WCDMA Radio Network Planning

WCDMA Radio Network Planning

10. UMTS services

10. UMTS services

Table of Contents

TopicPage

16010.1. Introduction

16010.2. UMTS service architecture

16110.2.1. Virtual Home Environment (VHE)

16210.2.2. Open Service Access (OSA)

16310.2.3. Mobile Execution Environment (MExE)

16410.3. UMTS bearer services

16510.4. UMTS QoS classes

16510.4.1. Conversational class

16610.4.2. Streaming class

16610.4.3. Interactive class

16710.4.4. Background class

16810.5. QoS attributes

10.1. Introduction

In GSM the available services e.g. voice, fax, data, are standardised. This ensures capability between different networks and terminals but it impedes development of new services. The introduction of SIM Application Toolkit (SAT) and Wireless Application Protocol (WAP) was the first steep towards an open service environment. However both concept are not sufficient for complex UMTS services because they are design for very limited GSM phones and do not provide access to all relevant .network elements like the user profile server or multimedia subsystem.

For the end-user the UMTS is a network of services, since a service is that what he actually sees. The UMTS standardisation has defined a framework, which allows quick service development.

10.2. UMTS service architecture

High bit rate offers many opportunities in implementation of new services. The major UMTS services known nowadays are, see also Figure 10.1:

Traditional telecommunication services like speech, teleconferencing or SMS.

M-commerce, for example ticket booking.

E-banking services.

Entertainment, for example games, music and video files downloading.

Information services, that is ability to determine the position of a mobile subscriber.

Figure 10.1 UMTS services nowadays.

Multimedia services, including videoconferencing of terminals connected to different networks, like PSTN, ISDN or Internet.

Emergency calls with enhanced features like emergency call location.

Since peoples needs vary to much to be satisfied by a single application. UMTS will only be successful if it provides a portfolio of attractive services. Therefore, UMTS standardization has defined a framework to develop a rich set of services. The framework consists of a concept for service access (Virtual Home Environment), a network architecture (Open Service Access) and a terminal architecture (Mobile Execution Environment).

Figure 10.2. Virtual Home Environment (VHE), Mobile station application Execution Environment (MExE) and Open Service Access (OSA).

Source: Hermann Anegg, Harald Kunczier, Elke Michlmayr, Gnther Pospischil, Martina Umlauft LoL@: Designing a location based UMTS application, Forschungszentrum Telekommunikation Wien, Donau-City-Strae 1, 1220 Wien/Austria.

10.2.1. Virtual Home Environment (VHE)

The Virtual Home Environment (VHE) is a concept of service access with different device (Smart Phone, Personal Digital Organizer (PDA) or Laptop) over different network (GSM/GPRS, UMTS, wireless LAN). In all situations the functionality and look & feel shall remain the same as far as possible. The use will not see a difference in using his services wile roaming in different networks.

Figure 10.3 illustrates the concept. It presents a user accessing his service from various kinds of terminals (laptop, PC, smart phone) and through various networks, which he even might not be aware. Modification in his service profile made with one terminal will be valid on all terminals he is using, and in all networks.

Figure 10.3. Online cinema ticket booking.Benefits of Virtual Home Environment:

Provides users with the ability to receive customized and personalized services with a common look & feel, wherever and on whatever kind of terminal.

Offers the network operators the flexibility to develop customized services across different networks (e.g. cordless, cellular or satellite networks), without requiring modifications of the underlying network infrastructure.

Offers the service providers a set of components for flexible service creation, enabling them to develop services whose appearance adapts to the network and terminal capabilities.

To realize the VHE in mobile networks the Open Service Access (OSA) and Mobile Execution Environment (MExE) are used. VHE service control can be based on the Open Service Architecture (OSA).

10.2.2. Open Service Access (OSA)

In the Internet, the transport network is usually seen only as bit-pipe. However, mobile networks offer additional functionality, e.g. call control, localization, user/device profile access.

Open Service Access (OSA) is an architecture, enabling applications to make use of additional network functionality via standardised interfaces (namely OSA interfaces). The OSA interfaces are defined between the applications and the Service Capability Servers (SCSs), see Figure 10.4. Service Capability Servers provide abstractions of the underlying network functionalities. This way, applications become independent from the network technology.

The OSA consists of three parts:

Applications. Examples of applications could be teleconferencing or location-based applications. They are implemented in one or more Application Servers.

Framework. The Framework takes responsibility for all security aspects of OSA. First applications authenticate themselves to the Framework. The Framework then offers functionality to applications so they can select the services they want to use. The framework also supports integrity management. In this context the integrity deals with performance and availability aspects of OSA services.

Service Capability Servers (SCSs). Service Capability Servers are designed to provide the applications with OSA services accessed by the methods defined in the OSA interfaces. Examples of OSA services are Call Control and User Location.

Benefits of Open Service Access:

Application logic is separated from network access.

The application can be run at a service provider.

Applications can be third party developed.

Communication between the applications and the network is through standard OSA interface (Application Programming Interface). The OSA provides an Application Programming Interface (API) to network elements allowing applications providers the ability to create solutions using networks services such as User location, Charging, Call control etc.

Figure 10.4. OSA overview.Note

OSA stood for Open Service Architecture in Release 99 of the UMTS specifications, release 4 of UMTS has seen a change in name to Open Service Access

10.2.3. Mobile Execution Environment (MExE)

The Mobile Execution Environment provides a standardized execution environment in an MS (Mobile Station), and an ability to negotiate its supported capabilities with a MExE service provider, allowing applications to be developed independently of any MS platform. The MS can then be targeted at a range of implementations for MExE from small devices with low bandwidth, limited displays, low processor speeds, limited memory, etc., to sophisticated PDA type devices with a complete MExE execution environment.

To integrate the set of existing mobile application technologies under one common standards umbrella, the MExE standardization has begun with the standardization of three application classmarks. Each classmark represents a set of common terminal device features. A typical MExE device only supports a subset of the three classmarks (e.g. one or two):

Classmark 1 WAP Environment.Classmark 1 MExE devices are based on Wireless Application Protocol (WAP). They require limited input and output facilities on the client side only (e.g. as simple as a 3 lines by 15 characters display and a numeric keypad), and enable efficient information access even over low bandwidth connections.

Classmark 2 PersonalJava Environment.Classmark 2 MExE devices enabled PersonalJava applications with the addition of the JavaPhone API. The PersonalJava application environment is the standard Java environment optimised for consumer electronic devices designed to support World Wide Web content including Java applets.

Classmark 3 J2ME Environment. Classmark 3 MExE devices are based on the Connected Limited Device Configuration (CLDC) with the Mobile Information Device Profile (MIDP). The Java 2 Platform Micro Edition (J2ME) is a version of the Java 2 platform targeted at consumer electronics and embedded devices. CLDC consists of a virtual machine and a set of APIs suitable for providing tailored runtime environments. The J2ME CLDC is targeted at resource constrained connected devices (e.g. memory size, processor speed etc.).

10.3. UMTS bearer services

Each service require another Quality of Service (QoS). The UMTS network must provide the required QoS so, that the end-user is satisfied with the service used. Therefore in UMTS it is possible to negotiate properties of a radio bearer, e.g. throughput, transfer delay and data error rate, depending on the service used.

In order to support the End-to-End Service, see Figure 10.5, e.g. videoconferencing, the application running the videoconferencing service must receive required for the service QoS (throughput, transfer delay etc.) in the UMTS network. That is the application requests for a required UMTS Bearer Service. UMTS allows a user/application to negotiate bearer characteristics that are the most appropriate for a End-to-End Service used. Bearer negotiation is initiated by an application. The application requests a bearer depending on its needs and the network checks the available resources and the users subscription before responds. The properties of a bearer affect directly the price of the service.

UMTS Bearer Service provides QoS between Mobile Terminal (MT) and Core Network (CN) Gateway, see Figure 10.5. The UMTS Bear Service uses bearer services provided by the lower layers: Radio Access Bearer Service and CN Bearer Service. Each bearer service on a specific layer offers its individual service using those provided by the layers below.

Note, that satisfactory End-to-End Service quality depends not only on UMTS Bearer Service, but also on the External Bearer Service. Therefore QoS problems in the External Bearer Service, i.e. between networks, will impact on the End-to-End Service.

Figure 10.5. UMTS bearer services architecture.

10.4. UMTS QoS classes

One of the most important challenges in UMTS is to provide the QoS mechanisms for all kinds of services offered to customers. It is the end user who decides if the perceived quality is satisfactory or not. In UMTS four traffic classes with different QoS requirements are identified:

Conversational.

Streaming.

Interactive.

Background.

The most important factor that distinguish these classes is the delay sensitivity (or time of delivery) of the traffic.

10.4.1. Conversational class

This class is meant as very delay sensitive traffic class. It is transmitted as a real-time connection with the most demanding requirements, see Table 10.1. The best known application of this class is speech service over circuit-switched bearers. A number of new applications require this type of class. Their characteristics are strictly imposed by human perception. The examples are internet multimedia services like voice over IP or video telephony and teleconferencing.

The real-time conversation is characterised by a low end-to-end delay and symmetric or nearly symmetric traffic. The maximum end-to-end delay is governed by human perception and is less than 400ms. Therefore required quality is expressed by sufficiently low delay.

Another example of conversation class service is video telephony. It has similar delay requirements as speech service. Due to the nature of video compression, the BER requirement is more stringent comparing to speech.

10.4.2. Streaming class

Steaming class is another example of real-time traffic but the delay requirement is not so critical. However the delay variations should be still preserved. Streaming class is used by applications with one direction transfer, like audio streaming or video streaming, and provides a steady or continuous stream of data.

Streaming technologies become important with the growth of the internet because most users do not have fast enough access to quickly download multimedia files. With streaming the data can be displayed before the entire file has been transmitted. Streaming applications are very asymmetric and therefore withstand more delay that symmetric conversational class services.

10.4.3. Interactive class

In the interactive class the traffic is not so delay sensitive, however more important than the transfer delay is the content of the data. Information should be transferred with low error rate.

Interactive class is transmitted as scheduled non-real time packet data. A user sends a request and waits for a response from the other side. The response should arrive within a certain delay limit. It is said, that the interactive class is characterised by the request response pattern of the end user. There are two kinds of interactions: human and machine. Examples of human interactions with the remote equipment are web browsing, database retrieval, server access. Examples of machine interactions with remote equipment are polling for measurement records, automatic database inquiry (tele-machines).

The most widely adopted interactive class applications are location-based services and computer games. However depending on the nature of a game, that is how intensive the data transfer is, it may rather belong to the conversational class due to high requirements for the maximum allowed end-to-end delay.

Location-based services

There are two possibilities of provisioning of location-based services: either by a teleoperator or by a third party service provider that utilises available information on the terminal location. The service can be a push type, that is automatic distribution of local information, or pull type, that is localisation of emergency calls.

Examples of location-based services are discount calls in a certain area, broadcasting of service over limited number of sites and retrieval and display of location-based information, such as the location of the nearest police station, hotel, restaurant, etc. Depending on the service, the data can be retrieved interactively or as a background. The location information can be input by the user or detected by the network or mobile station. There are the following positioning methods, suited for different purposes:

The cell coverage-based positioning method.

Observed Time Difference Of Arrival Idle Period Downlink (OTDOA-IPDL).

Network-assisted Global Positioning System (GPS) methods.

For location-based services, accuracy is the most important feature. The measurement of position is a statistical process. The overall system accuracy reported involves a statistical measure of many operations at many times and at many locations through the network coverage area. The accuracy reported for an individual measurement may vary considerably from the overall system performance statistics. At the moment UMTS specifies that it provides location information for a mobile station with an accuracy of 50m.

10.4.4. Background class

The background class is the least demanding one as far as delay is concerned. The destination does not expect the data within a certain time. Another characteristic is that the content of the packets does not need to be transferred transparently but transmitted data has to be error free received. Also payload content must be preserved. Examples of background applications are data download (FTP), e-mail delivery (POP), SMS, receptions of measurements records, electronic postcards.

Table 10.1. WCDMA traffic classes.

10.5. QoS attributes

At the connection establishment the User Equipment (UE) may request a QoS profile for a given application. The QoS profile is the required traffic class together with QoS attributes, see Table 10.2. Not all of the QoS attributes apply to each of the traffic classes, as presented in the table. If no specific QoS attributes are requested, some default values are used. The QoS profile may be renegotiated during the connection.

Table 10.2. QoS attributes associated with different traffic classes.

The most important UMTS Bearer Service attributes are presented in Table 10.3. The maximum bit rate is the upper throughput an application may receive. All bearer service attributes may be fulfilled for throughput up to maximum bit rate depending on the network conditions.

UMTS Bearer Service attributes, e.g. transfer delay, are guaranteed up to guaranteed bit rate. For throughput exceeding the guaranteed bit rate the bearer service attributes are not guaranteed.

Allocation priority identifies an importance for allocation of UMTS bearers. It is a subscription attribute and can not be negotiated by the UE.

Table 10.3. Some of the UMTS Bearer Service attributes.159168165