Unused Frequencies in the TV Broadcasting Band
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UNIVERSITY OF OSLO Department of Physics TV receiver registration to utilize unused frequencies in the TV broadcasting band Master thesis Hemdan M. Bezabih June 1, 2011 Abstract In this thesis the registration of TV receiver information in a database is introduced to utilize unused frequencies in the TV broadcasting band. The unused frequencies are split in White space and Gray space. By conducting simulations at three areas in Norway the amount of unused frequencies with focus on the Gray Space is found. The result is evaluated in regards to the level of information retrieved from each TV receiver. There are three knowledge levels evaluated: when the information changes from only knowing the available channels at a location, to having information on which broad- caster delivers TV service information at a household, and finally how the amount of Gray Space changes when knowing the TV usage in time. The available White and Gray Space amount is calculated considering a Cognitive radio with transmit power of 100mW and 4 W. Using realistic TV broadcast environments, the method of introducing an RX receiver database opens for 80-96 MHz of Gray Space in average when considering a Cognitive radio device with 4 W transmit power. This level increases to 109-115 MHz in average when considering a 100mW Cognitive radio device. These levels are present in addition to the White Space of about 200 MHz. iii Abstract iv Contents Abstract iii Acknowledgements ix 1 Introduction1 1.1 Goal........................................1 1.2 Motivation....................................1 1.3 Brief overview..................................2 1.4 Services and application areas.........................3 1.4.1 Cognitive radio usage scenario....................4 1.4.2 Application for the TV band......................4 1.5 Problem statement...............................5 1.6 Chapter overview................................6 2 Background9 2.1 Introduction...................................9 2.2 Interference affects on receiver antenna when unlicensed operation occurs9 2.2.1 Frequency reuse.............................9 2.2.2 Signal to interference ratio.......................9 3 Related work regarding unlicensed operation of TV White Space 13 3.1 Introduction................................... 13 3.2 White Space................................... 13 3.2.1 White Space and Gray Space..................... 14 3.2.2 White Space amount.......................... 17 3.3 Method of accessing the White Space..................... 17 3.3.1 Sensing.................................. 18 3.3.2 Geo- locationd database: TX database................ 19 3.3.3 Discussion................................ 19 3.4 Regulatory framework............................. 20 3.4.1 US.................................... 20 3.4.2 UK/Europe/ Norway......................... 20 3.5 Database technical parameters........................ 21 v Contents 3.5.1 Protecting services within the TV service area........... 21 3.5.2 Operation rules depending on CR device type........... 23 4 TV receiver registration 27 4.1 Introduction................................... 27 4.2 Overview..................................... 27 4.3 Description of the concept........................... 27 4.3.1 Summary................................ 31 4.4 Method used for Tv receiver registration................... 31 4.5 TV receiver protection............................. 32 4.5.1 Signal strength............................. 32 4.5.2 Frequency................................ 32 4.5.3 Position................................. 32 5 Scenario 35 5.1 Introduction................................... 35 5.2 TV broadcasting in Norway.......................... 35 5.2.1 Technology............................... 36 5.2.2 License.................................. 36 5.2.3 Network capacity............................ 36 5.2.4 TV service receiver........................... 38 5.2.5 Coverage................................. 38 5.2.6 Evaluation................................ 38 5.3 White space amount in Norway........................ 40 5.3.1 Finding Gray Space amount in Norway............... 40 5.3.2 Knowledge level 1: Depending on TV receiver location...... 40 5.3.3 Knowledge level 2: Depending on broadcaster information... 41 5.3.4 Knowledge level 3: Depending on usage on a hourly basis.... 42 5.4 Detailed tasks of the thesis........................... 44 5.4.1 Introduction............................... 44 5.4.2 Method.................................. 45 5.4.3 Simulation method........................... 46 6 CR device parameters 47 6.1 Introduction................................... 47 6.2 Cognitive radio device............................. 47 6.3 Maximum range................................. 47 6.4 Max allowed CR field strenght at TV receiver................ 49 6.5 Propagation loss between CR device and TV receiver........... 49 6.5.1 Free space model............................ 50 6.5.2 Okumura- hata propagation model................. 50 vi Contents 6.6 Result....................................... 52 6.7 Dicussion..................................... 53 7 Implementation 57 7.1 Introduction................................... 57 7.2 Programming structure............................. 57 7.2.1 Method.................................. 58 7.2.2 Defining Start inputs.......................... 60 7.2.3 Channel usage for each knowledge level.............. 60 7.3 Simulation Testcase............................... 62 7.3.1 Introduction............................... 62 7.3.2 Defining Start inputs.......................... 63 7.3.3 Channel usage for each knowledge level.............. 64 7.3.4 Result.................................. 68 7.4 Evaluation.................................... 70 7.4.1 Topology................................. 70 7.4.2 TV receiver locations.......................... 70 8 Simulation based on real values 73 8.1 Introduction................................... 73 8.2 Defining basic inputs.............................. 73 8.2.1 TV transmitter information...................... 74 8.2.2 Topology and TV receiver locations................. 74 8.2.3 Running code.............................. 76 8.3 Vinje....................................... 76 8.3.1 Area description:............................ 76 8.3.2 Topology and receivers........................ 77 8.3.3 Result setup............................... 77 8.3.4 KN1: Possible channel usage..................... 79 8.3.5 KN2:Actual channel usage...................... 81 8.3.6 KN3: Time based channel usage................... 83 8.3.7 Discussion of the result........................ 85 8.3.8 Discussion summary.......................... 89 8.3.9 Evaluation of Result.......................... 91 8.4 Other areas.................................... 94 8.4.1 Tynset.................................. 95 8.4.2 Lillehammer............................... 96 8.4.3 Result Summary............................ 98 9 Evaluation of method 101 9.1 Grid size: Overestimates the protection................... 101 vii Contents 9.2 Co-channel and adjacent channel C/I levels................. 102 10 Conclusion and future work 107 10.1 Conclusion................................... 107 10.2 Summary of method.............................. 108 10.3 Comparing the methods............................ 110 Bibliography 115 Appendices 119 .1 Matlab code................................... 121 .1.1 Function Protection........................... 128 .1.2 Function positionReceiversReal and function receiversForTimeBased- Info .................................... 130 .1.3 Function FindSum ............................ 131 .2 Simulation method............................... 136 .2.1 Crop the matrix to fit Area of Vinje, Lillehammer and Tynset... 136 .3 Vinje....................................... 138 .4 Tynset....................................... 138 .5 Lillehammer................................... 143 viii Acknowledgements This thesis would have not been possible with guidance and support from several in- dividuals. First and foremost, my utmost gratitude to my mentor Josef Noll for his guidance and support throughout the course of this thesis and beyond. Second I want to thank Torleiv Maseng for introduction me to this field and the insight he has shared. And Stig Johannessen from NPT- The Norwegian Post and Telecommu- nications Authority, which as helped me get a clearer understanding on the TV broad- casting system used in Norway. In addition I would like to thank the staff and students at UNIK for support throughout my graduate years. I wish you all the best. Last but not least I thank my family and friends for their moral support and positive remarks, with special thanks to my mother and sister. This thesis is dedicated to my late father and grandfather. Hemdan M. Bezabih 1. June 2011 ix Acknowledgements x List of Figures 2.1 Typical scenario of TV antenna and Cognitive radio(CR)......... 10 3.1 Illustration of White Space and Gray Space................. 16 3.2 Hidden node problem............................. 18 3.3 Required separation distance defined by FCC................ 24 4.1 Population density in Norway for 2008, based on information from SSB 28 4.2 Illustation of a Tv service area at a location in Norway........... 29 4.3 Possible scenario based on terrain information............... 30 5.1 TV viewing per person for a given time-period............... 44 6.1 Illustration of the variables affecting the min. distance when considering co-channel and adjacent channel interference ratio............. 48 6.2 Propagation loss