Mobile and Ad hoc Networks

1. Mobile and Ad hoc Networks Background of Ad hoc Wireless Networks Wireless Communication Technology and Research Ad hoc Routing and Mobile IP and Mobility Wireless Sensor and Mesh Networks Student Presentations Introductory Lecture http://web.uettaxila.edu.pk/CMS/SP2012/teAWNms/

2. Objectives • Where is Wireless Communication today? Where has it come from in the last decade? What is its future potential? • Introduction to Mobile Ad hoc, Sensor and Mesh networks • What are key research areas in wireless communication? • How do the features in Ad hoc wireless networks different from traditional wireless systems (WiFi: 802.11a/b/g/n, 3G, mobile WIMAX: 802.16e)? • Mobility issues • Security and other issues • Research topics

3. Text Books • AD HOC NETWORKS Technologies And Protocols by PrasantMohapatra and SrikanthKrishnamurthy • The handbook of AD HOC WIRELESS NETWORKS byMohammad Ilyas

4. Text Books • Ad Hoc Mobile Wireless Networks Protocols and Systems by C.K. Toh • Mobile Ad hoc Networking by Stefano Basagni, Marco Conti, Silvia Giordano and Ivan Stojmenovic

5. Introduction Foundations of Wireless Communications - Wireless Channel Foundations of Wireless Communications – Modulation Review of Networking Wireless Physical and MAC layer Wireless Area Networks (WPAN, WLAN, WWAN) and MAC Layer Wireless MAC protocols Wireless Routing Wireless TCP Mobile IP Quality of service Wireless Sensor Networks Mobile Ad hoc Networks Vehicular Ad hoc Networks Mesh Networks Wireless Network Security Standardization Research Papers Physical and MAC layer Routing in Wireless Opportunistic routing and network coding Network Layer and Routing Routing Metrics Geographic Routing Routing and Scalability Routing Algorithms Algorithmic foundations for scalability Energy issues Sensor Networks Wireless Routing Security Trust and Reputation systems Incentives, mechanisms, etc. Physical and link level issues Presentations Overview of the Course

6. Objectives of course • Learn about challenges in wireless networking • What forces us to reconsider many traditional designs? • Understand state-of-the-art in wireless/ubiquitous systems • Get a broad view of the ongoing research in the wireless domain • Have a good understanding of their capabilities and limitations

7. Course Materials • Course Web page • http://web.uettaxila.edu.pk/CMS/SP2012/teAWNms • Visit regularly • Announcements • Lecture Notes and Assignments • Research papers • Pdf/ps version of the papers will be on the Web page • ~30 papers, Combination of classic and recent work.

8. Reading Papers • Is this a vision/position/direction paper, or just a measurement/implementation? • How the paper is compared to others? • Can I mentally categorize this paper somewhere in the taxonomy? “Differs from X as follows; has the following in common with Y” • What is the most important contribution?

9. Reading Papers (2) • Does this advance the state of the art? • Did you learn anything new? • Does it provide evidence which supports/contradicts hypotheses? • Is there experimental validation? • Any technical flaws? • Will the paper generate discussion in the class? • How readable is the paper? • Is the paper relevant to a broader community?

10. Overview The challenges, technologies, and trends Wireless Fundamentals Source and channel coding Frequency spectrums Wireless LAN MAC protocols Wireless Internet – Mobile IP Covered Topics (will try!)

11. Routing for Wireless Ad Hoc Routing TCP in wireless enviroment Power Management wireless Sensor Networks Quality of Services (QoS) Hybrid Wireless Networks – Architectures– Pricing, Power Control, Load Balancing Special Topics Covered Topics (2)

12. Why wireless networks? • Mobility: to support mobile applications • Costs: reductions in infrastructure and operating costs: no cabling or cable replacement • Special situations: No cabling is possible or it is very expensive. • Reduce downtime: Moisture or hazards may cut connections.

13. Why wireless networks? (cont.) • Rapidly growing market attests to public need for mobility and uninterrupted access • Consumers are used to the flexibility and will demand instantaneous, uninterrupted, fast access regardless of the application. • Consumers and businesses are willing to pay for it

14. The Two Hottest Trends inTelecommunications Networks Millions Mobile Telephone Users Internet Users Years Source: Ericsson Radio Systems, Inc.

15. Growth of Home wireless

16. Wireless is THE Key Driver for the Future Internet • Historic shift from PC’s to mobile computing and embedded devices… • >2B cell phones vs. 500M Internet-connected PC’s in 2005 • >400M cell phones with Internet capability, rising rapidly • Sensor deployment just starting, but some estimates ~5-10B units by 2015 ~750M servers/PC’s, >1B laptops, PDA’s, cell phones, sensors ~500M server/PC’s, ~100M laptops/PDA’s Wireless Edge Network INTERNET INTERNET Wireless Edge Network 2005 2010

17. Market Size • Wireless as the common case vs. the exception • Laptop (54%) vs. desktop sales (46%) • >2B cell phones vs. 500M Internet-connected PCs • Estimates of ~5-10B wireless sensors by 2015 • Rapid deployment of new technology • Highly dynamic environment • Must accommodate new/unexpected technologies Staggering Market Statistics • 9 million hotspot usersin 2003 (30 million in 2004) • Approx 4.5 million WiFi access pointssold in 3Q04 • Sales have tripled by 2009 • Many more non-802.11 devices

18. Why is it so popular? • Flexible • Low cost • Easy to deploy • Support mobility

19. Applications ? • Ubiquitous, Pervasive computing or nomadic access. • Ad hoc networking: Where it is difficult or impossible to set infrastructure. • LAN extensions: Robots or industrial equipment communicate each others. Sensor network where elements are two many and they can not be wired!. • Sensor Networks: for monitoring, controlling, e

20. Infostations • Mobile hosts traveling through fixed network • Good for periodic download or upload of bulky data • Wireless islands (interconnected by wired network) • Gas stations • Here and there on the freeway • Possibly an invisible infrastructure with mobile-aware applications • In reality, you may need to know to go to it • Original paper assumes this: information kiosks • Coverage is spotty • Cost is lower than complete coverage

21. Ad hoc networks • Collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. • Hop-by-hop routing due to limited range of each node • Nodes may enter and leave the network • Usage scenarios: • Military • Disaster Relief • Temporary groups of participants (conferences)

22. Sensor networks • Deployment of small, usually wireless sensor nodes. • Collect data, stream to central site • Maybe have actuators • Hugely resource constrained • Internet protocols have implicit assumptions about node capabilities • Power cost to transmit each bit is very high relative to node battery lifetime • Loss / etc., like other wireless • Ad-hoc: Deployment is often somewhat random

23. Ad hoc networks, continued • Very mobile – whole network may travel • Applications vary according to purpose of network • No pre-existing infrastructure. Do-it-yourself infrastructure • Coverage may be very uneven

24. Networked Embedded Computers • Connected to network • send and/or receive • May be embedded only for network access • networked appliances • sensors Network • historical sites & other locations

25. Embedded Peer • Composite devices (HW+SW) • security system • Distributed composites vs. hardwired devices • client-defined composites • reuse of constituents Network • ease of change • extendibility & scalability

26. Networked Embedded Computers • Issues • Late binding • Naming • Discovery • IPC • User-interface deployment • Multi-appliance control • Access control • Existing social protocols not supported by existing mechanisms • All co-located users can use appliance • Restriction to contents per user Network

27. Location-Aware Computing • Motivation • location-based action • nearby local printer, doctor • nearby remote phone • directions/maps • location-based information • real • person’s location • history/sales/events • virtual • walkthrough • story of city • augmented • touring machine

28. Pose-Aware Computing • Operations based on locations and orientations of users and devices • Motivation • Augmented reality

29. Wearable Pose-Aware Computers • Computers on body • track body relative movements • monitor person • train person

30. Location Sensor Mobile Embedded Interactive Flight Simulator Active badge Wearable Beyond Desktops/Servers

31. Summary • Need to be connected from everywhere and anytime. • Need to be connected on movement • Need to good quality service on those situation. • Interworking with the existing networks

32. Classification of Wireless Networks • Mobility: fixed wireless or mobile • Analog or digital • Ad hoc (decentralized) or centralized (fixed base stations) • Services: voice (isochronous) or data (asynchronous) • Ownership: public or private

33. Classification of Wireless Networks • Area: wide (WAN), metropolitan (MAN), local (LAN), or personal (PAN) area networks • Switched (circuit- or packet-switched) or broadcast • Low bit-rate (voice grade) or high bit-rate (video, multimedia) • Terrestrial or satellite

34. What is special on wireless? • Channel characteristics • Half-Duplex • Location dependency • Very noisy channel, fading effects, etc., • Resource limitation • Bandwidth • Frequency • Battery, power. • Wireless problems are usually optimization problems.

35. What is special on wireless? • Mobility in the network elements • Very diverse applications/devices. • Connectivity and coverage (internetworking) is a problem. • Maintaining quality of service over very unreliable links • Security (privacy, authentication,...) is very serious here. Broadcast media. • Cost efficiency

36. Big issues! • Integration with existing data networks sounds very difficult. • It is not always possible to apply wired networks design methods/principles here.

37. Internet Design Goals • Connect existing networks • initially ARPANET and ARPA packet radio network • Survivability • ensure communication service even in the presence of network and router failures • Support multiple types of services • Must accommodate a variety of networks • Allow distributed management • Allow host attachment with a low level of effort • Allow resource accountability

38. Problems • Host mobility is not considered in the design. • There is a hierarchal design. How Ad hoc wireless networks can be handled • A layered design. Layer should be independent of each other. It is not work at all in wireless • TCP • Battery shortages; • Etc,.

39. Disconnection / store & forward • Many Internet protocols assume frequent connectivity • What if your node is only on the Internet for 5 minutes every 6 hours? • How do you browse the web? • Receive SMTP-based email?

40. High availbility requirements • No QoS assumed from below • Reasonable but non-zero loss rates • What’s minimum recovery time? • 1 RTT • But conservative assumptions end-to-end • TCP RTO • Interconnect independent networks • Federation makes things harder: • My network is good. Is yours? Is the one in the middle working? • Scale • Routing convergence times, etc.

41. Trends • Multimedia over IP networks • Next Generation Internet with features for “soft” QoS • RSVP, Class-based Queuing, Link Scheduling • Voice over IP networks • Packet Voice and Video • RTP and ALF • Intelligence shifts to the network edges • Better, more agile software-based voice and video codecs • Programmable intelligence inside the network • Proxy servers intermixed with switching infrastructure • Java code: “write once, run anywhere” Implications for cellular network infrastructure of the 21st century?

42. Issues • Scalability • Must scale to support hundreds of thousands of simultaneous users in a region. • Functionality • Computer-phone integration • Real-time, multipoint/multicast, location-aware services, security • Home networking, “active” spaces, sensors/actuators

43. Issues(2) • Leverage evolving IP traffic models • Provisioning the network for the extrapolated traffic and services • Proactive Infrastructure • Computing resources spread among switching infrastructure • Computationally intensive services: e.g., voice-to-text • Service and server discovery

44. Wireless Differences 1 • Physical layer: signals travel in open space • Subject to interference • From other sources and self (multipath) • Creates interference for other wireless devices • Noisy  lots of losses • Channel conditions can be very dynamic

45. Wireless Differences 2 • Need to share airwaves rather than wire • Don’t know what hosts are involved • Hosts may not be using same link technology • Interaction of multiple transmitters at receiver • Collisions, capture, interference • Use of spectrum: limited resource. • Cannot “create” more capacity easily • More pressure to use spectrum efficiently

46. Wireless Differences 3 • Mobility • Must update routing protocols to handle frequent changes • Requires hand off as mobile host moves in/out range • Changes in the channel conditions. • Coarse time scale: distance/interference/obstacles change • Fine time scale: Doppler effect • Other characteristics of wireless • Slow

47. Growing Application Diversity Collision Avoidance:Car Networks Mesh Networks Wired Internet Access Point Sensor Relay Node Ad-Hoc/Sensor Networks Wireless Home Multimedia

48. Challenge: Diversity Wireless Edge Network INTERNET INTERNET • New architectures must accommodate rapidly evolving technology • Must accommodate different optimization goals • Power, coverage, capacity, price Wireless Edge Network 2005 2010

49. Spectrum Scarcity • Interference and unpredictable behavior • Need better management/diagnosis tools • Lack of isolation between deployments • Cross-domain and cross-technology Why is my 802.11 not working?

50. Other Challenges • Performance: Nothing is really working well • Security: It is a broadcast medium • Cross layer interception • TCP performance