Bluetooth Address or Name Sharing

1. Bluetooth Address or Name Sharing By Joseph Charboneau

2. Overview • Bluetooth • Establishing a Connection • Inquiry Process • Paging Procedure • Problem • Solution • Conclusion

3. Bluetooth • Bluetooth specifications were designed by Ericsson. • Bluetooth was formalized by the Bluetooth SIG (Special Interest Group). • Bluetooth SIG currently contains over 4,000 members. • Bluetooth is a radio standard used to send and receive data packets while being low power, short range, and low cost.

4. Bluetooth (Cont.) • Bluetooth has three different operating ranges. • 1 Meter. • 10 Meters. • 100 Meters. • The data rate for Bluetooth Version 1.2 is 1Mbps. • The data rate for Bluetooth Version 2+EDR is 3Mbps.

5. Bluetooth (Cont.) • Bluetooth operates in the license free ISM band from 2.4 to 2.485GHz. • The frequency band is divided into 79 channels 1MHz wide. • Bluetooth also uses frequency hopping at 1600 hops per second to help interference.

6. Establishing a Connection • There are two major steps in making a connection in a Bluetooth network. • Inquiry Process. • Paging Procedure. • The first step is the inquiry process and the second step is the paging procedure.

7. Inquiry Process • Used by the master of a Bluetooth network to find a new slave. • Used by a slave to find a master. • During the process the master sends out inquiry requests. • New slaves in the range will pick up the inquiry request. • After the new slaves receives the inquiry request it generates a response.

8. Inquiry Process (Cont.) • The response will contain the following information. • Device Address or Device Name. • Device Class. • List of Services. • Technical Information. • The process uses a special physical channel.

9. Paging Procedure • Targeted procedure. • The master uses the response to generate a DAC. • The master sends out the DAC. • When a new slave receives its corresponding DAC it will respond by only sending out its DAC only.

10. Paging Procedure (Cont.) • When the DAC is received the master will send its device address or device name and clock to the slave. • When the slave receives the information from the master it will generate an acknowledgement. • Then it will offset its native clock to match the master clock.

11. Inquiry Process and Paging Procedure T. Lindholm, “Setting up a Bluetooth Packet Transport Link,” http://www.cs.hut.fi/~ctl/btpacket.pdf

12. Problem • Two devices trying to use the same device address or device name. • The second device may not connect. • Leads to data collisions. • Leads to slaves receiving the same data from the master.

13. Solution • There are three components to the solution. • Updated Header. • Table entries. • Updated DAC.

14. Solution (Cont.) • The first part of the solution is an updated header file. • The header file will have an extra bit added to the front to determine the device number.

15. Solution (Cont.) • The current header file is: • The updated header file is: Silan Liu, “Bluetooth Technology,” http://progtutorials.tripod.com/Bluetooth_Technology.htm#_Toc41989845.

16. Solution (Cont.) • The second part of the solution is to use a table entry system. • Each of the table entries contain: • Device address or device name. • Device number from the header. • The table entries will be compared with every new slave that connects to the master.

17. Solution (Cont.) • The third part is an updated the DAC. • The DAC will be generated as before. • The DAC will have an extra bit added from the device number bit from the updated header.

18. Solution (Cont.) • New Inquiry Process: • The process will begin in the same manner. • The process will change after the response is received. • New Paging Procedure: • The DAC sent to the slave will be the updated DAC. • The slave will return the DAC and the procedure will continue as normal.

19. Solution (Cont.) • Master and slave communication.

20. Conclusion • Problem of address sharing. • Solution: • Updated Header File. • Updated DAC. • Table.