Mobile & Wireless Systems

1. Mobile & Wireless Systems EE206A (Spring 2003): Lecture #1

2. Welcome to EE206A! • Course logistics • Administrivia • Course overview • Focus on ad hoc multihop networks as opposed to cellular networks • Topics from • Wireless technology • Wireless and mobile networking • Mobile and pervasive computing • Sensor and actuator networks

3. Course Logistics: Instructor Info • Email: mbs@ee.ucla.edu • Phone: 310-267-2098 • Office: 6731-H BH • Office hours: MoWe 2-3 PM, or by appointment • I’m very responsive with email • Please put “EE206A” in the subject header • Assistant: Marilyn Saunders, 7440D BH marilyn@ea.ucla.edu

4. Course Logistics: About This Course • Elective course for EE’s ECS Major Field Students as well as those with ECS minor • Question in Communications Field exam • Related courses at UCLA • Estrin’s CS213 - Advanced Topics in Distributed, Embedded Systems (Winter) • http://www.cens.ucla.edu/CS213/ • Songwu Lu’s CS219 - Wireless Networking and Mobile Computing (Fall) • http://www.cs.ucla.edu/~slu/readme.html • My EE202A - Embedded and Real-time Systems (Fall) • http://nesl.ee.ucla.edu/courses/ee202a

5. Course Logistics: Prerequisites • No official prerequisite graduate courses as the course covers a wide range of topics, but I’ll assume that you have • Background equivalent to UCLA CSE or EE/CE option • Requirement #1: knowledge • Computer networking, digital communications • Requirement #2: skills • Using simulation and analysis tools • Advanced ability to program & use simulation/analysis tools • Strong ability to communicate your ideas (talks, reports) • Requirement #3: initiative • Definitely not a spoon-fed undergrad or basic grad course • Open-ended problems with no single answer requiring thinking and research • Requirement #4: interest • Have strong interest in research in this or related fields • Don’t take this course if you’re here for a quick-and-dirty course work MS

6. Course Logistics: Enrollment • If you want to enroll • Limit of 25-30 students • I’ll hand out PTEs as needed • wait till end of week 2 as many students drop out • If you are an EE student, remember to drop out by 4th week • otherwise you will be kicked out of the EE program • If you want to audit, following is the priority • You are an ECS student • You contacted me • Rest If you are not serious about the course,please drop out officially ASAP!

7. Course Logistics: Grading • One take-home examination: 25% • 9th or 10th week … most likely during the weekend between Weeks 9 & 10 • Assignments: 20% total • Analysis, simulation, programming, library/web research, paper reviews • Topic survey : 15% • Groups of 2-3 students • Survey an area (topics and resources specified by me on a continual basis) • Prepare slides and do a 30-35 minute presentation in the class • slides prepared jointly • either all students share the presentation or I will select randomly at the presentation time • Prepare a web site that should contain a report based on your survey, a bibliography, and links to resources and of course your slides • One project: 20% results, 10% report, 5% presentation = 35% total • Software/hardware design, tools, analysis, simulation • Implementation projects strongly encouraged • Literature surveys unacceptable, bogus hand-wavy stuff won’t get you far • Groups of 1-3 students • Up to 30 minute presentation during the finals week, like a conference talk with a demo • Up to 12 page report in the style of a technical conference paper • use ACM’s template at http://www.acm.org/sigs/pubs/proceed/template.html • Class participation: 5% • E.g. questions that you ask during lectures and student presentations • E.g. how much you interact with me regarding the project

8. Course Logistics: Project • Dig deep into a focus area on your own • lectures would provide a “broad” coverage • Should have some new idea/result, even if minor • one or more of simulation, analysis, implementation • no paper reviews and surveys • Project topics • some suggested project topics on class web page by early Week 2 • I encourage you to think of your own topic • may relate to your own research • you may not “reuse” work already done or being done for some other purpose • come and discuss possible project ideas with me! • What should be your goal? • something useful • similar style/quality as a conference paper and talk • key is to keep the project simple, and focused • aim for high quality! • Timeline • Project topics and groups finalized by Monday of Week 3 • Detailed proposal, timeline, and work till date by Friday of Week 4 • Weekly progress reports thereafter

9. Course Logistics: On the Web • Course web site URL http://nesl.ee.ucla.edu/courses/ee206a/2003s/ • On-line material • lecture viewgraphs in PDF & PPT • check before class, and print them • viewgraphs are organized topic-wise and would span several classes • copies of handouts, home works, exams etc. • important announcements • on-line reader with pointers to URLs, Melvyl • last year’s course at http://nesl.ee.ucla.edu/courses/ee206a/2002s/ • Class mailing list • ee206@ee.ucla.edu • make sure to write your name on the sign-up sheet • If auditing, please let me know if you wish to be on the list

10. Course Logistics: Reader & Textbooks • No books required • unfortunately NO single adequate book exists • I’d mention books as we go along • A set of papers will be required reading • average of one paper per class • will relate to the core topic of that class • you are expected to read it before the class • In addition, there are student presentations • cover alternate ideas or related topics • lead discussion but every one is supposed to participate • selected from a set of topics of my choosing • I will give pointers to papers and web resources

11. Course Logistics: Reader & Textbooks (contd.) • No paper reader - an “on-line reader” at the course web site • bibliographic entries for various papers • links to on-line versions if available • or, indication whether available through Melvyl’s INSPEC database • hardcopies will be handed out for papers not available on-line • You must know or learn how to locate papers • use Melvyl to access on-line databases • user web resources such as google and NEC’s CiteSeer (http://citeseer.nj.nec.com/cs)

12. Course Logistics: Some Books (for your interest only…) • Wireless Communications : Principles And Practice; Rappaport, Theodore S. Prince Hall Publishing; 09/1995; • Mobility: Processes, Computers, and Agents; Milojicic, D. S./ Douglis, F./ Wheeler, R.G.; Addison-Wesley, 04/1999. • Mobile Computing (Kluwer International Series in Engineering and Computer Science, No 353); Imielinski, Tomasz (Edt)/ Korth, Henry F. (Edt). Kluwer Academic Pub; 1/96; • Mobile IP : Design Principles And Practices; Perkins, Charles / Woolf, Bobby. Addison Wesley; 11/1997; • Wireless Multimedia Communications : Networking Video, Voice and Data; Wesel, Ellen Kayata. Addison Wesley; 12/1997; • Wireless Personal Communications; A Systems Approach; Goodman, David J. Addison Wesley; 09/1997;Principles of Mobile Communication; Stuber, Gordon L. Kluwer Academic Publishing; 6/96; • Second Generation Mobile And Wireless Technologies; Black, Uyless Prentice Hall; 09/1998;

13. Course Logistics: Conferences and Journals • Conferences & Workshops • Main: MobiCom, MobiHoc, INFOCOM, MobiSys • Others: SIGCOM, WSNA, SPNA, IPSN, WCNC, MoMuC, ICUPC, PIMRC, WoWMoM, ICC, Globecom, etc. • Journals & Magazines • Main: ACM/Baltzer WINET, ACM/Baltzer MONET, IEEE Transactions on Mobile Computing, IEEE Wireless Communications • Others: IEEE Trans of N/W, JSAC etc.

14. Course Logistics: Impact of Travel on Class Schedule • Missed classes due to conference travel • Wed April 23 (IPSN) • Possibly more • Will schedule make up if needed

15. Course Logistics: Cheating & Plagiarism • What is cheating & plagiarism? • Acting dishonestly, practicing fraud • Stealing or using (without permission) other people’s writings or ideas • E.g. from other students, other sources such as web sites, solutions from previous offerings of this course etc. • Note that it doesn’t have to be literal copying – stealing ideas but presenting in a different style is still cheating and plagiarism. • You are also guilty if you aid in cheating & plagiarism • My policy: zero tolerance • HWs, presentations: 0 score + one level (e.g. A to B) reduction in course grade • Exam, project: “F” grade for the course + report to Dean • More than 1 incident: : “F” grade for the course + report to Dean • Moreover, remember that you may have to face me in other exams (e.g. M.S. comprehensive, Ph.D. prelims, Ph.D. qualifiers) and professionally! • Bottomline: don’t risk it - you will regret it!

16. Course Logistics: Useful Simulation Tools • Ns-2 • http://www.isi.edu/nsnam/ • Tutorial at http://www.isi.edu/nsnam/ns/ns-tutorial/tutorial-02/index.html • SensorSim library on top of NS-2 • http://nesl.ee.ucla.edu/projects/sensorsim/ • Qualnet • http://www.scalable-networks.com/ • Parsec • http://pcl.cs.ucla.edu/projects/parsec/ • NESLSim sensornet library on top of Parsec • http://www.ee.ucla.edu/~saurabh/NESLsim/ • Emstar • http://lecs.cs.ucla.edu/Publications/papers/emstar.pdf

18. Reading List for This Lecture • MANDATORY READING [Weiser91] M. Weiser, "The Computer for the 21st Century," Scientific American, vol. 265, no. 3, pp. 94-104, September 1991.(draft copy at http://www.ubiq.com/hypertext/weiser/SciAmDraft3.html) • RECOMMENDED READING None.

19. HW #1 (due Mon 4/7, 5PM) • Read Weiser’s paper and write a 1-2 page essay that critiques the paper, focusing particularly on what Weiser got right and what he got wrong from your 2003 perspective of technology trends and market place • Remember, I am not looking for a summary! • Submit electronically by the above deadline using the following • Must be done as word, html, PDF, ascii files • One {word, pdf, html, ascii} file per problem, with a name such as pN.pdf where N = prob # • supporting files or subdirectories may have names such as pN_code.c • Store all the files and directories for HW #1 in a directory called hw1 • Archive the hw1 directory using zip or tar or tar followed by gnuzip or compress • upon extraction, your archive should yield a single top directory called hw1 • Send me email with a URL of the for http://<host>/<path>/hw1.{zip,tar,tgz,tZ} • In future, I’d assume your submission is available by the deadline at http://<host>/<path>/hwN.{zip,tar,tgz,tZ} • In addition, submit a hardcopy printout within 24 hours of the deadline • slip under my office door or leave in the mail slot next to my office door

20. HW #2 (due Mon 4/14, 5PM) Select an emerging technology area, new commercial product class, newstandard, or a major non-UCLA research project that is relevant to this course and create a web page with discussion that surveys/summarizes and critiques the selected technology, product, or project. In addition, provide WWW links and paper references to important sources of information. • Use Web (e.g. Google) and Melvyl (California Digital Library) as your primary source • Since I want every student to pick a distinct topic, please get your choice approved by me via email • I’d approve topics in the first come first served order • I won’t allow topics on which I know such web pages already exist! • Look at various solutions to problem 2 of HW #1 of Spring 2001 EE206A to see what I am looking for • http://nesl.ee.ucla.edu/courses/ee206a/2001s/hw1_submissions.htm • Or, look at http://www.cs.berkeley.edu/~culler/cs294-s00/knowledgeweb.html for a similar exercise in David Culler’s course at Berkeley • Submission: as “hw2” using the same process (and URL path) as HW1 • Name your top-level file inside hw2 as index.html • No hardcopy required

21. Sample Topics for HW #2 • Radio technologies: Zigbee, UWB, MIMO • Comparison of available low-power radios • Security in wireless networks (e.g. new 802.11 security standard) • QoS in wireless networks (e.g. new 802.11 extensions for MAC) • Directional and smart antennas • Any other topic relating to

22. Growth in Wireless Systems • Rapid growth in cellular voice services • Cell phones everywhere! • Wireless data still a small market, but a fast growing one with lots of exciting action • WLAN rapidly growing • 802.11a/b/g hotspots, Bluetooth • PDAs and laptops with integrated WLANs • Wide area wireless data also growing rapidly • SMS, GPRS, Edge, 1xEV-DO • Variety of interesting devices (e.g. Treo, Sidekick) • Ad hoc networking • Battlefield, homeland defense, commercial • Networking of embedded devices • Smart spaces, sensor networks

23. Evolution in Information Systems • Wired  wireless, e.g. wired phones  cellular • more freedom of location and time • Voice telephony, data  multimedia • Intelligent telecom n/w  networked computing • intelligence at the edges of the network • programmable servers intermixed with switching infrastructure for rapid service deployment • Networked computing is becoming pervasive • personal  networked  mobile  pervasive • more flexible resource usage, more freedom of location and time, more efficient flow of information • Moving beyond phones and PCs • embedded devices & sensor-based smart spaces

24. Evolution of Mobile and RF Wireless Systems • 1st generation: analog - voice • AMPS with manual roaming • cordless phones • packet radio • 2nd generation: digital - voice, data • cellular & PCS with seamless roaming and integrated paging (IS-95, IS-136, GSM) • multizone digital cordless • wireless LANs (802.11), MANs (Metricom), and WANs (CDPD, Ardis, RAM, Mobitext)

25. Beyond the 2nd Generation • Wide-area mobile voice/data • 2.5G: GPRS • 3G standards: UMTS,/IMT2000, wideband CDMA, CDMA2000, EDGE • Fixed Point-to-multipoint broadband wireless access 802.16 • LMDS (local multipoint distribution) 24-28GHz • MMDS below 5 GHz • Free space optics (Terabeam) • Higher-speed WLAN • 802.11b (2.4GHz, 11 Mbps), 802.11a (5GHz, 54 Mbps & higher) • HomeRF • Personal area Networks • Bluetooth, 802.15 • Wireless device networks • Sensor networks, wirelessly networked robots

26. Satellite Regional Area Low-tier High-tier Local Area Wide Area Low Mobility High Mobility Heterogeneous Networks • Seamless mobility across diverse overlay networks • “vertical” hand-offs • software “agents” for heterogeneity management • IP as the common denominator

27. Ad Hoc Networks • Disaster recovery • Battlefield • ‘Smart’ office • Etc. • Rapidly deployable infrastructure • Wireless: cabling impractical • Ad-Hoc: no advance planning • Backbone network: wireless IP routers • Network of access devices • Wireless: untethered • Ad-hoc: random deployment • Edge network: Sensor networks, Personal Area Networks (PANs), etc.

28. “The Network is the Sensor”[Oakridge National Labs] Gateway • Distributed and large-scale like the current Internet • But, • physical instead of virtual • resource constrained • real-time control loops instead of interactive human loops

29. Smart Indoor Spaces Sylph Middleware Framework NetworkManagement SensorManagement SensorFusion Speech Recognizer Database & Data Miner Wired Network Collaboration: Muntz (CS) Alwan (EE) Potkonjak (CS) Baker (Education) WLAN Access Point High-speed Wireless LAN (WLAN) WLAN-Piconet Bridge WLAN-Piconet Bridge Piconet Piconet SensorsModules Sensor Badge Networked Toys “Fusing the Physical and the Cognitive”

30. Wireless Technologyin Transportation

31. Battlefield Networks • Mobile ‘users’ query and track mobile targets in a battle space instrumented with a number of ‘sensor networks’ composed of a large number of energy limited air-borne and ground-based ‘sensor nodes’ (e.g. cameras) • Users: rovers, UAVs, soldiers • Sensors: rovers & UAVs carrying sensors, static sensor nodes • Targets: vehicles, soldiers

32. Alternate Models of Mobile Computing Systems • Ubiquitous Information Access • information distributed everywhere by the “net” • terminal centric • users carry wireless terminals • terminal is the universal service access device • terminal adapts to location and services • Ubiquitous Computing • cheap computers of different scales and types embedded everywhere • 100s of computer in every room in the form of common, day-to-day objects • user centric • computers swapped among users • computers dedicated to service • computers adapt to location and users

33. Telecom View of theFuture Information Systems People and their machines should be able to access information and communicate with each other easily and securely, in any medium or combination of media - voice, data, image, video, or multimedia - anytime, anywhere, in a timely, cost-effective way. George Heilmeier (CEO of Bellcore)IEEE Communication Magazine, 1992

34. Computing View of theFuture Information Systems The most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it... the idea of a “personal computer” itself is misplaced... the vision of laptop machines, dynabooks and “knowledge navigators” is only a transitional step... a new way of thinking about computers, one that takes into account the human world and allows the computers themselves to vanish into the background. Mark Weiser (Chief Technologist, Xerox PARC)Scientific American, September1991

35. Wireless Technology in Transition Until Now • Provide interaction between people and human-mediated data sources (other people, web services) • # of users ~= # of networked nodes • Resource-rich nodes • Facilitate human-centered interactive decision making • Communicate bits among geographically distributed nodes Focus on networking interactive computers The Future • Provide interaction between people and the instrumented physical world (sensors, actuators) • # of users << # of networked nodes • Resource-constrained nodes • Facilitate human-supervised autonomous decision making • Compute answers by fusing real-time information from distributed nodes Focus on distributed embedded computation

36. What is this course about? • Emphasis on emerging systems • beyond cellular telephone systems • wireless packet-switched multimedia • beyond network of cell phones and 802.11 PCs • networks of large # of wireless embedded systems • Emphasis on interaction between layers of the system • not about radio design or communication theory • link/network/transport, application, OS/middleware • optimizations across layers

37. Main Attributes of Mobile and Wireless Systems • Wireless • limited bandwidth • high latency • < 3 ms indoor • > 100 ms outdoor (cellular, satellite) • variable link quality • noise, disconnections, interference • link asymmetry • heterogeneous air interfaces • easier snooping • Mobility • Portability More Signal Processing

38. Main Attributes of Mobile and Wireless Systems • Wireless • Mobility • user and terminal location • are system variables of interest • change dynamically • speed of terminal mobility impactswireless bandwidth • constants become variable • location, environment, connectivity, b/w,I/O devices, security domain • easier spoofing • Portability More Protocol Processing

39. Main Attributes of Mobile and Wireless Systems • Wireless • Mobility • Portability • limited battery capacity • limited computing • limited storage • small dimensions • risk to data (easily lost) More Energy Efficiency

40. Disconnections • Planned vs. unplanned • Choices? • engineer to prevent disconnections • gracefully cope (adapt) to disconnections • Mask disconnections and round-trip latencies • decouple communication from data production/consumption • asynchronous operation (multiple REQs before ACKs), prefetching, delayed write-back etc. • Tolerate by autonomous operation, caching/hoarding, local applications etc. • disconnected filesystems, e.g. CMU’s CODA • Good user interfaces to give feedback about disconnection

41. Limited Bandwidth • Difference between indoor (1-10Mbps) and outdoor (10s of Kbps) • mobility, multipath • Right metric? • bps vs. bps per user vs. bps per unit volume • Cope by improving bandwidth usage • compression, buffering • techniques for disconnection (caching, delayed write-back) help • Schedule link bandwidth to improve user satisfaction • differentiate data according to quality of service • fair allocation of bandwidth

42. Bandwidth Variability • Variations due to change of network • ethernet vs. wavelan vs. CDPD • Variations due to changing wireless link condition • fading • How can applications cope? • operate only when all bandwidth available • design for worst case minimum bandwidth • adapt to available bandwidth • appropriate scheduling of packets on the link

43. Time Varying Wireless Environment • Wired networks • problem is congestion… need to share resources • resource reservation + scheduling can provide QoS • Wireless networks • sharing is only part of the problem • available wireless link resource undergoes dramatic and rapid changes • multipath reflection, doppler fading, frequency collisions • rapid signal fades and distortions as a receiver moves • necessitates aggressive signal processing and adaptive protocols

44. Address Migration due to Mobility • Dynamically changing network access point • In current internet (and PSTN) address corresponds to the point of attachment to n/w • applications/calls connect to a fixed address • active connections cannot be moved to new address • How to support changing network access point? • How to find the current address? • How to do rerouting? • How to do route optimization? • How to do multicast?

45. Rethinking Naming and Addresses in Wireless Systems • Conventional networks • Destination has a name represented by an id • Name maps to an address represented by an id • Routing done by id-based address • Large ad hoc networks, e.g. sensor networks • Hard to name by an id • Attribute based naming (“a sensor in the SW corner”) • Map attributes to id, and then route using id • Or, perhaps route using the attributes? • How about no addresses? (get address for each transaction) • Dynamically chosen addresses according to local density?

46. Location-dependent Information • Location affects configuration parameters • DNS, timezone, printer etc. • Location affects answer to user queries • e.g. where is the nearest printer • More complex location-dependent queries • e.g. where is the nearest taxi • Privacy concerns due to location tracking • Changing context • small movements may cause large changes • caching may become ineffective • dynamic transfer to nearest server for a service • Localization

47. Portability • Power is key • long mean-time-to-recharge, small weight, volume • Risk to data due to easier privacy breach • network integrated terminals with no local storage • Small user interfaces • small displays, analog inputs (speech, handwriting) instead of buttons and keyboards • Small storage capacity • data compression, network storage, compressed virtual memory, compact scripts vs. compiled code

48. Low Power & Energy-awareness • Battery technology is a hurdle… no Moore’s Law to help out • Typical laptop: 30% display, 30% CPU, 30% rest • wireless communication and multimedia processing incur significant power overhead • Low power • circuits, architectures, protocols • Power management • Right power at the right place at the right time • Battery model

49. Battery Technology • Battery technology has historically improved at a very slow pace • NiCd improved by x2 over 30 years! • require breakthroughs in chemistry

50. Summary of Challenges • Portable, energy-efficient devices • End-to-end quality of service • Seamless operation under context changes • Context-aware operation • Secure operation • Sophisticated services for simple clients