Practical Education in Mobile Communications

STANISLAV HANUS Department of Radio Electronics Brno University of Technology Purkyňova 118, 612 00 Brno

CZECH REPUBLIC http://www.feec.vutbr.cz/UREL

Abstract: - This paper presents the basic information about establishing of the laboratory for Mobile Communications on Department of Radio Electronics, FEEC, Brno University of Technology. This information allow to experts from the practice to obtain the general image about the extent of theoretical knowledge and practical experiences of our students in this field. This information can be also useful for the specialists from high schools making simple comparison of their pedagogical activity in this field respecting the activity in another institute. Key-Words: - Mobile, wireless, systems, laboratory, courses, practices

1 Introduction In the last years the mobile communications have shown strong expansion either not only abroad and also in Czech Republic. It is possible to say, that in the imminent future the mobile communications will dominant participate in transfer of information between two subjects anywhere on globe. The new digital systems being used in mobile radio communications are operated upon quite new principles and use the latest technology discoveries. 2 New Courses on Wireless and Mobile Communications The High schools try to follow all new trends in field of mobile communications including its mediating to both students of Graduate and Post Graduate Doctoral Study. Therefore Faculty of Electrical Engineering and Communications, Brno University of Technology have entered the new optional course named „Wireless and Mobile Communications“ under recommendation of Specialisation Board of „Electronics and Communication“. After the following approving by Scientific Board of faculty, the new course has been introduced in teaching process for Master Study within 3 hours of the lectures and 2 hours of laboratory exercises per week. On Institute of Radio Electronics this course is lectured since four years ago and enjoy a great interest of students. The same course is lectured also for foreign students in English language since academic year 1999/2000. For students of Doctoral Study the course named „The Selected Topics of Wireless and Mobile Communications“ has been open since

academic year 1999/2000 within 3 hours of lectures per week. For a successful understanding of mobile communication systems problems there are presumed some theoretical knowledge of students. Students can obtain these theoretical fundaments in previous annual years mainly in following obligatory courses „Theory of Communication“ (2nd annual course, 1st stage), „Data Communication“ and „High Frequency and Microwave Techniques“ (Winter Term, 2nd annual course, 2nd stage). After finishing the obligatory courses named earlier, the students of 2nd annual year of 2nd stage can choose the course „Wireless and Mobile Communications“ the content structure of which can be described in following items: • The Distribution of Frequency Spectrum, the Distribution of Radio Communication Systems, a general circuit diagram of Radio Communication System and the basic relations. • Signal processing in Radio Communication Systems (Source Encoding, Channel Encoding, Interleaving, Digital modulations). • The basic philosophy of function of Radio Communication Systems. • The spurious effects affecting the signals and our possibilities to limit it (equalization, diversity reception, etc.). • Radio Telephone Systems (GSM 900, GSM 1800, including GPRS, HSCSD and EDGE, IS-95). • Cordless Telephony Systems (DECT). • Radio Paging (ERMES).

• The Advanced Radio Communication Systems (Universal Mobile Telecommunication System UMTS) • Universal Bluetooth System. • WiFi standards. After finishing this course the students of 3rd annual year of 2nd stage can select from menu of optional courses, which continue in and/or complete the previous one, i.e. the following courses: Radio Receivers and Transmitters, Radio Relay and Satellite Communication, Optoelectronics, Radio Communication Design or Signal processors. 3 Cooperation with Communications Companies Except the last theoretical recognition it has been very important to find and to ensure the corresponding practical form of teaching including the individual scientific work of students. Thanks to faculty cooperation with several Czech telecommunication companies, first of all with RadioMobil (at present time T-Mobile Czech Republic) and Wirelesscom Praha (which is ensured by reciprocal advantage contracts), the students can see, within the excursions, the operation of peak technology being used in current modern mobile systems. In addition to popular excursions it was necessary to complete the teaching process by some form of laboratory measuring and by individual work of students. 4 Research and Developing Projects In order to setting up the laboratory for the Mobile Communications, there have been made the developing project named „The Laboratory for practical training of the Mobile Communication Problems“. The project was approved in selective searching process within the subvention two million crowns from Ministry of Education Czech Republic. The aim of the project was built-up the laboratory and to create the collection of modern laboratory experimental tasks in branch of wireless and mobile communications. The conception of project is in coincidence with the world trend of Technical Universities on over the world - to enhance both the practical and the individual work of students. It must be said, that the building-up of the laboratory was a sophisticated task that cannot be cover by funds delivered by Foundation of Advancement of High Schools. It was necessary to use the funds of Institute of Radio Electronics together with the help of Faculty of Electrical Engineering and Communications. The establishing of

laboratory was a part of concept of research named „Research of Electronic Communication Systems and Technologies“, ID code CEZ: MSM 26200011, key number VUT: CZ 400011. During the building-up of laboratory there were entered the cooperation with several companies. By the expressive manner help us the company T-Mobile Czech Republic not only with material in costs of several millions crowns but also during consultations concerning the contents of laboratory experiments, including the ensuring of needful software together with delivered computers, the printout of printed lectures for course „Wireless and Mobile Communications“ etc. All activities named above make possible to built-up the laboratory having both unique measuring equipments and possibilities to solve modern laboratory tasks. 5 New Apparatus and Equipments in Laboratory The following measuring equipments have been ordered to utilize the funds of Foundation of Advancement of High Schools and Institute of Radio Electronics: • Digital radio communication tester CTS 65 R&S with accessories (436 330 Kč) • Digital radio communication tester CMD 53 R&S with accessories (741 730 Kč) – Fig. 1 • Spectrum analyser R 3132 R&S (509 290 Kč) – Fig. 2 • Spectrum analyser FSP3 R&S (over one milion crowns) – Fig 3.

Fig.1. Digital radio communication tester CMD 53

• Five notebooks with WiFi and Bluetooth. • TEMS program for monitoring radio environment of GSM system. • Mobile stations with GPRS, EDGE, etc.

Simultaneously there were ordered a many special books in publishing house Artech House in London. Using the help of company T-Mobile Czech Republic, the base station BTS of GSM system, produced by Motorola, have been installed in laboratory together with two antenna systems (one is diversity system). The base station BTS (Fig. 5) has two HF power stages (two radio duplex channels) with maximum output power 50W in each. The useful output power is limited in following circuits so, that radiated power in any place in laboratory and in neighbourhood does not exceed the health limits. The control of the base station (the change of settings) needs to connect the station to controller BTS of T-Mobile network. In regard to distance 1.5 km to the nearest controller BSC, the connection of both subsystems has been made using an optical cable connecting both buildings within academic metropolitan net.

Fig.2. Spectrum analyser R 3132

Fig.3. Spectrum analyser FSP3 6 Practical Experiments For the laboratory exercises there were prepared and realized the following experiments:

• The check of mobile station (MS) Motorola for GSM system - verification of synchronizing functions, up-dating of received data, setting-up of both the incoming and out coming calls, control of high frequency output power, measuring of PEP (Peak Envelope Power) and the test of echo. • The check of mobile station Ericsson for system GSM (or DECT) - auto-test for check of all functions of data terminal, measuring the tolerance diagram of time slot - power ramping function. • The synthesiser with undirected coherent synthesis - the laboratory aid with Motorola integrated circuit. The checking of output signal frequency stability, measuring of phase noise of the output signal. Interleaving on PC demonstration. • The identification of basic capabilities of Ericsson’s TEMS routine. The tracking of both the call processing and the call decay in GSM network using program TEMS, etc. • The check of mobile station Motorola for GSM system - measuring of both the frequency and phase error, analysis of high dynamic bursts, quick spectra measuring during switching terminal and modulation, narrow-band signal spectrum analysis and the testing of SIM card. • The check of mobile station Ericsson for system GSM - the analysis of demodulated signal, the check of timing and its accuracy and error rate measuring of BER. • The check of MS Nokia for system GSM - the check of HF blocks frequency characteristics, the display and determination of single bursts in signalling channels FCCH (frequency synchronization), SCH (time synchronizing) and BCCH (important data for MS). • Repeater in GSM system (Fig.4).

Fig.4. Testing of repeater in GSM system

• The observation of mobile station during handover transfer using TEMS routine. • The data transmission in GSM network using modems - determination of transmission rate and error rate BER. • Frequency hopping in GSM network. Simulation in MatLab program.

• GPRS user data throughput in GSM system. Program for testing different coding schemas of GPRS standard. • Coexistence of Bluetooth and WLAN systems. Simulation of transmission in MatLab environment over radio channel with AVGN. • Bluetooth data transmission • WiFi data transmission. • At present time are prepared laboratory experiments on testing of EDGE transmission over real network and simulation of UMTS transmission in MatLab program.

Fig.5. Base Transceiver Station in Laboratory

7 Utilization of Laboratory The teaching processing of course Wireless and Mobile Communications where the laboratory is dominant exploited was began in summer term of academic year 2000/2001. In course there were registered 51 students. Simultaneously was carried out the teaching of Selected Topics of Wireless and Mobile Communications for doctoral study. At present academic year 2004/2005 is registered in this course over 200 students. The utilisation of laboratory and also the measuring laboratory equipments is predicted also in following courses: HF and Microwave Techniques (obligatory course), Radio Receivers and a Transmitters (optional course) and in Radio Relay and Satellite Communications (optional course). The exploitation of laboratory is planned also for a new prepared specialisations Electronics and Communication Techniques and Teleinformatics for bachelor study and Electronics and Radio Communication and Telecommunication and Informatics Techniques for master study. Acknowledgement This research is supported by Czech Ministry of Education, FRVŠ project No. IS 1840140 and also the Grant Agency of the Czech Republic, Grant project No. 102/04/2080. This research also represents a part of the Research Programme of the Czech Ministry of Education MSM 262200011, “Research of Electronic Communication Systems and Technologies” and MSM 262200022, “Research of Microelectronic Systems and Technologies MIKROSYT”. References: [1] SVAČINA, J. Laboratory for Practice Education of Mobile Communications Problems. The Ministry of Education, Youth and Sports of Czech Republic. Final Report. Brno, 2000 [2] HANUS, S. The Laboratory of Wireless and Mobile Communications on Institute of Radio Electronics, FEECS, Brno University of Technology. Proceedings of the 11th International Czech-Slovak Scientific Conference RADIOELEKTRONIKA 2001. Brno 2001, pp. 306-309.