1. BLUETOOTH TECHNOLOGY Coexistence Of Bluetooth And Wi-Fi
Presented by:
JIGAR A. SHAH
K.K. Wagh College of Engg.
YUGA SOMVANSHI

2. Coexistence scenario

3. 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

4. Frequency occupancy of three Wi-Fi Networks

5. 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

6. Bluetooth frequency occupancy example

7. 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 GHz
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

8. TESTING

9. Testing Notation

10. Wi-Fi throughput – baseline performance

11. Bluetooth throughput - baseline

12. Wi-Fi performance with Bluetooth interference – Testing setup
Test -1 with Bluetooth
Test – 2 with Bluetooth at 10m

13. Wi-Fi performance with Bluetooth interference

14. Bluetooth performance with Wi-Fi interference

15. 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

16. FCC Regulations for transmitting power
Section of FCC regulation specifies high power transmission for FHSS and DSSS
Section a 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

17. Factors on which determination of best channel depends:
Packet error rate
Channel noise
Channel multipath and intersymbol interference
Received signal strength

18. Wi-Fi and Bluetooth Interference

19. Adaptive Frequency Hopping (AFH) Example

20. AFH (Adaptive Frequency Hopping)

21. 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

22. 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
change

23. AFH is used with other coexistence technology
UltimateBlue™ by siliconwave
Intel Wireless Coexistence System (WCS)
Blue802™ technology

24. Coexistence Technique Comparison by Design Parameters

25. Standardization Activities
IEEE WPAN has formed different task groups:
TG1 ( ) : reformulating BT 1.x spec into IEEE standards
TG2 ( ) : 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

26. References Andrew Tanenbaum: Computer networks, fourth edition
Douglas Comer: Computer Networks and Internet
Jennifer Bray, Charles Struman: Bluetooth-connect without cable

27. Web - References www.ti.com/wlan (Texas Instrument) www.wimaxforum.com

28. Thank You!
Questions?