Technical Working Paper 2002, Ericsson Education Written by Paul Landers, Katy Graham and Desmond Keegan

Introduction Chapter 1 Aims of the Project Chapter 2 Technical Considerations Chapter 3 Possibilities and Limitations Appendix Transcript of the course “2G to 3G” Introduction This paper describes the technical work carried out at Ericsson Education during the year 2002 of the EU Leonardo Project, “From e-Learning to m-Learning”. The work in the second year of the project was intended to extend the use of the mobile learning features that were used in the first year of the project. Further information on the project can be found on the website, http://learning.ericsson.net/leonardo/

Chapter 1 Aims of the project dLearning The first one hundred years of distance education were met with criticism. Governments ignored it, corporate trainers concentrated on ILT (instructor led training) and university professors looked down on its correspondence image. In the 1970s a new level of quality and quantity of provision arrived with the foundation of the Open Universities. Television, audiocassettes and videocassettes were added to the former text-based provision and a multimedia approach added to the status of this form of provision. It gradually became accepted that nationally and internationally recognised university degrees, college diplomas and training certification could legitimally be awarded for courses taken at a distance. In the early 1990s distance education finally came of age and was accepted as a normal form of government education and training provision. The proof of this came when the British Ministry of Education, imbued with Thatcherite principles, set out to measure the quality of the 100 universities in Britain. To the astonishment of many, the British Open University was ranked in the top 10 with Oxford, Cambridge, Manchester and other top universities in the country. This meant that 90 other British universities were ranked below the distance education university in terms of quality of teaching and learning. When one considers that the average age of the Open University students was 40 and that few of them had the basic two A levels, which were the prerequisite for entry into the other universities, this is clearly a major achievement. It means that 90 universities, teaching face-to-face with their professors, readers, senior lecturers and lecturers to the top cohorts of high school leavers, could not match the excellence of the distance university. eLearning There is now little doubt that the World Wide Web is the most successful educational tool to have appeared in a long time. It combines and integrates text, audio and video with interaction amongst participants. It can be used on a global scale and is platform independent. While largely an asynchronous medium, it can also be used for synchronous events. It is not surprising therefore, that trainers, lecturers, distance education providers and teaching institutions at all levels are increasingly using the World Wide Web as a medium for course provision. In 1995 teaching at a distance went electronic and eLearning was born. It quickly established that there was a considerable market for electronic learning from adults, many of whom already spent 20 hours per week in front of a computer screen and who wanted to be trained in front of a computer screen too.

Today eLearning is the state-of-the-art for distance learning. The proof of this is that listings of universities which offer eLearning include many or most of the universities throughout the world, and the penetration of the corporate market of large and multinational companies is even greater. Another proof is the sophistication of the market with comprehensive LMSs (Learning management systems) or VLEs (Virtual learning environments), like WebCT, Blackboard, TopClass and others, providing complete systems for electronic learning. Major eLearning vendors like SmartForce and Riverdeep are listed on the Nasdaq. mLearning If the whole world, as it is said, went digital in the 1980s, then in the closing years of the 20th century the whole world went wireless. Mobile telephones and technologies proliferated with 1,000,000,000 of them by the end of 2003 for a world population of 6,000,000,000. China with 170,000,000 is the greatest user. The move to wirelessness in society is now irreversible. mLearning is the working out of this mobile revolution for training. It means the provision of education and training on mobile devices: PDAs (Personal digital assistants), palmtops and mobile telephones. One of the great benefits to society of distance learning was the provision of education and training at any time and in any place that the student wished. This provision was to a certain extent attenuated by electronic learning which required the presence of the student in front of a wired computer, and frequently a costly and powerful computer, for the purposes of learning. The use of mobile technologies in training can restore the anytime, anywhere approach to lifelong learning of distance education. Much of the pioneering work in mobile learning has been done on PDAs in which the provision of a touch sensitive screen and stylus, together with memory for at least 1000 pages of course materials, provide a satisfactory environment for study, especially when combined with software like Microsoft Reader, which adds greatly to the readability of text. It is unlikely, however, that sufficient PDAs will be purchased throughout the world for PDAs to become a universal medium. The challenge, therefore, is to harness the universal availability of mobile telephones for training.

Chapter 2 Technical considerations Choosing the course matter In choosing the course itself, it was necessary to decide upon a subject matter that lent itself to the medium of m-Learning. Unless a suitable course was chosen, the course would not communicate information as effectively as it should and may even be less effective than more traditional forms of learning. The reality of delivering content to WAP devices is the small size of the screens. Applications that are built for small screen devices will still look good on larger screen devices, but the reverse is not necessarily true. The limitations of the handset as an interface dictated that the course should not present long blocks of text to the student, as both navigation and the size of the screen are among the limiting factors. For students to scroll through pages of text is not optimizing the use of a handset as an educational tool. Quite simply, long courses that require much reading on the part of the student are just not suited to the devices that are currently on the market. Short technical overview courses are much better suited and this was what was examined when searching for the course matter. Meaningful information should be presented very near the top of a card, or students might not discover it. Obviously, the course must still be educational and informative. To eliminate the need for many lines of text, a course that could use simple graphics to communicate information was ideal. These graphics could replace whole paragraphs of text. The course should also be clearly structured so as to make it easily navigable. For example, clearly numbered chapters and the use of “soft keys”. The hindrances of the mobile phone handset as a learning aid are more obvious than the advantages at first because of the small screen size of most popular handsets. Rather than be hindered by the medium of m-Learning, the course should use the additional interactive and mobile features of m-Learning to enhance it’s educational value and make it a viable alternative to e-Learning or distance education. For example, it is possible to call the course tutor or send an SMS (short message service) to a forum on an internet site where other students can answer them. The WAP course 2G to 3G The course chosen is an adaptation of an Ericsson power point presentation by Kjell Samuelsson GSM into 3rd Generation. It was possible to adapt this to a WAP course and even to convert some of the graphics in the slides to wbmps (wireless bitmaps), reducing the amount of text needed to explain an idea (eg. Chapter 1.1 What is 3G?). The only graphic file format that is currently supported by the Open Mobile Alliance (formerly the WAP Forum) is the wireless

bitmap (WBMP). For this course it was possible to use some images from the presentation and using Paint Shop Pro 5, convert them to wbmp images. Others were created directly in Paint Shop Pro 5 as wbmp images. The Open Mobile Alliance recommends that images be no larger than 81 pixels wide and 44 pixels high. The course was designed for use on the Ericsson R380 and Ericsson R520 phones, so it was possible to have the images used within the course slightly larger than the Open Mobile Alliance recommendations.

Fig1_1 in Chapter 1.1

All alt tags are non-empty and the images are located at the top, or near to the top of the cards in which they are positioned, in order to give the student an overview of what the following text will cover. This reduces the amount of lines of text presented, thereby making the mobile learning environment with its limited size and navigational capabilities more user-friendly.

The use of animated graphics was also investigated. Using the ontimer attribute within the <card> tag, it is possible to load a sequence of wbmps thus creating an animation. Again this could be a useful learning aid in the m-Learning medium. Chapter 2.1 Evolved 2G contains an animated graphic as shown below:

Fig 2_1 in Chapter 2.4 Evolved 3G Using WMLScript might be a more effective way of animating a graphic and is worth investigating in the future. WML Script eliminates roundtrips over the air interface and over the Internet. It potentially saves the user money and improves the user experience. Development Environment The Ericsson WAPIDE 3.2.1 Software development Kit (SDK) was used to design (and also to test) the course. WAP IDE is a Software Development Kit that enables application developers to develop and test real WAP applications. WapIDE was downloaded from Ericsson Mobility World. The browser can access content from a web server via a WAP gateway or from the local disk. During development, content was accessed locally during development, and later when the pages were uploaded to the server they were accessed via the Ericsson Mobile Internet Enabling Proxy, a WAP gateway proxy. Software requirements Microsoft Windows NT 4.0, Windows 98 or Windows 2000. Java Platform 2 version 1.3 or later. (Java Platform 1.4.1beta was used for development) Microsoft Internet Explorer 5, or a later version is required for local WML file access, including the use of the application designer. The font Arial Narrow is required to get a correct simulation of the real telephones. Arial Narrow is part of many Microsoft software packages such as Office 97, Outlook 2000, Word 2000, etc. Hardware requirements 20 Mbytes free disk space is required for installation Pentium II, 266 MHz and 128 Mbytes RAM is recommended to get acceptable performance

The WapIDE application designer is a WML editor with which WAP applications can be designed and tested. There is also a WMLScript editor for writing and compiling WMLScript code. The Wap IDE browser is used to view WAP applications. It can be used instead of a WAP device to access WML decks. It also interprets WMLScript. By default, Wap IDE 3.2.1 creates WML files with WML version 1.2. The r380 uses only WML 1.1 so it was necessary to change this setting when creating a new project. To simplify the administration of WAP applications, the sources files are grouped into projects. Information about a project is saved in a project file with the extension .wpr. One or many projects can be opened at a time, but only one of them is shown in the Project Pane. The diagram below shows the project “Newleo.wpr” which contains all the files for the course “2G to 3G”. Menu bar Toolbar Source pane

Project pane Attribute pane Message pane

The test Environment The application designer is integrated with the WapIDE browser so applications could be tested on different the devices: the R380 and R520.

R380s and R530 as seen on the WapIDE emulator The Opera web browser was also used to test the content of the wml pages after they had been uploaded onto the server. This browser allows wml pages to be displayed as well as html pages. The course was tested on the Ericsson R380s and Ericsson R520 mobile phones.

Format of the course The overall structure of the course is illustrated in the diagram below.

The course is divided into six chapters. Each chapter has several subsections. The last subsection is always a summary of the chapter. In this way it is possible to just get a summary of each chapter if a student wishes to get a quick overview of the course content. The student types in the url for the course: http://learning.ericsson.net/leonardo/2gto3g/course/splash.wml This will load a “splash page” which displays a brief message using the ontimer attribute of the <card> tag.

The splash page will automatically load the index page as shown below.

The index displays the six chapters of the course. Each of these is divided up into subsections. The student can choose which subsection of which chapter to study.

The code below shows how this drop down menu is generated. Within the card “contents” the selection list is created. Restricting input from the user by presenting the user with a finite number of choices, the user can only pick one from the list presented onscreen. In WML, this means using the <select> tag. Each choice is specified using the <option> tag. The browser displays the body of this tag as the selection text eg. 1.1 What is 3G?. The onpick attribute of the option element holds a URL to which the browser must redirect when the user selects it.

<card id = "contents" title = "Evolution into 3G"> <p> <b>Contents</b> <br/> <select name = "intro"> <option onpick="chapter1.wml">1. Introduction</option> <option onpick="chapter1.wml#one">1.1 What is 3G?</option> <option onpick="chapter1.wml#two">1.2 Past-1G</option> <option onpick="chapter1.wml#three">1.3 Present-2G</option> <option onpick="chapter1.wml#four">1.4 Evolved 2G</option> <option onpick="chapter1.wml#five">1.5 Future-3G</option> <option onpick="chapter1.wml#six">1.6 Evolution</option> <option onpick="chapter1.wml#summary">1.7 Summary</option> </select> <br/>

Tools provided for the student Within the body of the text in each chapter, important words are highlighted in bold. All acronyms are explained by clicking on them eg. GPRS will appear in several chapters. To reduce the length of the body of the text it is never explained within the text, but it is always possible to select and click on the letters which will redirect to a page which does explain what GPRS stands for.

The bottom of each page in the course contains a navigation bar. These are simply images of forward or backward arrows which are links to the next or previous pages in the chapter. Double arrows will load the last or the first subsection in the chapter (the last subsection is always the summary). The letters TOC on the navigation bar indicate the Table of Contents and redirect to the index page. It was intended that these features make the course more navigable. The index contains an item called “Contact”. This enables the student to make a voice call to the tutor by clicking on the link provided. This is done with the following code:

<a href='wtai://wp/mc;23324301024'>Call the tutor (+35312362074)</a>

The text “Call the tutor” will appear as a link. When the student selects it a voice call will be made to the tutor. The WTAI (wireless telephony applications interface) defines a set of WTA-related functions in a wireless device that can be invoked via WML or WMLScript. Another index item is “Quiz”. When opened, this page presents a set of 5 multiple choice questions intended to test the students knowledge of the course. A drop down menu enables the student to choose an answer. This is done using the <option> tag as before. This time however when a selection is made, the variable specified in the value of the <select> tag’s name attribute is set to the value of the <option> tag’s value attribute. This value is passed to a WMLScript

file which evaluates the answers and returns the number of questions successfully answered. A separate website – the student support pages is provided for the students at http://learning.ericsson.net/leonardo/wap_test/questionnaire.html This contains a brief description of the course, a form for students to register for the course, a list of currently registered students and their contact details. There is also a page provided where students can email or sms the tutor. Frequently asked questions are then displayed on this page. The resources page contains a list of useful websites for the students.There is also and evaluation form which students were asked to fill out during the trials of the course.

Chapter 3 Possibilities and Limitations Investigated but not included in the current version of the course was the use of a user name and password for sitting the course. Assuming user data will be stored in a database, registration and logging in should be possible via either a webpage or through WAP. It may be for feasible for initial registration to take place on a web page, as more user data can be requested than would be feasible on a WAP interface e.g. Full Name, location, phone number, email address, occupation and any other applicable information. Once a user registers, a confirmation email or SMS message with their username & password would be sent to them. This would be automatically sent when the registration form is submitted. An option to choose which method they receive this information via (SMS or email) could be selectable in the registration form. This username & password is then used to login prior to the user taking the course on the WAP phone. A webpage where users can retrieve lost passwords would also be required. They can enter their email address into a form and will be emailed their password. Another possibility is using a WAP phone, the user could enter their mobile number through a WML form and receive an SMS with the password on the phone associated with the entered number. Also examined was the idea of an e-mail confirmation automatically being sent to a course instructor upon commencing and concluding course. An easy way of doing this is to include code on the opening and concluding pages of the course that automatically send an email to the course instructor telling them the user has started/finished the course. If the user is logging in with a username/password as discussed above, it may also be possible to include some of that user’s details within the email so the instructor knows exactly who is taking the course. It may be useful to have detailed tracking of user path through course. It may be possible to track which pages were visited. A timer to measure the total time a student spends on a course could inform the student and/or the tutor of how long the student spent studying during their last session. To further help the student with their time and learning management, it might be possible to bookmark the position that they were last at in the course, if studying in more than one sitting. Cookies could be used to do this. These would be stored on the Wap gateway proxy. Push notifications could be sent to the student at a particular time to remind them that it is time to sit the course. This could be set by the student or the tutor. SMS Forum messaging, users can submit queries to a public forum via SMS and then check for replies via Internet. At present, the sms.ericsson.se server converts emails into SMS. For this to work we would need a system that does the opposite – converts SMS to email or more specifically, a message on a forum.

Formatting would also be an issue. On a forum, a topic usually has a subject and then content (like an email). An SMS is just an unformatted block of text with no specific subject or content boundaries. Formatting that into a forum topic with subject and content defined could be problematic however. Quiz results in the present version of the course are returned to users instantly as the questions are multi-choice and the user just selects a check box for their answer. The user’s answers are automatically compared with the correct answers and a score determined and immediately returned. If, however, a detailed written text answer is required, an instructor may be needed to evaluate the answer and grade it. An email with the answers could be sent to the instructor who can then contact the user with their result. In terms of listing phone numbers and contact details of other users of the course, the information could be extracted from a database and listed on a WAP WML page. However, if the list is very long, it would need to be categorised based on certain details about the users e.g. location, occupation, skill level etc. Also, the issue of privacy must be addressed. Users must explicitly agree to have their information shared. This could be included in the initial user registration form where the user must tick a checkbox to agree to share their contact details with other participants of the course. If they don’t agree, they will not be listed.

Appendix Transcript of the WML course “2G to 3G”

The Evolution into 3rd Generation

Contents 1. Introduction

1.1 What is 3G? 1.2 Past – 1G 1.3 Present - 2G 1.4 Future - 3G 1.5 Evolution to 3G 1.6 Summary

2. Current limitations

2.1 The Need for Speed 2.2 Circuit switching 2.3 Packet switching 2.4 Packet switching: A basis for 3G 2.5 Summary

3. Evolution

3.1 WISE up! 3.2 Integrated Access Server 3.3 High Speed Circuit Switched Data 3.4 HDLC Encapsulation 3.5 The WebOnAir™ Filter Proxy 3.6 Summary

4. GPRS

4.1 Why GPRS 4.2 GPRS vs High Speed Internet 4.3 What is GPRS? 4.4 Summary

5. EDGE

5.1 What is EDGE? 5.2 How to get EDGE 5.3 Summary

6. UMTS

6.1 Why UMTS? 6.2 What is UMTS? 6.3 Migration to UMTS 6.4 Layered Network Architecture 6.5 Summary

7. Abbreviations 8. Links 9. Contact

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1. Introduction

1.1 What is 3G? A third generation system supports data rates up to 384 kbit/s in all radio environments and up to 2Mbit/s in short range and indoor applications. It also supports a wide range of applications such as High speed Data, Internet and Mobile Multimedia. Third generation systems will open up a whole new arena of applications. With the expanded capabilities of the system, only the imagination will be the main limiting factor of the vast range of information and communication services that can be implemented. To gain and understanding of where mobile communication is going to, let’s first look at where it has come from. 1.2 Past – 1G Between first and second generation of mobile networks the transmission of speech went from analogue to digital. While mobile communication is now voice-centered, offering the benefits of person-to-person voice contact anywhere and anytime, personal telephony is rapidly being transformed into a mass market of personal mobile multimedia services and terminals able to access the Internet, Intranets and entertainment services. Now let’s have a look at the evolution steps going from 2G to 3G 1.3 Present - 2G

The four existing 2G digital mobile standards of today are TDMA, GSM, PDC and cdmaOne, all offering up to 10 Kbit/s of bit rate. Current mobile networks are originally designed for narrowband voice and data traffic. These networks can be described as vertically integrated in the sense that they combine very different functionality, like transport, control and services, in one and the same network element. This reduces the possibilities to create synergies among the different networks in order to reduce cost of ownership, provide service portability etc. Operators base charging on the amount of connection time.

TOP EVOLVED 2G Evolved 2G systems offer bit rates from 64 Kbit/s to 144 Kbit/s. GSM is evolving towards 3G via GPRS (General Packet Radio Service). GPRS is a standard from the European Telecommunications Standards Institute on packet data in GSM (Global System for Mobile communication) systems and is the essential step towards 3G systems such as EDGE (Enhanced Data Rates for Global Evolution) and WCDMA (Wideband Code Division Multiple Access). The GPRS system supports end-users wishing to access the Internet and Intranets using a GSM mobile telephone as the connecting device. GPRS allows users to share the same air-interface resources and enables operators to base charging on the amount of transferred data instead of on connection time. PDC evolves via Packet PDC, and cdmaOne via cdma2000-1X. 1.4 Future - 3G By leaving the vertically integrated networks in 2G and entering the three-layered network in 3G, mobility becomes a fundamental aspect of many services. The 3G network creates synergy between the IP world (Internet) and mobile communication. The 3G systems such as EDGE and cdma2000-3X will provide traditional telecommunication services and new Internet-based services over the same network due to high bit rates (384 Kbit/s-2 Mbit/s) and packet switched transmission. EDGE and cdma2000-3X use the existing spectrum. WCDMA is a new radio transmission technology, proposed by leading standardization organizations. It is optimized for 3G services and is intended for deployment in the 2GHz frequency band. 1.5 Evolution to 3G

The evolution from second generation (2G) to third generation (3G) mobile

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systems will provide mobile access to Internet-based services and expand mobility in many areas of our lives.

There is a clearly defined migration path defined to take GSM networks into the Third Generation. It will provide networks with packet switching and radio networks that can handle the transmission speeds required. 1.6 Summary

In this chapter we have looked at the evolution of mobile networks from 1G through 2G to 3G. The next 5 chapters will examine the current restraints of 2G networks and we will take a more detailed look at to progressing toward the Third Generation.

BACK TO CONTENTS

TOP 2. Current limitations

2.1 The need for speed Mobile phone users and Internet users to a large extent are the same people. Sending e-mails and surfing the web is a part of their daily life, so is using mobile phones. It would be reasonable to assume that they would use their mobile phones to send e-mails and surf the web, but despite the fact that it’s possible to do so, most of them don’t. The main reason for this is low data speeds. If the speed was increased, more people would start using wireless Internet. The main problem with wireless Internet today is that we are sending data packets over circuit switched connections which means that we are making poor use of the available capacity. What’s really needed is packet switching in the mobile network. Let’s have a more detailed look at the meaning of the terms circuit switching and packet switching. 2.2 Circuit switching Imagine that a connection in the network is like a highway. A circuit switched connection means that you reserve the highway between two end points for a single connection and block all other entrances and exits. No one else can use the highway. This is a good solution for ordinary voice calls, where the connection is needed all the time. Consider how you surf the web. You click on a link and a short message is sent to a server somewhere in the world. After some delay, the web page appears on your screen and you read the information on the page for some time. While you are reading or waiting for information, the highway is not used, but it’s still blocked and can not be used by anyone else. This is an inefficient use of the network connection.

2.3 Packet switching

With packet switching, all entrances and exits on this information highway are always open. If a packet of information wants to enter the highway and it’s busy, it just simply waits until the road is clear.

TOP This method is ideal for applications like e-mail and web surfing where data is not sent continuously.

2.4 Packet switching: A basis for 3G Packet switching cannot perform miracles! With packet switching, sufficient network capacity is still required. If there are more packets than fit into the highway delays will occur. The advantage of packet switching is that it optimizes the usage of available connections when they are used for wireless Internet applications. So does packet switching in a network mean it is a 3G network? No, but it is a step towards it. Packet switching has more to do with how you use available resources rather than what capacity the system has. It is one of the major steps in building a third generation system, since it’s the basis for implementation of most wireless internet services. 2.5 Summary We have looked at how circuit switching can lead to low data rates and how packet switching can increase these speeds. In this way circuit switching can be regarded as a step towards 3G. The next chapter looks at what else is needed to evolve a network into a Third Generation network.

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TOP 3. Evolution towards 3G

3.1 WISE up! Going back to the definition of 3G, the first thing that’s needed is even more speed. New technologies that are being developed will make it possible to reach the required speeds. The WISE High Speed Internet is the first step in the evolution towards the third generation, a solution package that will turn GSM networks into wireless Internet networks. It includes the Integrated Access Server, High Speed Circuit Switched Data, HDLC Encapsulation, the Web on Air Filter Proxy and the services needed to get it going. Now to explain these technologies. 3.2 Integrated Access Server

If you want to connect a mobile user to Internet today, you have to go via the PSTN. The Integrated Access Server allows you to connect directly to the Internet. This way you save transmission, you avoid interconnection charges to the PSTN operator and you reduce the set-up time. 3.3 High Speed Circuit Switched Data High Speed Circuit Switched Data makes it possible to speed up the transmission over the air interface by using more than one time slot. There is no need for any additional equipment if the network already has a Data Transmission Interworking unit in the MSC and a subrate Switch in the BSC. In this case all that is needed for HSCSD is a software download. 3.4 HDLC Encapsulation

HDLC is an international standard protocol for reliably sending data over synchronous, serial communications lines. HDLC Encapsulation reduces the amount of data that has to be transmitted by removing information that is not

needed for this particular type of transmission. This is also a software only feature.

TOP 3.5 The WebOnAir™ Filter Proxy The WebOnAir™ Filter Proxy takes away information that doesn’t need to be transmitted and then compresses the remaining information to reduce even further the amount of data that has to be transmitted.

3.6 Summary

The combined effect of the different parts of High Speed Internet is a connection that can exceed an equivalent throughput of over 100 kbit/s, which is almost twice as fast as with a fixed network modem! Having looked at the advantages of the High Speed Internet, the question arises as to why we need GPRS (General Packet Radio Service) for 3G at all. The next chapter looks at the value of GPRS and how both GPRS and High Speed Internet will coexist for a long time to come.

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TOP 4. GPRS and the High Speed Internet

4.1 Why GPRS? GPRS (General Packet Radio Service) combines two of the worlds most successful businesses, Internet and GSM. A small but demanding share of the subscribers usually generate a large share of the profit. These subscribers expect to be supplied with the best available services. With GPRS you get a tool that allows you to create a whole range of new applications and services. These new services can be packaged with existing ones to create attractive offerings that will create more revenue and help operators stay competitive. GPRS will take you a big step towards the third generation. You can gain vital experience of applications and markets. 4.2 GPRS vs High Speed Internet Does this mean that High Speed Internet will have to be scrapped when GPRS comes along? Absolutely not. Circuit switching and packet switching are suited for different types of applications and will coexist for a long period. GPRS when it comes will use the existing GSM radio network, but not the switching network. Circuit switching and packet switching are very different in their nature. If they were to be integrated in the same node it would be quite complex. The disadvantage of having separate nodes is outweighed by the fact that they will become simpler and more efficient. 4.3 What is GPRS? Since GPRS is about wireless Internet, lets start at the Internet. The Gateway GPRS Support Node provides a gateway between the Internet and the PLMN, the mobile network that is. The Serving GPRS Support Node routes packets to and from GPRS subscribers that are located within an area called the SGSN service area. It also provides charging services by producing Call Data Records that are used for billing. When a subscriber wants to sign on to the network, the SGSN

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performs authentication. It also helps to keep track of subscribers who are moving around between different areas. The SGSN is connected to the GGSN. When a packet arrives from the Internet, the GGSN keeps track of which SGSN the packet has to be sent to. The SGSN passes the packet on to the Base Station Controller for delivery via the Base Station to the subscribers terminal. The SGSN is also connected to the Home Location Register to get authentication parameters and location and charging information. The Base Station Controller is not equipped to handle packets, so it will need a Packet Control Unit. From a network point of view we now have everything for GPRS, but mobile datacom isn’t only about the network. applications and services are needed to offer to subscribers. 4.4 Summary

Even with High Speed Internet and GPRS, we still haven’t come all the way to a third generation system. This is mainly because there are applications, like video for instance, that require higher speeds. So how do we get this even higher speed? The next step in the evolution of the GSM network is EDGE.

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TOP 5. EDGE

5.1 What is EDGE? EDGE stands for Enhanced Data rates for Global Evolution. EDGE is a technique that makes it possible to squeeze in three bits of information instead of one on the air interface. 5.2 How to get EDGE It is not necessary to install a new set of nodes. What you required is an EDGE-capable transceiver in your base station. Nor will it be necessary to visit every single site to install new transceivers. The next time another transceiver has to be added to the network to add capacity, you just make sure its an EDGE-capable transceiver. That way, when it’s time to roll out EDGE, all that needs to be done is download the software. The other nodes will get all the additional software they need in the same release.

5.3 Summary EDGE optimizes the use of existing network resources. So now we have a third generation system. The next question to ask is if an operator has EDGE, does it really need a UMTS license?

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TOP 6. UMTS

6.1 Why UMTS? Why buy a UMTS license? GSM and UMTS will exist and evolve in parallel. Mark Twain once said: “Buy land, they don’t make it any more”. The same goes for frequencies. Just like land, frequencies area limited resource.

6.2 What is UMTS?

UMTS (Universal Mobile Telecommunications System) is one of a number of third generation systems. The International Telecommunication Union has defined a framework for third generation systems called International Mobile Telecommunications-2000. UMTS one of these systems. UMTS has evolved from the GSM world. It has a new frequency spectrum and another transmission method, called Wideband CDMA, on the air interface. UMTS is also capable of even higher speeds than EDGE, and it has better spectrum efficiency. 6.3 Migration to UMTS

The migration to a UMTS network is similar to the migration to GPRS, but this time you need a new radio network. The UMTS and GSM radio networks are quite different, but there are also some similarities. UTRAN There are Radio Base Stations just like in GSM. There are also Radio Network Controllers. The Radio Network Controllers are connected to the Radio Base Stations, but also to each other to allow a mobile station to be connected to more than one Radio Base Station at the time, so called soft handover. All of this together forms the UMTS Terrestrial Radio Access Network, UTRAN for short. The Radio Network Controllers are also connected to the MSC as well as the SGSN. GSM phones will not work in UTRAN. Special UMTS phones will be needed. Dual mode phones, however, will work in both networks.

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Co-sited with GSM 1800, UMTS can provide coverage from the same sites, but if GSM 900 will need additional sites. GSM base stations will be able to handle UMTS. There will be a plug-in unit for the RBS 2000 series of base stations that makes it possible to handle UMTS. UMTS needs a new radio network. The rest of the network can be reused, but these nodes will have to be upgraded to provide UMTS functionality. Some new hardware will also be required, but the upgrades will mainly be software. Lets have a look at our network and see which nodes will be affected. Since UMTS is focused on datacom, lets start at the Internet. If packet is addressed to a UMTS subscriber, it first arrives to the GGSN, so this node must have a UMTS addition. The GGSN passes it on to the right SGSN. So this node must also have a UMTS addition. To find the subscriber, the SGSN has to ask the HLR for location information, so the HLR needs a UMTS addition. We still want to be able to receive ordinary voice calls in UMTS. An incoming call from say PSTN enters the network through the GMSC, so this node must have a UMTS addition. It’s switched to the serving MSC, so the MSC must also have a UMTS addition. As you see all nodes except the Integrated Access Server and the WebOnAir Filter Proxy were affected. All these nodes fit into a structure. Just like there was the UTRAN, there is the GSM Base Station System. Both radio networks are connected to a common GSM/UMTS Core Network. Within that core network, there is a separate circuit switched core network and a packet switched core network. 6.4 Layered Network Architecture There are many nodes in a UMTS network. Development is ongoing to create a simpler structure. This is in the form of layered network architecture. TRANSPORT LAYER At the base there will be a transport layer. I guess you could call it the body of the network. Here you find routine tasks like switching, routing and user data handling.

TOP CONTROL LAYER On top of that you have a control layer. If the transport layer was the body, then the control layer is the brain. Here you find network servers like MSC and HLR and others that perform more complex tasks like controlling calls and sessions and keeping track of moving mobiles. APPLICATION LAYER At the very top you find the application layer. This is where most end user applications, like for instance Internet applications will be implemented. In UMTS, a new concept called Virtual Home Environment will be introduced. It will make it possible to use any terminal in any network anywhere and still get access to the same services. It will also make it possible for independent application designers to offer services via standardised interfaces. 6.5 Summary

Finally we have evolved to a third generation system – UMTS, one of a number of third generation systems. This chapter looked at how the new UMTS network, UTRAN, is capable of even higher speeds than EDGE, and it has better spectrum efficiency. This new network affects many nodes and has a complex structure. We saw how research into a layered network architecture will endeavour to simplify this structure.

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TOP 7. Abbreviations cdma2000 CDMA2000, also known as IMT-CDMA Multi-Carrier or IS-136, is a code-division multiple access (CDMA) version of the IMT-2000 standard developed by the International Telecommunication Union (ITU). CdmaOne CDMA One, also written cdmaOne, refers to the original ITU IS-95 wireless interface protocol that was first standardized in 1993. It is considered a second-generation (2G) mobile wireless technology. EDGE Enhanced Data Rates for Global. GGSN Gateway GPRS Support Nodes GPRS General Packet Radio Services GSM Global System for Mobile communication HDLC High-level Data Link Control HLR Home location register HSCSD High-Speed Circuit-Switched Data IAS Integrated Access Server MSC Mobile Switching Centre PDC Personal Digital Cellular PLMN Public Land Mobile Network

TOP PSTN Public Switched Telephone Network SGSN Gateway Serving GPRS Support Nodes TDMA Time division multiple access UMTS Universal Mobile Telecommunications Service UTRAN UMTS Terrestrial Radio Access Network WCDMA wideband code-division multiple access WISE High Speed Internet Wireless Internet Solutions from Ericsson

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