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What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture

What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture Key Technologies of Mobile Computing Applications. Heterogeneous Wireless Communication World. DAB: Digital Audio Broadcast VHE: Virtual Home Environment.

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What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture

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  1. What is Mobile Computing? • Wireless Communication Systems • Mobile Communication Systems Architecture • Key Technologies of Mobile Computing • Applications

  2. Heterogeneous Wireless Communication World DAB: Digital Audio Broadcast VHE: Virtual Home Environment DVB-T: Digital Video Broadcast Terrestrial UMTS: Universal Mobile Telecommunication System

  3. Wireless Networks • Wireless communication networks • IEEE 802.11 • IEEE 802.15 • IEEE 802.16 • IEEE 802.20 • Mobile communication networks • GSM • GPRS • WCDMA • HSPA+ • LTE

  4. IEEE 802 IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20 • Refers to a family of IEEE standards dealing with local area networks and metropolitan area networks • The services and protocols specified in IEEE 802 map to the lower two layers • Data Link • Logical Link Control (LLC) • Media Access Control (MAC) • Physical

  5. IEEE 802 Standards

  6. WWAN / WMAN / WLAN / WPAN

  7. Note: NFC (Near Field Communication) • A short-rangehigh frequency wireless communication technology which enables the exchange of data between devices over about a 10 centimetre (around 4 inches) distance • The technology is a simple extension of the ISO/IEC 14443 proximity-card standard (contactless card, RFID) that combines the interface of a smartcard and a reader into a single device

  8. An NFC device can communicate with both existing ISO/IEC 14443 smartcards and readers, as well as with other NFC devices, and is thereby compatible with existing contactless infrastructure already in use for public transportation and payment • NFC technology is currently mainly aimed at being used with mobile phones

  9. Three main use cases for NFC • card emulation: the NFC device behaves like an existing contactless card • reader mode: the NFC device is active and read a passive RFID tag, for example for interactive advertising • P2P mode: two NFC devices are communicating together and exchanging information

  10. Applications • Mobile ticketing in public transport — an extension of the existing contactless infrastructure • Mobile payment — the device acts as a debit/ credit payment card • Smart poster — the mobile phone is used to read RFID tags on outdoor billboards in order to get info on the move • Bluetooth pairing — pairing of Bluetooth devices with NFC bringing them close together and accepting the pairing

  11. Other applications • Electronic ticketing — airline tickets, concert/event tickets, and others • Electronic money • Travel cards • Identity documents • Mobile commerce • Electronic keys — car keys, house/office keys, hotel room keys, etc. • NFC can be used to configure and initiate other wireless network connections such as Bluetooth, Wi-Fi or Ultra-wideband

  12. IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20 IEEE 802.11 Standard and Amendments • IEEE 802.11 - The WLAN standard was original 1 Mbit/s and 2 Mbit/s, 2.4 GHz RF and infrared [IR] standard (1997), all the others listed below are Amendments to this standard, except for Recommended Practices 802.11F and 802.11T. • IEEE 802.11a - 54 Mbit/s, 5 GHz standard (1999, shipping products in 2001) • IEEE 802.11b - Enhancements to 802.11 to support 5.5 and 11 Mbit/s, 2.4 GHz (1999) • IEEE 802.11c — Bridge operation procedures; included in the IEEE 802.1D standard (2001) • IEEE 802.11d - International (country-to-country) roaming extensions (2001) • IEEE 802.11e - Enhancements: QoS, including packet bursting (2005) • IEEE 802.11f - Inter-Access Point Protocol (2003) Withdrawn February 2006

  13. IEEE 802.11g - 54 Mbit/s, 2.4 GHz standard (backwards compatible with b) (2003) • IEEE 802.11h - Spectrum Managed 802.11a (5 GHz) for European compatibility (2004) • IEEE 802.11i - Enhanced security (2004) • IEEE 802.11j - Extensions for Japan (2004) • IEEE 802.11-2007 - A new release of the standard that includes amendments a, b, d, e, g, h, i & j. (July 2007) • IEEE 802.11k - Radio resource measurement enhancements (2008) • IEEE 802.11n - Higher throughput improvements using MIMO (multiple input, multiple output antennas) (September 2009) • IEEE 802.11p - WAVE — Wireless Access for the Vehicular Environment (such as ambulances and passenger cars) (working — June 2010) • IEEE 802.11r - Fast roaming Working "Task Group r" - (2008) • IEEE 802.11s - Mesh Networking, Extended Service Set (ESS) (working — September 2010)

  14. IEEE 802.11T — Wireless Performance Prediction (WPP) - test methods and metrics Recommendation cancelled • IEEE 802.11u - Interworking with non-802 networks (for example, cellular) (working — September 2010) • IEEE 802.11v - Wireless network management (working — June 2010) • IEEE 802.11w - Protected Management Frames (September 2009) • IEEE 802.11y - 3650-3700 MHz Operation in the U.S. (2008) • IEEE 802.11z - Extensions to Direct Link Setup (DLS) (August 2007 - December 2011) • IEEE 802.11aa - Robust streaming of Audio Video Transport Streams (March 2008 - June 2011) • IEEE 802.11mb — Maintenance of the standard. Expected to become 802.11-2011. (ongoing) • IEEE 802.11ac - Very High Throughput < 6 GHz (September 2008 - December 2012) • IEEE 802.11ad - Extremely High Throughput 60 GHz (December 2008 - December 2012)

  15. IEEE 802.11 / Wi-Fi [/ˈWaɪFaɪ/] • Wireless Fidelity (無線相容性認證) • A wireless-technology brand owned by the Wi-Fi alliance • Promotes standards with the aim of • improving the interoperability of wireless local area network products based on the IEEE 802.11 standards

  16. Common applications for Wi-Fi • Internet and VoIP phone access, gaming • network connectivity for consumer electronics such as televisions, DVD players, and digital cameras • Wi-Fi Alliance • a consortium of separate and independent companies • agrees on a set of common interoperable products based on the family of IEEE 802.11 standards

  17. IEEE 802.11 Infrastructure Mode • Uses fixed base stations (infrastructure) which are responsible for coordinating communication between the mobile hosts (nodes)

  18. IEEE 802.11 Ad Hoc Mode • Mobile nodes communicate with each other through wireless medium without any fixed infrastructure

  19. B A A B Mobile Ad Hoc Networks (MANET) • Host moves frequently • Topology changes frequently • No cellular infrastructure • Multi-hop wireless links • Data must be routed via intermediate nodes

  20. 802.11 /11a/11b/11g/11n

  21. IEEE 802.11n • Improve network throughput over 802.11a and 802.11g • with a significant increase in the maximum raw data rate from 54 Mbit/s to 600 Mbit/s with the use of four spatial streams at a channel width of 40 MHz • In spatial multiplexing • a high rate signal is split into multiple lower rate streams • each stream is transmitted from a different transmit antenna in the same frequency channel

  22. 802.11n uses MIMO (Multiple Input Multiple Output)

  23. IEEE 802.11p (VANET) – Motivation • Vehicular Ad hoc NETwork (VANET) • Safety • on US highways (2004) • 42,800 fatalities, 2.8 million injuries • ~$230.6 billion cost to society • Efficiency • traffic jams waste time and fuel • in 2003, US drivers lost a total of 3.5 billion hours and 5.7 billion gallons of fuel to traffic congestion • Profit • safety features and high-tech devices have become product differentiators

  24. VANET-based Emergency Vehicle Warning System http://www.youtube.com/watch?v=yqtLvZrz2qE • Ford's "Talking" Vehicles - Car-to-Car Communication Demo http://www.youtube.com/watch?v=XBqCAVwQv0E • BMW Car-to-X Communication http://www.youtube.com/watch?v=JzgwlXzO6v0 • InfoFueling network http://www.youtube.com/watch?v=Cc19mcnzvpE • * Ford Demonstrates Vehicle-to-Vehicle Communication for Increased Safety http://www.youtube.com/watch?v=RrCyl6pOAC0

  25. What is VANET?

  26. RSU RSU • Components in a VANET • Moving vehicles with On-Board Unit (OBU) • Road Side Units (RSU) • local broadcasting information • IEEE 802.11 access point

  27. On-Board Unit (OBU) • Vehicle OBU • WinXP devices • Windows mobile PDAs • GPS tracker without user interface • Text-based OBUs • Pedestrian OBU • GPS phone • Personal tracker

  28. Smart Vehicle A modern vehicle is a network of sensors/actuators on wheels !

  29. VANET Architecture

  30. Differences between VANET and MANET

  31. Vehicle Communication (VC) • VC promisessaferroads

  32. … more efficient driving

  33. … more fun

  34. VANET – Applications • Congestion detection • Vehicle platooning • Road conditions warning • Collision alert • Stoplight assistant • Emergency vehicle warning • Deceleration warning • Toll collection • Border clearance • Adaptive cruise control • Drive-through payment • Merge assistance

  35. A Taxonomy of Vehicular Communication Systems

  36. Communication Types Roadside-to-Vehicle Communications (RVC) Inter-Vehicle Communications (IVC) Hybrid-Vehicle Communications (HVC) +

  37. Inter-vehicle communication (IVC) Systems • Completely infrastructure-free • Only onboard units (OBUs) are needed

  38. IVC systems • SIVC (Single-hop Inter-Vehicle Communication) • applications of short-range communications • e.g., lane merging, automatic cruise control • MIVC (Multihop Inter-Vehicle Communication) • applications of long-range communications • e.g., traffic monitoring (a) SIVC (b) MIVC

  39. Roadside-to-Vehicle Communication (RVC) Systems • Communication between roadside infrastructure (RSU) and OBU • Two types of infrastructures • Sparse RVC (SRVC) system • Ubiquitous RVC (URVC) system

  40. RVC Systems - SRVC • Provide communication services at hot spots • Examples • a busy intersection scheduling its traffic light • a gas station advertising its existence (and prices) • parking availability at an airport

  41. RVC Systems - URVC • Provide all roads with high-speed communication • Require considerable investments for providing full (even significant) coverage of existing roadways

  42. Hybrid Vehicular Communication (HVC) Systems • Extend the transmission range of RVC systems • Vehicles communicate with roadside infrastructure even when they are not in direct wireless range by using other vehicles as mobile routers

  43. HVC – Adv. & Disadv. • Advantage • less roadside infrastructure • Disadvantage • network connectivity may not be guaranteed in scenarios with low vehicle density

  44. Vehicular Ad Hoc Network (VANET) • Messagepropagatestodestinationusing a numberofintermediatelinks

  45. If vehicle mobility causes links to break, message rerouted using a different path

  46. Challenges • Physicallayer • limited bandwidth • Link layer • congestioncontrol, latency, throughput, fairness andscalability • Network (routing) layer • rapidtopology changesandnetwork fragmentation

  47. WAVE (IEEE 1609) / DSRC (802.11p)

  48. WAVE (Wireless Access in Vehicular Environments)

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