MOBILE Chapter 1 COMPUTING INTRODUCTION Distributed Roger Wattenhofer Distributed Mobile Computing Computing Computing Group Summer 2004 Group Summer 2004 Overview A computer in 2010? • What is it? • Advances in technology • Who needs it? – More computing power in smaller devices • History – Flat, lightweight displays with low power consumption • Future [Der Spiegel] – New user interfaces due to small dimensions – More bandwidth (per second? per space?) – Multiple wireless techniques • Course overview • Technology in the background • Organization of exercises – Device location awareness: computers adapt to their environment • Literature – User location awareness: computers recognize the location of the user and react appropriately (call forwarding) • Thanks to J. Schiller for slides • “Computers” evolve – Small, cheap, portable, replaceable – Integration or disintegration? Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/3 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/4 What is Mobile Computing? Application Scenarios • Aspects of mobility • Vehicles – User mobility: users communicate “anytime, anywhere, with anyone” (example: read/write email on web browser) • Nomadic user – Device portability: devices can be connected anytime, anywhere to the • Smart mobile phone network • Invisible computing • Wireless vs. mobile Examples • Wearable computing 88Stationary computer 8 9 Notebook in a hotel • Intelligent house or office 9 8 Wireless LANs in historic buildings • Meeting room/conference What is important? 99Personal Digital Assistant (PDA) • Taxi/Police/Fire squad fleet • The demand for mobile communication creates the need for • Service worker integration of wireless networks and existing fixed networks • Lonely wolf – Local area networks: standardization of IEEE 802.11 or HIPERLAN • Disaster relief and Disaster alarm – Wide area networks: GSM and ISDN – Internet: Mobile IP extension of the Internet protocol IP • Games • Military / Security Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/5 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/6 Vehicles Vehicles 2 GSM, UMTS GPS oc h d a DAB [J. Schiller] [Der Spiegel] Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/7 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/8 Nomadic user Smart mobile phone • Nomadic user has laptop/palmtop • Connect to network infrequently • Mobile phones get smarter • Interim period operate in disconnected mode • Converge with PDA? [Nokia] • Access her or customer data • Voice calls, video calls (really?) • Consistent database for all agents • Email or instant messaging • Print on local printer (or other service) • Play games – How do we find it? • Up-to-date localized information – Is it safe? –Map – Do we need wires? – Pull: Find the next Pizzeria – Push: “Hey, we have great Pizza!” • Does nomadic user need her own hardware? • Stock/weather/sports info • Read/write email on web browser • Ticketing • Access data OK too B 1 u •Trade stock 5 i l 0 t B [J. Schiller] •etc. C Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/9 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/10 Invisible/ubiquitous/pervasive and wearable computing Intelligent Office and Intelligent House • Tiny embedded “computers” • Bluetooth replaces cables •Everywhere • Plug and play, without the “plug” • Example: Microsoft’s Doll • Again: Find the local printer • I refer to my colleagues • House recognizes inhabitant Friedemann Mattern and • House regulates temperature Bernt Schiele and their according to person in a room courses • Trade Shows • Home without cables looks better • LAN in historic buildings [MS] [ABC, Schiele] Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/11 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/12 Meeting room or Conference Taxi / Police / Fire squad / Service fleet • Share data instantly • Connect • Send a message to someone •Control else in the room •Communicate • Secretly vote on controversial issue • Service Worker • Find person with similar interests • Example: SBB service workers • Broadcast last minute changes have PDA – Map help finding broken signal • Ad-Hoc Network – PDA gives type of signal, so that service person can bring the right tools right away Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/13 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/14 Lonely wolf Disaster relief • We really mean everywhere! • After earthquake, tsunami, volcano, etc: • Cargo’s and yachts • You cannot rely on • Journalists infrastructure but you need to orchestrate disaster relief • Scientists • Early transmission of patient • Travelers data to hospital • Sometimes cheaper than • Satellite infrastructure? • Ad-Hoc network [Red Cross] • Commercial flop [Motorola] Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/15 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/16 Disaster alarm Games • With sensors you might be • Nintendo Gameboy [Advance]: able to alarm early Industry standard mobile • Example: Tsunami game station • Example: Cooling room • Connectable to other • Or simpler: Weather station Gameboys • Can be used as game pad for Nintendo Gamecube • Satellite • Ad-Hoc network • Cybiko [Extreme] is a competitor that has radio capabilities built in [Cybiko] • Second generation already • Also email, chat, etc. Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/17 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/18 Military / Security Application Scenarios: Discussion • Vehicles • From a technology standpoint • Nomadic user this is similar to disaster relief • Smart mobile phone • Invisible computing • Sensoria says “US army is the • Wearable computing best costumer” • Intelligent house or office • Meeting room/conference • Not (important) in this course • Taxi/Police/Fire squad fleet What do you like? • Service worker • Lonely wolf • Disaster relief and Disaster alarm [Der Spiegel] • Games • Military / Security • Anything missing? Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/19 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/20 Mobile devices What do you have? What would you buy? PDA Pager • simple graphical displays Laptop • Laptop (Linux, Mac, Windows?) 8 • fully functional • receive only • character recognition • Palmtop (Linux, Mac, Windows?) 8 • tiny displays • simplified WWW • standard applications • simple text • PDA/Organizer (Palm, Pocket PC, other?) 8 messages • Mobile phone Sensors, • Satellite phone embedded controllers • Pager Palmtop • Wireless LAN Card 8 • tiny keyboard Mobile phone • Wireless LAN Base Station (for home networking) • simple versions • voice, data of standard applications • Ethernet Plug in every room (for home networking) • simple text display • Bluetooth • Proprietary device (what kind?) performance and size for exercises 8 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/21 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/22 Effects of device portability Wireless networks in comparison to fixed networks • Energy consumption • Higher loss-rates due to interference – there is no Moore’s law for batteries or solar cells – emissions of, e.g., engines, lightning – limited computing power, low quality displays, small disks • Restrictive regulations of frequencies – Limited memory (no moving parts) – frequencies have to be coordinated, useful frequencies are almost all – Radio transmission has a high energy consumption occupied – CPU: power consumption ~ CV2f • Low transmission rates • C: total capacitance, reduced by integration – local some Mbit/s, regional currently, e.g., 9.6kbit/s with GSM • V: supply voltage, can be reduced to a certain limit • Higher delays, more jitter • f: clock frequency, can be reduced temporally – connection setup time with GSM in the second range, several hundred • Limited user interfaces milliseconds for other wireless systems, tens of seconds with Bluetooth – compromise between size of fingers and portability • Lower security, simpler active attacking – integration of character/voice recognition, abstract symbols – radio interface accessible for everyone, base station can be simulated, • Loss of data thus attracting calls from mobile phones – higher probability (e.g., defects, theft) • Always shared medium – secure access mechanisms important Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/23 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/24 History: Antiquity – 1890 History: 1890 – 1920 • Many people in history used • 1895: Guglielmo Marconi (1874 – 1937) light for communication – first demonstration of wireless – Heliographs (sun on mirrors), telegraphy (digital!) flags („semaphore“), ... – long wave transmission, high transmission power necessary (> 200kW) – 150 BC: smoke signals for – Nobel Prize in Physics 1909 communication (Polybius, Greece) • 1901: First transatlantic connection – 1794: Optical telegraph by Claude Chappe • 1906 (Xmas): First radio broadcast • 1906: Vacuum tube invented • Electromagnetic waves – By Lee DeForest and Robert von Lieben – 1831: Michael Faraday (and Joseph Henry) • 1907: Commercial transatlantic connections demonstrate electromagnetic induction – huge base stations (30 100m high antennas) – 1864: James Maxwell (1831-79): Theory of electromagnetic fields, wave equations • 1911: First mobile sender – on board of a Zeppelin – 1886: Heinrich Hertz (1857-94): demonstrates with an experiment