, such as channel coding,interleaving, rate adaptation, and spreading. The Node B also processes signalingprocedures with the RNC. The RNC controls the Node B to allocate and modify the

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common physical channel resources in a cell. The RNC can also control the Node B toallocate, modify, and delete the physical-layer resources for subscribers.

The Node B also performs physical-layer procedures for the UE, such as the randomaccess indication and the inner loop power control for the dedicated physical channel.

Moreover, the Node B sends data reports required by the RNC, providing the input dataRNC needs to perform radio resource management.

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Chapter 3Interfaces in the UMTSTable of Contents

System Interfaces ......................................................................................................3-1Functions of Major Interfaces .....................................................................................3-4

3.1 System InterfacesThe interfaces between different network elements are shown in Figure 3-1.

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Figure 3-1 System Interfaces

Note:

The bold lines indicate data bearer, and the thin lines indicate signaling bearer.

Table 3-1 lists the major interfaces, connection entities, and bearer modes involved inFigure 3-1.

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Chapter 3 Interfaces in the UMTS

Table 3-1 Description of Major System Interfaces

Interface Connection Entity Signaling andProtocol

Bearer Mode

A MSC-BSC BSSAP ATM/TDM/IP

B MSC-VLR Internal Protocols Internal Protocols

C MSC-HLR MAP ATM/TDM/IP

D VLR-HLR MAP ATM/TDM/IP

E MSC-MSC MAP ATM/TDM/IP

F MSC-VLR MAP ATM/TDM/IP

G VLR-VLR MAP ATM/TDM/IP

Gb SGSN-BSC BSSGP ATM/TDM/IP

Gc GGSN-HLR MAP ATM/TDM/IP

Gd SGSN—SMS-

GMSC/IWMSC

MAP ATM/TDM/IP

Gf SGSN-EIR MAP ATM/TDM/IP

Gi GGSN-External Data

Network

TCP/IP IP

Gn SGSN-GGSN

(intra-PLMN)

GTP IP

Gp SGSN-GGSN

(inter-PLMN)

GTP IP

Gr SGSN-HLR MAP ATM/TDM/IP

Gs MSC-SGSN BSSAP+ TDM/IP

H HLR-AUC Internal Protocols Internal Protocols

Iub RNC-Node B NBAP ATM/IP

Iur RNC-RNC RNSAP ATM/IP

Iu-CS RNC-MSC/CS MGW RANAP ATM/IP

Iu-PS RNC-SGSN RANAP ATM/IP

Mc (G)MSC Server-(G)CS

MGW

H.248 IP

Nb CS MGW-CS MGW RTP/AAL2/AMR IP/ATM,TDM

Nc (G)MSC Server-

(G)MSC Server

BICC IP/ATM,ISUP/TDM

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3.2 Functions of Major Interfaces

3.2.1 Radio Access Network Internal Interfaces

3.2.1.1 Iub InterfaceThe Iub is the RNC-Node B interface. The RNC and the Node B communicates over theIub.

Iub is also made up of control plane and user plane. The Iub uses the NBAP as itscontrol-plane protocol of the radio network layer. By using the NBAP protocol, the Iubinterface performs a collection of functions, including the configuration and managementof the cell and the public transmission channels, the management of system broadcastmessages, resources, and radio links, and the measurement of dedicated resources. Theuser plane of the Iub interface is in charge of user data transmission.

3.2.1.2 Iur InterfaceThe Iub is the RNC-RNC interface. The RNC communicates with another RNC over theIub.

The functions of the Iur interface are as follows:

l Radio link management functions

à Management of dedicated resources in the drift RNS by the SRNC

à Reallocation of physical channels

à Radio link supervision

à Compressed mode

l The transmission of the CCCH signaling over the Iur interfacel Management of common transport channelsl Pagingl Relocationl Report of common error statesl Measurement of dedicated resources

3.2.2 RAN-CN Interface

3.2.2.1 Iu InterfaceIu is the RNC-CN interface. The RNC communicates with the CS domain of the CoreNetwork (CN) over the Iu-CS interface, and communicates with the PS domain of the CNover the Iu-PS interface.

Iu-CS and Iu-PS consist of the user plane and control plane. The Iu interface controlplane uses the RANAP to perform signaling exchanges between the CN and the RNC.The signaling includes both the control and report messages between the RNC and the

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core network, and the Non-Access Stratum (NAS) messages between the UE and the corenetwork. The Iu interface user plane transmits the service data between the RNC and thecore network.

3.2.3 Core Network Internal Interfaces

3.2.3.1 CS Domain InterfacesThe CS interfaces of the Core Network performs circuit switching among functional entitiesinside the CN. The functions of the CS domain interfaces are described as follows:

B Interface

The B interface connects the VLR to the MSC. When an MSC needs the user data withinits serving area, the MSC query the data from the VLR via the B interface. When theMS location is updated, the MSC requests the VLR to store related information via theB interface. If a user activates a supplementary service or modifies data, the MSC willrequest the HLR to update data via the VLR.

C Interface

The C interface connects the HLR to the GMSC. If the fixed network cannot obtain thelocation of mobile subscribers when establishing a call, the GMSCmust query the roamingnumber of the called party from the HLR. When forwarding a short message, the SMSGMSC needs to query the MSC number of the called party from the HLR.

D Interface

The D interface connects the HLR to the VLR. The interface exchanges the location andprocess information of subscribers. To enable subscribers to initiate and receive calls inthe whole serving area, the HLR and the VLR need to exchange data. The VLR notifies theHLR about the location and roaming number of subscribers. The HLR sends necessarysubscriber service data to the VLR. Data exchanges occur when a subscriber requests fora particular service or the subscriber data changes.

E Interface

The E interface connects different MSCs. When a Mobile Station (MS) is roaming fromone MSC to another during a call, the MS needs a handover between the two MSCs tomaintain the call. In this case, the two MSCs must exchange data over the E interface.

F Interface

The F interface connects the MSC to the EIR. The MSC and the EIR exchanges data overthe F interface to check the IMEI state of the MS.

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G Interface

The G interface connects two VLRs. When a Mobile Station (MS) roams from one VLR toanother, the source VLR sends the IMSI and authentication parameters to the target VLRover the G interface.

H Interface

The H interface connects the HLR to the AuC. When the HLR has no information about anMS after receiving the authentication request from the MS, the HLR requests for the MSinformation from the AuC.

Mc Interface

The Mc interface connects the (G)MSC server to the MGW. The interface has the followingfeatures:

l The Mc interface complies with the H.248 standards, which are jointly defined by theITU-T G16 and the IETF MEGACO work groups.

l The Mc interface supports flexible connections of different call models, and supportsthe non-restricted processing of different media used by subscribers specified inH.323.

l The open structure supports data packet definition and supplementary definition ofinterfaces.

l The physical MGW nodes support dynamic sharing. That means a physical MGWcan be divided into multiple independent logical MGWs.

l According to the H.248 protocol, transmission resources can be shared dynamicallybetween the bearer and management resources controlled by the MGW.

l The Mc interface Supports specific mobile functions, such as SRNS relocation andhandover.

Nb Interface

The Nb interface connects two MGWs. It provides the bearer control and transmissionfunctions.

Nc Interface

The Nc interface connects the MSC server to the GMSC server. The interface performsinter-network call control.

3.2.3.2 PS Domain Interfaces

Gn/Gp Interface

The Gn/Gp interface connects the SGSN to the GGSN. Gn is the interface between theSGSN and GGSN in the same PLMN, while Gp is the interface between the SGSN andGGSN in different PLMNs.

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Gr/Gf/Gd Interfaces

Gr is the SGSN-HLR interface. Gf is the SGSN-EIR interface. Gd connects the SGSN tothe SMS-GMSC or SMS-IWMSC.

These interfaces use the MAP protocol to provide SS7-based functions, such asauthentication, registration, mobility management, and short message transmission.

Gs Interface

The Gs interface connects the SGSN to the MSC or VLR. Gs is an optional interface thatonly transmits signaling.

The Gs interface uses the BSSAP+ protocol to perform combined mobility managementand paging. Over the Gs interface, signaling is transmitted as SS7.

Gc Interface

Gc connects the GGSN to the HLR. It is an optional interface using the MAP protocol. TheGc interface obtains the SGSN address of the MS to establish a reverse PDP connection,thus activating the PDP context upon the start of the network.

3.2.4 Air Interface

3.2.4.1 Uu InterfaceThe Uu interface connects the RNS to the UE, enabling the interworking between UEand the UMTS Radio Access Network (RAN). The main functions of the Uu interfaceinclude: broadcasting, paging, and RRC connection processing, decision and executionof handover and power control, transmission of messages related to the management andcontrol of radio resources, and transmission of messages related to baseband and radiofrequency processing.

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FiguresFigure 1-1 UMTS R99 Network Architecture ............................................................. 1-2

Figure 1-2 UMTS R4 Network Architecture ............................................................... 1-3

Figure 3-1 System Interfaces .................................................................................... 3-2

I

Figures


TablesTable 1-1 Network Architecture of Other Versions ..................................................... 1-4

Table 3-1 Description of Major System Interfaces ..................................................... 3-3

III

Tables


Glossary3GPP- 3rd Generation Partnership Project

AAL2- ATM Adaptation Layer type 2

AMR- Adaptive Multiple Rate

ATM- Asynchronous Transfer Mode

BICC- Bearer Independent Call Control protocol

BSS- Base Station Subsystem

BSSAP- Base Station Subsystem Application Part

BSSGP- Base Station Subsystem GPRS Protocol

CAMEL- Customised Applications for Mobile Network Enhanced Logic

CCCH- Common Control Channel

CN- Core Network

CS- Circuit Switched

EIR- Equipment Identity Register

GGSN- Gateway GPRS Supporting Node

GMSC- Gateway Mobile Switching Center

GPRS- General Packet Radio Service

GSM- Global System for Mobile Communication

V


GTP- GPRS Tunneling Protocol

HLR- Home Location Register

HSDPA- High Speed Downlink Packet Access

HSPA- High Speed Packet Access

HSUPA- High Speed Uplink Packet Access

IMEI- International Mobile Equipment Identity

IMS- IP Multimedia Subsystem

IMSI- International Mobile Subscriber Identity

IP- Internet Protocol

IPv6- Internet Protocol Version 6

ISDN- Integrated Services Digital Network

ISUP- ISDN User Part

LTE- Long Term Evolution

MAP- Mobile Application Part

MBMS- Multimedia Broadcast/Multicast Service

MGW- Media GateWay

MIMO- Multiple-Input Multiple-Output

MS- Mobile Station

MSC- Mobile Switching Center

VI

Glossary

NAS- Non-Access Stratum

NBAP- Node B Application Part

OFDM- Orthogonal Frequency Division Multiplexing

OMC- Operation & Maintenance Center

PDN- Packet Data Network

PDP- Packet Data Protocol

PLMN- Public Land Mobile Network

PS- Packet Switched

PSTN- Public Switched Telephone Network

RAN- Radio Access Network

RANAP- Radio Access Network Application Protocol

RNC- Radio Network Controller

RNS- Radio Network Subsystem

RNSAP- Radio Network Subsystem Application Part

RRC- Radio Resource Control

RTP- Real-time Transport Protocol

SGSN- Service GPRS Supporting Node

SRNC- Serving Radio Network Controller

SRNS- Serving RNS

VII


TCP- Transfer Control Protocol

TDM- Time Division Multiplexing

UE- User Equipment

UMTS- Universal Mobile Telecommunication System

UTRAN- UMTS Terrestrial Radio Access Network

VLR- Visitor Location Register

WCDMA- Wideband Code Division Multiple Access

VIII

zxur 9000 umts (v4.11.10) system description

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