Faculty of Electrical Engineering Universiti Teknologi Malaysia

Transcription

1 COEXISTENCE BETWEEN THE MOBILE SERVICE AND TERRESTRIAL- DIGITAL VIDEO BROADCASTING IN THE MHz FREQUENCY BAND MOHAMMED B. MAJED A dissertation submitted in partial fulfilment of the requirements for the award of the degree of Master of Engineering (Communication Engineering) Faculty of Electrical Engineering Universiti Teknologi Malaysia JANUARY 2010

2 iii This work is dedicated to my beloved parents, my family, my friends and all my teachers who helped me to become who I m.

3 iv ACKNOWLEDGMENT Firstly, I thank Allah, for giving me this opportunity of life, and for acquainting me with all those beautiful people. This dissertation would not have been possible without the kind support and encouragement of Professor Dr. Tharek Abd. Rahman. I am grateful to him for his caring supervision, his enthusiastic involvement in this dissertation and his supportive suggestions and comments. Finally, My family for their never ending loves and support in all my efforts, and for giving me the foundation to be who I am. My fellow graduate students, for their friendships and support. The last year in the UTM has been quite an experience and you have all made it a memorable time of my life.

4 v ABSTRACT The International Telecommunication Union for Radiocommunication (ITU-R) became involved with the spectrum allocation for next generation mobile communication services in World Radio Communication conference 2007 (WRC- 07). The reason is to minimize the adjacent channel interference between Mobile service and DVB-T system within the same geographical area. Therefore the objective of this research is to study the compatibility between Mobile services as a case study for the International Mobile Telecommunication (IMT-Advanced) and Digital Video Broadcasting Terrestrial (DVB-T) in the 790 to 862 MHz frequency band. This research also involves the studies and propagation characteristics within this band which can provide better coverage. Possibility of coexistence and sharing analysis were obtained by taking into account the detailed calculations of the path loss effect by using the practical parameters of DVB-T and Mobile service. The interference has been analyzed and simulated for several environments (rural and suburban) in different channel bandwidths for Mobile service at 5MHz and 20MHz, and in different transmitted power for Digital Video Broadcasting Terrestrial. From simulation on ICS telecom (Information Communication Solutions) software the best separation distance are Km and Km for bandwidth of 5MHz and 20 MHz respectively. In the simulation two scenarios in two different places; Johor Bahru and Terual state in France were applied. The project involves identification of the spectrum suitability for systems to operate in the band 790 to 862 MHz. This is done by taking into account that the operation of broadcasting stations in the same geographical area may create incompatibility issues and intersystem interference between two wireless communication systems.

5 vi ABSTRAK Kesatuan Telekomunikasi Antarabangsa bagi radiokomunikasi (ITU-R) terlibat dalam agihan frekuensi spektrum untuk generasi radio bergerak masa hadapan dalam seminar komunikasi radio sedunia 2007 (WRC-07). Alasannya adalah untuk meminimumkan gangguan saluran yang berdekatan antara perkhidmatan sistem radio bergerak dan Digital Video Broadcasting - Terrestrial DVB-T sistem dalam kawasan geografi yang sama. Oleh kerana itu objektif kajian adalah untuk mengkaji keserasian antara perkhidmatan sistem radio bergerak sebagai kajian kes untuk International Mobile Telecommunication (IMT-Advanced) dan (DVB-T) pada julat frekuensi MHz. Penyelidikan ini juga melibatkan kajian dan ciri perambatan dalam jalur ini bagi menyediakan liputam yang lebih baik. Analisis kemungkinan perdampingan dan perkongsian diperolehi dengan mempertimbangkan pengiraan terperinci kehilangan dengan menggunakan parameter praktikal yang digunakan dalam DVB-T dan perkhidmatan bergerak. Gangguan ini telah dianalisia dan disimulasikan untuk beberapa kawasan (luar bandar dan pinggiran bandar) pada berbagai lebarjalur saluran untuk perkhidmatan Mobile 5MHz dan 20MHz, dan pada pelbagai kuasa terpancar dari DVB-T. Dengan menggunakan perisian simulasi ICS telecom, jarak tebaik adalah Km dan Km dan untuk lebarjalur 5MHz dan 20MHz. Dalam simulasi ini dua senario di dua tempat yang berbeza; Johor Bahru dan kawasan Terual di Perancis telah digunakan. Projek ini adalah untuk mengenalpasti kesesuaian sistem spektrum yang beroperasi pada jalur MHz. Ini dilakukan dengan mengambil kira bahawa pengoperasian stesen penyiaran di kawasan geografi yang sama mungkin menimbulkan masalah ketidakserasian dan gangguan antara dua sistem komunikasi wayarles.

6 vii TABLE OF CONTENTS CHAPTER TITLE PAGE DECLARATION DEDICATION ACKNOLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS LIST OF APPENDICES ii iii iv v vi vii xi xii xiv xvi 1 INTRODUCTION Problem Statement Objectives Scope of Work Thesis Organization Summary 5

7 viii 2 LITERATURE REVIEW Introduction Background Compatibility an EU Spectrum Plan Spectrum-Related Requirements DVB-T DVB-T Single Frequency Network The Digital Dividend Digital Dividend in Europe Spectrum Policy of Digital Dividend The Propagation Characteristics of Spectrum Interference Interference Types Adjacent Channel Interference Interference Problem Managing Interference Between 25 Systems Co-existence in the UHF TV Band Interference Assessment from DVB-T into IMT-Advanced Analytical Results Conclusion Summary 30

8 ix 3 METHODOLOGY Introduction Data Collection Analysis and Calculation Method Propagation Model Egli Model Longley Rice model Okumura model COST 231 model Hata Model Summary 44 4 SIMULATIONS AND MEASUREMENTS 45 RESULTS 4.1 Introduction MATLAB Simulation Calculation for 5MHz Channel 46 Bandwidth Calculation for 20MHz Channel 48 Bandwidth 4.3 ATDI (ICS-TELECOM) Simulation Propagation Model ATDI Simulation Measurements Scenarios 53

9 x Suburban Region Without 54 Buildings 1. Coverage and 54 Measurements for 5MHz channel bandwidth 2. Coverage and Measurements for 20MHz channel bandwidth Suburban Region With 57 Buildings 1. Coverage and 58 Measurements for 5MHz channel bandwidth 2. Coverage and Measurements for 20MHz channel bandwidth Comparison between two 62 scenarios 4.4 Summary 63 5 CONCLUSION AND RECOMMENDATION Conclusion Future Works 65 REFERENCES 67 Appendices A-C

10 xi LIST OF TABLES TABLE NO. TITLE PAGE 2.1 The outcome and result of the WRC-07 for the 9 band /862 MHz 2.2 Available bitrates (Mbit/s) for a DVB-T system in 15 8 MHz channels 2.3 IMT-Advanced and DVB-T services parameters IMT-Advanced Mobile Station Parameters IMT-Advanced Base Station Parameters DVB-T System Parameters Separation Distance in Different Interference 48 Level 4.2 Separation Distance in Different Antenna Height 51

11 xii LIST OF FIGURES FIGURE NO. TITLE PAGE 2.1 ITU-R Framework WRC-07 outcome for IMT system bands The propagation characteristics of spectrum Range of powers in wireless systems Interference margin between wanted signal and 26 interference signal 3.1 Flowchart of Research Methodology Represent carrier to interference level in related to 35 the noise level 4.1 The separation distance between mobile service 47 5MHz channel bandwidth and DVB-T station in different transmitted power 4.2 The separation distance between mobile service 49 20MHz channel bandwidth and DVB-T station in different transmitted power, and antenna height (hb)=100 m 4.3 The separation distance between mobile service 50 20MHz channel bandwidth and DVB-T station in different transmitted power, and antenna height (hb)=30 m 4.4 ATDI simulation coverage result for 5MHz channel 54 bandwidth. 4.5 Points sites inside Johor Bahru. 55

12 xiii 4.6 ATDI simulation coverage result for 20MHz channel 56 bandwidth. 4.7 Points sites inside Johor Bahru Coverage area in Terual state, French for 5MHz 58 channel bandwidth. 4.9 Points sites inside Terual state, French Profile Terrain from DVB-T station towards Mobile 60 service (point 4) 4.11 Coverage area in French for 20MHz channel 61 bandwidth Profile Terrain from DVB-T station towards Mobile service (point 5) 62

13 xiv LIST OF ABBREVIATIONS ITU-R - International Telecommunication Union for Radiocommunication WRC - World Radiocommunication Conference IMT - International Mobile Telecommunications UHF - Ultra high frequency DVB-T - Digital Video Broadcasting Terrestrial DVB-H - Digital Video Broadcasting Handheld GE06 - Geneva agreement 2006 WARC - World Administrative Radio Conference FPLMTS - Future Public Land Mobile Telecommunication Systems GSM - Global System for Mobile communications CIS - Commonwealth of Independent States PPDR - Public Protection and Disaster Relief WiMAX - Worldwide Interoperability for Microwave Access EU - European Union DTT - Digital Terrestrial Television MPEG - Moving Picture Experts Group COFDM - Coded Orthogonal frequency-division multiplexing OFDM - Orthogonal frequency-division multiplexing ETSI - European Telecommunications Standards Institute SFN - Single-Frequency Network GPS - Global Positioning System ISI - Inter Symbol Interference OFCOM - Office of Communications FCC - Federal Communications Commission

14 xv EC - European Commission CEPT - European Conference of Postal and Telecommunications Administrations DSO - Digital Switchover ACLR - Adjacent Channel Leakage Ratio ACS - Adjacent Channel Selectivity ACI - Adjacent Channel Interference BER - Bit Error Rate ACIR - Adjacent Channel Interference Ratio RSPG - Radio Spectrum Policy Group BEM - Block Edge Mask BS - Base Station LOS - Line-of-sight

15 xvi LIST OF APPENDICES APPENDIX. TITLE PAGE A DVB-T system parameters (EIRP= dbm) 70 DVB-T system parameters (EIRP= 48.4 dbm) 71 B DVB-T Antenna Transmitter Radiation Pattern 72 C Propagation Model Specifications 73

16 CHAPTER 1 INTRODUCTION The radio spectrum is a limited resource, and as a result of the drastic growth demand for wireless communication applications, radio spectrum regulation and management have become increasingly significant. On the other hand, it is commonly believed that the usage of spectrum is vastly underutilized all over the world [1]. In recent years, this inefficient utilization of spectrum motivates many communication engineers to pay attention to spectrum management such as resource allocation, coexistence, and spectrum sharing in order to promote more flexibility in spectrum usage. Due to scarcity of the frequency spectrum, many bands are allocated for more than one radio service and thus the sharing is necessity. Consequently, the increased sharing of spectrum translates into a higher likelihood of users interfering with one another [2].

17 2 Interference between two wireless communication systems (intersystem interference) occurs when these systems operate at overlapping frequencies, sharing the same physical environment, at the same time with overlapping antenna patterns which leads to capacity loss and coverage limitation [3]. International Telecommunication Union for Radiocommunication (ITU-R) has become involved with the spectrum allocation for next generation mobile communication services in WRC-07. During work performed within ITU-R working party (WP) 8F (the last WRC-07), the frequency band of MHz (the 800 MHz band) has been allocated to the mobile service and identified for the future development of International Mobile Telecommunications IMT which includes (IMT-2000 and IMT-Advanced) systems in Europe and others countries from the year 2015, meanwhile, this frequency band is currently used by broadcasting services in most of the world countries including Malaysia [4,5]. This means that interference probability due to frequency sharing between these two systems is bound to happen if the two systems operate in adjacent areas with same carrier frequency (co-channel frequency) or in the same area with an adjacent carrier frequency. This amount of spectrum is in fact limited when compared to the frequency bands identified for mobile in other regions. Nevertheless, it will allow a valuable positive evolution of spectrum usage in Europe and some countries have decided to start using this capacity earlier than The band plan for mobile services in the UHF band will play a crucial role in enabling mobile operators to make the most efficient use of this spectrum, and hence to provide the greatest economic and social benefit [5].

18 3 Meanwhile, the said band is currently allocated for broadcasting services which means that interference may be occurred between the mobile service and broadcasting services and thus systems performance will be degraded, therefore interference and coexistence studies between these systems should be done to investigate the probability of the harmful interference effects on the possibility of coexistence and spectrum sharing between these systems. 1.1 Problem Statement Communication technologies in the 800 MHz band are used for broadcasting television signals, radio navigation, internet delivery, data communication and voice telephony. The systems that operate in this band (800 MHz) are suffering substantial interference, to the point of system failure. Several national administrations have designated portions of the frequency band MHz for terrestrial wireless applications such as mobile services and (IMT advanced, beyond 3G, 4G). This band was already allocated to the broadcasting and radio navigation services. The problem is the adjacent channel interference that causes degradation in user connectivity in term of throughput, connection quality and in range. The Adjacent channel interference from the name is caused by the neighbouring channels. Adjacent channel interference, when is not minimized, decreases the ratio of carrier to interference. This ratio of carrier to interference will then be used in measuring the adjacent channel interference.

19 4 1.2 Objectives In this dissertation the interference between Mobile Service and TVbroadcasting (DVB-T) is considered and the aim of the dissertation is to avoid adjacent interference between Mobile Service and DVB-T by using minimum separation distance. The other objectives to achieve the aim aforementioned are outlined as below: To calculate the exact value of the mutual power interference between two systems. To verify the feasibility of coexistence between the mobile service and broadcasting services in the specified band depending on the input specification. To determine the separation distance to coexist each two systems, decrease the interference. 1.3 Scope of Work The scope of this dissertation is to carry out the spectrum sharing and coexistence studies, Spectrum occupation and Systems Specifications for mobile service and broadcasting will be covered. All necessary formulas that should be applied for sharing studies have to be analyzed and the required parameters are going to be determined. The required coexistence and interference criterion values for each

20 5 service should be adjusted and assessed. Specifications, suitable radio propagation models and its parameters and coefficients should be estimated. 1.4 Thesis Organization The thesis comprises of five chapters beginning with a brief introduction. Literature review shall be discussed in the next chapter. Previous researches related to the effect of the adjacent channel interference and the separation distance as the mitigation technique have been presented in the Chapter 2. The methodology and the calculation methods, analysis and the specification to find the separation distance between Mobile Service and DVB-T have been existing in Chapter 3. Chapter 4 demonstrated the two simulations MATLAB and ATDI to calculate and measure the separation distance between Mobile Service and DVB-T. Finally, conclusion and future works are showed in Chapter Summary This chapter defines the importance of this research, the aim and objectives, scope of work as well as the problem statement observed. The outline has been also described.

21 CHAPTER 2 LITERATURE REVIEW 2.1 Introduction ITU-R WRC 2007 decided to allocate 72 MHz, in the frequency range MHz in region 1 (Europe, Middle East, Africa) for mobile services on a coprimary basis, and the band MHz was already allocated to broadcasting in region 1 (as well as on co-primary basis with fixed service in the sub-band MHz only) on a primary basis [4]. It should be noted that these measures do not limit mobile service to this frequency range. The Radio Regulations and the Geneva agreement 2006 (GE06) enable mobile services to operate anywhere in the MHz frequency range, subject to bilateral agreement among the countries that might be affected in order to avoid harmful interference [5].

22 7 Broadcasting services in band IV( ) and V( )MHz would be limited to the frequency band MHz, when deploying mobile services in the frequency range MHz there is a potential risk of adjacent channel interference into existing digital TV services using channels below channel 61 (below 790 MHz) [6]. The technical analysis considers the different interference mechanisms and shows that unacceptable interference can be caused even by DVB-T transmitters that are located several kilometers away from the affected Mobile Station [4]. 2.2 Background Spectrum is an essential but limited resource in wireless communications. The continuous increase in number and popularity of wireless communication systems has led together with the emergence of new services to an increased demand for more spectrum. Initially the WARC-92 identified some bands for Future Public Land Mobile Telecommunication Systems (FPLMTS). This name was later changed to IMT As a consequence of the global success of GSM already by the year 2000 a need for more spectrum was recognized. This ended up in that the WRC-2000 identified additional spectrum for IMT and the amount was estimated to be sufficient by year The identified spectrum was meant to facilitate the predicted capacity growth of IMT-2000 with high data rate, delay sensitive and high envisioned services. However, it was foreseen that the evolution does not stop by year 2010 [4].

23 8 Accordingly ITU-R prepared soon after the WRC-2000 a Framework Recommendation M.1645 to address the vision of the future mobile communication. The vision of the ITU-R and international research community of IMT-Advanced is a ubiquitous radio system concept offering further enhanced performance and providing wireless access for a wide range of services and applications across all environments. The widened scope of IMT-Advanced is shown in Figure 2.1 Figure 2.1, ITU-R Framework [4] As mentioned in the ITU-R regulation, the band MHz was already allocated to broadcasting in region 1 (with fixed service in the sub-band MHz only). While in region 3 including Malaysia, the band MHz was already allocated to the fixed, mobile and broadcasting services on co-primary basis. The part MHz is now identified for IMT in some countries but the part MHz is identified for IMT in the whole Asia, as shown in Figure 2.2 [7].

24 9 Figure 2.2 WRC-07 outcome for IMT system bands [7] The current outcomes of WRC-07 for the frequency bands /862 MHz are (Table 2.1) as follows: MHz band in Region 2 (Americas) - allocated for mobile services and identified for IMT MHz band in Region 1 (Europe, Middle East, Africa) allocated to the mobile service and identified for IMT from However, in more than 70 Region 1 countries, the mobile allocation and IMT identification in all or parts of the MHz band will come into effect immediately MHz identified for IMT in Region 3 (Asia-Pacific): India, Korea, New Zealand and Singapore identified all or part of the MHz band for IMT consistent with actions taken in Region 2, China to wait until 2015 for implementation.

25 10 Table 2.1 The outcome and result of the WRC-07 for the band /862 MHz The band Region MHz Region 2 (Americas) MHz Region 1 (Europe, Middle East, Africa, Russia and CIS) MHz identified for IMT in Region 3 (Asia-Pacific) The sub-bands MHz is currently used in some countries for Public Protection and Disaster Relief (PPDR); and the bands MHz (in Region 2) and MHz and MHz (in Region 3) are currently identified for PPDR. The UHF band ( MHz) is the only band for widespread development of digital terrestrial television services, whereas mobile telecommunications services, including wireless broadband services (e.g. WiMAX), can be deployed in other frequency bands. Requirements for transmission capacity in the broadband networks are continually increasing owing to ever more complex content and services, and a constantly growing usage time. The capacity of the UHF bands (e.g. in the range MHz which is co-allocated to mobile services alongside broadcasting) will most probably become insufficient to meet such growing demand [8].

26 Compatibility European Union spectrum plan The European Commission proposes the creation of three sub-bands within the UHF band, one for broadcasting, one for mobile television, and one for fixed and mobile broadband access services. This would mean that part of the complex Geneva 2006 Plan (GE-06) would have to be reworked. This international frequency agreement defined the use of the whole UHF bands IV/V ( MHz) for digital terrestrial television services in Europe, Africa and the Middle East. The last ITU World Radiocommuncation Conference (WRC-07) in November 2007 clearly recognized the inherent interference problem between broadcasting and mobile telecommunications services. While WRC-07 gave ITU Member States in European countries an option to open up part of the UHF bands for mobile services under certain conditions, it also confirmed that the GE-06 Plan with all future developments needs to be respected. Countries that wish to implement mobile services in the UHF band 790 MHz 862 MHz are requested to protect broadcasting services against harmful interference from mobile services. In addition, it was decided that the ITU would carry out technical studies on the sharing of broadcasting and mobile services. The results of these studies will be considered at the next World Radiocommunication Conference, in 2011 [8].

27 Spectrum-related requirements This section describes the high level spectrum related minimum requirements suggested to be set for the IMT-Advanced systems. These minimum requirements were contributed to ITU-R WP 8F and can be found in ITU-R Document 8F/1295 Finland [32]. The need for spectrum related minimum requirements has arisen with the evolution of IMT-2000 and introduction of IMT-Advanced in different bands and with different services. The requirements include more efficient spectrum utilization to allow spectrum resources to be shared with other users or systems, and to enable harmonized use of spectrum thereby facilitating global roaming. At World Radiocommunication Conference 2007, the following bands were identified for use by IMT-Advanced: MHz, MHz, MHz and MHz. There are however some conditions linked to the bands. In addition to these bands, the following bands are identified in the Radio Regulations for IMT: MHz and MHz (WARC-92, No ), 806/ MHz (WRC-2000, No A), MHz and MHz (WRC- 2000, No A). IMT-Advanced technologies are expected to cover a wide range of services by having a range of performance capabilities beyond those of IMT For the highest performance and/or capacity, wide bandwidths are needed, whereas if the coverage is emphasized narrow bandwidths can be employed. In the ideal case the IMT-Advanced bands would be globally common, however, it should also be foreseen that the actual bands made available in various countries may be different. For these reasons the IMT-Advanced candidate technologies should be able to utilize any of the bands identified for IMT-2000 as well as in all bands identified in WRC- 07 for IMT-Advanced [4].

28 13 Some bands identified for IMT are shared with other primary services. IMT- Advanced in the Mobile Service (MS) should be able to share spectrum and coexist with stations of the existing primary services in the new bands identified for IMT. This could mean that IMT-Advanced may require spectrum functionalities e.g. control of the emissions into the bands shared between IMT-Advanced and the other co-primary Services. Each IMT-Advanced concept should specify how the sharing is planned with other Services. 2.5 DVB-T DVB-T is an abbreviation for Digital Video Broadcasting Terrestrial, it is the DVB European-based consortium standard for the broadcast transmission of Digital Terrestrial Television DTT that was first broadcast in the UK in This system transmits compressed digital audio, video and other data in an MPEG transport stream, using COFDM modulation [9]. Rather than carrying the data on a single radio frequency carrier, OFDM works by splitting the digital data stream into a large number of slower digital streams, each of which digitally modulate a set of closely spaced adjacent carrier frequencies. In the case of DVB-T, there are two choices for the number of carriers known as 2K-mode or 8K-mode. These are actually 1705 or 6817 carriers that are approximately 4 khz or 1 khz apart. DVB-T offers three different modulation schemes which are QPSK, 16QAM and 64QAM. DVB-T has been adopted or proposed for digital television broadcasting by many countries, using mainly VHF 7 MHz and UHF 8 MHz channels [10].

29 14 The DVB-T Standard is published as EN , and as ETSI TS , which gives details of the DVB use of source coding methods for MPEG-2 and, more recently, H.264/MPEG-4 AVC as well as audio encoding systems. Many countries that have adopted DVB-T have published standards for their implementation [33,34]. DVB-T has been further developed into newer standards such as DVB-H (Handheld), now in operation, and DVB-T2, which was recently finalized. DVB-T as a digital transmission delivers data in a series of discrete blocks at the symbol rate. DVB-T is a COFDM transmission technique which includes the use of a Guard Interval. It allows the receiver to cope with strong multipath situations. Within a geographical area, DVB-T also allows single-frequency network (SFN) operation, where two or more transmitters carrying the same data operate on the same frequency. In such cases the signals from each transmitter in the SFN needs to be accurately time-aligned, which is done by sync information in the stream and timing at each transmitter referenced to GPS [11]. The length of the Guard Interval can be chosen, it is a tradeoff between data rate and SFN capability. The longer the guard interval the larger is the potential SFN area without creating Inter Symbol Interference (ISI). It can be possible to operate SFNs which do not fulfill the guard interval condition if the interference is properly planned and monitored.

30 15 Table 2.2 Available bitrates (Mbit/s) for a DVB-T system in 8 MHz channels Modulation Coding rate Guard interval MER per carrier (db) 1/4 1/8 1/16 1/32 1/ / QPSK 3/ / / / / QAM 3/ / / / / QAM 3/ / /

31 DVB-T single frequency network One of the advantages of using OFDM as the form of modulation is that it allows the network to implement what is termed a single frequency network. A single frequency network, or SFN is one where a number of transmitters operate on the same frequency without causing interference. Many forms of transmission, including the old analogue television broadcasts would interfere with one another. Therefore when planning a network, adjacent areas could not use the same channels and this greatly increased the amount of spectrum required to cover a country. By using OFDM an SFN can be implemented and this provides a significant degree of spectrum efficiency improvement. A further advantage of using a system such as DVB-T that uses OFDM and allows the implementation of an SFN is that very small size transmitters can be used to enhance local coverage [10]. 2.6 The Digital Dividend The transition from analogue to digital television is expected to result in situations where the band MHz will be used for both analogue and digital terrestrial transmission, and the demand for spectrum during the transition period may be even greater than the stand-alone usage of analogue broadcasting systems, the switch-over to digital may result in spectrum opportunities for new applications and the timing of the switch-over to digital is likely to vary from country to country. Furthermore, the Radio Regulations provide that the identification of a given band

32 17 for IMT does not preclude the use of that band by any application of the services to which it is allocated and does not establish priority in the Radio Regulations. Therefore the use of spectrum for different services should take into account the need for sharing studies. The Radio Regulations and the GE06 agreement enable mobile services to operate anywhere in the MHz frequency range, subject to bilateral agreement among the countries that might be affected in order to avoid harmful interference [5] Digital Dividend in Europe Today broadcasters use the whole band MHz which has been planned by the Regional Radiocommunication Conference in 2006 in relation to the digital switchover. Transition from analogue to digital broadcasting will free some spectrum, due to the higher spectrum efficiency of digital technology. The released spectrum is called Digital dividend and is expected to present a significant amount of spectrum: At least 100 MHz according to UK OFCOM and FCC. 300 to 375 MHz of the current amount allocated to terrestrial broadcasting could be freed and become newly available if analogue TV broadcasting is switched to digital transmission (same image resolution and size, same number of channels).

33 18 The Digital Dividend will open the way for real wireless innovation and the potential for new services, such as [12]: Additional terrestrial broadcasting, including data services and increased quality to the traditional broadcasting services and HDTV (high definition TV). Mobile services, with high quality video and interactive media delivered to handheld devices (DVB-H). Convergence between broadcasting and telecommunication services. Wireless broadband services, with high-speed data and voice services. Wider coverage for advanced services in remote and rural areas. This spectrum is particularly suitable for low cost, wider-area coverage Spectrum Policy of Digital Dividend The communication of the European Commission, notably the EC study appears as giving full support to the national initiatives to open the 800 MHz to wireless broadband services, even the allocation of the whole sub band to those new services, as the most pragmatic way forward. CEPT has elaborated a non mandatory, flexible approach, to a preferred solution, Report 31, including some second best alternatives concerning the partial use of the 800 MHz for other primary services including broadcasting [8]. This flexible concept should be part of

34 19 EC policy and Digital Dividend Roadmap, to integrate those Member States which cannot cope with the moving of digital TV spectrum. The principal virtue of the CEPT arrangement is to have only one spectral point of adjacency, 790 MHz, to ease the interference levels from the mobile terminal stations over the DTT reception. The drawback is to oblige to administrations, broadcasters, operators, to undertake a very complex migration of the current DTT frequencies to lower UHF spectrum under the auspices of GE06 agreement without altering the structure of this international treaty. It is of strategic importance to avoid any proposal to further insert other systems into the UHF, band. The implementation of the Digital Dividend should be accomplished by means of a timely coordination with the culmination of DSO, digital switchover, the migration of DTT frequencies, the launch of advanced Digital TV services, etc. The protection of both services, mobile and broadcasting, and the treatment given to the definition of the technical measures on both sides of the 790 MHz boundary, should be confirmed in the Digital Dividend Roadmap and Policy [13].

35 The Propagation Characteristics of Spectrum This spectrum is very valuable, particularly to wireless operators, because of the propagation characteristics at these frequencies. They offer an optimal combination of range and data capacity. For example, at 3.5 GHz, the signal covers a reception radius, or cell size, of about 5 km while at 800 MHz it is about 8-10 km, as shown in Figure 2.3 Figure 2.3 The propagation characteristics of spectrum [14] Economically, these features determine infrastructure cost. Better propagation means fewer base stations, thus the network infrastructure investment is nearly seven times higher if wireless operators have to use 3500MHz compared to the larger cell sizes at 700 MHz, or even higher at the lower frequencies in the Digital Dividend. Moreover, improved propagation qualities also means better reception for mobile phones inside buildings a factor that may hold back substitution of wireless for fixed- line communications in the future. Thus the UHF band has particularly valuable properties for wireless communications networks, using any generation of

36 21 technology whether it be 2G cellular, 2.5G, 3G or 4G or, as we look to the future, novel radio technologies such as WiMax or WiFi [14]. 2.8 Interference The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy [15] Interference Types When a system IMT-Advanced of other is considered, main type of interference is intrasystem interference, including interference coming from given cell, adjacent cell, and thermal noise. Whereas two systems coexist in the same geographic area, the interference includes not only intrasystem interference, but also intersystem interference [16] which is considered in this chapter.

37 Adjacent Channel Interference The level of interference received depends on the spectral leakage of the interferer s transmitter and the adjacent channel blocking performance of the receiver. For the transmitter, the spectral leakage is characterized by the ACLR, which is defined as the ratio of the transmitted power to the power measured in the adjacent radio frequency (RF) channel at the output of a receiver filter. Similarly, the adjacent channel performance of the receiver is characterized by the ACS, which is the ratio of the power level of unwanted ACI to the power level of co-channel interference that produces the same bit error ratio (BER) performance in the receiver. In order to determine the composite effect of the transmitter and receiver imperfections, the ACLR and ACS values are combined to give a single Adjacent Channel Interference Ratio (ACIR) [17]. 2.9 Interference Problem Digital broadcasting is characterized by a rapid transition from near perfect reception to no reception at all - and thus it is more critical to harmful interference than it is the case for analogue broadcasting. The implementation of other services than broadcasting in the 800 MHz band has to be carried out in a way that no additional constraints are imposed on broadcasting services according to the current GEO6 plan and its evolution. In particular, it has to be ensured that there is neither additional interference nor restriction on the of the usage of UHF channel 60. In this respect it likes to recall that the RSPG stated in its opinion on the Digital Dividend that a mobile allocation would be sought after under conditions that broadcasting services are not adversely impacted.

38 23 In many situations, it may be difficult to protect broadcasting services from interference caused by mobile services. Such types of interference may also be difficult to identify, and to remedy rapidly. Especially the results of recent compatibility studies (adjacent band compatibility between broadcast services below 790 MHz and mobile services above 790 MHz) between the broadcasting service and the fixed/mobile services (including uplinks) should be taken into consideration. Results from preliminary compatibility studies between broadcasting and mobile services show the difficulties. The studies conclude that interference will occur with the currently discussed channeling arrangement and BEM (Block Edge Mask) and that additional measures will be needed to protect the broadcast services [18]. Radio signals are characterized by the frequency on which they are transmitted. To receive a radio signal, it must be above both the noise floor and the level of any unwanted signals on the same frequency. These unwanted signals are called interference. The level of this noise floor is extremely low many radio systems can successfully receive a signal that is at least a million billion times weaker than what was transmitted, as Figure 2.4.

39 24 Figure 2.4 Range of powers in wireless systems Radio signals have a tendency to spill into other frequencies, and can then cause interference to other radio signals on those frequencies. There are technical ways to constrain a radio signal to its operating frequency and to limit this interference, it becomes much better at doing so with advances in technology. These have costs in terms of equipment price, energy efficiency and the ability of the equipment to operate on multiple frequencies. The effect of these limitations is greatest when different signals are immediately adjacent in frequency. The traditional way to manage interference has

40 25 therefore been to put small guard bands between different spectrum users, which are either left vacant or used less fully. However, these guard bands reduce the overall efficiency of use of the spectrum. Today, spectrum regulators ensure that other techniques are used as far as possible to mitigate the effects of interference, to minimize this loss of usable spectrum. Managing interference is not only an issue between users but also for each individual spectrum user. Every frequency must be reused many times in different geographic areas. It is therefore necessary to predict how far these areas need to be separated to avoid transmissions in one area causing interference to users in another [19] Managing interference between systems Interference occurs when an interfering signal exceeds a margin below the level of a wanted signal. Interference mainly affects the users with weak signals, and even then, the interference will exceed this margin in only a small proportion of cases. Interference that exceeds this criterion is known as harmful interference, see Figure 2.5.

41 26 Figure 2.5 Interference margin between wanted signal and interference signal For a new service to be introduced in the radio spectrum, it must be demonstrated that it does not cause harmful interference to existing users that have rights to protection from interference. This means that there should not be any significant change in the overall grade of service to existing spectrum users Co-existence in the UHF TV band Mobile operators are among the most intensive users of the radio spectrum. They have narrow frequency bands shared between several operators, and some of the neighboring bands are heavily used. They therefore have considerable experience in managing interference. In contrast, the UHF TV band is very wide, with generally only one broadcast transmission operator. Broadcasting was the first widespread use of the UHF band. Broadcasters have therefore needed less experience in managing interference between different users on neighboring frequencies.

42 27 Mobile services generally use separate frequency ranges for base stations and handsets to transmit in, called the downlink and uplink bands. The transmissions from handsets have more potential to cause interference to broadcast reception, because they can be used close to television sets with indoor antennas. It is therefore expected that the mobile frequencies will be arranged so that the uplink band is furthest from the television channels. The minimum frequency separation will be greater than at present if mobile uses digital dividend spectrum as envisaged. The risk of interference will therefore be no greater than today and probably less. Furthermore, most broadcast networks use different frequencies for the same multiplex in neighboring areas, to avoid one transmitter causing interference to viewers receiving signals from another. The highest DVB-T frequency will therefore only be used in around one sixth of a country, and typically there will be several unused TV channels between the top channel in use and any mobile services [19] Interference Assessment from DVB-T into IMT-Advanced The method consists in calculating the I/N ratio and then comparing it with the necessary I/N (-6 db) at the victim receiver. Firstly, the interference level I (dbm) at the victim receiver is evaluated by assessing the level of emissions from the interferer falling within the victim receiver bandwidth for both co-channel frequency and adjacent frequency situations according to: I (Δf) = Pt + Gt + Gr + Mask (Δf) + Corr_band Att (1)

43 28 Table 2.3 IMT-Advanced and DVB-T services parameters [20,24] Parameter IMT-Advanced Value DVB-T Frequency of operation (MHz) EIRP (dbm) , 48.4 Base station antenna gain (dbi) Base station antenna height (m) Interference limit power (dbm) Channel bandwidth (MHz) 5, 20 8 Interference to noise ratio I/N (db) Noise Figure db 4 7 Where Pt is the transmitted power of the interferer in dbm, Gt and Gr are the gain of the interferer transmitter and the victim receiver antennas in dbi, Mask(Δf) represents attenuation of adjacent frequency due to mask where Δf f is the difference between the carriers of interferer and the victim. Corr_band denotes correction factor of band ratio, Att represents attenuation due to the propagation model. Secondly, to determine the thermal noise floor of victim receiver the following equation is used [21]: N = NF + 10 log10 (BWvictim) (2)

44 29 Where NF is noise figure of receiver in db and BWvictim represents victim receiver bandwidth in MHz. Finally, by dividing I over N as a ratio, sharing and coexistence feasibility between the two systems can be determined Analytical Results The interference from T-DVB Transmitter into 5MHz and 20MHz WiMAX BS, respectively, as a victim receiver is applied, where the minimum separation distance and frequency separation for the minimum I/N ratio of -6 db are analyzed in the dense urban area. For adjacent channel coexistence it can be observed that the minimum separation distance between the two services must be greater than 5.5km and 3.5km for bandwidth of 5MHz and 20 MHz, respectively, with frequency separation of 12MHz from the carrier frequency. For deploying the two systems with a null guard band, the separation distances must be greater than 57km for WiMAX bandwidth of 5MHz and the two systems can be overlapping with coexisting operation if the distance is more than 3.5km at 20MHz WiMAX channel bandwidth [20] Conclusion It can be conclude from the above that coexistence between DVB-T system and mobile service in the same geographic area and the same frequency channel is possible, but difficult to share without mitigation techniques due to high separation

45 30 distance required to satisfy coexistence requirements. Methods for enabling the coexistence of both systems would be inevitable especially at small geographical offset between two systems, at adjacent channels frequency. Mitigation techniques may be employed and developed to reduce the interference, in order to help and ease both systems to operate together at adjacent channel, and it relies on many factors such as systems specifications, antenna height, propagation wave model, geographical area, interference type, transmitted power, etc Summary An overview of previous researches done which are relevant to this research work is presented. The study on interference attenuation (adjacent channel interference) which is discussed to find the solution. And some mitigation techniques presented to find coexistence between the DVB-T system and Mobile service in 800 MHz band.

46 CHAPTER 3 METHODOLOGY 3.1 Introduction The research methodology in this chapter serves as a method to achieve the aim and objective of this study. This research methodology study is carried out in the flowchart of methodology involved as depicted in Figure 3.1. First step was finding the formulas for path loss effect within the specific propagation model, these path loss formulas are mainly focus on fixed services. In addition, the systems specification (standard power values, transmitter and receiver characteristics, suitable waves propagation models, intersystem interference models, etc) will be determined. Calculating the interference level as the worst case situation was presented and the interference to noise ratio as an interference and coexistence criteria determines the feasibility of coexistence and sharing possibilities by comparing the resulting values (interference to noise I/N ratio), a scenario had been made for rural, suburban and urban environments. Modulation technique, system specifications, and radiation pattern had been stayed, collected and determined consequently.

47 32 START Literature review Specifying parameters Mathematical methods (analysis & calculation) for integrated area Compare separation distance with current methods No Sufficient Yes MatLab simulation to verify the calculation results Target achieved No Yes ATDI simulation for channel production measurements ATDI simulation measurements in suburban area without buildings ATDI simulation measurements in suburban area with buildings END Figure 3.1 Flowchart of Research Methodology

48 Data Collection Data collection will be done based on the articles which done by researching on the interference between DVB-T and Mobile service, also measurements were done and the ITU studies. Collected data consists of all the information which is needed to be collected such as 800 MHz frequency band properties and its importance, adjacent channel interference, systems parameters and etc. 3.3 Analysis and Calculation Method The interference power received from the DVB-T transmitter at Mobile service depends on many specifications. The DVB-T output power in the direction of the Mobile service, the radio propagation loss, the Mobile service gain and the isolation at the receiving site. To find the separation distance, two scenarios have been proposed in terms of channel bandwidth for Mobile service and as follows: First scenario is when channel bandwidth 5MHz for Mobile service, the assessment would establish the maximum permissible level of interference signal from the DVB-T station which would cause interference with the Mobile service and as shown the formulas to calculate the Maximum permissible level of interference level: C/I = (I/N + C/N) db (3.1) = ( ) db = 13 db

49 34 Where C/I is carrier to interference ratio and C/N is the required carrier to noise ratio (19dB) [6], I is the interference level, C is the carrier signal, N is the receiver noise level. It follows that I = (C - 13) db (3.2) Furthermore C = C/N +10 log (KTB) dbw (3.3) Where the KTB is the thermal noise floor, K is the Boltzmann's constant (1.38 *10-23 ), B is the channel band width and T is noise temperature [22]. By substitute all the values the carrier power can calculated: C = 19 + (-136.8) = dbw By substitute C in (3.2), the I will be equaled to dbw ( dbm). Figure 3.2 illustrates the relationship between carrier to interference level in related to the noise level.

50 35 Figure 3.2 Represent carrier to interference level in related to the noise level The separation distance calculated by depending on the formula that uses it to calculate the permissible received interference power as shown: I = EIRP DVB-T L DVB-T (d) + Gr (3.4) Where: EIRP DVB-T = off-axis EIRP from the DVB-T transmitter (dbw) L DVB-T (d) = path loss (db) Gr = Mobile service antenna receiving gain (dbi) The path loss will be as follows [23]:

51 36 L DVB-T (d)= log(f) log(hb) Ch+( log(hb))*log(d) (3.5) where, in the case of propagation loss in a medium to small city: Ch = (1.1 log(f) - 0.7) * hm log( f ) and for large cities, 8.29 ( log (1.54 hm)) if 150 f 200 Ch = 3.2 ( log (11.75 hm)) if 200 < f 1500 Where: f = Frequency of transmission (MHz) d = Distance (km) hb = Height of base station antenna between 30 m and 200 m Ch = Antenna height correction factor hm = Height of mobile station antenna between 1 m and 10 m Correction factor (69.55 db) Finally, the calculation of required protection distance d, is where the interference power from DVB-T transmitter to the Mobile service reaches the threshold level and is given by substituted the (3.5) in (3.4) the protection distance (separation distance) will be:

52 Log(d)= - I+EIRP Log( f ) Log(hb) + Ch + Gr (3.6) d (( 10 I EIRP DVB T Log ( f ) Log ( hb ) Ch Gr ) / ) (3.7) Second scenario is when channel bandwidth 20MHz for Mobile service, the assessment would establish the maximum permissible level of interference signal from the DVB-T station which would cause interference with the Mobile service and as shown the formulas to calculate the Maximum permissible level of interference level: C/I = (I/N + C/N) db (3.8) = ( ) db = 13 db Where C/I is carrier to interference ratio and C/N is the required carrier to noise ratio (19dB) [6], I is the interference level, C is the carrier signal, N is the receiver noise level. It follows that I = (C - 13) db (3.9)

53 38 Furthermore C = C/N +10 log (KTB) dbw (3.10) where the KTB is the thermal noise floor, K is the Boltzmann's constant (1.38 *10-23 ), B is the channel bandwidth and T is noise temperature [22]. By substitute all the values the carrier power can calculated: C = 19 + (-130.8) = dbw By substitute C in the (3.9), the I will equal to dbw (-94.8 dbm). And for path loss calculation will be same, the calculation of required protection distance d, is where the interference power from DVB-T transmitter to the Mobile service reaches the new threshold level for 20MHz channel bandwidth, the protection distance (separation distance) will be: Log(d)= - I+EIRP Log( f ) Log(hb) + Ch + Gr (3.6) d (( 10 I EIRP DVB T Log ( f ) Log ( hb ) Ch Gr ) / ) (3.7) The calculation of the separation distance (d) for two scenarios has been done by MatLab simulation as will be presented in Chapter 4.

54 39 The result of the interference calculation is the minimum required loss. Having chosen an appropriate path loss model, this can subsequently be converted into a physical separation. The standard model agreed upon in the ITU and CEPT for a Terrestrial interference assessment at microwave frequencies is Hata model [25]. Therefore, this propagation model, which includes the attenuation due to LOSpropagation as well as additional attenuation due to clutter in various environments, is used for the frequency sharing study for DVB-T system and Mobile service. As well as, the separation distance calculation need to dedicate the parameters for each DVB-T and Mobile system also specific the propagation model as shown: Table 3.1 IMT-Advanced Mobile Station Parameters Parameter Frequency of operation Channel bandwidth EIRP Antenna Gain Antenna Height Antenna pattern Interference limit power Interference to noise ratio I/N Noise Figure Receiver thermal noise, N=KTB Value 800 MHz 5, 20 MHz 24.5 dbm 0 dbi 1.5 m Omni , dbm -6 db 4 db , dbw Antenna height correction factor

55 40 Table 3.2 IMT-Advanced Base Station Parameters Parameter Frequency of operation EIRP Base station antenna gain Base station antenna height Interference limit power Channel bandwidth Interference to noise ratio I/N Noise Figure Value 800 MHz 43 dbm 15 dbi 20 m , dbm 5, 20 MHz -6 db 4 db Table 3.3 DVB-T System Parameters Parameter Frequency of operation EIRP Base station antenna height Channel bandwidth Noise Figure Antenna pattern Interference limit power Value 800 MHz 72.15, 48.4 dbm 30 m 8 MHz 7 db Omni , dbm

56 Propagation Model It is an empirical mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions. A single model is usually developed to predict the behavior of propagation for all similar links under similar constraints. Created with the goal of formalizing the way radio waves are propagated from one place to another, such models typically predict the path loss along a link or the effective coverage area of a transmitter [26]. As mentioned before, the using of Hata propagation model not other propagation models, because it is the suitable model for the specifications and environment that used Egli Model The Egli Model is a terrain model for radio frequency propagation. This model, which was first introduced by John Egli in his 1957 paper, was derived from real-world data on UHF and VHF television transmissions in several large cities. It predicts the total path loss for a point-to-point link. Typically used for outdoor lineof-sight transmission, this model provides the path loss as a single quantity. The model is applicable to scenarios where the transmission has to go over an irregular terrain. However, the model does not take into account travel through some vegetative obstruction, such as trees or shrubbery. This model is typically applied to VHF and UHF ( MHz) spectrum transmissions [27].

57 Longley Rice model It is a radio propagation model, a method for predicting the attenuation of radio signals for a telecommunication link in the frequency range of 20 MHz to 20 GHz. Longley-Rice (LR) is also known as the irregular terrain model (ITM). It was created for the needs of frequency planning in television broadcasting in the United States in the 1960s and was extensively used for preparing the tables of channel allocations for VHF/UHF broadcasting there. LR has two parts: a model for predictions over an area and a model for point-to-point link predictions [28] Okumura model The Okumura model is a radio propagation model that was built using the data collected in the city of Tokyo, Japan. The model is ideal for using in cities with many urban structures but not many tall blocking structures. The model served as a base for the Hata Model. Okumura model was built into three modes. The ones for urban, suburban and open areas. The model for urban areas was built first and used as the base for others. The model is typically applied in the frequency range of 200 MHz to 1900 MHz [29].

58 COST 231 model It is also called the Hata Model PCS Extension, it is a radio propagation model that extends the Hata Model (which in turn is based on the Okumura Model) to cover a more elaborated range of frequencies. This model is applicable to urban areas. To further evaluate Path Loss in Suburban or Rural Quasi-open/Open Areas, this path loss has to be substituted into Urban to Rural/Urban to Suburban Conversions. The model is typically applied in the frequency range of 1500 MHz to 2000 MHz [30] Hata Model It is also known as the Okumura-Hata model for being a developed version of the Okumura Model, is the most widely used model in radio frequency propagation for predicting the behavior of cellular transmissions in city outskirts and other rural areas. This model incorporates the graphical information from Okumura model and develops it further to better suite the need. This model also has two more varieties for transmission in Urban Areas, Suburban Areas and Open Areas. Hata Model predicts the total path loss along a link of terrestrial microwave or other type of cellular communications. And is a function of transmission frequency and the average path loss in urban areas. This model is suited for both point-to-point and broadcast transmissions. The model is typically applied in the frequency range of 150 MHz to 1.5 GHz [31].

59 Summary The chapter has described the steps that were applied throughout the research. The calculation methods, analysis and the specification to find the separation distance between DVB-T system and Mobile service has been presented. Furthermore, the chosen of suitable propagation model that matching with the data, specifications and environment that had been used.

60 CHAPTER 4 SIMULATIONS AND MEASUREMENTS RESULTS 4.1 Introduction In this chapter two simulations will be presented using Matlab and ATDI software. The study initiated within detailed calculations of the most useful formulas for path loss effect by using the existing parameters of DVB-T system and the parameters for the Mobile service as presented in Chapter 3. The interference between two systems have been calculated, analyzed and simulated using Matlab software for two scenarios by applying numerical formulas to calculate the power of the interference signal received at the Mobile service when DVB-T base stations (BS) are operated in the 800MHz frequency to find best separation distance. ATDI simulation has likewise presented in two different scenarios to measure and discuss the separation distance in different ways. The first scenario of deploying DVB-T is in Johor Bahru and covers most of the city with broadcasting service (high transmitted power), by considering suburban area without buildings (rural area), suburban area with buildings and urban area. The second scenario of deploying DVB-T is in a Terual state in France and covers most of the city with broadcasting service (low transmitted power), by considering suburban area with buildings. Extensive study for

61 46 received signal strength considered for around 4 points was identified by ATDI software. 4.2 MATLAB Simulation The calculation of the equations (which mentioned in Chapter 3 Section 3.3) to find the separation distance in different scenarios appliyed through MatLab which gave results for what ever schemes used of each senario Separation Distance Calculation for 5MHz Channel Bandwidth The calculation of the separation distance between the DVB-T station with the Mobile service by applying (3.7) in Chapter 3 by considering interference level (I) is dbw, as shown in Figure 4.1.

62 47 Figure 4.1 The separation distance between mobile service 5MHz channel bandwidth and DVB-T station in different transmitted power. Table 4.1 presents how the permissible interference changing the separation distances in term of considering all the other constant parameters.

63 48 Table 4.1 Separation Distance in Different Interference Level separation distance separation distance Height of maximum (Km), DVB-T (Km), DVB-T base station permissible transmitter(eirp=42.15 transmitter(eirp=18.4 Antenna interfering dbw) dbw) (DVB-T) (I)in dbw Separation Distance Calculation for 20MHz Channel Bandwidth The calculation of the separation distance between the DVB-T station with the Mobile service by applying (3.7) in Chapter 3 by considering interference level (I) is dbw and height of base station antenna (DVB-T) will taken as range in measurement from 30 to 100 m as shown in Figure 4.2.

64 49 Figure 4.2 The separation distance between mobile service 20MHz channel bandwidth and DVB-T station in different transmitted power, and antenna height (hb)=100 m.

65 50 Figure 4.3 The separation distance between mobile service 20MHz channel bandwidth and DVB-T station in different transmitted power, and antenna height (hb)=30 m. The interference from a DVB-T base station transmitter to a Mobile service is worked out and the results are summarized in Figure 4.2 and Figure 4.3 as well the separation distance will be less in each time the antenna height hb decreases, Table 4.2 will represent how the distance will be changing in term of antenna height hb as shown:

66 51 Table 4.2 Separation Distance in Different Antenna Height separation distance separation distance Height of maximum (Km), DVB-T (Km), DVB-T base station permissible transmitter(eirp=42.15 transmitter(eirp=18.4 Antenna interfering dbw) dbw) (DVB-T) (I)in dbw Also the calculation represent that the signal power from the DVB-T station also have impact on the Mobile service and as long as decreased it, the separation goes small. 4.3 ATDI (ICS-TELECOM) Simulation ICS telecom is ATDI's modeling platform for planning telecommunication networks and managing frequency spectrum. ICS telecom focuses on the network design needs for commercial operators, spectrum regulators, equipment manufacturers and consultants. One of ICS telecom's main strengths is in the modeling of heterogenous networks with dedicated features that address the following technologies.

67 52 ICS telecom is a comprehensive tool box for modeling radio communications in the MF/HF/VHF/UHF/SHF/EHF frequency bands. Included are analysis features for the following technologies [35]: land mobile radio fixed wireless access (point-to-point and point-to-multipoint d WiMAX, WiFi Mesh, Microwave, LMDS/MMDS, TETRA/TETRAPOL, etc.) cellular/mobile (GSM, GPRS, CDMA/EVDO/EDGE, HSDPA/HSUPA, e WiMAX, LTE broadcast (Analog and Digital TV and Radio) telemetry indoor(wifi, e WiMAX) maritime aeronautical radar satellite earth stations To find out or measure the separation distance through measure the coverage area in specific region by using ATDI, firstly many specification or requirements must be provided to do the work as shown : i. DVB-T station specifications need to construct the station through the simulation, all specification was mentioned in Chapter 3 as well for each scenario the parameters will be provided in appendix A as will be assigned. ii. Radiation Patterns for the transmitter antenna of DVB-T station needed to be determined inside the ATDI, it is also will be provided in appendix B. iii. Propagation model, as presented in the Chapter 3.

68 Propagation Model As mentioned in Chapter 3 how the propagation model had been chosen, also in ATDI some specifications must be set in the propagation model: i. Model types: there are many models can be considered to predict the propagation like Free space, Ground wave, Diffraction around a smooth earth, Ground reflections, Effect of terrain, etc. in ATDI measurements used the propagation model of Hata Model to see the effect of terrain profile on the separation distance of the two systems for frequency sharing. ii. Diffraction geometry effect: The diffraction effect is used in order to quantify the attenuation due to an obstruction of the direct path between the Tx and the Rx by one or several obstacles. iii. Area type: there are many types can be considered to determine the area, like Suburban area without buildings (rural area), Suburban area with buildings and Urban area ATDI Simulation Measurements Scenarios Two scenarios will be considered, suburban without buildings (high transmitted power) and suburban with buildings (low transmitted power), to find the effect of clutter loss (buildings terrain) in different points. Also in each scenario will be applied in 5MHz and 20 MHz channel bandwidth for Mobile service.

69 Suburban Region without Buildings Using ATDI simulation software on map of Johor Bahru, Malaysia. 1. Coverage and Measurements for 5MHz channel bandwidth Simulation and analysis for DVB-T system and check the coverage for area around 2500 Km2 as shown in Figure 4.4, Mobile service can be deploy it anywhere after the violet area. In other word, the Mobile service can install at the region not interfere with DVB-T station. Figure 4.4 ATDI simulation coverage result for 5MHz channel bandwidth.

70 55 4 points at different places at Johor Bahru established using Johor map as displayed in Figure 4.5, then all these points are transferred the grid for each point to the ATDI program, to distribute these points at ATDI program using Johor Bahru map. Figure 4.5 Points sites inside Johor Bahru. The most noticeable result to emerge from the data is the good signal for this area, and approximately there is a good converge for Johor Bahru, but these results for this simulation for Johor Bahru map without any buildings layers. The interference effects from DVB-T base station to the Mobile service can be reduced by terrain effect like dense urban area. And because of the high transmitted power the coverage becomes large. Point 4 is km far away from DVB-T base station.

71 56 2. Coverage and Measurements for 20MHz channel bandwidth For 20MHz Mobile service the coverage will reduce as shown in Figure 4.6 because of interference level changes from for 5MHz to for 20MHz as mentioned in Chapter 3. Figure 4.6 ATDI simulation coverage result for 20MHz channel bandwidth. Also 4 points at different places at Johor Bahru established using Johor map as displayed in Figure 4.7, then all these points are transferred the grid for each point to the ATDI program, to distribute these points at ATDI program using Johor Bahru map.

72 57 Figure 4.7 Points sites inside Johor Bahru. The interference effects from DVB-T base station to the Mobile service can be reduced by terrain effect like dense urban area. And because of the high transmitted power the coverage becomes large. Point 4 is km far away from DVB-T base station. Point 4 is km far away from DVB-T base station Suburban Region with Buildings In this scenario including buildings, ATDI applied on the high resolution map in region located in French to study the coverage of DVB-T station and find the best regions to deploy Mobile service without any effective coming from DVB-T transmitter. Also here applied in 5MHz and 20 MHz channel bandwidth for Mobile service.

73 58 1. Coverage and Measurements for 5MHz channel bandwidth Simulation and analysis for DVB-T system and check the coverage for area around 400 Km2 as shown in Figure 4.8, where Figure 4.8 illustrates how well interference is reduced with terrain propagation effect. Figure 4.8 Coverage area in Terual state, French for 5MHz channel bandwidth. 4 points at different places at Terual state, French established using France map as displayed in Figure 4.11, then all these points are transferred the grid for each point to the ATDI program, to distribute these points at ATDI program using France map.

74 59 Figure 4.9 Points sites inside Terual state, French. These points in Figure 4.9 represent the best site to deploy Mobile service because the interference level I becomes smaller than dbm where there is no interference from DVB-T station, and Figure 4.10 illustrates the signal profile from DVB-T to point 4 that is 6.56 km far away from DVB-T base station.

75 60 Figure Profile Terrain from DVB-T station towards Mobile service (point 4) Coverage and Measurements for 20MHz channel bandwidth For 20MHz Mobile service the coverage will reduce as shown in Figure 4.11 because of interference level decreases from dbm for 5MHz to dbm for 20MHz.

76 61 Figure 4.11 Coverage area in French for 20MHz channel bandwidth. These 4 points in Figure 4.11 above represent the best site to deploy Mobile service where there is no impact from DVB-T station, and Figure 4.12 illustrates the signal profile from DVB-T to point 5 that is 5.22 km far away from DVB-T base station.

77 62 Figure 4.12 Profile Terrain from DVB-T station towards Mobile service (point 5) Comparison between two scenarios From the results that been found from the ATDI simulation for two scenarios, the separation distance will be more smaller in the suburban with buildings than this suburban without buildings, and that is back to the effect of buildings to make restriction or limitation on the DVB-T transmitter signals. Where in the first scenario the best separation distance is km (for 20MHz mobile service channel bandwidth), (at point 4 in Figure 4.7). At the time of, in second scenario the best separation distance is 5.22 km (at point 5 in Figure 4.11) for same channel bandwidth.

78 Summary The chapter has described the steps of two simulations MATLAB and ATDI to calculate and measure the separation distance for deploy Mobile service without any impact from DVB-T transmitter. The calculation of two scenarios suburban without building and suburban with building (5MHz and 20MHz) have been done by Matlab to calculate the separation distance. The effectiveness of the mechanisms for co-existence between Mobile service and DVB-T is dependent on its application. Different scenarios with different transmitted power and channel bandwidth as well presented and comparison in the ATDI scenarios have been done.

79 CHAPTER 5 CONCLUSION AND RECOMMENDATION 5.1 Conclusion The signal that received to the Mobile service must be protected from the DVB-T station transmitter, by controlling the signal power in the same direction of the Mobile service as well, the minimum required loss at Mobile service must be specified and always be greater than or equal the path loss power, to make sure that the DVB-T transmitter not impact or block the signal received. The separation distance in term of suburban area without buildings longer than the distance in term suburban area with buildings and that is back to the DVB-T transmitted signal will be directly affected on the Mobile service signal received because there is no clutter loss through the propagation just free path loss will be considered. Also the separation distance in 5MHz channel bandwidth for Mobile service longer than the distance in 20MHz.

80 65 Methods for enabling the coexistence of both systems would be inevitable especially at small geographical offset between two systems at adjacent channels frequency. More coexistence studies between mobile and DVB-T services at MHz are recommended. 5.2 Future Works Some works can be applied to enhance and find the best separation distance to prevent blocked the Mobile service from the DVB-T transmitters, as follows: 1. Filtering. Insert a frequency-selective filter between the receiver and its antenna, to reject strong signals on neighboring frequencies. 2. Sector limitation in the direction of the victim if DVB-T has transmitted in sectored antenna, to improve the sharing and to reduce the transmitting output power of DVB-T base station. However, it doesn t give sufficient operation region for both services. 3. Antenna down tilting in case of sectored antenna and also antenna height for the benefits of DVB-T cell size reduction to support high speed transmissions, Mitigate the interference of DVB-T over Mobile service and for the limitation of transmission power. 4. Improve the quality of the transmitted signal so that less of it spills into neighboring channels. And improve the performance of the receiver, so that it is able to reject strong signals on neighboring frequencies.

81 66 5. Spectrum allocation had been proposed by some researchers as the most favorable for radio resources distribution to gain high spectrum efficiency. It operates like that; in the case when an Mobile service changes its frequency of operation, the DVB-T system may also have to change its frequency in the surrounding area.

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85 70 APPENDIX A DVB-T system parameters (EIRP= dbm)

86 DVB-T system parameters (EIRP= 48.4 dbm) 71

87 72 APPENDIX B DVB-T Antenna Transmitter Radiation Pattern

88 73 APPENDIX C Propagation Model Specifications