Ad-Hoc Networks Part 1 PDF

Wireless Mobile & Multimedia Networking 7COM1076 Ad-hoc Networks 1 Dr Tazeen Syed [email protected] Senior Lecturer School of Physics Engineering and Computer Science (SPECS) ...

Wireless Mobile & Multimedia Networking 7COM1076 Ad-hoc Networks 1 Dr Tazeen Syed [email protected] Senior Lecturer School of Physics Engineering and Computer Science (SPECS)  7COM1076 –Wireless Mobile & Multimedia Networking Outline ❑ Ad-hoc Networks ▪ Introduction ▪ Classification ▪ MANET ▪ Comparison with Cellular Networks ▪ Applications ❑ Routing Protocols ▪ Challenges in Routing ▪ Mobility and Link breakage ▪ Perfect routing ▪ Classification of Routing Protocols  7COM1076 –Wireless Mobile & Multimedia Networking Ad-hoc Networks – Introduction ❑ Meaning of the word “Ad hoc” is “for this”, means “for this purpose only”, implies it is a special network for a particular application. ❑ The nodes are free to move randomly and organize themselves arbitrarily; dynamic topology, the wireless network topology changes rapidly and unpredictably  7COM1076 –Wireless Mobile & Multimedia Networking Ad-hoc Networks – Classification Ad-Hoc Networks Wireless Mesh Network Mobile Ad-hoc Network Wireless Sensor Network WMN MANET WSN Cognitive Radio Wireless Vehicular Ad-hoc Network Intelligent Vehicle Ad-hoc Network Sensor Network VANET In VANET CR-WSN  7COM1076 –Wireless Mobile & Multimedia Networking Mobile Ad-hoc Networks (MANET) ▪ A MANET is an autonomous system of mobile nodes which are free to move about arbitrarily. ▪ It is a type of wireless network that is formed spontaneously and does not require an infrastructure for deployment. ▪ It is a collection of isolated mobile nodes that are connected to each other in a self-configurable, infrastructure-less, dynamic, and decentralized network. ▪ Mobile nodes are equipped with wireless interfaces that utilize radio channels to communicate with each other, without the need for centralized management. ▪ A mobile node in a MANET acts as both an end system (host) and a router to participate in data routing within the network.  7COM1076 –Wireless Mobile & Multimedia Networking MANET - Features ▪ Dynamic topologies / infrastructure-less ▪ Bandwidth constrained, variable capacity links ▪ Energy constrained operation ▪ Limited physical security ▪ Distributed administration/self-organized ▪ Multi-hop communications  7COM1076 –Wireless Mobile & Multimedia Networking MANET ❖ Why MANET? ❑ Development in wireless communications ❑ Ease of deployment ❑ Speed of deployment ❑ Less dependent on infrastructure  7COM1076 –Wireless Mobile & Multimedia Networking Ad-hoc Networks Vehicle Ad-hoc Network Cognitive Radio Sensor Network Cognitive radios (CRs) are smart wireless radio devices that have the capability to VANETs is a subset of MANETs with a unique characteristic of sense, learn and adapt to the environment in real time. CRs are intelligent devices dynamic nature, frequently exchanges information, uses real that can also make decisions based on what it has learned. CR technology is an time processing, self-organizing, and infrastructure less nature. advancement of software defined radios and it performs, sensing of the It provides the ability of vehicle to communicate among nearby spectrum, altering of its operating parameters, and utilising the frequency band vehicle and road-side unit (RSUs) when it is unoccupied  7COM1076 –Wireless Mobile & Multimedia Networking Nodes in WLan ❑ Ad-hoc mode ❑ Infrastructure mode  7COM1076 –Wireless Mobile & Multimedia Networking Ad-hoc Networks Vs Cellular Networks ▪ Fixed infrastructure-based vs. infrastructure-less ▪ Single-hop wireless links vs. Multi-hop wireless links ▪ Centralized administration vs. distributed administration ▪ Guaranteed bandwidth vs. shared radio channel ▪ High cost & time of deployment vs. quick & cost- effective deployment  7COM1076 –Wireless Mobile & Multimedia Networking Ad-hoc Networks Vs Cellular Networks  7COM1076 –Wireless Mobile & Multimedia Networking Application of Ad-hoc Wireless Networks Military Applications ▪ Inhospitable terrain ▪ Efficient & quick communication ▪ Secure multimedia multicasting ▪ High power transceivers Emergency Operations ▪ Self-configuration ▪ Minimal overhead ▪ Freedom and flexibility of mobility ▪ Quick deployment ▪ Real-time communication capability ▪ Fault-tolerant communication paths  7COM1076 –Wireless Mobile & Multimedia Networking Application of Ad-hoc Wireless Networks (cont.) Wireless Sensor Networks ▪ Tiny senor nodes ▪ Capable of sensing environmental factors such as temperature, humidity and nuclear radiation. ▪ Processing of the data gathered ▪ Communicate the processed data to the monitoring station through the network  7COM1076 –Wireless Mobile & Multimedia Networking Applications of Ad-hoc Wireless Networks (cont.) ❑ Collaborative and Distributed Computing ▪ Temporary communication infrastructure ▪ Minimal configuration ▪ Requires reliable multicast routing ▪ Level of security is not high ▪ High reliability of data transfer ▪ Desired receivers must have the replica of the transmitted file.  7COM1076 –Wireless Mobile & Multimedia Networking Challenging Issues for Ad-hoc Networks Medium access scheme ▪ Hidden terminal problem ▪ Exposed terminal problem ▪ Throughput ▪ Fairness Routing ▪ Dynamic topology ▪ Route breakage due to node mobility Transport layer protocol ▪ TCP performs poorly in MANETs Quality of service provisioning Security Energy management  7COM1076 –Wireless Mobile & Multimedia Networking Routing Protocols - Challenges in Routing ❑ Mobility ▪ Frequent path breaks ▪ Packet collisions ❑ Bandwidth constraint ❑ Error-prone and shared channel ▪ Bit error rate (BER) for wireless links: of the order of 10^-5 to 10^-3 ▪ BER for wired links: 10^-12 to 10^-9 ❑ Location-dependant contention ❑ Traffic-dependant contention  7COM1076 –Wireless Mobile & Multimedia Networking Mobility and Link Breakage  7COM1076 –Wireless Mobile & Multimedia Networking Major Requirements of a Perfect Routing Protocol ❑ Minimum route acquisition delay ❑ Quick route reconfiguration/maintenance ❑ Loop-free routing ❑ Distributed Routing Approach ❑ Minimum control overhead ❑ Scalability ❑ QoS support ❑ Secure  7COM1076 –Wireless Mobile & Multimedia Networking Classification of Routing Protocols ❑ Broadly classified based on the following: ▪ Routing information update mechanism ▪ Routing topology ▪ Use of temporal information for routing ▪ Utilization of specific resources  7COM1076 –Wireless Mobile & Multimedia Networking Classification of Routing Protocols (cont.) ❑ Based on routing information update mechanism ▪ Proactive or table –driven routing protocols ▪ Reactive or on-demand routing protocol ▪ Hybrid protocol ❑ Based on the Routing Topology ▪ Flat topology routing protocols ▪ Hierarchical topology routing protocols ❑ Based on Utilization of Specific Resources ▪ Power ▪ Location ▪ Temporal information  7COM1076 –Wireless Mobile & Multimedia Networking Table Driven Vs. On-demand ❑ Proactive / table driven protocols ▪ Every node maintains the network topology information in the form of routing tables by periodically exchanging routing information. ▪ Whenever a node requires a path to a destination, it runs an appropriate path-finding algorithm on the topology information it maintains. ❑ Reactive/on-demand routing protocols ▪ Nodes do not maintain the network topology information, nor exchange routing information periodically. ▪ The protocols obtain the necessary path when it is required, by using a connection establishment.  7COM1076 –Wireless Mobile & Multimedia Networking Table-Driven Routing Protocols ▪ Idea adapted from the routing protocols for wired network. ▪ Natural approach ▪ Each node needs to exchange information periodically with others. ▪ Is it good for ad hoc networks? ▪ Each node knows the global topology information in the form of tables at every node. ▪ Is it good for ad hoc networks?  7COM1076 –Wireless Mobile & Multimedia Networking References ❑ Ad Hoc Wireless Networks, architectures and protocols. C. Siva Ram Murthy and B. S. Manoj, 1st edition. ▪ Sections 5.1, 5.2, and their subsections. ❑ RFC 2501. ▪ http://www.ietf.org/rfc/rfc2501.txt  7COM1076 –Wireless Mobile & Multimedia Networking Any Thank you Questions? [email protected]