bluetooth technology coexistence of bluetooth and wi-fi presented by: jigar a. shah k.k. wagh...
TRANSCRIPT
BLUETOOTH TECHNOLOGY
Coexistence Of Bluetooth And Wi-Fi
Presented by:JIGAR A. SHAHK.K. Wagh College of [email protected]
YUGA SOMVANSHIK.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
Wi-Fi performance with Bluetooth interference – Testing setup
Test – 2 with Bluetooth at 10m
Test -1 with Bluetooth
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
Web - References www.ti.com/wlan
(Texas Instrument) www.wimaxforum.co
m
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
Thank You!
Questions?