1. CS 6910 – Pervasive Computing Spring 2007 Section 1 (Ch.1): Introduction to Wireless and Mobile Systems Prof. Leszek Lilien Department of Computer Science Western Michigan University Slides based on publisher’s slides for 1 st and 2 nd edition of: Introduction to Wireless and Mobile Systems by Agrawal & Zeng © 2003, 2006, Dharma P. Agrawal and Qing-An Zeng. All rights reserved. Some original slides were modified by L. Lilien, who strived to make such modifications clearly visible. Some slides were added by L. Lilien, and are © 2006-2007 by Leszek T. Lilien. Requests to use L. Lilien’s slides for non-profit purposes will be gladly granted upon a written request.

2. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 2 Chapter 1 INTRODUCTION [Image of 2 nd ed. cover added by L. Lilien.]

3. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 3 Evolution Distributed Computing (DIST) Originally wireline only Wireless Computing Originally non-mobile wireless only Mobile Computing (MOBI) Really: Wireless & Mobile Computing Pervasive Computing (PERV) Note: Textbook uses “wireless” and “mobile” as synonyms Not precise: e.g., can have wireless but not mobile Q: Why to study Wireless & Mobile Computing? A: It is foundation for PERV, its critical technology & building block Some other technologies for Pervasive Computing: Embedded computing Sensornets Opportunistic networks (oppnets) and systems See Lecture Section 0.B © 2007 by Leszek T. Lilien Pervasive vs. Wireless & Mobile Systems

4. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 4 1.1. The History of Mobile Radio Communication (1/3) 1880: Hertz – Initial demonstration of practical radio communication 1897: Marconi – Radio transmission to a tugboat over an 18 mi path 1921: Detroit Police Department: -- Police car radio dispatch (2 MHz frequency band) 1933: FCC (Federal Communications Commission) – Authorized four channels in the 30 to 40 MHz range 1938: FCC – Ruled for regular service 1946: Bell Telephone Laboratories – 152 MHz (Simplex) 1956: FCC – 450 MHz (Simplex) 1959: Bell Telephone Laboratories – Suggested 32 MHz band for high capacity mobile radio communication 1964: FCC – 152 MHz (Full Duplex) 1964: Bell Telephone Laboratories – Active research at 800 MHz 1969: FCC – 450 MHz (Full Duplex) 1974: FCC – 40 MHz bandwidth allocation in the 800 to 900 MHz range 1981: FCC – Release of cellular land mobile phone service in the 40 MHz bandwidth in the 800 to 900 MHz range for commercial operation Emphasis (underlines) on this and next 2 slides added by LTL

5. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 5 The History of Mobile Radio Communication (2/3) 1981: AT&T and RCC (Radio Common Carrier) reach an agreement to split 40 MHz spectrum into two 20 MHz bands. Band A belongs to nonwireline operators (RCC), and Band B belongs to wireline operators (telephone companies). Each market has two operators. 1982: AT&T is divested, and seven RBOCs (Regional Bell Operating Companies) are formed to manage the cellular operations 1982: MFJ (Modified Final Judgment) is issued by the government DOJ [LTL: Dept of Justice]. All the operators [LTL: RBOCs] were prohibited to (1) operate long-distance business, (2) provide information services, and (3) do manufacturing business 1983: Ameritech system in operation in Chicago 1984: Most RBOC markets in operation 1986: FCC allocates 5 MHz in extended band 1987: FCC makes lottery on the small MSA [LTL: Metropolitan Statistical Area] and all RSA [LTL: Rural Service Area] licenses 1988: TDMA (Time Division Multiple Access) voted as a digital cellular standard in North America 1992: GSM (Groupe Speciale Mobile) operable in Germany D2 system

6. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 6 The History of Mobile Radio Communication (3/3) 1993: CDMA (Code Division Multiple Access) voted as another digital cellular standard in North America 1994: American TDMA operable in Seattle, Washington 1994: PDC (Personal Digital Cellular) operable in Tokyo, Japan 1994: Two of six broadband PCS (Personal Communication Service) license bands in auction 1995: CDMA operable in Hong Kong 1996: US Congress passes Telecommunication Reform Act Bill 1996: The auction money for six broadband PCS licensed bands (120 MHz) almost reaches 20 billion US dollars 1997: Broadband CDMA considered as one of the third generation mobile communication technologies for UMTS (Universal Mobile Telecommu- nication Systems) During the UMTS workshop conference held in Korea 1999: ITU (International Telecommunication Union) decides the next generation mobile communication systems (e.g., W-CDMA, cdma2000, etc.) 2001: W-CDMA commercial service beginning from October in Japan 2002: FCC approves additional frequency band for Ultra-Wideband (UWB)

7. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 7 [LTL:] RF = radio frequency

8. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 8

9. 9 Applications [LTL:] Wireless Telephone Cincinnati, OH Washington, DC [LTL:] User moves but phone # unchanged Maintaining the telephone number across geographical areas in a wireless and mobile system

10. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 10 1G - First Generation Primarily for voice communication Using FDM (frequency division multiplexing) 2G - Second Generation Emphasis still on voice communication but allows for… … Data communication Using TDM (time division multiplexing) Indoor/outdoor and vehicular environment 3G - Third Generation Integrated voice, data, and multimedia communication Need for: High volume of traffic / Real time data communication Flexibility, incl. Frequent Internet access Multimedia data transfer Compatibility with 2G Using compression Without compromising quality © 2007 by Leszek T. Lilien Generations of Wireless Systems & Services

11. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 11 First Generation Wireless Systems and Services 1970sDevelopments of radio and computer technologies for 800/900 MHz mobile communications [1 st mobile band] 1976WARC (World Administrative Radio Conference) allocates spectrum for cellular radio 1979NTT (Nippon Telephone & Telegraph) introduces the first cellular system in Japan 1981NMT (Nordic Mobile Telephone) 900 system introduced by Ericsson Radio System AB and deployed in Scandinavia 1984AMPS (Advanced Mobile Phone Service) [cellular] introduced by AT&T in North America Emphasis (underlines) and text in square brackets on this and next slide added by LTL Note: “Cellular systems” called “mobile systems” outside North America.

12. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 12 Second Generation Wireless Systems and Services 1982CEPT (Conference Europeenne des Post et Telecommunications) established GSM [global special mobile] to define future Pan-European Cellular Radio Standards 1990Interim Standard IS-54 (USDC [US digital cellular] ) adopted by TIA (Telecommunications Industry Association) 1990Interim Std IS-19B (NAMPS [narrowband AMPS] ) adopted by TIA 1991Japanese PDC (Personal Digital Cellular) system standardized by the MPT (Ministry of Posts and Telecommunications) 1992Phase I GSM system is operational 1993Interim Standard IS-95 (CDMA) adopted by TIA 1994Interim Standard IS-136 adopted by TIA 1995 PCS Licenses [added 2 nd band (1900 MHz)] issued in North America 1996Phase II GSM operational 1997North American PCS deploys GSM, IS-54, IS-95 1999IS-54: in North America IS-95: in North America, Hong Kong, Israel, Japan, China, etc GSM: in 110 countries

13. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 13 Basic technology in the U.S. cdma2000 Basic technology in Europe & Japan W-CDMA Similar but design & implementation differences © 2007 by Leszek T. Lilien Two Basic Technology Choices for 3G

14. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 14 Third Generation Wireless Systems and Services (1/2) IMT-2000 (International Mobile Telecommunications-2000): - Fulfill one's dream of anywhere, anytime communications a reality. Key Features of IMT-2000 include: - High degree of commonality of design worldwide; - Compatibility of services within IMT-2000 and with the fixed networks; - High quality; - Small terminal for worldwide use; - Worldwide roaming capability; - Capability for multimedia applications, and a wide range of services and terminals.

15. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 15 Third Generation Wireless Systems and Services (2/2) Important Component of IMT-2000 is ability to provide high bearer rate capabilities: - 2 Mbps for fixed environment; - 384 Kbps for indoor/outdoor and pedestrian environments; - 144 Kbps for vehicular environment. Standardization Work: - Release 1999 specifications - In processing Scheduled Service: - Started in October 2001 in Japan (W-CDMA)

16. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 16 Future: 4G 4G Expected to implement all standards from 2G & 3G Infrastructure only packet-based, all-IP Some of the standards paving the way for 4G: WiMax WiBro (Korean) WiBro 3GPP Long Term Evolution To improves the UMTS mobile phone standardUMTS Work-in-progress technologies E.g., HSOPA, a part of 3GPP Long Term EvolutiononHSOPA © 2007 by Leszek T. Lilien

17. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 17 Subscriber Growth for Wireless Phones 3G Subscribers 2G Digital-only Subscribers 1G Analog-only Subscribers Subscribers 199019911992199319941995199619971998199920002001200220032004200520062007200820092010 Year

18. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 18 China Leads World in Mobile Phone Users Total [World] Mobile Users > 800 million [2003] Total [World] Analogue Users > 70 million [2003] ZDNet UK reports that the number of mobile phone users in China reached 167 million in April, 2002, a rise of 6 million subscribers on March, 2002. The US, which is the second biggest market, has 136 million subscribers. Mobile phones are the preferred mode of communication in Japan, with 56.8 million subscribers as of the end of March, 2003.

19. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 19 Many diverse subsystems Different requirements for different needs Different characteristics Corresponding to the requirements Different coverage areas Cell = area that can be covered by a single transmitting station (usually called base station) Picocells, microcells, macrocells & global “cell” Figure – next slide Why different cell sizes? Limited nr of channels per cell Smaller cells can serve more users E.g. 2x smaller => can serve 2x more users on the same band (with smaller range) © 2007 by Leszek T. Lilien Flexibility & Versatility of 3G

20. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 20 Coverage Aspect of Next Generation Mobile Communication Systems PicocellMicrocell Macrocell Global Urban Suburban Global Satellite In-Building

21. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 21 Transmission Capacity as a Function of Mobility Broadband radio Global System for Mobile Communications 0.010.1110100 Transmission capacity as a function of mobility in some radio access systems Mobility Universal Mobile Telecommunica- tions System Mobile Broadband System Broadband Satellite Multimedia Local Multipoint Distribution System Satellite Universal Mo- bile Telecommunica- tions System Data Rate (Mb/s) Stationary Pedestrian Vehicular

22. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 22 1.2. Characteristics of Cellular Systems Wireless Technology & Associated Characteristics Wireless Technologies Cellular WLAN (Wireless LAN) GPS Satellite Based PCS Campus network (e.g., Ricochet, Carnegie Mellon U.) Home Networking Ad Hoc Networks WPAN (Wireless PAN = [personal area network]) Incl. Bluetooth Sensor Networks Different technologies needed for different applications -- Details on the next slide – [From 1 st ed. slides – Slightly modified by LTL]

23. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 23 [ LTL: Yellow and red highlights added] (phone calls) (CMU campus) (also oppnets, IANs) (WPAN = wireless personal area network)

24. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 24 Wireless Technologies for Application Classes [ LTL: Yellow and red highlights added] Notice the following: Infrastructure-based networks vs. ad hoc networks (p. 11/2) Terms & acronyms: Access point – AP (p. 8/-1, 10/2) Mobile station – MS (p. 11/2) Handoff and switching radio resources (p. 11/3)

25. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 25 Application Example: Medical Application Wireless remote consultation ATM backbone network Possibility for remote consulting (including audio visual communication) ATM switch Remote databases In hospital physician Ambulance

26. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 26 Wireless Features & Their Potential Apps [LTL:] Notice the following (p. 11/-1): “Anytime anywhere” not always required Often “many time” or “many where” is adeqate Permanent connectivity not necessary MS can: Start transaction at AP1, then move away (loosing connection to it) Get close to AP99 & complete transaction at AP99

27. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 27 1.3. Fundamentals of Cellular Systems Illustration of a cell with a mobile station (MS) and a base station (BS) BS MS Cell Hexagonal cell area used in most models Ideal cell area (2-10 km radius) (circle) Alterative shape of a cell (square) MS [LTL:] Cell shapes (above) Actually, cell may have a zigzag shape Hexagon is a good approximation in practice Also, gives non-overlapping cells (used by clever bees for beehives) E.g., circles would either overlap, or would have gaps in between

28. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 28 Single BS per cell => limited bandwidth per cell Increase bandwidth use efficiency by multiplexing 4 +1 basic multiplexing techniques FDMA – frequency division multiple access TDMA – time division multiple access CDMA – code division multiple access OFDM – orthogonal frequency division multiplexing New: SDMA – space division multiple access Specialized for microwave antennas © 2007 by Leszek T. Lilien Cell Bandwidth Limitations & Multiplexing BSBS Service area (Zone) MS

29. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 29 FDMA (Frequency Division Multiple Access) User 1 User 2 User n … Time Frequency [LTL:] Used in all 1G cellular systems BS allocates to each of n users a channel (a frequency subband) for time the user needs it

30. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 30 FDMA Bandwidth Structure 123 … n Frequency Total bandwidth [LTL:] Divided into n channels (frequency subbands) 4

31. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 31 FDMA Channel Allocation Channel 1 User 1 Channel 2 User 2 Channel n User n Base Station …… Mobile Stations

32. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 32 TDMA (Time Division Multiple Access) User 1User 2User n … Time Frequency [LTL:] Used in most 2G cellular systems BS allocates to each user full bandwidth for duration of a time slot

33. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 33 TDMA Frame Structure 123 … n Time Frame [LTL:] Divided into n time slots (by a round-robin method) 4

34. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 34 TDMA Frame Illustration for Multiple Users Time 1 Time 2 Time n … … Base Station User 1 User 2 User n … n Mobile Stations [LTL:] Note: Non-overlapping time slices “Time 2” slot starts after “Time 1” slot is over, etc.

35. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 35 CDMA a.k.a. spread spectrum technique Used in some 2G and most 3G cellular systems Simultaneous transmission of data from multiple users on full frequency band Figure shows all users using: Same range of frequencies Same time range But Different codes CDMA is enabled by orthogonal codes (= keys) One distinct code assigned by BS to each user © 2007 by Leszek T. Lilien CDMA (Code Division Multiple Access)

36. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 36 CDMA transmission Transmitter: Codes (using the key) each user’s data “stream” Puts all coded individual data “streams” on data link Creates a common “mixed” data stream Receiver: Gets common “mixed” data stream from data link Uses keys to decode (“unmix”) individual data stream from the “mixed” data stream # of simultaneous users limited by # of possible orthogonal codes Complex but robust technique © 2007 by Leszek T. Lilien CDMA (Code Division Multiple Access) – cont.

37. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 37 [SKIP:] Transmitted & Received Signals in a CDMA System Information bits Code at transmitting end Transmitted signal Received signal Code at receiving end Decoded signal at the receiver [LTL:] 10-bit codewords

38. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 38 Frequency Ranges used for FDMA, TDMA & CDMA

39. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 39 OFDM idea – to reduce interference Convert single high-speed data stream to multiple low- speed data streams Low-speed data streams sent in parallel using (sub)channels working on multiple-frequencies Frequencies of subchannels in FDMA vs. OFDM FDMA – non-overlapping frequen- cies of subchannels Even with gaps between subchannel bands to reduce interference OFDM - overlapping frequencies of subchannels © 2007 by Leszek T. Lilien OFDM (Orthogonal Frequency Division Multiplexing) Figure: Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 39

40. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 40 Many variants & combinations of FDMA, TDMA & CDMA - beyond the scope of this discussion Frequency hopping – combines FDMA & TDMA Idea: One user uses one channel for a time slot, then changes to another channel for another time slot See the next slide Receiver needs to know frequency hopping sequence Main advantage (e.g., in defense applications): Message gets through even if one frequency band jammed © 2007 by Leszek T. Lilien Variants & Combinations of FDMA, TDMA & CDMA

41. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 41 Frequency Hopping [LTL:] Each user gets one time slot per frame, on a different frequency (round-robin used for frequency selection)

42. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 42 1.4. Cellular System Infrastructure BS Service area (Zone) Early wireless system: Large zone [LTL:] Large zone requires a high-power BS Better: replace large zone with smaller hexagonal zones (next slide)

43. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 43 Cellular System: Small Zone BS Service area [LTL:] BS covers much smaller area now Requires much less power (for a given area)

44. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 44 Various kinds of Mobile Stations (MSs) a.k.a. wireless devices Cellphone, PDA, PalmPilot, laptop with WiFi card, … MSs need connectivity on the move E.g., connectivity from BSs in the cells they visit BS is a gateway to wired infrastructure Typical support for MSs: Cellular infrastructure See next slide © 2007 by Leszek T. Lilien Cellular System Infrastructure

45. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 45 Home phone PSTN MSC BSC … BS … … MS … BS MS BSC BS MS … BS MS BSC BS MS … BS MS BSC BS MS … BS MS MSC MS, BS, BSC, MSC, and PSTN [LTL:] Several BSs connected via wireline links to one BSC (BS controller) Several BSCs connected via wireline links to one MSC (Mobile Switching Center) Several MSCs interconnected via wireline links to PSTN (Public Switched Telephone Network) and the ATM backbone wired link

46. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 46 BS consists of Base Tranceiver System (BTS) Includes tower & antenna BSC Contains all associated electronics © 2007 by Leszek T. Lilien BS Structure

47. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 47 MSC database for supporting MS mobility 1) Home location register (HLR) for MS Located at the “home MSC” for MS Where MS is registered, billed, etc. Indicates current location of MS Could be within home MSC’s area OR Could be in the area of any MSC in the world 2) Visitor location register (VLR) on each MSC Contains info on all MSs visiting area of this MSC Incoming call scenario Based on the called #, incoming call for an MS is directed to the HLR of the “home MSC” for this MS HLR redirects the call to MSC/BSC/BS where the MS is now VLR of the “current MSC” has info on MS (one of visiting MSs) © 2007 by Leszek T. Lilien MSC Database Supporting MS Mobility & Incoming Call Scenario

48. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 48 Control and Traffic Channels Base Station Forward (downlink) control channel Mobile Station Reverse (uplink) control channel Forward (downlink) traffic channel Reverse (uplink) traffic channel Note: Forward/reverse in the U.S., downlink/uplink elsewhere [LTL:] 4 simplex channels needed for control & traffic 2 control channels Exchange control msgs Forward channel & reverse channel 2 traffic channels For data Forward channel & reverse channel

49. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 49 More on Control and Traffic Channels [LTL:] Traffic channels used for call duration => Large # of traffic channels on each BS Handshake steps for call setup use control channels Control channels used for short duration => Small # of control channels on each BS MSs compete for these few control channels For call setup, etc. © 2007 by Leszek T. Lilien

50. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 50 Steps for a Call Setup from MS to BS BSMS 1. Need to establish path 2. Frequency/time slot/code assigned (FDMA/TDMA/CDMA) 3. Control information acknowledgement 4. Start communic. on assigned traffic channel [LTL:] Steps for a call setup from MS to BS - When MS initiates a call Time

51. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 51 Steps for a Call Setup from BS to MS BSMS 2. Ready to establish a path 3. Use frequency / time slot / code (FDMA/TDMA/CDMA) 4. Ready for communication 5. Start communic on assigned traffic channel 1. Call for MS # pending [LTL:] Steps for a call setup from BS to MS: When MS responds to a call (somebody calls MS) Time

52. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 52 A Simplified Wireless Communication System Representation Information to be transmitted (Voice/Data) CodingModulatorTransmitter Information received (Voice/Data) DecodingDemodulatorReceiver Antenna Carrier [LTL:] The figure shows major steps in wireless communications Signal processing operations – beyond the lecture scope Lecture will concentrate on system aspects of wireless data communication

53. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 53 1.5. Satellite Systems Application areas of satellite systems Traditional Applications Weather satellite Radio and TV broadcasting Military satellites Navigation and localization (e.g., GPS) Telecommunication Applications Global telephone connections Backbone for global network Connections for communication in remote places or underdeveloped areas Global mobile communications

54. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 54 Basic Concepts & Terminology Only LOS communication is possible LOS = line of sight Satellites further away from earth cover a wider area Satelites can emit one or more satellite beams Satellites w.r.t. position over earth Geostationary Rotating around the earth ES – earth station © 2007 by Leszek T. Lilien

55. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 55 History of Satellite Systems 50 th anniversary of the space age on October 4, 2007

56. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 56 1.6. Network Architectures and Protocols [LTL:] Protocol = basic set of rules followed to provide systematic signaling steps for information exchange Other protocols: Diplomatic protocols, protocol to login, … [LTL:] We will cover later following protocol reference models and protocols: Open Systems Interconnections (OSI) reference model Transmission Control Protocol (TCP) (on top of IP) Internet Protocol (IP) Internet Protocol Version 4 (IPv4) Internet Protocol Version 6 (IPv6) – work in progress Mobile IP (MIP)

57. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 57 1.7. Ad Hoc Network [LTL:] Ad hoc network (AHN) Def 1: AHN is a local network with wireless connections or temporary plug-in connections, in which mobile or portable device are a part of the network only while they are in close proximity Def 2: AHN is a collection of wireless MHs forming a temporary network without the aid of any centralized administration or standard support services regularly available on the wide area network (WAN) to which the hosts may normally be connected Examples: AHN 1: Instructor’s and students’ computers can create an AHN during lectures AHN 2: Oppnet used after an earthquake © 2007 by Leszek T. Lilien

58. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 58 1.7. MANET Source Destination [LTL:] MANET = mobile ad hoc network - an autonomous system of mobile nodes, mobile hosts (MHs), or mobile stations (MSs) connected by wireless links MSs of a MANET also serve as routers These routers are mobile Route messages from SRC to DEST - see Figure Multihop routing Store-and-forward passing of info in P2P (peer-to-peer) way

59. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 59 MANETs – cont.1 MANETs are highly dynamic All nodes, incl. routers, are mobile => topology highly dynamic, unpredictable Topology change due to MSs mobility made known to (some) other nodes Types w.r.t. infrastructure support Stand alone - no infrastructure support Limited infrastructure support Some routers have access to a fixed infrastructure E.g., access to Internet – like in oppnets E.g., stub network (SN) – Stub network = a single LAN which never carries packets between two remote hosts; all traffic is to and/or from local hosts Multiple routers on SN don't route to one another, they will only route a packet into SN (if it's destined for SN), and out from SN (if it originated on SN) [cf. “stub network“ in Wikipedia]

60. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 60 MANETs – cont.2 Location of MSs in a MANET: within buildings, highways, vehicles, on and within human bodies MANET nodes equipped with a “radio” “Radio” = wireless transmitter & receiver (or: wireless transceiver) With antenna Types of antennas: Omnidirectional Directional Steerable Any combination of these Xmit/rcv parameters affect MANET topology at any given moment

61. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 61 Wireless Sensor Networks Base Station Antenna Sensor Target [LTL:] (Ad Hoc) Wireless Sensor Networks (WSNs) – a specia- lized subclass of AHNs Sensor(s) in each node in addition to processor and radio Sensors sense/measure some physical characteristcs Temperature, humidity, acceleration, pressure, toxicity, … Can be planted at random Even thrown out of a speeding vehicle, even from a plane Note: The plane in the Figure is BS & collects data. Another one could have dropped sensor nodes earlier BS collects & aggregates sensed info Example 1 (Fig): Sensing enemy’s moves

62. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 62 Example 2: Sensing a Cloud of Smoke

63. Copyright © 2003, Dharma P. Agrawal and Qing-An Zeng. All rights reserved 63 1.8. Wireless LAN and PAN IEEE 802.11 = Wireless Local Area Network (WLAN) using the IEEE 802.11 HiperLAN is a European Standard Bluetooth nets are examples of Wireless Personal Area Networks (WPAN)

64. End of Section 1 (Ch.1)