INTRODUCTION TO AD HOC WIRELESS NETWORKS 2/12/08 Seminar on Wireless Ad Hoc & Sensor Networks

contents Taxonomy of networks Categoies of wireless network Ad-hoc network Characteristics of ad-hoc network Application of ad-hoc network Sensor networks Characteristics of sensor network Application of sensor network Lmitation of ad-hoc and sensor networks

Network: What is network? Network is series of points or nodes Interconnected by communication paths Network can interconnect with other netowrks contains subnetworks

Taxonomy of wireless networks fixed mobile access ad hoc networks networks networks cellular random wireless sensor networks access internets networks networks

Categories of wireless networks Cellular (one hop) networks Wireless ad hoc (multi hop)networks. Wireless Sensor Networks Seminar on Wireless Ad hoc & Sensor Networks 5/02/09

Cellular Networks Cellular Networks Networking Wireless Hosts Infrastructure dependent High setup costs Large setup time Reliable

Seminar on Wireless Ad hoc & Sensor Networks What is Ad-hoc? A local area network, or some small networks, parts are time-limited, and only usable for the duration of a communication session The routers are free to move randomly, organize themselves arbitrarily The wireless topology vary rapidly and unpredictably Seminar on Wireless Ad hoc & Sensor Networks 05/02/09

A wireless ad hoc network

IEEE 802.11 in OSI Model Wireless

802.11 – Architecture of an ad-hoc network Direct communication within a limited range – Station (STA): terminal with access mechanisms to the wireless medium – [Independent] Basic Service Set group of stations using the same radio frequency • You may use SDM or FDM to establish several BSS Seminar on Wireless Ad hoc & Sensor Networks 05/02/09

Dynamic network topology The mobile nodes are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidl and unpredictably. Seminar on Wireless Ad hoc & Sensor Networks move 05/02/09

What are ad hoc/sensor networks? Sometimes there is no coverages – remote areas, ad hoc meetings, disaster areas – cost can also be an argument against an infrastructure Sometimes not every station can hear every other station – Data needs to be forwarded in a “multihop” manner Seminar on Wireless Ad hoc & Sensor Networks 05/02/09

Advent of Ad hoc Wireless Networks(Cont) 1 2 3 4 5 6 7

Comparisons between Cellular and Ad Hoc Wireless Networks (I) Cellular Networks Ad Hoc Wireless Networks Fixed infrastructure-based Infrastructureless Guaranteed bandwidth (designed for voice traffic) Shared radio channel (more suitable for best-effort data traffic) Centralized routing Distributed routing Circuit-switched (evolving toward packet switching) Packet-switched (evolving toward emulation of circuit switching) Seamless connectivity (low call drops during handoffs) Frequent path breaks due to mobility High cost and time of deployment Quick and cost-effective deployment Reuse of frequency spectrum through geographical channel reuse Dynamic frequency reuse based on carrier sense mechanism Easier to employ bandwidth reservation Bandwidth reservation requires complex medium access control protocols

Comparisons between Cellular and Ad Hoc Wireless Networks (II) Cellular Networks Ad Hoc Wireless Networks Application domains include mainly civilian and commercial sectors Application domains include battlefields, emergency search and rescue operations, and collaborative computing High cost of network maintenance (backup power source, staffing, etc.) Self-organization and maintenance properties are built into the network Mobile hosts are of relatively low complexity Mobile hosts require more intelligence (should have a transceiver as well as routing/switching capability)

Mobile Ad hoc Networks mobile hosts multi-hop routes between nodes may not use infrastructure

Motivation Ad-hoc nodes are typically battery powered and may not support energy scavenging Node and network lifetime must be prolonged Most energy consumption is at the node’s transceiver Minimum transmit power decreases contention Higher number of simultaneous transmissions can be allowed Increase in Capacity

Motivation (Cont) wireless networks have special limitations and properties such as limited bandwidth, highly dynamic topology, link interference, limited range of links, and broadcast.

Characteristics and tradeoffs Self-organized Self-deployed Decentralized Dynamic network topology Tradeoffs Limited Bandwidth Need Multi-hop router Energy consumption problem Security problem

Characteristics of MANETs Dynamic topology links formed and broken with mobility Possibly uni-directional links Constrained resources battery power wireless transmitter range Network partitions A B

Limitations of MANET Power: network life limited by battery life Short radio range Packet Collisions Network topology changes Address allocation

Mobile Ad Hoc Networks (MANET) 4/10/08 One day Workshop on Wireless Ad Hoc Networks

Broadcasting Unlike wired network, every hop is broadcasting Every packet can reach every node in the radio range of the sender Flooding messages make the problem even worse Wasted bandwidth High collision rate

Applications Personal area networking Emergency operations Cell phone, laptop, PDA , tablet pc Meeting room/conference Emergency operations Search and rescue(Disaster &Relief) Policing and fire fighting Civilian environments Taxi cab network Boats, aircrafts Military use On the battle field Military applications Ad hoc wireless networks is useful in establishing communication in a battle field. Collaborative and Distributed Computing A group of people in a conference can share data in ad hoc networks. Streaming of multimedia objects among the participating nodes. Emergency Operations Ad hoc wireless networks are useful in emergency operations such as search and rescue, and crowd control. A Wireless Mesh Network is a mesh network that is built upon wireless communications and allows for continuous connections and reconfiguration around blocked paths by "hopping" from node to node until a connection can be established.

Wireless Ad Hoc Sensor Networks                                                                                                                                                        Wireless Ad Hoc Sensor Networks

Layers in Use Ad-hoc networks – link layer: medium access control – network layer: routing – transport layer: TCP/IP

NETWORK LAYETRS:

Ad-hoc routing protocols AODV: Ad-hoc On-Demand Distance Vector Routing LMR: Lightweight Mobile RoutingTORA: Temporally-Ordered Routing Algorithm ABR: Associatively-Based Routing SSR: Signal Stability Routing DSR: Dynamic Source Routing Table Driven:DSDV: Destination-sequenced Distance-vector Routing CGSR: Cluster-head Gateway Switch Routing WRP: Wireless Routing Protocol 28 05/02/09 28

functional diagram of a wireless sensor communication node.

IEEE 802.11 in OSI Model

CHARACTERISTICS OF WIRELESS SENSOR NODES AND NETWORKS Batteries in an ad hod network can be recharged, while they are not replaceable in wireless sensor networks. The goal of a wireless sensor network is to prolong battery life at the expense of QoS and bandwidth utilization [7], whereas the objective of an ad hoc network is to provide QoS. Seminar on Wireless Ad hoc & Sensor Networks 05/02/09

One day Workshop on Wireless Ad Hoc Networks Applications Structural, seismic Bridges, highways, buildings Smart roads Traffic monitoring, accident detection, recovery assistance highway camera microphone Contaminants detection 4/10/08 One day Workshop on Wireless Ad Hoc Networks 32 32

Wireless Ad Hoc Sensor Networks                                                                                                                                                        Wireless Ad Hoc Sensor Networks

Wireless Sensor Networks (WSN) New technologies have reduced the cost, size and power of micro-sensors and wireless interfaces Circulatory Net Sensing Computation Networking Environmental Monitoring Benefits from 3 technologies digital circuitry wireless communication silicon micro-machining 4/10/08 One day Workshop on Wireless Ad Hoc Networks 34

7 Comparisons between Cellular and Ad Hoc Wireless Networks (I) Cellular Networks Ad Hoc Wireless Networks Fixed infrastructure-based Infrastructureless Guaranteed bandwidth (designed for voice traffic) Shared radio channel (more suitable for best-effort data traffic) Centralized routing Distributed routing Circuit-switched (evolving toward packet switching) Packet-switched (evolving toward emulation of circuit switching) Seamless connectivity (low call drops during handoffs) Frequent path breaks due to mobility High cost and time of deployment Quick and cost-effective deployment Reuse of frequency spectrum through geographical channel reuse Dynamic frequency reuse based on carrier sense mechanism Easier to employ bandwidth reservation Bandwidth reservation requires complex medium access control protocols on Wireless Ad Hoc Networks 35 35

Comparisons between Cellular and Ad Hoc Wireless Networks (II) Cellular Networks Ad Hoc Wireless Networks Application domains include mainly civilian and commercial sectors Application domains include battlefields, emergency search and rescue operations, and collaborative computing High cost of network maintenance (backup power source, staffing, etc.) Self-organization and maintenance properties are built into the network Mobile hosts are of relatively low complexity Mobile hosts require more intelligence (should have a transceiver as well as routing/switching capability) Seminar on Wireless Ad Hoc Networks 36 36

CONCLUSION Ad-hoc and sensor network is everywhere . The development of Ad-hoc wireless networks & senior networks provides tremendous opportunities in many areas including & industrial environments. CONCLUSION

Ad hoc Wireless Network Everywhere FUTURE? Ad hoc Wireless Network Everywhere Seminar on Wireless Ad hoc & Sensor Networks 05/02/09

Seminar on Wireless Ad hoc & Sensor Networks Thanks Seminar on Wireless Ad hoc & Sensor Networks 05/02/09