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Indoor Communications

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

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

  2. Outline • Overview • Technologies • Challenges • Paper Discussion • Research Progress • Conclusion

  3. 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

  4. Wired vs. Wireless Indoor Communications?

  5. Indoor Wireless Communication Technologies • IEEE 802.11a/b/g • Bluetooth • IrDA • ZigBee • Powerline

  6. Electronic Gadgets

  7. 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

  8. 802.11 Logistics • Standardization • IEEE 802.11 Specification • Many revisions • Involve multiple parties • Companies, governments • Wi-Fi Alliance • 260+ member companies

  9. 802.11 Technicalities • Signal Strength • Depend on signal-to-noise ratio • Receive power ~ to 1/d2 (distance square) • Handoff Decision • RSSI indicator

  10. 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

  11. Bluetooth Topology • Piconet Formation • Comprise of master, slave (active), parked (ready), and stand-by nodes • Synchronization of hopping pattern required

  12. Bluetooth Transmission • Scatternet – joining of multiple piconets • Frequency Selection

  13. IrDA • Characteristics • Short-range communications with infrared light • Requires line-of-sight • Low power, cost, size • Getting replaced by Bluetooth

  14. 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

  15. ZigBee in Home Automation

  16. 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

  17. 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

  18. 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

  19. 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)

  20. Seidel – Mean path loss exponent and standard deviation

  21. Seidel - Analysis

  22. Indoor Communication Tools – specifically for IEEE 802.11 • Access Point Detection • NetStumbler, Kismet • Wireless Packet Data Capture • OmniPeek (aka, Ethereal) • Network Topology Management • Ekahau

  23. Indoor Comm Tools - NetStumbler • Demo

  24. Indoor Comm Tools – Ekahau

  25. Indoor Comm Tools – Ekahau (2)

  26. Indoor Comm Tools – Ekahau (3)

  27. 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

  28. The Future of Indoor Communications • Everything Wi-Fi enabled?

  29. 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

  30. 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

  31. The FONERA Movement • http://www.fon.com

  32. Open Discussion

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