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2	Course Overview Introduction Data in Wireless Cellular Systems Data in Wireless Local Area Networks Internet Protocols TCP over Wireless Link Ad-Hoc Networks, Sensor Networks Services and Service Discovery System Support for Mobile Applications
3	Course Overview Introduction overview of technologies for wireless communication some comments on marketplace (growth, dominant technologies) Data in Wireless Cellular Systems regulatory issues AMPS/CDPD, GSM Data in Wireless Local Area Networks Wireless LANs: IEEE 802.11 Personal Area Networks: Bluetooth
4	Course Overview Internet Protocols Mobile IP (in IPv4 and IPv6) MicroMobility Proposals TCP over Wireless Link Datalink Layer Solutions Transport Layer Solutions Network Layer Solutions Ad Hoc Networks, Sensor Networks Unicast Routing in ad-hoc networks (AODV, OLSR) Multicast Routing Intro to Wireless Sensor Networks
5	Course Overview Services and Service Discovery RFC 2165 (Service Location Protocol) Jini: Overview, Service Discovery System Support for Mobile Applications (if time allows) File Systems and Databases WWW WAP (Wireless Application Protocol) Java 2 ME
6	Course Overview Marking scheme: Three lab assignments (20% each) To be completed August 10 One final exam (40%) In class Thursday, July 26, 1 hour
7	Course Overview References: No single textbook, but relatively good/complete books are Jochen Schiller, Mobile Communications, 2^nd edition, Pearson Education Ltd. 2003, ISBN 0-321-12381-6 C. Siva Ram Murthy and B.S. Manoj, Ad Hoc Wireless Networks: Architectures and Protocols, Prentice Hall 2004, ISBN 0-13-147023-X (despite the title, it also covers many cellular/WLAN topics briefly). Course webpage: http://kunz-pc.sce.carleton.ca/tongji/ List of major relevant conferences/journals/magazines provided in Appendix to course notes
8	Course Overview Introduction Data in Wireless Cellular Systems Data in Wireless Local Area Networks Internet Protocols TCP over Wireless Link Ad-Hoc Networks, Sensor Networks Services and Service Discovery System Support for Mobile Applications
9	The New Yorker
10	The New Yorker
11	The New Yorker
12	Drivers of Mobile Computing Portable Devices Laptops Cellphones RIM Blackberry Wireless Communication Cellular Systems WLAN
13	Big Machines
14	Big Machines
15	Portable Computers: The Early Days
16	Today: Many “Sleek” Devices
17	Mobile Phone Processor Power Today Compares to Desktop PCs of the 90s
18	Mobile Phone Storage Today Compares to Desktop PCs of the 1990’s
19	2004 Camera Phone Resolution Exceeds 2001 Digital Cameras
20	Yesterday’s Products = Today’s Features?
21	Mobile devices
22	Computers for the next decades? Computers are integrated small, cheap, portable, replaceable - no more separate devices Technology is in the background computer are aware of their environment and adapt (“location awareness”) computer recognize the location of the user and react appropriately (e.g., call forwarding, fax forwarding, “context awareness”) Advances in technology more computing power in smaller devices flat, lightweight displays with low power consumption new user interfaces due to small dimensions more bandwidth per cubic meter multiple wireless interfaces: wireless LANs, wireless WANs, regional wireless telecommunication networks etc. („overlay networks“)
23	Effects of device portability Power consumption limited computing power, low quality displays, small disks due to limited battery capacity CPU: power consumption ~ CV2f C: internal capacity, reduced by integration V: supply voltage, can be reduced to a certain limit f: clock frequency, can be reduced temporally Loss of data higher probability, has to be included in advance into the design (e.g., defects, theft) Limited user interfaces compromise between size of fingers and portability integration of character/voice recognition, abstract symbols Limited memory limited value of mass memories with moving parts flash-memory or ? as alternative
24	Internet: From Humble Beginnings in 1969 ….
25	Internet: … slowly….
26	Internet: … to a global communications network in 2007
27	Wireless Communication: Cellular Networks Today
28	Wireless Communication: Cellular Networks Tomorrow
29	Evolution of Cellular Networks 1G (AMPS, etc) Analog, primarily voice, less secure, low bit data rate 2G (GSM, CDMA, etc) and 2.5 G (GPRS) Digital, more secure, voice and data 3G (W-CDMA, CDMA2000, etc) and 3.5 G Digital, multimedia, global roaming across a single network, 144Kbps to several Mbps, limited IP interoperability 4G (TBD) Global roaming across multiple wireless networks, 10-100 Mbps, IP interoperability for seamless mobile Internet
30	Mobile communication Two aspects of mobility: user mobility: users communicate (wireless) “anytime, anywhere, with anyone” device portability: devices can be connected anytime, anywhere to the network Wireless vs. mobile Examples û û stationary computer û ü notebook in a hotel ü û wireless LANs in historic buildings ü ü Personal Digital Assistant (PDA) The demand for mobile communication creates the need for integration of wireless networks into existing fixed networks: local area networks: standardization of IEEE 802.11, ETSI (HIPERLAN) Internet: Mobile IP extension of the internet protocol IP wide area networks: e.g., internetworking of GSM and ISDN
31	Wireless networks in comparison to fixed networks Higher loss-rates due to interference emissions of, e.g., engines, lightning Restrictive regulations of frequencies frequencies have to be coordinated, useful frequencies are almost all occupied Low transmission rates local some Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRS Higher delays, higher jitter connection setup time with GSM in the second range, several hundred milliseconds for other wireless systems Lower security, simpler active attacking radio interface accessible for everyone, base station can be simulated, thus attracting calls from mobile phones Always shared medium secure access mechanisms important
32	Applications I Vehicles 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 Emergencies early transmission of patient data to the hospital, current status, first diagnosis replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc. crisis, war, ...
33	Typical application: road traffic
34	Applications II Traveling salesmen direct access to customer files stored in a central location consistent databases for all agents mobile office Replacement of fixed networks remote sensors, e.g., weather, earth activities flexibility for trade shows LANs in historic buildings Entertainment, education, ... outdoor Internet access intelligent travel guide with up-to-date location dependent information ad-hoc networks for multi user games
35	Location dependent services Location aware services what services, e.g., printer, fax, phone, server etc. exist in the local environment Follow-on services automatic call-forwarding, transmission of the actual workspace to the current location Information services „push“: e.g., current special offers in the supermarket „pull“: e.g., where is the Black Forrest Cherry Cake? Support services caches, intermediate results, state information etc. „follow“ the mobile device through the fixed network Privacy who should gain knowledge about the location
36	The Holy Grail: Universal Broadband Access
37	Wireless systems: overview of the development
38	Universal Broadband Access: Higher Bandwidth
39	Complementary access solutions for different mobility needs
40	TCP/IP and Mobile Computing TCP/IP core designed 30+ years ago Extremely successful: Size of Internet Integration of different networking technologies So integrating all these new wireless networks using TCP/IP obviously the way to go, right? J
41	Well….. TCP/IP protocols are not quite without problems of their own (even for wired networks) Lack of QoS Weak Security “Business model” with intelligence at the edge does not suit operators all that well à most cellular network access netwoks and cores are NOT based on TCP/IP (though this is changing)
42	Wireless access technologies: No uniform standard (similar to Ethernet) in sight
43	Overlay Networks - the global goal
44	Key features of future mobile and wireless networks Improved radio technology and antennas smart antennas, beam forming, multiple-input multiple-output (MIMO) space division multiplex to increase capacity, benefit from multipath software defined radios (SDR) use of different air interfaces, download new modulation/coding/... requires a lot of processing power (UMTS RF 10000 GIPS) dynamic spectrum allocation spectrum on demand results in higher overall capacity Core network convergence IP-based, quality of service, mobile IP Ad-hoc technologies 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
45	Example IP-based 4G/Next G/… network
46	Potential problems Quality of service Today‘s Internet is best-effort Integrated services did not work out Differentiated service have to prove scalability and manageability What about the simplicity of the Internet? DoS attacks on QoS? Internet protocols are well known… …also to attackers, hackers, intruders security by obscurity does not really work, however, closed systems provide some protection Reliability, maintenance Open question if Internet technology is really cheaper as soon as high reliability (99.9999%) is required plus all features are integrated Missing charging models Charging by technical parameters (volume, time) is not reasonable Pay-per-application may make much more sense Killer application? There is no single killer application! Choice of services and seamless access to networks determine the success
47	Challenges Wireless Technology Higher bandwidth Cheaper radios (Bluetooth, ZigBee) Operate in licence-free spectrum, or co-exist with other services/exploit unused portions of frequency band Services Networks are more than dump bitpipes (3G was initially big on services, difference between “beyond 3G” and 4G) Internet Protocols Existing protocols ill-suited to wireless transmissions and mobile end-hosts New protocol requirements (mobility mgmt, different types of handoff, QoS, security) Yet another “nail in the coffin” for IPv4 (3 billion handsets!)
48	Mobile Computing is Fun