Study of Smart Antenas on Mobile Communications

CONTENTS

DEDICACE Error! Bookmark not defined.

ACKNOWLEDGEMENTS ii

ABSTRACT iii

RESUME iv

CONTENTS v

List of Figures vii

List of Tables viii

List of Abbreviations ix

INTRODUCTION 1

CHAP 1 TOWARD SMART ANTENNA 3

1.1 Antenna synthesis 3

1.1.1 Woodward-Lawson Method 4

1.1.2 Dolph-Chebyshev Method 6

1.2 Evolution from Omni directional to Smart Antennas 8

1.2.1 Omni directional Antennas 9

1.2.2 Directional Antennas and Sectorized Systems 10

1.2.3 Smart antenna 11

1.2.3.1 Switching-Beam Array (SBA) 12

1.2.3.2 Adaptive Array 13

CHAP 2 SYSTEM ASPECTS OF SMART ANTENNA 16

2.1 Key characteristics of smart antennas Technology 16

2.2 Signal Propagation: Multipath and cochannel Interference 17

2.2.1 Multipath and problem associated with it. 17

2.2.2 Cochannel Interference 19

2.3 Difference between uplink and downlink 20

2.3.1 Uplink Processing 20

2.3.2 Downlink Processing 21

2.4 Handling of common channels 21

CHAP 3 ANTENNA ARRAYS AND BEAM FORMING 23

3.1 Antenna Arrays 23

3.1.1 Introduction 23

3.1.2 Theoretical model for an antenna array 24

3.1.2.1 Linear array antenna 24

3.1.2.2 Planar array antenna 25

3.1.3. Elements spacing 28

3.1.4. Microstrip patch antennas design 29

3.2. Beam forming 30

3.2.1. Nulling Beam Forming 31

3.2.2. Steering Vector 31

3.2.3. Recursive Least Squares Algorithm 32

CHAP 4 Multiple Access Schemes 34

4.1 Introduction 34

4.2 Frequency Division Multiple Access (FDMA) 34

4.3 Time Division Multiple Access (TDMA) 35

4.4 Code Division Multiple Access (CDMA) 35

4.4 Space Division Multiple Access (SDMA) 36

CHAP 5 SIMULATION USING MATLAB 37

5.1 Analysis and Simulation on array antenna 37

5.1.1 Variation of number of elements N 37

5.1.2 Variation of Side Lobe Level 39

5.1.3 Variation of Inter-element Spacing. 41

5.2 Discussion 44

CONCLUSION AND RECOMMANDATIONS. 45

References 46

APPENDIX 49

List of Figures

Fig.1.1 Omni directional Antennas and coverage patterns [7]. 9

Fig 1.2: Sectorized antenna system and coverage pattern [10]. 10

Fig 1. 3: Concept of smart antenna systems [8]. 11

Fig 1.4 Switch-Beam Systems [11]. 12

Fig 1.5: A Switch-Beam network [11]. 13

Fig 1.6: An adaptive antenna [11]. 14

Fig 1.7: Network structure of an adaptive array [11]. 15

Fig 2.1: The effect of Multipath on a mobile user[8]. 17

Fig 2.2: Two out-of-Phase Multipath Signal [8]. 18

Fig 2.3:.Representation of Fade Effect on User Signal [8]. 18

Fig 2.4: Illustration of Phase Cancellation [8]. 19

Fig 2.5: Illustration of Co channel Interference in a Typical Cellular Grid [8]. 20

Fig 3.1: Linear array of micro strip [5]. 24

Fig 3.2: Linear and Planar geometries [6]. 26

Fig 4.1: Concept of FDMI system 35

Fig 4.2: Concept of TDMA system 35

Fig 4.3: Concept of a CDMA system 36

Fig 4.4 Concept of SDMA system 36

Fig 5.1 : Radiation pattern with 4 elements 37

Fig 5.2 Radiation pattern with 8 elements 38

Fig 5.3 : Radiation pattern with 10 elements 38

Fig 5.4: Radiation pattern with 5dB. 39

Fig 5.5: Radiation pattern with 15dB 39

Fig 5.6: Radiation pattern with 37dB 40

Fig 5.7: Radiation pattern with 40dB 40

Fig 5.8 Radiation Pattern with normalized inter-element spacing of 0.125 41

Fig 5.9: Radiation Pattern with normalized inter-element spacing of 0.5 41

Fig 5.10: Radiation Pattern with normalized inter- element spacing of 0.75 42

Fig 5.11 Radiation Pattern with normalized inter-element spacing of 1 42