cmc by abhijit mitra (lecture notes)

Download CMC by Abhijit Mitra (Lecture Notes)

Post on 11-Oct-2015

39 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Lecture Notes on Mobile Communication

    A Curriculum Development Cell Project Under QIP, IIT Guwahati

    Dr. Abhijit Mitra

    Department of Electronics and Communication EngineeringIndian Institute of Technology Guwahati

    Guwahati 781039, IndiaNovember 2009

  • Preface

    Its been many years that Im teaching the subject Mobile Communication

    (EC632) to the IIT Guwahati students and the current lecture notes intend to act

    as a supplement to that course so that our students can have an access to this

    course anytime. This course is mainly aimed toward senior year students of the

    ECE discipline, and in particular, for the final year BTech, first year MTech and

    PhD students. However, this does not necessarily imply that any other discipline

    students can not study this course. Rather, they also should delve deeper into

    this course since mobile communication is a familiar term to everyone nowadays.

    Although the communication aspects of this subject depends on the fundamentals of

    another interesting subject, communication engineering, I would strongly advocate

    the engineering students to go through the same in order to grow up adequate

    interest in this field. In fact, the present lecture notes are designed in such a way

    that even a non-ECE student also would get certain basic notions of this subject.

    The entire lecture notes are broadly divided into 8 chapters, which, I consider to

    be most rudimentary topics to know the basics of this subject. The advance level

    topics are avoided intensionally so as to give space to the possibility of developing

    another lecture note in that area. In fact, this area is so vast and changing so fast

    over time, there is no limit of discussing the advanced level topics. The current focus

    has been therefore to deal with those main topics which would give a senior student

    sufficient exposure to this field to carry out further study and/or research. Initially,

    after dealing with the introductory concepts (i.e., what is mobile communication,

    how a mobile call is made etc) and the evolution of mobile communication systems till

    the present day status, the cellular engineering fundamentals are discussed at length

    to make the students realize the importance of the practical engineering aspects of

    this subject. Next, the different kinds of mobile communication channels is taken

    up and large scale path loss model as well as small scale fading effects are dealt,

    both with simulation and statistical approaches. To enhance the link performance

    amidst the adverse channel conditions, the transmitter and receiver techniques are

    i

  • discussed next. It is further extended with three main signal processing techniques

    at the receiver, namely, equalization, diversity and channel coding. Finally, different

    kinds of multiple access techniques are covered at length with the emphasis on how

    several mobile communication techniques evolve via this. It should also be mentioned

    that many figures in the lecture notes have been adopted from some standard text

    books to keep the easy flow of the understanding of the topics.

    During the process of developing the lecture notes, I have received kind helps

    from my friends, colleagues as well as my post graduate and doctoral students which

    I must acknowledge at the onset. Im fortunate to have a group of energetic students

    who have helped me a lot. It is for them only I could finish this project, albeit a

    bit late. My sincere acknowledgment should also go to my parents and my younger

    brother who have nicely reciprocated my oblivion nature by their nourishing and

    generous attitude toward me since my childhood.

    Finally, about the satisfaction of the author. In general, an author becomes

    happy if he/she sees that his/her creation could instill certain sparks in the readers

    mind. The same is true for me too. Once Bertrand Russell said Science may set

    limits to knowledge, but should not set limits to imagination. If the readers can

    visualize the continuously changing technology in this field after reading this lecture

    notes and also can dream about a future career in the same, Ill consider my en-

    deavor to be successful. My best wishes to all the readers.

    Abhijit Mitra

    November 2009

    ii

  • Contents

    1 Introductory Concepts 1

    1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

    1.2 Evolution of Mobile Radio Communications . . . . . . . . . . . . . . 1

    1.3 Present Day Mobile Communication . . . . . . . . . . . . . . . . . . 3

    1.4 Fundamental Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 4

    1.4.1 Radio Transmission Techniques . . . . . . . . . . . . . . . . . 5

    1.5 How a Mobile Call is Actually Made? . . . . . . . . . . . . . . . . . 7

    1.5.1 Cellular Concept . . . . . . . . . . . . . . . . . . . . . . . . . 7

    1.5.2 Operational Channels . . . . . . . . . . . . . . . . . . . . . . 8

    1.5.3 Making a Call . . . . . . . . . . . . . . . . . . . . . . . . . . 8

    1.6 Future Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

    1.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

    2 Modern Wireless Communication Systems 11

    2.1 1G: First Generation Networks . . . . . . . . . . . . . . . . . . . . . 11

    2.2 2G: Second Generation Networks . . . . . . . . . . . . . . . . . . . . 11

    2.2.1 TDMA/FDD Standards . . . . . . . . . . . . . . . . . . . . . 12

    2.2.2 CDMA/FDD Standard . . . . . . . . . . . . . . . . . . . . . 12

    2.2.3 2.5G Mobile Networks . . . . . . . . . . . . . . . . . . . . . . 12

    2.3 3G: Third Generation Networks . . . . . . . . . . . . . . . . . . . . . 13

    2.3.1 3G Standards and Access Technologies . . . . . . . . . . . . . 14

    2.3.2 3G W-CDMA (UMTS) . . . . . . . . . . . . . . . . . . . . . 14

    2.3.3 3G CDMA2000 . . . . . . . . . . . . . . . . . . . . . . . . . . 16

    2.3.4 3G TD-SCDMA . . . . . . . . . . . . . . . . . . . . . . . . . 18

    2.4 Wireless Transmission Protocols . . . . . . . . . . . . . . . . . . . . 19

    iii

  • 2.4.1 Wireless Local Loop (WLL) and LMDS . . . . . . . . . . . . 19

    2.4.2 Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

    2.4.3 Wireless Local Area Networks (W-LAN) . . . . . . . . . . . . 20

    2.4.4 WiMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

    2.4.5 Zigbee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

    2.4.6 Wibree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

    2.5 Conclusion: Beyond 3G Networks . . . . . . . . . . . . . . . . . . . . 22

    2.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

    3 The Cellular Engineering Fundamentals 23

    3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

    3.2 What is a Cell? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

    3.3 Frequency Reuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

    3.4 Channel Assignment Strategies . . . . . . . . . . . . . . . . . . . . . 27

    3.4.1 Fixed Channel Assignment (FCA) . . . . . . . . . . . . . . . 27

    3.4.2 Dynamic Channel Assignment (DCA) . . . . . . . . . . . . . 27

    3.5 Handoff Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

    3.5.1 Factors Influencing Handoffs . . . . . . . . . . . . . . . . . . 29

    3.5.2 Handoffs In Different Generations . . . . . . . . . . . . . . . 31

    3.5.3 Handoff Priority . . . . . . . . . . . . . . . . . . . . . . . . . 33

    3.5.4 A Few Practical Problems in Handoff Scenario . . . . . . . . 33

    3.6 Interference & System Capacity . . . . . . . . . . . . . . . . . . . . . 34

    3.6.1 Co-channel interference (CCI) . . . . . . . . . . . . . . . . . . 34

    3.6.2 Adjacent Channel Interference (ACI) . . . . . . . . . . . . . . 37

    3.7 Enhancing Capacity And Cell Coverage . . . . . . . . . . . . . . . . 38

    3.7.1 The Key Trade-off . . . . . . . . . . . . . . . . . . . . . . . . 38

    3.7.2 Cell-Splitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

    3.7.3 Sectoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

    3.7.4 Microcell Zone Concept . . . . . . . . . . . . . . . . . . . . . 46

    3.8 Trunked Radio System . . . . . . . . . . . . . . . . . . . . . . . . . . 47

    3.9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

    iv

  • 4 Free Space Radio Wave Propagation 54

    4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

    4.2 Free Space Propagation Model . . . . . . . . . . . . . . . . . . . . . 55

    4.3 Basic Methods of Propagation . . . . . . . . . . . . . . . . . . . . . . 57

    4.3.1 Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

    4.3.2 Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

    4.3.3 Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

    4.4 Two Ray Reflection Model . . . . . . . . . . . . . . . . . . . . . . . . 59

    4.5 Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

    4.5.1 Knife-Edge Diffraction Geometry . . . . . . . . . . . . . . . . 64

    4.5.2 Fresnel Zones: the Concept of Diffraction Loss . . . . . . . . 66

    4.5.3 Knife-edge diffraction model . . . . . . . . . . . . . . . . . . . 68

    4.6 Link Budget Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 69

    4.6.1 Log-di