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Indoor Communications. Rex Chen rex@ics.uci.edu. 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

Indoor Communications

Rex Chen

rex@ics.uci.edu

outline
Outline
  • Overview
  • Technologies
  • Challenges
  • Paper Discussion
  • Research Progress
  • Conclusion
overview of indoor communication
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
indoor wireless communication technologies
Indoor Wireless Communication Technologies
  • IEEE 802.11a/b/g
  • Bluetooth
  • IrDA
  • ZigBee
  • Powerline
a closer look at 802 11 wlan
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
802 11 logistics
802.11 Logistics
  • Standardization
    • IEEE 802.11 Specification
      • Many revisions
    • Involve multiple parties
      • Companies, governments
  • Wi-Fi Alliance
    • 260+ member companies
802 11 technicalities
802.11 Technicalities
  • Signal Strength
    • Depend on signal-to-noise ratio
    • Receive power ~ to 1/d2 (distance square)
  • Handoff Decision
    • RSSI indicator
bluetooth
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
bluetooth topology
Bluetooth Topology
  • Piconet Formation
      • Comprise of master, slave (active), parked (ready), and stand-by nodes
      • Synchronization of hopping pattern required
bluetooth transmission
Bluetooth Transmission
  • Scatternet – joining of multiple piconets
  • Frequency Selection
slide13
IrDA
  • Characteristics
    • Short-range communications with infrared light
    • Requires line-of-sight
    • Low power, cost, size
    • Getting replaced by Bluetooth
zigbee
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
power line communications
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
the challenge for indoor wireless communications
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
the challenge for indoor wireless communications 2
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
seidel on path loss prediction models for indoor communication
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)
indoor communication tools specifically for ieee 802 11
Indoor Communication Tools – specifically for IEEE 802.11
  • Access Point Detection
    • NetStumbler, Kismet
  • Wireless Packet Data Capture
    • OmniPeek (aka, Ethereal)
  • Network Topology Management
    • Ekahau
relevant projects with indoor communications
Relevant Projects withIndoor 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
the future of indoor communications
The Future of Indoor Communications
  • Everything Wi-Fi enabled?
the future of indoor communications 2
The Future of Indoor Communications (2)
  • 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
concluding remarks
Concluding Remarks
  • 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
the fonera movement
The FONERA Movement
  • http://www.fon.com
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