Bluetooth technology coexistence of bluetooth and wi fi
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BLUETOOTH TECHNOLOGY Coexistence Of Bluetooth And Wi-Fi. Presented by: JIGAR A. SHAH K.K. Wagh College of Engg. [email protected] YUGA SOMVANSHI K.K. Wagh College of Engg. Coexistence scenario. Overview of Wi-Fi (802.11b). It is specification for WLAN

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BLUETOOTH TECHNOLOGY Coexistence Of Bluetooth And Wi-Fi

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BLUETOOTH TECHNOLOGYCoexistence Of Bluetooth And Wi-Fi

Presented by:

JIGAR A. SHAH

K.K. Wagh College of Engg.

[email protected]

YUGA SOMVANSHI

K.K. Wagh College of Engg.


Coexistence scenario


Overview of Wi-Fi (802.11b)

  • It is specification for WLAN

  • Wireless Ethernet Compatibility Alliance certify product as Wi-Fi compatible

  • Data transmission on BPSK and QPSK

  • Data transmission at 11 Mbps

  • Direct Sequence Spread Spectrum (DSSS)

  • Devices are classified as Access Point and Station

  • Range of data transmission up to 100m


Frequency occupancy of three Wi-Fi Networks


Overview of Bluetooth

  • It is WPAN technology

  • Data transmission on GFSK

  • Hops at 1600Hz over 79 channels of 1MHz

  • Uses Frequency Hopping Spread Spectrum (FHSS)

  • Devices are classified as Master and Slave

  • Generally used as cable replacement technology

  • Communication range up to 10m

  • Data transmission at 724Kbps


Bluetooth frequency occupancy example


What is coexistence ?

  • “Coexistence”, the ability for multiple protocols to operate in the same frequency band without significant degradation to either’s operation

  • 2.4GHz ISM band is 83.5MHz wide with lower limit from 2.400GHz and higher limit from 2.4835GHz

  • Both Bluetooth and Wi-Fi utilizes same 2.4GHz ISM band

  • Bluetooth device hops over 79MHz channel and Wi-Fi requires 16MHz bandwidth – chances of interference are very high

  • Wi-Fi and Bluetooth are complementary rather than competing


Testing Notation


Wi-Fi throughput – baseline performance


Bluetooth throughput - baseline


Test -1 with Bluetooth

Test – 2 with Bluetooth at 10m

Wi-Fi performance with Bluetooth interference – Testing setup


Wi-Fi performance with Bluetooth interference


Bluetooth performance with Wi-Fi interference


Methods for Improved Coexistence

  • MAC layer switching

  • Adaptive Fragmentation for Wi-Fi Networks

  • Transmit Power control

  • Dynamic Channel Selection for Wi-Fi Network

  • Adaptive Frequency Hopping for Bluetooth Networks


FCC Regulations for transmitting power

  • Section 15.247 of FCC regulation specifies high power transmission for FHSS and DSSS

  • Section 15.247a of FCC regulations limits high power transmitters up to 1 Watt for DSSS and FHSS

  • Minimum No. of channel to be hopped was 75 in 2002

  • To limit transmission power FCC changed min. number of channel to be hopped to 20 channels


Factors on which determination of best channel depends:

  • Packet error rate

  • Channel noise

  • Channel multipath and intersymbol interference

  • Received signal strength


Wi-Fi and Bluetooth Interference


Adaptive Frequency Hopping (AFH) Example


AFH (Adaptive Frequency Hopping)


Changes in Bluetooth 1.2 specification

  • AFH is specified in Bluetooth 1.2 specification

  • Base band: Updated base band describes the algorithm used for generating an adapted hop channel set

  • LMP (Link Manger Protocol): it is updated with new message for communicating the bit mask that identifies which channel may be used and which are to be avoided

    • The bit mask consist of 79 bits which gives detail about which channel is to be used and unused

  • HCI (Host Controller Interface): it includes two new commands ;

    • First to exclude channels from list

    • Second one to read channel map currently in use


Limitation of AFH

  • Not suitable for collocated Wi-Fi and Bluetooth devices,

  • Effectiveness depends on antenna isolation, transmit power of devices and the sensitivity of receiver

  • Requires antenna isolation

  • Cannot be used if either master or slave does not support it

  • Not effective for Bluetooth 1.1 compatible devices


AFH is used with other coexistence technology

  • UltimateBlue™ by siliconwave

  • Intel Wireless Coexistence System (WCS)

  • Blue802™ technology


Standardization Activities

  • IEEE 802.15 WPAN has formed different task groups:

    • TG1 (802.15.1) : reformulating BT 1.x spec into IEEE standards

    • TG2 (802.15.2) : Recommend practices coexistence of wireless devices operating in the 2.4GHz band

  • Bluetooth SIG coexistence Working Group is established to make changes in Bluetooth standards


References

  • Andrew Tanenbaum: Computer networks, fourth edition

  • Douglas Comer: Computer Networks and Internet

  • Jennifer Bray, Charles Struman: Bluetooth-connect without cable


www.ti.com/wlan (Texas Instrument)

www.wimaxforum.com

www.alcatel.com

www.stdsbbs.ieee.org/groups/802/11

www.bitpipe.com

www.interop.com

www.ieee802.org/15

www.bluetooth.org

www.codebluecommunication.com

www.3com.com

www.trillium.com

www.motorola.com

www.itpapers.com

www.siliconwave.com

www.wi-fi.org

www.mobilian.com

www.intel.com

Web - References


Thank You!

Questions?


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