Copyright 2002 Mani Srivastava 2 Course Logistics: Instructor Info Phone: Office: 6731-H BH Office hours: Th 12-2 PM, or by appointment Im very responsive with Usually around on weekend Assistant: Letty Marr, 7440D BH
Copyright 2002 Mani Srivastava 3 Course Logistics: Prerequisites and Status in Curriculum No prerequisite graduate courses Knowledge of computer networking and digital communications at advanced undergraduate level Embedded Computing Systems elective Prelim question in Communications Related courses Estrins CS213 (Distributed Embedded Systems)
Copyright 2002 Mani Srivastava 4 Course Logistics: Grading One take-home examination: 17.5% 9 th or 10 th week of classes Homeworks: 17.5% problem solving, analysis, theoretical, simulation Class presentation: 15% one topic per group from a specified set 30 minute presentation Project: 25% results, 10% report, 5% presentation groups of 1-3 students 30 minute presentation during final week like a conference paper and talk Class participation: 10% E.g. question you ask and how much you interact
Copyright 2002 Mani Srivastava 5 Course Logistics: Enrollment Limit of 30 students Wait till end of week 2 as many students drop out If you want to audit, following is the priority You are on the official wait list You contacted me - unofficial wait list to get on to wait list If you are not serious about the course, please drop out soon so that those is the waiting list can enroll!
Copyright 2002 Mani Srivastava 6 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 proposal due by beginning of week 3 project web page will have suggested project topics may relate to your own research but you cannot reuse work already done or being done for some other purpose What should be your goal? something useful similar quality as a conference paper and talk key is to keep the project simple, and focused aim high – past projects have led to papers top conferences!
Copyright 2002 Mani Srivastava 7 Course Logistics: On the Web Course web site URL 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 Class mailing list 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
Copyright 2002 Mani Srivastava 8 Course Logistics: Reader & Textbooks No books are required. A set of papers will be required reading average of 1-2 paper per lecture will relate to the core topic of that lecture you should read them before the lecture In addition, every student will present a talk 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
Copyright 2002 Mani Srivastava 9 Course Logistics: Reader & Textbooks (contd.) No paper reader - an on-line reader is being maintained at the course web site bibliographic entries for various papers links to on-line versions if available –or, indication whether available through Melvyls INSPEC database hardcopies will be handed out for papers not available on-line Typically access on-line papers from Melvyl (http://www.melvyl.ucop.edu)http://www.melvyl.ucop.edu
Copyright 2002 Mani Srivastava 10 Course Logistics: Some Books (for your interest only…) Wireless Communications : Principles And Practice; Rappaport, Theodore S. Prince Hall Publishing; 09/1995; Wireless Communications : Principles And Practice 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 Computing (Kluwer International Series in Engineering and Computer Science, No 353) Mobile IP : Design Principles And Practices; Perkins, Charles / Woolf, Bobby. Addison Wesley; 11/1997; Mobile IP : Design Principles And Practices Wireless Multimedia Communications : Networking Video, Voice and Data; Wesel, Ellen Kayata. Addison Wesley; 12/1997; Wireless Multimedia Communications : Networking Video, Voice and Data 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; Wireless Personal Communications; A Systems Approach Principles of Mobile Communication Second Generation Mobile And Wireless Technologies; Black, Uyless Prentice Hall; 09/1998; Second Generation Mobile And Wireless Technologies
Copyright 2002 Mani Srivastava 11 Course Logistics: Conferences and Journals Conferences & Workshops Main: MOBICOM, MOBIHOC, INFOCOM Others: SIGCOM, MoMuC, ICUPC, PIMRC, WoWMoM, ICC, Globecom, etc. Journals & Magazines Main: ACM/Baltzer WINET, ACM/Baltzer MONET, IEEE Personal Communications Others: IEEE Trans of N/W, JSAC etc.
Copyright 2002 Mani Srivastava 12 Cheating & Plagiarism My apologies if you are one of the vast majority of students who dont resort to academic dishonesty but unfortunate incidents in my previous grad and undergrad courses What is cheating & plagiarism? Acting dishonestly, practicing fraud Stealing or using (without my permission) other peoples 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 doesnt 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, paper presentation: zero score + one level 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, please remember that you may have to face me in other exams (e.g. prelims, qualifiers) and professionally!
Copyright 2002 Mani Srivastava 13
Copyright 2002 Mani Srivastava 14 Growth in Wireless Systems Rapid growth in cellular/PCS voice services over the last decade Cell phones everywhere! Wireless data still a small market, but a fast growing one with lots of exciting action WLAN rapidly growing b, a, Bluetooth Wide area wireless data also growing Ricochets 128 kbps IP service support for data in 2.5G and 3G wireless Wireless broadband Location-based services, WAP
Copyright 2002 Mani Srivastava 15 Why is Wireless Data Still a Small Market? Lack of killer application Unsuitable terminal devices Lack of standard air interfaces and services Lack of universal coverage Poor performance of wireless WANs due to low bit rates, high latencies, and high error rates of existing wide-area wireless air interfaces But, technology trends augur well... However, business factors high pricing and cost: offering voice service more lucrative spectrum shortage
Copyright 2002 Mani Srivastava 16 Favorable Technology Trends Availability of a pervasive data network (Internet) Innovative Internet-based applications and services particularly useful to mobile users personalized information retrieval, access to airline reservations systems, online trading Novel terminal devices compact size, low power, ease of use next generation will have built-in wireless interfaces Emerging wide-area wireless packet data services aggregate data rates of several 100 kbps TCP/IP-friendly link layer protocols
Copyright 2002 Mani Srivastava 17 WWW + Mobile Telephony = Mobile Access to Information Mobile Telephone Users Internet Users
Copyright 2002 Mani Srivastava 18 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
Copyright 2002 Mani Srivastava 19 Novel Wireless Terminals Qubits Orbit Webpad Kyocera QCP 6035 Smartphone with Palm Handspring Treo Dangers Hiptop iPaq with Bluetooth
Copyright 2002 Mani Srivastava 20 Network Infrastructure Dynamic, programmatic creation/composition of scalable, highly available & customizable services automatic adaptation to end device characteristics and network connectivity dynamic composition of component services Diverse appliances beyond the phone and the PC devices plus servers in the infrastructure Arbitrarily powerful services on arbitrarily small clients using an adaptive infrastructure computing resources mixed with switching fabric WAP: wireless application protocol
Copyright 2002 Mani Srivastava 22 Berkeley: Imagine… n You walk into a room You have complete, secure, optimized access to local devices and your private resources n Your PDA connects to the local infrastructure and asks it to build a custom GUI n Next, your PDA asks the infrastructure for a path out to your personal information space, where agents are processing your , v-mail, faxes, and pages
Copyright 2002 Mani Srivastava 23 Transparent Information Access: a Killer Application? Policy-based Location-based Activity-based Speech-to-Text Speech-to-Voice Attached- Call-to-Pager/ Notification -to-Speech All compositions of the above! Universal In-box
Copyright 2002 Mani Srivastava 24 What is this course about? Mobile and wireless networked computing and communication systems Emphasis on emerging systems beyond traditional cellular telephone systems wireless packet-switched data and multimedia beyond network of phones and 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
Copyright 2002 Mani Srivastava 25 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)
Copyright 2002 Mani Srivastava 26 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 LMDS (local multipoint distribution) 24-28GHz MMDS below 5 GHz Free space optics (Terabeam) Higher-speed WLAN b (2.4GHz, 11 Mbps), a (5GHz, 54 Mbps & higher) HomeRF Personal area Networks Bluetooth, Wireless device networks Sensor networks, wirelessly networked robots
Copyright 2002 Mani Srivastava 27 Example: Sensor-Enhanced Gadgets SmartQuill (by British Telecom) ADXL 202 monitors movement using spatial sensing Password by signature recognition ADXL202 Dual Axis, ±2g 2.7V-5.25V Single Supply 1000g Shock Survival $40
Copyright 2002 Mani Srivastava 28 Example: MITs Expressive Footwear Dance shoes with wireless link & a suite of sensors measure dynamic parameters at a dancer's foot differential pressure at 3 points and bend in the sole, 2-axis tilt, 3- axis shock, height off the stage, orientation, angular rate and translational position) example use: generate accompanying music
Copyright 2002 Mani Srivastava 29 Telecom View of the Future 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
Copyright 2002 Mani Srivastava 30 Computing View of the Future 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
Copyright 2002 Mani Srivastava 31 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
Copyright 2002 Mani Srivastava 32 Novel 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
Copyright 2002 Mani Srivastava 33 Novel Attributes of Mobile and Wireless Systems Wireless Mobility user and terminal location –are system variables of interest –change dynamically speed of terminal mobility impacts wireless bandwidth constants become variable –location, environment, connectivity, b/w, I/O devices, security domain easier spoofing Portability More Protocol Processing
Copyright 2002 Mani Srivastava 34 Novel 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
Copyright 2002 Mani Srivastava 35 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. CMUs CODA Good user interfaces to give feedback about disconnection
Copyright 2002 Mani Srivastava 36 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
Copyright 2002 Mani Srivastava 37 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
Copyright 2002 Mani Srivastava 38 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
Copyright 2002 Mani Srivastava 39 Heterogeneous Networks Seamless mobility across diverse overlay networks vertical hand-offs software agents for heterogeneity management IP as the common denominator? High-tier Low-tier Satellite High Mobility Low Mobility Wide Area Regional Area Local Area
Copyright 2002 Mani Srivastava 40 Ad Hoc Networks 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. Disaster recovery Battlefield Smart office Etc.
Copyright 2002 Mani Srivastava 41 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?
Copyright 2002 Mani Srivastava 42 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?
Copyright 2002 Mani Srivastava 43 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
Copyright 2002 Mani Srivastava 44 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
Copyright 2002 Mani Srivastava 45 Low Power & Energy-awareness Battery technology is a hurdle… no Moores 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
Copyright 2002 Mani Srivastava 46 Battery Technology Battery technology has historically improved at a very slow pace NiCd improved by x2 over 30 years! require breakthroughs in chemistry
Copyright 2002 Mani Srivastava 47 Summary: Challenges in Mobile and Wireless Computing 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
Copyright 2002 Mani Srivastava 48 Key Issue: Resource Awareness Ad-hoc architectureSelf-configuration Wireless communicationsVariability Inherent unpredictability Solution: adaptation Select required performance levelOperate always at peak performance Settings based on external conditions Fixed settings set by worst case conditions Resource awareness right resource at the right time and the right place Wireless Backbone Networks High traffic load Limited available spectrum Focus on transmission resources Wireless Ad-Hoc Networks Unattended operation Limited available battery Focus on energy resources
Copyright 2002 Mani Srivastava 49 Generic Mobile and Wireless System Architecture Application & Services OS & Middleware Network Data Link Radio, IR Partitioning Source coding, DSP Context adaptation Disconnection management Power management QoS management Rerouting Impact on TCP Location tracking Multiple access Link error control Channel allocation Wireless channel models Channel coding RF circuits, Radio modems Antennas This Course Cross-layer Optimizations
Copyright 2002 Mani Srivastava 50 Goal for This Course Explain the impact of Mobility, Wireless, and Energy Efficiency on Link, Network, OS, and Application Layers in End-point, Network Infrastructure, and Services for Networked Wireless/Mobile Embedded Systems.
Copyright 2002 Mani Srivastava 51 Course Plan: Topics Physical layer concepts (radio propagation, wireless channel, antennas, novel forms of wireless comm) Link layer protocols, medium access, adaptivity, packet scheduling Mobile-IP, ad hoc routing, wireless TCP, QoS in mobile networks Sensor network protocols and algorithms Low power and power management OS, middleware, and application issues Other emerging topics as time permits
Copyright 2002 Mani Srivastava 52 Reading List for This Lecture MANDATORY READING [Weiser91] M. Weiser, "The Computer for the 21st Century," Scientific American, vol. 265, no. 3, pp , September (draft copy at RECOMMENDED READING None.