Past, Present and Future of Mobile Computing


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  • Sensors can be mobile if they are mounted on robots. See CMU’s minibots
    Cotsbots at Berkeley
  • Past, Present and Future of Mobile Computing

    1. 1. Past, Present, and Future of Mobile Computing Yu Cai Department of Computer Science University of Colorado at Colorado Springs 6/2/2005 Yu Cai/MTU Talk 1
    2. 2. Presentation outline Introduction Past on mobile computing of mobile computing Present of mobile computing * Wireless LAN * GSM/GPRS/CDMA *Bluetooth * Mobile IP * Mobile Ad Hoc Network (MANET) * PDA/SmartPhone/Laptop * Sensor/Zigbee Mesh * Security Future 6/2/2005 of mobile computing Yu Cai/MTU Talk 2 * RFID
    3. 3. What is mobile computing?  Mobile computing is to describe technologies that    enable people to access network services anyplace, anytime, and anywhere, with portable and wireless computing and communication devices. --- (where is this referenced? Provide citation!) Aspects of mobility  User mobility      Between different geographical locations Between different networks Between different communication devices Between different applications Device portability   6/2/2005 Between different geographical locations Between different networks Yu Cai/MTU Talk 3
    4. 4. Mobile Computing vs. Ubiquitous Computing/Pervasive Computing   Mobile Computing is a generic term describing the application of small, portable, and wireless computing and communication devices. This includes devices like laptops with wireless LAN technology, mobile phones, wearable computers and Personal Digital Assistants (PDAs) with Bluetooth or IRDA interfaces, and USB flash drives. Ubiquitous computing (ubicomp, or sometimes ubiqcomp) integrates computation into the environment, rather than having computers which are distinct objects. Another term for ubiquitous computing is pervasive computing. Promoters of this idea hope that embedding computation into the environment would enable people to move around and interact with computers more naturally than they currently do. -- 6/2/2005 Yu Cai/MTU Talk 4
    5. 5. Applications of mobile computing  Vehicles       Medical   Nurses/Doctors in Medical offices are now using Wireless Tablet PCs/WLAN to collect and share patient information. Sales   transmission of news, road condition, weather, music via DAB personal communication using GSM position via GPS local ad-hoc network with vehicles close-by to prevent accidents, guidance system, redundancy vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for maintenance Sales representatives are using Tablet PCs with Smart phones for presentation, transmitting/access information among office, hotel, and customer location. Emergencies Early transmission of patient data to the hospital, current status, first diagnosis  Provide mobile infrastructure in dealing with Natural Disaster (earthquake, hurricane, fire), terrorist attacks, war, ...  6/2/2005 Yu Cai/MTU Talk 5
    6. 6. Natural evolution of computing More Flexible Resource Usage Mobile Computing LANs + WorkStations Networking Timesharing Batch Single User OS Freedom from Collocation 6/2/2005 Yu Cai/MTU Talk 6
    7. 7. Challenges in mobile computing   Mobility means changes Hardware   Low bandwidth, high bandwidth variability   Locality adaptation Higher loss-rates, higher delays, more jitter   Different devices, interfaces and protocols Location awareness   Devices more vulnerable, endpoint authentication harder Heterogeneous network   Kbit/s to Mbit/s, bandwidth fluctuation Security risk   Lighter, smaller, energy management, user interface Connection setup time, hand-off Restrictive regulations of frequencies  Frequencies have to be coordinated 6/2/2005 Yu Cai/MTU Talk 7
    8. 8. History of wireless communication  1896 Guglielmo Marconi,    1907 Commercial Trans-Atlantic Wireless Service       Huge ground stations: 30 x 100m antenna masts 1920 Discovery of short waves by Marconi   First demonstration of wireless telegraphy Based on long wave, requiring very large transmitters Cheaper, smaller, better quality transmitters by vacuum tube 1982 1983 1992 1997 1998 Start of GSM in Europe (1G analog) Start of AMPS in America (1G analog) Start of GSM (2G digital) Wireless LAN - IEEE802.11 Iridium satellite system 66 6/2/2005 satellites  Yu Cai/MTU Talk 8
    9. 9. History of wireless communication 1999 Standardization of additional wireless LANs  IEEE standard 802.11b  Bluetooth  WAP (Wireless Application Protocol): access to many services via the mobile phone  2000 GSM with higher data rates (2.5G digital)  HSCSD offers up to 57,6kbit/s  First GPRS trials with up to 50 kbit/s  2001 Start of 3G systems  IMT - 2000, several “members” of a “family”, CDMA2000 in Korea, UMTS tests in Europe Yu Cai/MTU Talk 9 6/2/2005 
    10. 10. Overview of mobile devices Pager • receive only • tiny displays • simple text messages Sensors, embedded controllers 6/2/2005 Smart phone • voice, data • simple graphical displays Wearable device • human wearable • non standard I/O Laptop • fully functional • standard applications PDA • graphical displays • character recognition performance Yu Cai/MTU Talk 10
    11. 11. Overview of development cellular phones 1981: NMT 450 1G 2G 1986: NMT 900 1992: GSM 1991: CDMA 1991: D-AMPS 1997: IEEE 802.11 1987: CT1+ 1992: Inmarsat-B Inmarsat-M 1993: PDC 199x: proprietary 1984: CT1 1988: Inmarsat-C 1994: DCS 1800 1989: CT 2 1999: 802.11b, Bluetooth 1991: DECT 2000: IEEE 802.11a 1998: Iridium 2003: IEEE 802.11g 2000: GPRS 2.5G 2007?: IEEE 802.11N 2001: IMT-2000 3G 4G? 1980: CT0 1982: Inmarsat-A 1983: AMPS wireless LAN cordless phones satellites analogue digital 6/2/2005 20?? Fourth Generation? Yu Cai/MTU Talk 11
    12. 12. Overview of wireless services Data Rates 10 Mbps Wireless LAN IR 1 Mbps Cellular: GSM, GPRS, CDMA, 50 Kbps Satellite 10 Kbps 6/2/2005 Local Coverage Area Yu Cai/MTU Talk Wide 12
    13. 13. Wireless LAN   IEEE 802.11 standard: a family of specifications for wireless LAN technology. The IEEE accepted the specification in 1997. 802.11 specifies an over-the-air interface between a wireless client and a base station or between Point AP: Access two AP wireless clients.      802.11: up AP 2 Mbps in the Network band. to Wired 2.4 GHz AP 802.11b: up to 11 Mbps in the 2.4 GHz band. 802.11a/g: up to 54 Mbps in the 5/2.4 GHz band. 802.11n: up to 220+ Mbps in the 2.4/5 GHz band (two proposals not approved yet). Vendors already selling 802.11pre-n devices. 802.11 promises true vendor interoperability. Every vendor must have a viable 802.11 product strategy. 6/2/2005 Yu Cai/MTU Talk 13
    14. 14. Wireless LAN Security  WEP: Wired Equivalent Privacy.       A basic wireless LAN security mechanism. Easy to set up, commonly used. Don’t rely on WEP for wireless security. There are a number of flaws in the WEP. Many wireless home networks don’t even use WEP, which makes bad situation worse. MAC address based access control mechanism doesn’t work. Use other security mechanisms such as VPN, PEAP and TTLS.  Research project on PEAP / TTLS in our research group in University of Colorado. 6/2/2005 Yu Cai/MTU Talk 14
    15. 15. Wireless Ad Hoc Network  Wireless Ad Hoc Network (peer to peer)     Mobile Ad Hoc Networks (MANET)    A collection of autonomous nodes that communicate with each other by forming a multi-hop radio network in a decentralized manner. No infrastructure, no default router available “every” node needs to be a router Host movement frequent Topology change frequent Wireless Ad Hoc Sensor Networks   A number of sensors spread across a geographical area. Limited resources on sensors 6/2/2005 Yu Cai/MTU Talk 15
    16. 16. Mobile IP   Mobile IP is designed to allow mobile device users to move from one network to another while maintaining their permanent IP address. Motivation:     Changing the IP address is not desired when host moves. However, traditional scheme requires to change IP address when host moves between networks. Mobile IP provides an efficient, scalable mechanism for node mobility within the Internet. Mobile IP allows moving devices to maintain transport and higher-layer connections while moving. Applications:  Mobile IP is most often found in wireless WAN environments where users need to carry their mobile devices across multiple LANs with different IP addresses. 6/2/2005 Yu Cai/MTU Talk 16
    17. 17. Mobile IP: Basic Idea Mobile Node (MN) Home Agent (HA) 2 home network receiver 3 Internet foreign network COA: ? Foreign Agent (FA) 1 sender 6/2/2005 1. Sender sends to the IP address of MN, HA intercepts packet (proxy ARP) 2. HA tunnels packet to COA, here FA, by encapsulation 3. FA forwards the packet to the MN Yu Cai/MTU Talk 17
    18. 18. Mobile IP: Basic Idea HA 1 home network MN sender Internet FA CN receiver 6/2/2005 foreign network 1. Sender sends to the IP address of the receiver as usual, FA works as default router Yu Cai/MTU Talk 18
    19. 19. Bluetooth     Bluetooth is used to connect and exchange information between devices like PDAs, mobile phones, laptops, PCs, printers and digital cameras wirelessly. Named after a Denmark king Harold Bluetooth, who is known for his unification of previously warring tribes. Low-cost, short range (up to 10m), low power consumption, license-free 2.45 GHz band. Using the same frequency range, Bluetooth differs from Wi-Fi in that    Different multiplexing schemes. Wi-Fi with higher throughput, greater distances, more expensive hardware, and higher power consumption. Applications:  Wireless mouse, wireless headset 6/2/2005 Yu Cai/MTU Talk 19
    20. 20. RFID: Radio Frequency Identification  RFID is a method of remotely storing and retrieving data using devices called RFID tags.      Categories:    An RFID tag is a small object, such as an adhesive sticker, that can be attached to or incorporated into a product. RFID tags contain antennas to enable them to receive and respond to radio-frequency queries from an RFID transceiver. No line-of sight required (compared to laser scanners) Withstand difficult environmental conditions (cold, frost etc.) Active RFID: battery powered, distances up to 100 m Passive RFID: operating power comes from the reader over the air, distances up to 6 m Applications:  Automated toll collection: RFIDs mounted in windshields allow commuters to drive through toll plazas without stopping 6/2/2005 Yu Cai/MTU Talk 20
    21. 21. GSM  One of the most popular standards for mobile phones in the world.       Formerly: Groupe Spéciale Mobile (founded 1982) Now: Global System for Mobile Communication European standard, moving to North America More than one billion people use GSM phones as of 2005, making GSM the dominant mobile phone system worldwide with about 70% of the world's market. GSM is a cellular network, which means that mobile phones connect to it by searching for cells in the immediate vicinity. One of the key features of GSM is the Subscriber Identity Module (SIM), commonly known as a SIM card. The SIM is a detachable smartcard containing the user's subscription information and phonebook. 6/2/2005 Yu Cai/MTU Talk 21
    22. 22. GSM Overview OMC, EIR, AUC HLR GMSC fixed network NSS with OSS VLR MSC VLR MSC BSC BSC RSS MS MS BTS 6/2/2005 Yu Cai/MTU Talk RSS (Radio Subsystem) NSS (Network and switching subsystem) OSS (Operation Subsystem) MS (Mobile Station) BTS (Base Transceiver Station) BSC (Base Station Controller) MSC (Mobile Services Switching Center) GMSC (Gateway MSC) HLR (Home Location Register) VLR (Visitor Location Register) EIR (Equipment Identity Register) AUC (Authentication Center ) OMC (Operation and Maintenance Center ) 22
    23. 23. GPRS     GPRS: General Packet Radio Service It is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G“. GPRS is packet-switched which means that multiple users share the same transmission channel, only transmitting when they have data to send. GPRS provides moderate speed data transfer, by allocating unused cell bandwidth to transmit data.    Poor bit rate in busy cells Usually, GPRS data is billed per kilobytes of information transceived In 3G mobile systems like UMTS (Universal Mobile Telecommunication System), voice and data services will be mixed in a normal communication. 6/2/2005 Yu Cai/MTU Talk 23
    24. 24. PDA  Personal digital assistants (PDAs or palmtops)     handheld devices that were originally designed as personal organizers, but became much more versatile over the years. A basic PDA usually includes a clock, date book, address book, task list, memo pad and a simple calculator. One major advantage of using PDAs is their ability to synchronize data with desktop, notebook and desknote computers. The currently major PDA operating systems are:     Palm OS by PalmSource, Inc Windows Mobile (Windows CE) by Microsoft BlackBerry by Research In Motion Symbian by a group of companies According to a Gartner market study, the overall market for PDAs shrunk by 5% in the first quarter (Q1) of 2004, compared to Q1 2003. Yu Cai/MTU Talk 24 6/2/2005 
    25. 25. Satellite Systems    Like cellular systems, except that the base stations (i.e., satellites) move as will as mobile devices Satellite coverage attractive for areas of world not well served by existing terrestrial infrastructure: ocean areas, developing countries IRIDIUM  Motorola  Voice, Data (2.4 kbps), Fax, Location Services  66 satellites in 6 polar orbits (780 km)  Failed project 6/2/2005 Yu Cai/MTU Talk 25
    26. 26. Future mobile and wireless networks   Shift industrial paradigm from piecewise solutions to end-to-end information systems Improved radio technology and antennas    Core network convergence   IP-based, quality of service, mobile IP Ad-hoc technologies   smart antennas, beam forming, multiple-input multiple-output (MIMO) 802.11N dynamic spectrum allocation spontaneous communication, power saving, redundancy Simple and open service platform   intelligence at the edge, not in the network (as with IN) more service providers, not network operators only 6/2/2005 Yu Cai/MTU Talk 26
    27. 27. Integrated mobile computing Integration of heterogeneous fixed and mobile networks with varying transmission characteristics regional vertical handover metropolitan area campus-based 6/2/2005 in-car, in-house, personal area Yu Cai/MTU Talk horizontal handover 27
    28. 28. IP-based next generation network ? SS7 signalling server farm, gateways, proxies PSTN, CS core broadcast gateways MSC IP-based core SGSN GSM BSC firewall, GGSN, gateway router Internet access points private private WLAN WPAN RNC UMTS public WLAN 6/2/2005 Yu Cai/MTU Talk 28
    29. 29. Literature        Jochen Schiller – Mobile Communications Ivan Stojmeniovic – Handbook of Wireless Networks and Mobile Computing Andrew Tanenbaum – Computer Networks James D. Solomon – Mobile IP, the Internet unplugged Charles E. Perkins – Ad-hoc networking Papers, papers, papers, … Mobile Computing Courses  MIT:  Stanford:  UC Berkley:  UT Austin:     6/2/2005 Yu Cai/MTU Talk 29
    30. 30. Thank you! 6/2/2005 Yu Cai/MTU Talk 30