Chapter 2 WCDMA Services

Basic Principles of WCDMA SystemError! Style not

defined.WCDMA Services

Chapter 2 WCDMA Services

2.1 Overview

Compatible with abundant services and applications of GSM and GPRS, the WCDMA system has an open integrated service platform to provide a wide prospect for various 3G services. This chapter introduces the categories and features of 3G services, and presents several typical types of services and their implementation methods, so that the 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 in GSM.

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. For example, 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. Service characteristics vary greatly, so each service features differently. Generally, there are features 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. CAMEL Phase 3 needs to be implemented in UMTS. Phase 2 supports services such as CS, USSD (Unstructured Supplementary Service Data), SS (Supplementary

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Service) and CF (Call Forwarding). On this base, Phase 3 has added support for GPRS, SMS, MM and LCS (optional).

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 in China and other countries. In the 3G field, because of improvement of location precision and application of the open system structure, LCS is very attractive. It may become 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 Enhanced Emergency Services. The FCC (Federal Communications Commission) stipulated that wireless operators should provide an estimated value of longitude and latitude of the caller. The precision should be within 125 meters (67% of the estimated value) or lower than the result by root mean square. Mainly driven by national laws, this kind of service is provided by operators for the public interest. It is available without user’s application. To operators, it is a non-profitable service but can promote operator’s image. And this service is an inevitable development result of mobile communication technologies.

Besides emergency calls, there is also vehicle rescues: If a vehicle is broken on the road, a fault locating automatic report is available. If there is an accident, the detection device will detect it and auto report the related information such as location of the accident. Location Based ChargingSpecific user charging: Some location areas (LAs) can be set as discount areas. In these 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 this area. Enhanced Call Routing (ECR)The ECR enables user’s calls to be routed to the nearest service point according to the location. 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. This service is available for chain companies, such as Caltex and KFC. The companies can apply for specific access numbers or preferential access number that will be preferred for access among the counterparts (such as gas stations). To bank services, the user can get the latest bank information or ATM information through ECR.


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Location Based Information Services

Get the subscriber location information

Return the subscriber location information

The information about the nearby restaurant is returned and it can be in the

form of graphics or text

Query The nearby restaurant

Location Server

SP Web ServerPORTAL

Location Server

Radio network

SP Web ServerPORTAL

Figure 2-1 Location Based Information Services

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

City sightseeing: Providing direction navigation between touring sites, or indicating touring sites nearby, and finding the nearest hotel, bank, airport, bus station or relaxation 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 to users in or near a shopping center to attract customers. It can also filter users. For example, the administration of a port can deliver dispatch messages to the staff within the port area. In addition, activities schedules can also be delivered to tourists in the sightseeing area. Mobile yellow pageMobile yellow page is similar to ECR. It provides contact information of the nearest service point according to user’s needs. For example, the customer can input an entry “restaurant” or more conditions such as “Chinese food” and “within 3 kilometers” to search. The output result can be phone numbers or addresses. Network Enhancing ServicesThis 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) and Intercept 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 from other 3G systems, or roaming subscribers that can use the 3G system from other mobile 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 of high-compression-ratio MP3. The first application of video service is unidirectional video 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 in

the circuit domain mainly uses H.324/M protocol. Packet real-time multimedia serviceMultimedia 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 in Figure 2-2. Non real-time multimedia message serviceThis service is called MMS (Multimedia Message Service), a natural development of SMS. Technically speaking, SMS delivers text format messages through signaling, only able to deliver or receive text-only messages with a capacity of a little bit more than one hundred bytes. MMS, with rich service supporting capabilities, can deliver multi-functional message containing text, images, video, audio and data.

PlatformPortalWAP GW

Huawei OSS

WIN- CDMA

GPRS/ WCDMA

GGSN

WWW server

WSRAS server

Router

QuidwayQuidwayTMTMS2402S2402

QuidwayQuidwayTMTMS2402S2402

IntranetApplication server DB

WS

Still one hour before boarding, so I can see a

movie with my 3G MS

Figure 2-2 Example 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 web sites) initially pushes messages to subscribers, such as weather broadcast, stock information, news, adverting service, traffic information and other customized messages. To the research and discussion of PUSH service, 3GPP proposes series of implementation schemes. These schemes include: PUSH service implemented by using network-initiated PDP context activation process; PUSH service implemented by using network-initiated PDP context activation process triggered by DNS query; PUSH service implemented by using SMS; PUSH service implemented by using “on line for ever”, 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 the network 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 as weather, traffic and stock for free.

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

2.3 Brief Introduction to the Implementation of Typical 3G Services

2.3.1 CAMEL Phase 3 Intelligent Service

To introduce the intelligent network into the mobile communication system, the European Telecommunications Standards Institute (ETSI) defined CAMEL in Gsm Phase 2+ in 1997 to provide subscribers with service consistency unrelated to the specific service network. The CAMEL feature is not a supplementary service but a network 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 the subscriber with the specific service.

The network structure of CAMEL Phase3 is shown in Figure 2-3. Several function entities 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, and between GsmSCF and GsmSRF. While an internal protocol interface is used between MSC and GsmSRF, the others use MAP Phase3 interfaces.

The equipment designed specially for GsmSCF implementation is called the SCP, for GsmSSF 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 2-3 Network structure of CAMEL Phase3

CAMEL mainly embodies the separation of switching and services. The fundamental idea is as follows: The switch only implements the basic call connection function, but the control of all intelligent services is implemented by another network layer, i.e., the intelligent network. Of them, the Service Switching Function (SSF) implements the switching function, reports various events during the call to the Service Control Function (SCF) and possibly suspends the call, waiting for further instruction of SCF. The triggering points of these events are called the Detection Points (DPs). SCF implements the service logic control function. The essential of the CAMEL mechanism is a control mechanism between SCF and SSF.

2.3.2 LCS

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


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UE Node B

(LMUType B)

HLR

GatewayMLC

ExternalLCS client

LeLg

Lg

Lh

GatewayMLC

Other PLMN

LMUType A

Uu

IuIub

gsmSCF

Lc

CBCNote 1)

IuBC

3G-SGSN

3G-MSC/VLR

RNCNode B(LMU

Type B)

Iur

Iub

SRNC(SMLCfunctio-nality)

Figure 2-4 Network structure of LCS

The functions of the LCS system are described as follows: LCS ClientLCS Client is the source of sending location requests, and uses the location result to implement related services based on location. There are four kinds of clients according to the LCS Client functions. 1) Value-added LCS Clients - Using LCS to support various value-added services,

they may include UEs or no specific UEs. 2) PLMN operator LCS Clients - Using LCS to enhance or support some tasks

related to O&M, such as supplementary service, IN related service, bearer service and telecommunication service.

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

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

GMLC (Gateway Mobile Location Center)GMLC is a gateway device in the network connecting to the external LCS Client. After getting related location request messages through the Le interface, it is responsible for HLR addressing, and delivering the location requests to the SGSN through the Lg interface. GMLC is also responsible for delivering related location results to related LCS Clients, or convents the results into local coordinate information upon request. MSC/SGSN/VLRMSC/SGSN/VLR mainly implements the coding/decoding of related location information, version negotiation and processing of related signaling protocol information. In addition, it provides interface functions of related signaling tracing, maintenance and management. MSC/SGSN/VLR needs to implement the main processing and control of location procedure, and user privacy protection, and provides charging information according to the processing. HLR


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HLR stores the subscription data related to LCS, and provides the MSC number of the located subscriber. Target UEThe Target UE (also referred as MS) is a target mobile phone located. The network needs to locate the current or last location of the mobile subscriber according to the location 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 location request. RNCIn 3G networks, RNC implements the specific locating testing and calculation in LCS implementation.

Figure 2-5 Example 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 request information. 2) GMLC delivers a message to HLR/HSS to query the address of SGSN or

MSC/MSC Server. Upon receipt of the needed address, GMLC will deliver a location request to SGSN.

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

4) If RAN stores location information that meets the requirements of SGSN, it returns a location report to SGSN. Otherwise, RAN needs to initiate a special location processing message with the used location method. RAN returns a location information report that SGSN has estimated.

5) SGSN returns the estimated location information and acquisition time to GMLC.6) GMLC returns the location information to the LCS Client. GMLC records the LCS

Client CDR and the CDR of SGSN inter-network cooperation.


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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 as transfer, 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 2-6 MMS system structure

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

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

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

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

In terms of physical entities, the MMS Server, the MMS Relay and the MMS User DB can 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 the existing GPRS network.

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


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MSC/VLR/HLR

SMSC

GGSN1

SGSN1 SGSN2

BTS1

BSC1BTS2

BSC2

GPRS backbone network

MMSCWAP GW

Email Server

SMTP

Arrow 1

IP network

Figure 2-7 MMS service flow

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

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

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

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


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Chapter 2 WCDMA Services