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Wireless networks: from cellular to ad hoc

Wireless networks: from cellular to ad hoc. March 2008. Outline (Ch 1 - 4). Wireless introduction Wireless cellular (GSM, CDMA, UMTS, WiMAX) Wireless LANs, MAC layer Wireless Ad hoc networks routing: Proactive routing, On-demand routing, Scalable routing, Geo-routing multicast

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Wireless networks: from cellular to ad hoc

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  1. Wireless networks: from cellular to ad hoc March 2008

  2. Outline (Ch 1 - 4) Wireless introduction Wireless cellular (GSM, CDMA, UMTS, WiMAX) Wireless LANs, MAC layer Wireless Ad hoc networks routing: Proactive routing, On-demand routing, Scalable routing, Geo-routing multicast TCP QoS, adaptive voice/video apps Sensor networks

  3. The three wireless “waves” • Wave #1: cellular telephony • Still, biggest profit maker • Wave #2 : wireless Internet access • Most Internet access on US campuses is wireless • Hot spots are rapidly proliferating in the US; Europe and Asia to follow soon • 2.5 G, 3G and 4G trying to keep up; competitive edge? • Wave #3: ad hoc wireless nets (now) • Set up in an area with NO infrastructure; to respond to a specific, time limited need

  4. Wireless Internet Options - Cellular • 2.5 G • GPRS: Time Division based (GSM); 100Kbps • 1xRTT: CDMA based; 144Kbps • 3G • UMTS: Wide Band CDMA from 384 Kbps to 2Mbps • Integrates packet service with connection oriented service (voice, video, etc) • 4 G ? • WiMAX/IEEE802.16 (100Mbps) ->> 3G? 4G? • 上海:单路 512Kbps~3Mbps • other

  5. Wireless Internet Option: WiFi (IEEE802.11) • Replacement for wired Ethernet • Unlicensed spectrum (ISM) • Several options and rates • 802.11 b: 11, 5.5, 2, 1 Mbps; @ 2.4 GHz • 802.11 a: 54 Mbps in 5.7 GHz band • 802.11 g: 54 Mbps; @ 2.4 GHz • 802.11 n, up to 100Mps with MIMO and OFDM tech. • Range • Indoor 20 - 25 meters (more) • Outdoor: 50 – 100 meters (1 Km) • Transmit power: 30 - 100 mW (200mW, 500 mW)

  6. Wireless Internet options: Bluetooth (IEEE 802.15.1) • 1998: BT SIG : Ericsson, IBM, Intel, Nokia, Toshiba • A cable replacement technology • Max rate 700Kbps @2.4 Ghz • Range 10+ meters • Single chip radio + baseband • at low power (1mw) & low price point ($5) • Convergence of 802.15 and Bluetooth in a single PAN standard

  7. New developments are blurring the distinction • 802.11 for PDAs • Bluetooth for LAN access Emerging Landscape Bluetooth 802.11 • Both 802.11 and Bluetooth will be used for access • Complementary benefits Cordless headset LAN AP

  8. Current Wireless Internet 802.11 LAN Internet 2G/3G WAN Infrastructure • Wireless WAN: 2G/3G cellular infrastructure • Wireless LAN: IEEE 802.11

  9. Comparisons of 3G and 802.11 • Cost 802.11: cheaper 3G: expensive • Coverage • 3G: large coverage • 802.11b/a/g: small • Throughput • 802.11b/a/g: up to 11/54 Mbps • 3G: up to 2.4 Mbps • Cell size and density • 802.11: several hundred feet • 3G: up to several kilometers • Applications supported • 802.11: mainly data, but may support VoIP • 3G: data plus voice in 1XEVDV

  10. Integrating 2G, 3G and Wi-Fi • Creating one multi-speed, multimedia network • Integrate Wi-Fi and cellular communications • "total seamlessness" between the technologies

  11. 集成移动通信及互联网为一体的网络 • 互联网存在的问题: • 没有服务质量(QoS)控制/信令 • 安全问题突出(没有可靠的认证、保密) • 很难支持移动,形成全网覆盖 • 移动通信存在的问题: 3G • 价格贵-比无线局域网 • 接入速率有限-2Mbit/s • 很难与互联网/IP应用融合 • 哲学:集成---矛盾 • 通信---纪律,有中心,有组织 • 计算机网络---自由

  12. IEEE Communications Magazine 2003.11 • Interworking Architecture Between 3GPP and WLAN Systems • Security Aspects of 3G-WLAN Interworking • Design and Implementation of a WLAN /CDMA2000 Interworking Architecture • Efficient Mobility Management for Vertical Handoff between WWAN and WLAN • Seamless handover in terrestrial radio access networking: a case study • Policy-Based QoS Management Architecture in an Integrated UMTS and WLAN Environment

  13. Which Internet access to choose? • Most portables have multiple radio interfaces • 802.11, Bluetooth, GPRS, 1xRTT, 3G , and 4G • Dynamically select best access • Lowest connection charge • Best reception • Best power budget (must save battery power) • Suitable QoS • Challenges: • Integrating 2G, 3G, 4G and Wi-Fi • "total seamlessness" between the technologies • Creating one multi-speed, multimedia network

  14. The 3rd Wave: Infrastructure vs Ad Hoc Infrastructure Network (cellular or Hot spot) Ad Hoc, Multihop wireless Network

  15. General Ad Hoc Network Characteristics • Instantly deployable, re-configurable (No fixed infrastructure) • Created to satisfy a “temporary” need • Node portability (eg sensors), mobility • Limited battery power • Multi-hopping (to save power, overcome obstacles, enhance spatial spectrum reuse, etc.)

  16. The Battlefield • DoD was first to understand the value of ad hoc networks for the automated battlefield • In 1971 (two years after ARPANET), DARPA starts the Packet Radio project • ONR (Office of Naval Research) sponsors MINUTEMAN- a 5 year program at UCLA (2000–2005) • Goal: develop an “unmanned” , airborne ad hoc architecture


  18. Transferring Battlefield technology to civilian applications - Disaster recovery • Flood, mud slide, earthquakes, eruption, chemical or nuclear plant disaster, snow …. • Several rescue teams involved, with different functions • Autonomous vehicle swarms (ground/airborne) are deployed (with sensors/actuators) • Manned and unmanned teams cooperate in rescue • “Ad Hoc networking” will be central to make the operation work

  19. Ad Hoc Network Applications (cont)- Commercial • Sport events, festivals, conventions • Patient monitoring • Ad hoc collaborative computing (Bluetooth) • Networked video games at amusement parks, etc • Ad Hoc extensions (of Wireless Internet) • Opportunistic Evolution • Vehicle Communications and Urban Surveillance • Urban Homeland Defense • Mobile sensor platforms vs Cable TV • P2P applications • Car Torrent • MobEyes • Autonomous evacuation

  20. Vision: Opportunistic Evolution of Ad Hoc Networking • Key issue: wired-wireless convergence: Commercial ad hoc nets must coexist with the Internet • They will NOT follow the “military” model as isolated, self configured • Rather, they will emerge as a “no cost” extension of the “infrastructure” • Examples of Ad Hoc extensions (of Wireless Internet) • Indoor W-LAN extended coverage • Mesh Networks (Hot spot extensions) • Rural networks • Group of friends sharing 3G access via Bluetooth

  21. Alternative “All Wireless” Networks • “All wireless” architecture: Multihop wireless networking • Potential benefits: • “anytime, anywhere” network setup • Self-organized, small to large scales • Minimized wiring cost • Three architectural paradigms from resource perspective • Low-end: resource-constrained wireless sensor networks • Middle-ground: mobile ad-hoc networks • High-end: wireless mesh networks

  22. Multihop Wireless Networks Low-End Middle-Ground Wireless Sensor Networks Mobile Ad-Hoc Networks • Resource-constrained sensors • Potentially large population • Nodes with reasonable amount of resources • Data rates upto 10s Mbps

  23. Portal L3 Router L2 Switch High-End: Wireless Mesh Networks802.11s Mesh Portal Mesh Links 802.11 MAC/PHY Distribution System • High-speed wireless backbone at >100Mbps • Resource abundant • Promises to have both wide coverage and high rate 802.11 ESS STA Mesh AP Mesh router

  24. Wireless Mesh Networks

  25. Urban surveillance • CCTV surveillance • Cameras cannot be installed at all locations • Cameras can be taken out by terrorists • The central data collection facility can be sabotaged • Mobile video collection/storage platforms • Vehicles, People, Robots • Mobile “eyes” are an complement to CCTV • New challenges on VEHICLES • wireless communications medium • wireless data protocols/architectures • distributed storage strategy • search of the distributed, mobile data base

  26. Urban “opportunistic” ad hoc networking From Wireless to Wired network Via Multihop

  27. The Urban Vehicle Grid • Ad hoc networking to prevent/contain accidents

  28. Opportunistic piggy rides in the urban mesh • Pedestrian transmits a large file block by block to passing cars, busses • The carriers deliver the blocks to the hot spot

  29. More generally:New Vehicle Roles on the road • Vehicle as a producer of geo-referenced data about its environment • Pavement condition • Probe data for traffic management • Weather data • Physiological condition of passengers, …. • Vehicle as Information Gateway (Telematics) • Internet access, infotainment, dynamic route guidance, …… • These roles demand efficient communications

  30. Vehicle Roles: Vehicular Sensor Apps • Vehicle & Vehicle, Vehicle & Roadway as collaborators • Cooperative Active Safety • Forward Collision Warning, Blind Spot Warning, Intersection Collision Warning……. • In-Vehicle Advisories • “Ice on bridge”, “Congestion ahead”,…. • Environment • Traffic congestion monitoring • Urban pollution monitoring • Civic and Homeland security • Forensic accident or crime site investigations • Terrorist alerts

  31. Urban Ad Hoc net in action: Safe Driving Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 65 mphAcceleration: - 5m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 20m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: None Alert Status: None Alert Status: Inattentive Driver on Right Alert Status: Slowing vehicle ahead Alert Status: Passing vehicle on left Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 45 mphAcceleration: - 20m/sec^2Coefficient of friction: .65Driver Attention: NoEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 10m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: Passing Vehicle on left

  32. Vehicular Sensor Network (VSN)IEEE Wiress Communications 2006Uichin Lee, Eugenio Magistretti (UCLA)

  33. Accident Scenario: storage and retrieval • Designated Cars: • Continuously collect images on the street (store data locally) • Process the data and detect an event • Classify the event asMeta-data (Type, Option, Location, Vehicle ID) • Post it on distributed index • Police retrieve data from designated cars Meta-data : Img, -. (10,10), V10

  34. How to retrieve the data? • “Epidemic diffusion” : • Mobile nodes periodically broadcast meta-data of events to their neighbors • A mobileagent(the police) queries nodes and harvests events • Data dropped when stale and/or geographically irrelevant • Mobility-Assist Meta-Data Harvesting • Assumption • N disseminating nodes; each node ni advertises event ei , “k”-hop relaying • v: average speed, R: communication range • ρ : network density of disseminating nodes • Discrete time analysis (time step Δt) • Metrics • Average event “percolation” delay • Average delay until all relevant data is harvested

  35. U-Ve T: Ucla - Vehicular Testbed- Project Goals • Provide: • A platform to support car-to-car experiments in various traffic conditions and mobility patterns • A shared virtualized environment to test new protocols and applications • Remote access to U-VeT through web interface • Extendible to 1000’s of vehicles through WHYNET emulator • potential integration in the GENI infrastructure • Allow: • Collection of mobility traces and network statistics • Experiments on a real vehicular network

  36. Big Picture • We plan to install our node equipment in: • 50 Campus operated vehicles • “on a schedule” and “random” campus fleet mobility patterns • 50 Communing Vans • Measure freeway motion patterns • Hybrid cross campus connectivity using 10 WLAN Access Points • The U-Box Node: • Laptop/PC (Linux) (Windows), 2 x WLAN Interfaces, 1 Software Defined Radio (FPGA based) Interface, 1 Control Channel , 1 GPS, OLSR Used for the Demo

  37. The C2C testbed

  38. CarTorrent : Opportunistic Ad Hoc networking to download large multimedia files You are driving to VegasYou hear of this new show on the radioVideo preview on the web (10MB)

  39. Internet file Highway Infostation downloading Problem:Stopping at gas station to download is a nuisance Observation:many other drivers are downloading the same files (like in the Internet) Solution:Co-operative P2P Downloading using the Car to Car ad hoc nets (Car-Torrent)

  40. Partial download from Infostation Internet Download

  41. Co-operative P2P Download Internet P2P Exchange of Pieces Vehicle-Vehicle Communication

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