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

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? 10 th Century Denmark King 10 th Century Denmark King King Harald united Denmark and Norway. Bluetooth of today will unite the world of computers and telecom 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 Bluetooth Specifications Radio Baseband/Link Controller Link Manager Host Controller Interface L2CAP TCS SDP RFCOMM Applications OBEX WAP AT Commands The Bluetooth protocol stack Bluetooth Module Host

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

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

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

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 … MHz 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

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

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

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

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

24 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 Master Slave1

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 and HomeRF

28 Transmition type Master Slave1 Slave2 Slave3 SCO ACL