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Indoor Communications. Rex Chen [email protected] Outline. Overview Technologies Challenges Paper Discussion Research Progress Conclusion. Overview of Indoor Communication. Lots of electronic gadgets Need for connectivity Usually in proximity e.g. 1 to 30 meters Characteristics

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Indoor communications l.jpg

Indoor Communications

Rex Chen

[email protected]


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Outline

  • Overview

  • Technologies

  • Challenges

  • Paper Discussion

  • Research Progress

  • Conclusion


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Overview of Indoor Communication

  • Lots of electronic gadgets

  • Need for connectivity

  • Usually in proximity

    • e.g. 1 to 30 meters

  • Characteristics

    • Residential Homes

    • Corporate Offices

    • Public Facilities


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Wired vs. Wireless Indoor Communications?


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Indoor Wireless Communication Technologies

  • IEEE 802.11a/b/g

  • Bluetooth

  • IrDA

  • ZigBee

  • Powerline



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A Closer look at 802.11 WLAN

  • Actual vs. theoretical bandwidth a major gap

    • CSMA/CA overhead (contention-based access)

  • Spectrum Regulations

    • 2.4 to 2.5 GHz unlicensed spectrum for open usage

    • Interferences with microwave and cordless telephony


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802.11 Logistics

  • Standardization

    • IEEE 802.11 Specification

      • Many revisions

    • Involve multiple parties

      • Companies, governments

  • Wi-Fi Alliance

    • 260+ member companies


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802.11 Technicalities

  • Signal Strength

    • Depend on signal-to-noise ratio

    • Receive power ~ to 1/d2 (distance square)

  • Handoff Decision

    • RSSI indicator


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Bluetooth

  • Characteristics

    • Short-range, 2.4 GHz RF

    • Peak rates up to 1 Mbit/sec

    • Line-of-sight not required

    • Low power, cost, size

  • Applications

    • Personal Computers

      • Keyboard, mouse, printer

    • Communication Devices

      • Cell phone and wireless headset


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Bluetooth Topology

  • Piconet Formation

    • Comprise of master, slave (active), parked (ready), and stand-by nodes

    • Synchronization of hopping pattern required


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Bluetooth Transmission

  • Scatternet – joining of multiple piconets

  • Frequency Selection


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IrDA

  • Characteristics

    • Short-range communications with infrared light

    • Requires line-of-sight

    • Low power, cost, size

    • Getting replaced by Bluetooth


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ZigBee

  • Characteristics

    • Low data rate, very low power consumption

    • Cheaper than Bluetooth ($1 transceiver)

    • Device Types:

      • ZigBee coordinator(ZC)

      • ZigBee Router (ZR)

      • ZigBee End Device (ZED)

    • Organized nodes in ad-hoc networks



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Power line communications

  • Characteristics

    • Use electrical power wiring as transmission medium

    • Power plugs are ubiquitous

    • Several competing standards

    • Not widely adopted

    • Interference with outside signals

  • Applications

    • Home lighting and appliances


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The Challenge for Indoor Wireless Communications

  • Lack of standard or regulation

    • No protection against signal interferences

    • Interoperability issue in power line communications

  • Network planning problems in 802.11 WLAN

    • Dynamic building configurations

    • Physical object obstruction (e.g. walls, windows)

    • Dead spots


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The Challenge for Indoor Wireless Communications (2)

  • Security Problems

    • Encryption turn off in many access points WEP failure, can be cracked within a few days

    • Detecting unintended signals

    • Unauthorized network access

      • e.g. Using neighbor wireless access point while surfing for child porn

      • Intensive data traffic download of “pirated” data using P2P applications (e.g. music, software)

  • Usability

    • Setting up the wireless links can be difficult


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Seidel – On Path Loss Prediction Models for Indoor Communication

  • Goal

    • Understand implications of indoor wireless communication with respect to physical surroundings

    • Measurement Sample

      • Grocery store, retail store, two office buildings

  • Model

    • Mean path loss increases exponentially with distance

    • Path Loss (d) ~ (d/d0)n(solve for n)



  • Seidel analysis l.jpg
    Seidel - Analysis Communication


    Indoor communication tools specifically for ieee 802 11 l.jpg
    Indoor Communication Tools – Communicationspecifically for IEEE 802.11

    • Access Point Detection

      • NetStumbler, Kismet

    • Wireless Packet Data Capture

      • OmniPeek (aka, Ethereal)

    • Network Topology Management

      • Ekahau






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    Relevant Projects with CommunicationIndoor Communications

    • Ambient Networks

      • Integration of device communications

        • e.g. PDA-> (IrDA) -> Laptop-> (Bluetooth) ->

          Mobile -> (GPS) -> Mobile phone network

    • PlaceLab

      • Indoor location positioning

        • 802.11 access point using beacon frames


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    The Future of Indoor Communications Communication

    • Everything Wi-Fi enabled?


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    The Future of Indoor Communications (2) Communication

    • Extending coverage reach

      • Wi-Fi interface with WiMAX

      • Mesh routing

    • Higher throughput

      • 802.11n, 10x more bandwidth than 802.11a/g

      • Market Demand?

        • Multi-networked gaming

        • Wireless IPTV streaming


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    Concluding Remarks Communication

    • Many interested parties on indoor communications

      • Telephony and Cellular carriers

        • Dual-mode Wi-Fi and 3G handset

      • Wireless Internet Service Providers (WISP)

        • Inter-network from outdoor to indoor communication

      • Cable Operators

        • Set-top boxes streaming video contents to multiple indoor clients


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    The FONERA Movement Communication

    • http://www.fon.com


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