Essentials of Wireless Mesh Networking

Cover......Page 1
Half-title......Page 3
Series title......Page 4
Essentials of Wireless Mesh Networking......Page 5
Copyright......Page 6
Contents......Page 7
Preface......Page 11
Acknowledgements......Page 12
1 Mesh overview and terminology......Page 13
1.1 What is a mesh?......Page 14
1.2 The role of mesh in future networks......Page 17
1.3 How do meshes work?......Page 19
1.3.2 Planned versus ad hoc......Page 20
1.3.5 Meshing versus multi-hopping......Page 21
1.4 Key mesh issues and the structure of this book......Page 24
2 Attractive mesh attributes and applications......Page 27
2.1.1 Cellular or WLAN hotspot multi-hopping......Page 28
2.1.2 Community networking......Page 29
2.1.3 Home, office or college indoor networking......Page 30
2.1.5 Vehicular ad hoc networks (VANETs)......Page 31
2.1.6 Wireless sensor networks (WSNs)......Page 32
2.2 The coverage attribute......Page 33
2.2.1 Rural environment with open propagation......Page 35
2.2.2 Urban environment with dense obstacles......Page 36
2.2.3 Extension to a mixed environment......Page 37
Reference......Page 38
3.1 Overview......Page 39
3.2.1 Physical versus logical meshes......Page 41
3.2.2 Intra-mesh and extra-mesh traffic flows......Page 42
Intra-mesh traffic architectures......Page 44
Extra-mesh traffic flow......Page 47
3.3.1 MACs for fixed and planned applications......Page 48
3.3.2 MACs for mobile and ad hoc applications......Page 49
3.4.1 Every node is a router......Page 50
3.4.3 Proactive and reactive routing in ad hoc networks......Page 51
3.5 Transport and applications......Page 52
3.5.1 Elastic and inelastic applications......Page 53
3.6 Summary......Page 54
4 Mesh capacity, scalability and efficiency – hypothesis testing......Page 55
4.1.1 Starting with the answer......Page 57
4.1.2 Capacity and scaling issues – a thought experiment......Page 58
Mobile couriers......Page 61
Spread spectrum and infinite spectrum......Page 62
4.1.4 Analysis of pure mesh capacity limitations......Page 63
4.1.5 Underlying causes of limited capacity – mathematical insights......Page 67
4.1.6 Underlying causes of limited capacity – physical insights......Page 69
Traffic limitation......Page 71
Finding a way around the problem......Page 73
Practical performance......Page 74
Unbounded delay: the ‘mobile-courier’ scenario......Page 76
The potential of using ‘infinite’ bandwidth......Page 78
The benefit of traffic localisation......Page 79
4.1.8 Hybrid mesh network capacity, examples and conclusions......Page 80
4.1.9 Access mesh network capacity, examples and conclusions......Page 83
4.2 Conclusions – capacity......Page 85
4.3.1 Spectral efficiency......Page 87
4.3.2 Comparative efficiency of pure mesh and cellular......Page 91
4.3.3 Efficiency of multi-hopping......Page 92
Extended route length......Page 95
Propagation law......Page 96
Traffic concentration......Page 97
4.4 Conclusions – omni-directional antennas......Page 98
4.5 Hypothesis 3 – Do directional antennas help a mesh?......Page 99
4.5.1 Antenna steering......Page 100
Null steering......Page 101
Ideal antennas......Page 102
Real-world antennas......Page 103
4.6 Conclusions – directional antennas......Page 105
4.7.1 Spectrum ‘sweet spot’......Page 106
4.8 Conclusions – utilisation......Page 107
4.9 Summary of hypothesis testing......Page 108
References......Page 109
5 Mesh susceptibility......Page 111
5.1 Interference types......Page 112
5.2 Susceptibility to interference – PHY and MAC......Page 114
Carrier frequency: allocation......Page 116
Carrier frequency: hopping......Page 118
Carrier frequency: orthogonal frequency division multiplexing......Page 120
Signal bandwidth: narrowband......Page 121
Signal bandwidth: wideband......Page 122
Time structure: interleaving......Page 123
Time structure: throughput......Page 124
Modulation......Page 125
5.2.2 Medium access control......Page 126
Frequency division multiple access......Page 127
Code division multiple access......Page 128
Distributed medium access......Page 129
Distributed MAC inefficiencies......Page 131
5.2.3 Conclusions......Page 132
5.3.1 Routing......Page 133
Routing and mobility......Page 134
Routing overheads......Page 135
5.3.2 Transport......Page 138
Traffic models and implications......Page 140
5.4 Co-existence approaches......Page 141
5.4.1 Knowledge based approaches......Page 142
5.5 Summary of susceptibility and co-existence issues......Page 144
References......Page 145
6.1 Quality of service and levels required......Page 146
6.2.1 Would a mesh enable new services?......Page 149
Effects of mobility......Page 150
The need for new mobility modelling processes......Page 152
Example of network ‘brittleness’......Page 153
Network partitions caused by mobility......Page 154
6.3 Improving quality of service by adding network infrastructure......Page 156
6.3.1 Could a mesh guarantee a quality of service?......Page 157
6.3.2 Dependence of QoS on user behaviour......Page 158
Coverage, availability and quality of service......Page 159
6.4 Quality of service summary......Page 160
References......Page 161
7.1 Capacity......Page 163
7.3 Efficiency......Page 164
7.5 Initial roll-out......Page 165
7.7 Reliance on user behaviour......Page 166
7.8 Ad hoc versus quality of service......Page 167
7.10 Business case economics......Page 168
Reference......Page 169
8.1 User side mesh applications......Page 170
8.1.1 Cell boundary theory......Page 171
8.1.2 Cellular multi-hop or WLAN hotspot extension......Page 174
8.1.3 Community networking......Page 175
8.1.5 Conclusion on user side meshing......Page 176
8.2.1 Micro base station backhaul......Page 177
8.3.1 Vehicular ad hoc networks (VANETs)......Page 178
8.4 Time scales......Page 179
Reference......Page 180
9.1 Wireless cities......Page 181
9.2 Community Internet......Page 185
9.3 Vehicular ad hoc network (VANET) applications......Page 187
References......Page 191
10 Wireless sensor networks (WSNs) as mesh networks......Page 192
10.1 Introduction......Page 193
10.2 WSN sensors......Page 194
10.3.1 Energy scavenging/harvesting......Page 195
10.4.1 Sensor interfacing and calibration......Page 196
10.5.1 RFID......Page 198
10.5.2 Mesh networks......Page 199
10.5.4 Comparisons between mesh and sensor networks......Page 200
10.6 Differentiating 802.15.x, ZigBee and 6LoWPAN......Page 201
10.6.1 IEEE 802.15.4 and ZigBee......Page 202
10.6.2 6LoWPAN......Page 205
10.6.3 Summary......Page 206
10.8 System architecture in sensor networks......Page 207
10.8.1 WSN system requirements......Page 208
10.8.2 Classic IP address-based routing and transport – review......Page 209
10.9 Unstructured WSNs......Page 212
10.9.1 WSN approaches – data-centric routing......Page 214
10.9.2 WSN approaches – geographic routing......Page 216
10.9.3 WSN approaches – other routing mechanisms......Page 217
10.10.1 WSN approaches – hierarchical......Page 218
10.10.2 Structured versus unstructured......Page 219
ZigBee/802.15.4 configuration......Page 222
10.10.3 All nodes equal versus unequal......Page 223
10.11 External routing and transport options......Page 224
10.12 WSN summary......Page 225
References......Page 226
Abbreviations......Page 227
Selected definitions......Page 231
The random waypoint mobility model......Page 233
The random direction mobility model......Page 234
The city section or Manhattan mobility model......Page 235
Reference......Page 236
About the author......Page 237
Index......Page 238
Mesh hints and tips......Page 240