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