wcdma system structure and principle2

WCDMA System Overview

Course ContentsChapter 1 WCDMA SystemChapter 2 WCDMA ServicesChapter 3 WCDMA System StructureChapter 4 WCDMA RAN Interface & ProcedureChapter 5 WCDMA Basic Signaling Flow

WCDMA SYSTEM We have 3 generations:1stG analog cellular mobile communication, ex: AMPS (advanced mobile phone system) uses 800MHZ north& south America &TACS( Total access communication system) uses 900MHZ Britain.Disadvantages: no high speed services, limited types of services etc..To Solve this disadvantages 2ndG was developed. 2ndG ex: DAMPS or IS-54 of USA using 800MHZ & the IS-95 (CDMA mode) European using 800 or 1900MHZ.

2ndG designed as the TDMA support 64kbps, the GSM system uses FDD (Frequency Division Duplex) &TDMA modes and each carriers 8 channels 200KHZ B.W.Advantages: transmission of voice& low speed data service. 2.5G address the medium rate data transmission includes GPRS.3rdG system can provide multiple kinds of high quality multimedia service and implement global roaming and CDMA has a very large capacity which is 10 times than analog.

3rdG has 2 standardization: 3GPP(3rdG partner project) &3GPP2.3GPP: it adopts the WCDMA technologies to construct a new RAN and a core switching network.3GPP2:its adopts the cdma2000 is applied for radio access.3rdG consist of a family concept: network part &radio interface part.

The comparison between the three major technical systems:System: WCDMA cdma2000 TD-SCDMAChip rate: 3.84Mcps Nx1.2288Mcps 1.28McpsSignal bandwidth:5MHZ Nx1.25MHZ 1.6MHZInheritance from: GSM narrowband CDMA GSMAir interface: WCDMA IS-95 WCDMACore network: GSM MAP ANSI-41 GSM MAP (Mobile Application Part)Using countries: Europe &Japan USA& Korea China

NOTE: ( N= 1, 3, 6, 9, 12)

WCDMA SERVICESThere are many features of 3G services such as:Compatible backward with all the services provided by GSM.The concept of multimedia service introduced.The real time service such as voice generally have the QoS requirement.The typical service of 3G are CAMEL phase3 intelligent service needs to implement in UMTS &phase 2 needs to implement in providing the prepaid service &support services such as forwarding calls etc

In 3G improvement of location &application of the system structure, LCS is very attractive, types of LCS:Public security service (ex: emergency calls)Location based charging (ex: some LAs set as discount area)Enhanced call routing (ex:enables to the nearest service point, gas station)

Location based information service (ex: deliver msg. to user advertisements in to attract customers)Mobile yellow page (ex: same as ECR)Network enhancing services (ex: roaming user that can use 3G system from other mobile network).

In 3G multimedia service is the first to be developed with a little bandwidth, voice service is the first to be developed with the use of high compression ratio MP3, types of services:Circuit real time multimedia service: The implementation of multimedia service in the circuit domain. Packet real time multimedia service: Multimedia service in the packet domain is mainly implemented via the SIP (Session Initiation protocol). Non real time multimedia message service: This service is called MMS (Multimedia Message Service), a natural development of SMS.

UMTS Traffic Class Conversational Streaming Interactive Background

UMTS Traffic Class

Sheet1

Elementary ProcedureInitiating MessageSuccessful OutcomeUnsuccessful Outcome

Response messageResponse message

Iu ReleaseIU RELEASE COMMANDIU RELEASE COMPLETE

Relocation PreparationRELOCATION REQUIREDRELOCATION COMMANDRELOCATION PREPARATION FAILURE

Relocation Resource AllocationRELOCATION REQUESTRELOCATION REQUEST ACKNOWLEDGERELOCATION FAILURE

Relocation CancelRELOCATION CANCELRELOCATION CANCEL ACKNOWLEDGE

SRNS Context TransferSRNS CONTEXT REQUESTSRNS CONTEXT RESPONSE

Security Mode ControlSECURITY MODE COMMANDSECURITY MODE COMPLETESECURITY MODE REJECT

Data Volume ReportDATA VOLUME REPORT REQUESTDATA VOLUME REPORT

ResetRESETRESET ACKNOWLEDGE

Reset ResourceRESET RESOURCERESET RESOURCE ACKNOWLEDGE

Sheet2

Table 1: UMTS QoS classes

Traffic classConversational classStreaming classInteractive classBackground

Fundamental characteristics- Preserve time relation (variation) between information entities of the stream- Preserve time relation (variation) between information entities of the stream- Request response pattern- Destination is not expecting the data within a certain time

Conversational pattern (stringent and low delay )- Preserve payload content- Preserve payload content

Example of the application- voice, videotelephoneVOD, Web broadcast- Web browsing, network games- background download of emails

Sheet3

UMTS ArchitectureUMTS Network Elements Structure

WCDMA System ArchitectureIuUTRANUEUuUTRANUMTS Terrestrial Radio Access NetworkCNCore NetworkUEUser Equipment CN

UMTS (Universal Mobile Telecommunications System) is the 3rdG mobile telecommunication system by using the WCDMA air interface technology, including RAN &CN. UMTS system consist of UTRAN( UMTS Terrestrial Radio Access Network), CN &UE.RAN used to process all radio related functions.CN used to process all voice calls and data connections &implement the function of external network switching &routing, CN is divided into CS which covers MSC,VLR,IWF &GMSC, &PS which provides packet data services for subscriber including the SGSN &GGSN.

UTRAN System ArchitectureRNSRNCCore NetworkNode BNode BNode BNode BIuIuIurIubIubIubIub

UTRAN is divided into RNC (radio network controller) it implements connection establishment modulation/demodulation and Node B is the base station of WCDMA system.UE is divided into ME &USIM (UMTS subscriber module).R99 network structure has considered the 2G/3G compatibility so as to support the smooth transition of GSM/GPRS/3G, its main function includes MSC,VLR,HLR,AUC,EIR,GMSC,SGSN,GGSN. R4 the function entities (SGSN &GGSN) of the PS domain remain unchanged. But have MSC server, GMSC server, CS-MGW( Circuit switched media gateway) &T-SGW( Transport signaling Gateway).

RAN InterfacesVMSC/VLRIu-CSGsSGSNGMSCGGSNBSSRNCBTSBTSNODE BNODE BIu-PSAGbAbisIubUmUu

Common Protocol Model of UTRAN InterfacesThe principle of interface protocol architecture is the logical mutual-independence between layers and planes. Protocol layers of a specified protocol version, or even all layers in a plane can be modified if required in the future.

Basic NotionsUE Working Mode and StateServing RNCDrift RNC and Control RNC Source RNC and Target RNC

UE states- Scanning networks (PLMN)- Camp on cell- Monitor paging channel- cell re-selection- Dedicated Channel- Radio bearers Transmission Services- upper layer Signalingtrigger (CN)- Reduce actionDTXand save powerRRC connection

SRNC/DRNCIn WCDMA system notion of SRNC/DRNC is introduced because the existence of Iur InterfaceIn brief, the RNC directly connected to CN and controlling all the UEs resources is called SRNC(serving RNC) of this UEThe RNC with no connection to CN but only providing resources for UE is called DRNC(Drift RNC) of this UEA UE in connection state has at least and only one SRNC, but can has 0 or multiple DRNCs

Source RNC/Target RNCSRNC Relocation is the process of switching the SRNC of a specific UE. Source RNC is the SRNC before SRNC Relocation and Target RNC is the SRNC after SRNC Relocation Source RNC and Target RNC refer to different RNCs during a SRNC Relocation process

UTRAN Interface Protocols and FunctionsIu InterfaceIur InterfaceIub InterfaceUu Interface

Iu Interface System Structure

Iu-CS Interface Protocol Stack Structure

Iu-PS Interface Protocol Stack Structure

Iu Interface Functions(1)Mobility ManagementLocation Area ReportSRNS RelocationHard handover between RNCs and inter-system handoverRadio Access BearerRABManagementEstablishment, Modification and Release of RABIu data transmissionnormal data transmissionabnormal data transmissionTransparent transmission of UE-CN connection information

Iu Interface Functions(2)PagingIu ReleaseSecurity Mode ControlOverload ControlCommon UE IDIMSIManagementIu Signaling Trace ManagementIu Interface Abnormality Management

UTRAN Interfaces Protocols and FunctionsIu InterfaceIur InterfaceIub InterfaceUu Interface

Iur Interface Protocol Stack Structure

Iur Interface Functions(1)Support Basic Mobility Functions between RNCsSupport SRNC relocationCell Update and URA Update between RNCsPaging between RNCsProtocol Error ReportChannel FunctionsEstablish, Modify or Release Dedicated Channels in DRNC during handoverTransmission of DCH TB(Transmission Block) on IurManagement of RL(Radio Link) in DRNS by Dedicated Measurement Procedure and Filter ControlRL ManagementCompressed Mode Management

Iub Interface Protocol Stack

Iub Interface Functions(1)Common FunctionsCommon Transport Channel ManagementIub Common Channel Data TransmissionLogical O&M of Node Bmaintenance functions such as cell configuration ManagementFault ManagementBlock Management, etc.System Information ManagementCommon MeasurementResource VerificationAbnormality ManagementTiming and Synchronization Management

Iub Interface Functions(2)Dedicated FunctionsDedicated Transport Channel Management Radio Link(RL) Monitoring Dedicated Measurement ManagementTiming and Synchronization ManagementUp-link outer loop Power ControlIub Dedicated Data transmissionBalance on down-link power driftingCompressed Mode Control

Uu Interface Protocol Stack Structure

Uu InterfaceChannel StructurePhysical ChannelTransport ChannelLogical Channel

Physical Channel StructureDedicated Physical ChannelDPDCH: Dedicated Physical Data ChannelDPCCH: Dedicated Physical Control ChannelCommon Physical ChannelUplink: PRACH: Physical Random Access ChannelPCPCH: Physical Common Packet ChannelDownlink: CCPCH: Common Control Physical ChannelSCH: Synchronization Packet ChannelPDSCH: Physical Downlink Shared ChannelPICH: Paging Indicator ChannelCPICH: Common Pilot Channel

Transport Channel StructureDedicated Transport ChannelDCHCommon Transport ChannelBCH: Broadcast Channel(Downlink)PCH: Paging Channel(Downlink)FACH: Forward Access Channel(Downlink)RACH: Random Access Channel(Uplink)CPCH: Common Packet Channel(Uplink, Optional)DSCH: Downlink Shared Channel(Downlink, Optional)

Transport/Physical Channel Mapping

Logical Channel StructureControl ChannelsBCCH: Broadcast Control ChannelPCCH: Paging Control Channel(Downlink)DCCH: Dedicated Control Channel(bi-directional)Traffic ChannelsCCCH: Common Control Channel(bi-directional)DTCH: Dedicated Traffic Channel(bi-directional)CTCH: Common Traffic Channel(Downlink)

Logical/Transport Channel Mapping

Uu Interface ProtocolL3: Network Layer RRC: Radio Resource ControlL2: Data Link LayerPDCP: Packet Data Convergence ProtocolRLC: Radio Link Control ProtocolMAC: Medium Access Control ProtocolBMC: Broadcast/Multicast ControlL1: Physical Layer

Uu Interface L1 Functions(1)Multiplexing of transport channels and de-multiplexing of encoded composite channelsMapping of encoded composite transport channels on physical channelsMacro-diversity distribution/combining and soft handover executionError detection on transport channels and indication to higher layersFEC encoding/decoding and interleaving/de-interleaving of transport channelsRate matching of coded transport channels to physical channels

Uu Interface L1 Functions(2)closed-loop power controlopen-loop power controlModulation and spreading/demodulation and de-spreading of physical channelsSynchronization between frequency and time (chip, bit, slot, frame)Radio characters measurements (FER, SIR, Interference power) and indication to higher layersCompressed mode supportDiversity of Transmission/Receiving

BASIC SIGNALING PROCEDURES

We have two stratum signaling procedures:Access stratum: such as RRC( radio resource control) &RANAP( radio access network application protocol) layers refer to the procedures of which radio access stratum equipment such as RNC &NodeB.Non-access stratum: refer to the procedure in which only UE &CN participate. The UE may operates in one or two modes: Idle mode & Connected mode. After being switched on the UE operates in Idle mode and is identified as non-access stratum such as IMSI, TMSI or P-TMSI. UTRAN doesnt save the information of the UE in this mode. After establishing an RRC connection the UE shifts from the idle mode to the connected mode,

UMTS ArchitectureUMTS Network Elements Structure

Radio resource management procedures:RRC connection setup procedure: each UE has one RRC connection only. When the non access layer of the UE requests to establish a signaling connection in the idle mode the UE will initiate the RRC connection.Signaling setup procedure: after the RRC connection between the UE and the UTRAN is successfully setup the UE sets up signaling connection with the CN via the RNC .

RAB establishment: Radio Access Bearer refers to the user plane bearer that is used to transfer voice, data &multimedia services between UE &CN. Call release procedure: is a procedure that the RRC connection release procedure it falls into two types: UE initiated release &CN initiated release. The difference between the two release types lies in who sends the call release request message of the upper layer first, though the final resource release is initiated by the CN.

Hand over procedure: when the cell or the mode (TDD/FDD) used by the UE changes.SRNS (serving radio network subsystem): the RNC relocation refers to that the SRNC of the UE changes from one RNC to another RNC, it is divided into two cases based on UE location at the time of relocation: static relocation (UE not involved) & associated relocation (UE involved).

Call overall ProceduresStep 8Waiting for call again1cell selection2wait for call

Originating Call Procedure (1)

Soft Handover Illustration (Intra RNC)Before Soft HandoverAfter Soft HandoverDuring Soft Handover

Soft Handover Flow (Intra RNC add branch)Decision to setupnew RL7. DCCH : Active Set Update Complete 6.DCCH: Active Set Update CommandUENode B(new)SRNCNBAP1. Radio Link Setup RequestNBAPNBAP2. Radio Link Setup ResponseNBAP3 ALCAP Iub Data Transport Bearer SetupStart RX descriptionDCH-FP4. Downlink SynchronizationDCH-FPDCH-FP5.Uplink SynchronizationDCH-FPStart RX descriptionRRCRRCRRCRRC

Soft Handover Flow (Intra-RNC delete branch)Decision to deletea RL2. DCCH : Active Set Update Complete 1.DCCH: Active Set Update CommandUENode B(old)SRNCNBAP3. Radio Link Deletion RequestNBAPNBAP4. Radio Link Deletion ResponseNBAPRRCRRCRRCRRCStop RX and Tx5 ALCAP Iub Transport Bearer release

Soft Handover Illustration (Inter-RNC)Before Soft HandoverAfter Soft HandoverRadio Link(RL) is added and deleted simultaneously

Soft Handover Flow (Inter-RNC)7. Uplink SynchronizationRNSAPRNSAP1. Radio Link Setup RequestStart TX descriptionRNSAPRNSAP4. Radio Link SetupResponseNBAPNBAP2. Radio Link Setup RequestNBAPNBAP3. Radio Link Setup ResponseStart RX descriptionDecision to setupnew RL andrelease old RLNBAP 10. Radio Link Deletion RequestNBAPNBAP11. Radio Link Release ResponseStop RX and TX12. ALCAP Iub Data Transport Bearer ReleaseRRCRRC9. DCCH : Active Set Update CompleteRRCRRC 8. DCCH: Active Set Update Command[Radio Link Addition & Deletion]NBAPUENode BDrift RNSNode BServing RNSDrift RNCServing RNCALCAP Iur Bearer Setup5. ALCAP Iub Data Transport Bearer SetupDCH-FPDCH-FPDCH-FPDCH-FP6. Downlink Synchronization

THANK YOUDone By: UAE TSD Department

Good morning every one!Today I will introduce WCDMA RAN interface and procedure.DCA: Dynamic Channel Allocation Another way to group UMTS network elements is to divide them into sub-networks. This slide shows the UMTS network elements schematic diagram. The UTRAN architecture is presented in the next section. A short introduction to all the elements is given below. The UE consists of two parts:ME(Mobile Equipment) is radio terminal used for radio communication over the Uu interface.USIM(UMTS Subscriber Identity Module) is a smart card that holds the subscriber identity, performs authentication algorithms, and stores authentication and encryption keys and some subscription information that is needed at the terminal.

UTRAN also consists of two distinct elements:Node B: converts the data flow between the Iub and Uu interface. It also participates in radio resource management. RNC(Radio Network Controller): owns and controls the radio resources in its domain(the Node B connected to it). RNC is the service access point for all services UTRAN provides the CN, for example management of connections to the UE. The main elements of the Core Network are:HLR(Home Location Register): is a database located in the users home system that stores the master copy of the users service profile. The service profile consists of, for example, information on allowed services, forbidden roaming areas, and supplementary service information. It is created when a new user subscribers to the system, and remain stored as long as the subscription is active. For the purpose of routing incoming transactions to the UE, the HLR also stores the UE location on the level of MSC/VLR and/or SGSN. MSC(Mobile Services Switching Center)/VLR(Visitor Location Register) is the switch(MSC) and database(VLR) that servers the UE in its current location for Circuit Switched(CS) services. The part of the network that is accessed via MSC/VLR is often referred to as the CS domain. The MSC function is used to switch the CS transactions , and the VLR function hold a copy of the visiting users service profile, as well as more precise information on the UEs location within the serving system. GSMC(Gateway MSC) is the switch at the point where UMTS PLMN(Public Land Mobile Network) is connected to external CS networks. All incoming and outgoing CS connections go through GMSC.SGSN(Serving GPRS(General Packet Radio Service) Support Node ) functionality is similar to that of MSC/VLR but is typically used for Packet Switched(PS) services. GGSN(Gateway GPRS Support Node) functionality is close to that of GMSC but is in relation to PS services. The external works can be divided into two groups:CS network: These provide circuit-switched connections, like the existing telephony service, ISDN and PSTN are examples of CS network. PS network: These provide connections for packet data services. The Internet is one example of a PS network.

UMTS Interfaces: The UMTS standards are structured so that internal functionality of the network elements is not specified in detail. Instead, the interfaces between the logical network elements have been defined. The main open interfaces are specified:Cu Interface: This is the electrical interface between the USIM smart card and the ME. The interface follows a standard format for smart cards.Uu Interface: This is the WCDMA radio interface, which is the subject of the main part of this presentation. The Uu is interface through which the UE accessed the fixed part of the system, and is therefore probably the most import open interface in UMTS. There are likely to be many more UE manufactures than that of fixed network elements. Iu Interface: This connects UTRAN to the CN and is introduced in detail in the next chapter. Similarly to the corresponding interfaces in GSM, A(Circuit Switched) and Gb(Packet Switched), the open Iu interface give UMTS operators the possibility of acquiring UTRAN and CN from different manufacturers. The enabled competition in this area has been one of the success factors of GSM. Iur Interface. The open Iur interface allows soft handover between RNCs from different manufacturers, and therefore complements the open Iu interface.Iub Interface. The Iub connects a Node B and an RNC. UMTS is the first commercial mobile telephony system where the Controller-Base Station interface is standardized as a fully open interface. Like the other open interfaces, open Iub is expected to further motivate competition between manufacturers in this area. It is likely that new manufacturers concentrating exclusively on Node Bs will enter the market. Uu Interface: Interface between UE and UTRAN.

UMTS system architecture includes CN, UTRAN and UE. There are two important interfaces :Iu interface(between CN and UTRAN) and Uu interface(between UTRAN and UE).UTRAN:UMTS Terrestrial Radio Access Network.UTRAN include RNC and NodeB. Between UTRAN and core network is the Iu interface. Iu interface is divided into Iu-CS and Iu-PS. Between UTRAN and UE is the uu interface. Inside UTRAN, RNC connects to NodeB with Iub interface. Between two RNCs, there is Iur interface.

UTRAN UTRAN UTRAN On the horizontal plane, common protocol model can be divided into two layers: radio network layer and transport network layer. Radio network layer includes all the UTRAN matters and the transport network layer only provides the standard transport technologies.Vertical plane can be divided into control plane,transport network control plane and user plane. Control plane includes application protocol,such as NBAP,RANAP,RNSAP,and the signaling bearer. User plane includes data stream and data bearer. Transport network control plane includes ALCAP and signaling bearer. ALCAP is used to control the setup and release of the user planes data bearer...1. RANAP RNSAP NBAP ALCAP O&M

..2...3. ALCAP ALCAP ALCAPALCAP ALCAP ALCAP ALCAP ALCAP ALCAP O&M ..4. O&M

Lets discuss some basic notions.UE Working Mode and StateServing RNCDrift RNC and Control RNC Source RNC and Target RNCNotions about AREA

This is the UE states figure. These states are significant only for UTRAN and UE. They are transparent to CN. Lets focus on the switch between the states.

Now lets discuss SRNC and DRNC. Now lets see the distinction of Source RNC and Target RNC. First lets understand a notion:SRNC relocation. Source RNC and Target RNC refer to different RNCs during a SRNC Relocation process. Source RNC is the SRNC before SRNC Relocation and Target RNC is the SRNC after SRNC Relocation .

UTRAN interface includes Iu interface,Iur interface,Iub interface and Uu interface. Uu interface is the most important interface and will be focused on.First lets look at Iu interface.Iu interface is between the RNC and CN. Iu interface is a open interface.One RNC can only connect to one CN (one CS Domain and one PS Domain). But one CN can connect to several RNCs.

IuUTRANCNIuUTRANCN 2Iu CS/PSIuCSPSThe bottom layer is physical layer and then is ATM layer. This two layers are shared by the control plane and user plane. Control planes AAL is AAL5.Iu3ATMSONETSTME1BB SS7RANAPSCCPMTP-3B MTP-3B has the function of routing.SAAL-NNIATMSSCF-NNI and SSCOP can be named SAAL-NNI (signaling ATM adaptation layer). Manage the signaling connection.SSCFSDSCOPATM

AA55ATMFifth type ATM adaptation.

RANAP72IPM3UA(MTP3)SCTPIPSCTPInterM3UASS7

GTP/IPRANAP RAB ASS

AAL5 PVCGTP-UUDPIP Now lets look at the Iu interface functions.RAB is between the CN and RNC. So its setup through IU interface.Paging :CN sends paging message to SRNC through Iu interface.Iu release: after finishing the call, the Iu interface resource should be released.

IurRNC1.RNC2.3.4.All the information changing between RNC and NodeB should be through Iub interface.O&M:operation and maintenance Now begin to introduce Uu interface.This is Uu interface Protocol Stack Structure. Uu interface is divided into three layers: layer 1 is physical layer; layer 2 is link layer which includes the sub-layer of MAC, RLC, PDCP and BMC; layer 3 is RRC layer. Between RLC and MAC is logical channel. And between MAC and physical layer is transport channel.Before introducing Uu interface entity, lets take a few minutes to know something about the channel structure in WCDMA. In this class, we will introduce to L2 and L3 protocol in detail, the L1 has been introduced.The different transport channels are mapped to different physical channels. There exist physical channels to carry only information relevant to physical layer procedure and there is no transport channel mapped to them.1. SCH/CPICH/AICH are not directly visible to higher layer.2. CSICH, CD/CA-ICH are needed if CPCH is usedA general classification of logical channels is into two groups: Control Channel: transfer control plane informationTraffic Channel: for user plane informationIn this class, we will introduce to L2 and L3 protocol in detail, the L1 has been introduced.Now lets look at the L1 functions of Uu interface.FEC: Forward Error Correction Another way to group UMTS network elements is to divide them into sub-networks. This slide shows the UMTS network elements schematic diagram. The UTRAN architecture is presented in the next section. A short introduction to all the elements is given below. The UE consists of two parts:ME(Mobile Equipment) is radio terminal used for radio communication over the Uu interface.USIM(UMTS Subscriber Identity Module) is a smart card that holds the subscriber identity, performs authentication algorithms, and stores authentication and encryption keys and some subscription information that is needed at the terminal.

UTRAN also consists of two distinct elements:Node B: converts the data flow between the Iub and Uu interface. It also participates in radio resource management. RNC(Radio Network Controller): owns and controls the radio resources in its domain(the Node B connected to it). RNC is the service access point for all services UTRAN provides the CN, for example management of connections to the UE. The main elements of the Core Network are:HLR(Home Location Register): is a database located in the users home system that stores the master copy of the users service profile. The service profile consists of, for example, information on allowed services, forbidden roaming areas, and supplementary service information. It is created when a new user subscribers to the system, and remain stored as long as the subscription is active. For the purpose of routing incoming transactions to the UE, the HLR also stores the UE location on the level of MSC/VLR and/or SGSN. MSC(Mobile Services Switching Center)/VLR(Visitor Location Register) is the switch(MSC) and database(VLR) that servers the UE in its current location for Circuit Switched(CS) services. The part of the network that is accessed via MSC/VLR is often referred to as the CS domain. The MSC function is used to switch the CS transactions , and the VLR function hold a copy of the visiting users service profile, as well as more precise information on the UEs location within the serving system. GSMC(Gateway MSC) is the switch at the point where UMTS PLMN(Public Land Mobile Network) is connected to external CS networks. All incoming and outgoing CS connections go through GMSC.SGSN(Serving GPRS(General Packet Radio Service) Support Node ) functionality is similar to that of MSC/VLR but is typically used for Packet Switched(PS) services. GGSN(Gateway GPRS Support Node) functionality is close to that of GMSC but is in relation to PS services. The external works can be divided into two groups:CS network: These provide circuit-switched connections, like the existing telephony service, ISDN and PSTN are examples of CS network. PS network: These provide connections for packet data services. The Internet is one example of a PS network.

UMTS Interfaces: The UMTS standards are structured so that internal functionality of the network elements is not specified in detail. Instead, the interfaces between the logical network elements have been defined. The main open interfaces are specified:Cu Interface: This is the electrical interface between the USIM smart card and the ME. The interface follows a standard format for smart cards.Uu Interface: This is the WCDMA radio interface, which is the subject of the main part of this presentation. The Uu is interface through which the UE accessed the fixed part of the system, and is therefore probably the most import open interface in UMTS. There are likely to be many more UE manufactures than that of fixed network elements. Iu Interface: This connects UTRAN to the CN and is introduced in detail in the next chapter. Similarly to the corresponding interfaces in GSM, A(Circuit Switched) and Gb(Packet Switched), the open Iu interface give UMTS operators the possibility of acquiring UTRAN and CN from different manufacturers. The enabled competition in this area has been one of the success factors of GSM. Iur Interface. The open Iur interface allows soft handover between RNCs from different manufacturers, and therefore complements the open Iu interface.Iub Interface. The Iub connects a Node B and an RNC. UMTS is the first commercial mobile telephony system where the Controller-Base Station interface is standardized as a fully open interface. Like the other open interfaces, open Iub is expected to further motivate competition between manufacturers in this area. It is likely that new manufacturers concentrating exclusively on Node Bs will enter the market. Uu Interface: Interface between UE and UTRAN.

First of all, the network should be started. Then UE power on. After cell reselection and location registration UE enters idle mode and can call or waits for call. Now if UE receives a paging information, the UE will begin RRC connection establish and enter connected mode. RRC connection establish only setup the connection between UE and UTRAN. The next step of NAS signaling connection establish setup the connection between UTRAN and CN. Then CN processes RAB set up. RAB set up includes synchronous set up and asynchronous set up. The difference will introduce in the back slide. Now UE can begin call. During the call, if UE moves from one cell to another, handover will happen; if the service source rate changes, RAB/RB modification,physical channel reconfiguration and transport channel reconfiguration will happen. After the call, RRC connection release and UE enter idle mode again. RNC UECELL UPDATEURA UPDATESoft handover inter-RNC is more complex than intra-RNC. It will refer to DRNC.

wcdma system structure and principle2

Documents