Bluetooth: Technology for Short-Range Wireless Apps

1. Bluetooth:Technology for Short-Range Wireless Apps IEEE INTERNET COMPUTING MAY.JUNE 2001 Author:Pravin Bhagwat Presented by Chin-Yi Tsai

2. Outline • Introduction to Bluetooth • Bluetooth Specifications • The Frequency Hopping technique • Inquiry and Paging • Piconets and Scatternets • Bluetooth Applications • Conclusions

3. Introduction to Bluetooth • Why Bluetooth? • Bluetooth History • Bluetooth Feature and motivation

4. Why Bluetooth? • 10th Century Denmark King • King Harald united Denmark and Norway. Bluetooth of today will unite the world of computers and telecom

5. Bluetooth History • The Bluetooth Special Interest Group(SIG) • Initially the group comprised five companies-IBM,Intel,Ericsson,Nokia,Toshiba • The end of 1999 this number had increased to nine through the addition of 3Com, Motorola, Microsoft, Lucent • By December 2000 the Bluetooth SIG had over 2000 members

6. Bluetooth feature and motivation • Bluetooth feature • ISM 2.4 GHz • Small • Simple • Low cost • Low power • Short range • Voice and data • Point-to-point and point-to-multipoint

7. Bluetooth feature and motivation • Bluetooth motivation • Started as cable replement technology • Connecting with different devices • Mobile acces to LANs/Internet • Personal Area Network(PAN) • Automatic synchronization of data

8. Bluetooth Specifications • Core specification • The core specification defines all layers of the Bluetooth protocol stack • Profile specification • Special protocol • different device,OS, and application • interoperability

9. Host Bluetooth Module Bluetooth Specifications Applications OBEX SDP TCS WAP RFCOMM AT Commands L2CAP Host Controller Interface Link Manager Baseband/Link Controller Radio The Bluetooth protocol stack

10. Radio • Frequncy • 2.4000~2.4835 GHz(license-free) • Power:there are three power class • 1mW,2.5mW,100mW • Modulation • GFSK

11. Baseband • Physical channel • Formed after connection • Transmition type • SCO(cricuit switch):point-to-point,voice • ACL(packet switch),point-to-multipoint, data • Error correction • 1/3 FEC,2/3 FEC ,ARQ • Timer synchronization

12. Baseband • Link controller state • Standby • Intermediate:inquiry,inquiry scan,inquiry response,page,page scan,page response,master response • Connection:active,sniff,hold,park

13. LMP • Piconet management • Attach and detach slave • SCO and ACL connection,management • Switch role of master,slave • Handling low power • Link configuration • QoS • Security function • Authication,encryption,link key

14. Host dirver and applicaiton Bluetooth HCI Driver Bluetooth HCI Transport Driver (USB,UART,RS232) Transport Bus HCI Host transport fireware LMP Baseband Radio Host Controller Interface • Host control Bluetooth module

15. L2CAP • Protocol multiplexing • Segment and reassembly • Negotiation • MTU(maximum transmission unit) • Flush timeout • QoS

16. Applications OBEX SDP TCS WAP RFCOMM AT Commands L2CAP Host Controller Interface Link Manager Baseband/Link Controller Radio Others • RFCOMM • TCS • WAP • OBEX • PPP

17. Profile Specifications • Generic access • Service discovery • Cordless telephone • Intercom(Walkie-Talkie) • Serial port • Headset

18. Profile Specifications • Dial-up networking • Fax • LAN access • Generic object exchange • Object push • File transfer • Synchronization

19. The Frequency Hopping technique 1MHz • Divide Frequency band into 1 MHz hop channels • Radio hops from one channel to another in a pseudo -random manner as dictated by a hop sequence • Hopping sequence is different for each piconet(master’s device address and clock) • Hop rate:1600 time/second … 1 79

20. The Frequency Hopping technique f(2k) f(2k+2) f(2k+4) f(2k+1) f(2k+3) f(2k+5) Master Slave1 Slave2 Slave3 1 slot

21. Inquiry and Paging • The purpose of inquiry and paging • Connection establishment Connected Inquiry Paging

22. ID Packet with inquiry Access Code Randome delay before response Inquiry and Paging Master Slave Start inquiry Inquiry scan FHS Packet Inquiry result Inquiry complete

23. Page packet ID packet FHS packet ID packet POLL NULL Inquiry and Paging Master Slave Page Page Scan Slave Page Response Master Page Response Uses FHS to get CAC and clk info Assigns active addr Connected Connected

24. Slave1 Slave1 Master Slave1 Slave1 Piconets and Scatternets • Bluetooth unit can communicate with other units, by forming a piconet • One unit of a piconet is defined as the master (the unit that establishes the piconet), the others units are called slaves • One piconet consists of 1 master and up to 7 slaves

25. Piconets and Scatternets • A group of piconets in which connections consists between different piconets is called a scatternet • A unit cannot be the master in different piconet, since the master determines the property of a piconet A scatternet example

26. Bluetooth Applications • Three-in-one Phone • Ultimate Headset • Automatic Synchronizer • Internet Bridge • Interactive Conderence • Indoor positioning

27. Conclusions • Bluetooth eliminates the need for numerous and inconvenient cable attachments for devices • Bluetooth enables the design of low-power, small-sized, low-cost radios that can be embedded in existing (portable) devices • The Bluetooth technology will be built into hundreds of millions of electronic devices in 2005 • Commpared with 802.11 and HomeRF

28. Transmition type SCO ACL SCO ACL SCO Master Slave1 Slave2 Slave3