Bluetooth Low Energy

Preface xvii Acknowledgments xix

About the Author xxi







Part I: Overview 1

Chapter 1: What Is Bluetooth Low Energy? 3



1.1 Device Types 6

1.2 Design Goals 7

1.3 Terminology 9



Chapter 2: Basic Concepts 11

2.1 Button-Cell Batteries 11

2.2 Time Is Energy 12

2.3 Memory Is Expensive 13

2.4 Asymmetric Design 14

2.5 Design For Success 15

2.6 Everything Has State 16

2.7 Client-Server Architecture 17

2.8 Modular Architecture 18

2.9 One Billion Is a Small Number 19

2.10 Connectionless Model 19

2.11 Paradigms 20



Chapter 3: Architecture 27

3.1 Controller 27

3.2 The Host 32

3.3 The Application Layer 36

3.4 Stack Splits 38



Chapter 4: New Usage Models 41

4.1 Presence Detection 41

4.2 Broadcasting Data 42

4.3 Connectionless Model 43

4.4 Gateways 44



Part II: Controller 47

Chapter 5: The Physical Layer 49

5.1 Background 49

5.2 Analog Modulation 49

5.3 Digital Modulation 51

5.4 Frequency Band 54

5.5 Modulation 54

5.6 Radio Channels 55

5.7 Transmit Power 56

5.8 Tolerance 57

5.9 Receiver Sensitivity 57

5.10 Range 58



Chapter 6: Direct Test Mode 61

6.1 Background 61

6.2 Transceiver Testing 62

6.3 Hardware Interface 65

6.4 Direct Testing by Using HCI 67



Chapter 7: The Link Layer 69

7.1 The Link Layer State Machine 69

7.2 Packets 76

7.3 Packet Structure 79

7.4 Channels 84

7.5 Finding Devices 90

7.6 Broadcasting 92

7.7 Creating Connections 93

7.8 Sending Data 98

7.9 Encryption 104

7.10 Managing Connections 109

7.11 Robustness 120

7.12 Optimizations for Low Power 123



Chapter 8: The Host/Controller Interface 131

8.1 Introduction 131

8.2 Physical Interfaces 131

8.3 Logical Interface 135

8.4 Controller Setup 140

8.5 Broadcasting and Observing 148

8.6 Initiating Connections 153

8.7 Connection Management 158





Part III: Host 167

Chapter 9: Logical Link Control and Adaptation Protocol 169



9.1 Background 169

9.2 L2CAP Channels 171

9.3 The L2CAP Packet Structure 172

9.4 The LE Signaling Channel 173



Chapter 10: Attributes 179

10.1 Background 179

10.2 Attributes 189

10.3 Grouping 199

10.4 Services 199

10.5 Characteristics 210

10.6 The Attribute Protocol 217

10.7 The Generic Attribute Profile 231



Chapter 11: Security 241

11.1 Security Concepts 241

11.2 Pairing and Bonding 248

11.3 Signing of Data 252



Chapter 12: The Generic Access Profile 255

12.1 Background 255

12.2 GAP Roles 261

12.3 Modes and Procedures 262

12.4 Security Modes 270

12.5 Advertising Data 273

12.6 GAP Service 276





Part IV: Application 281

Chapter 13: Central 283



13.1 Background 283

13.2 Discovering Devices 283

13.3 Connecting to Devices 285

13.4 What Does This Device Do? 286

13.5 Generic Clients 287

13.6 Interacting with Services 288

13.7 Bonding 292

13.8 Changed Services 293

13.9 Implementing Profiles 294



Chapter 14: Peripherals 299

14.1 Background 299

14.2 Broadcast Only 299

14.3 Being Discoverable 300

14.4 Being Connectable 301

14.5 Exposing Services 301

14.6 Characteristics 302

14.7 Security Matters 303

14.8 Optimizing for Low Power 303

14.9 Optimizing Attributes 311



Chapter 15: Testing and Qualification 313

15.1 Starting a Project 313

15.2 Selecting Features 316

15.3 Consistency Check 316

15.4 Generating a Test Plan 317

15.5 Creating a Compliance Folder 317

15.6 Qualification Testing 318

15.7 Qualify Your Design 319

15.8 Declaring Compliance 320

15.9 Listing 321

15.10 Combining Components 321



Index 323