Redes Inalámbricas Tema 2.B Wireless PANs: Bluetooth

Redes Inalámbricas Tema 2.B Wireless PANs: Bluetooth Bluetooh Acknowledgments: Foo Chun Choong, Ericsson Research / Cyberlab Singapore, and Open Source Software Lab, ECE Dept, NUS Máster de Ingeniería de Computadores 2008/2009

2 IEEE 802.15 Working Group for WPAN IEEE Std 802.15.1-2002 - 1Mb/s WPAN/Bluetooth v1.x derivative work 802.15.2 - Recommended Practice for Coexistence in Unlicensed Bands 802.15.3-20+ Mb/s High Rate WPAN for Multimedia and Digital Imaging 802.15.3a - 110+ Mb/s Higher Rate Alternative PHY for 802.15.3 802.15.4-200 kb/s max for interactive toys, sensor and automation needs ZigBee

3 Bluetooth Market Installed base of Bluetooth enabled products reached 1 Billion devices in November of 2006. Every week, 13 million Bluetooth units are shipped. (~675 million per year or 21 every second) Every working day, more than five new Bluetooth enabled products are qualified. (~1300 per year) Broad surveys have shown that the Bluetooth brand is recognized by more than 75% of respondents world-wide. (Millward Brown internet survey for Bluetooth SIG: Bluetooth.org)

4 The Bluetooth Wireless Experience Replaces cables connecting portable and/or fixed devices while maintaining high levels of security, Robust, low power, low cost solution, Any Bluetooth enabled device, almost everywhere in the world, can connect to other Bluetooth enabled devices in proximity, Bluetooth enabled devices with common profiles work together to provide a uniform user experience. HEADSET PRINTING TRANSFER MUSIC HID http://bluetooth.com/bluetooth/press/sig/bluetooth_sig_launches_new_program_for_enhanced_visibility_of_ib LUETOOTHI_FUNCTIONALITY.htm

5 Billions of Bluetooth-enabled Devices Motorola expects that over 75% of our mobile phone production will include Bluetooth by 2008. Bluetooth -enabled Device Shipments 2000 1500 1000 500 Other Headsets Handsets 0 2005 2008 2011 Source IMS Sept. 2006

6 Bluetooth Mobile Handset Use Cases Headset and Hands Free Operation in Vehicles Synchronization of Personal Information Moving Digital Images, Video Clips, and Music Remote Access Link for PCs Streaming Music to Other Devices Printing of Digital Images Remote Control of Other Devices Integration with DLNA/UPnP

7 Bluetooth history De facto standard - open specifications. publicly available on Bluetooth.com: http://bluetooth.com/bluetooth/technology/works/ Bluetooth specs developed by Bluetooth SIG. February 1998: The Bluetooth SIG is formed promoter company group: Ericsson, IBM, Intel, Nokia, Toshiba May 1998: The Bluetooth SIG goes public July 1999: 1.0A spec (>1,500 pages) is published December 1999: ver. 1.0B is released December 1999: The promoter group increases to 9 3Com, Lucent, Microsoft, Motorola February 2000: There are 1,500+ adopters Versions: 0.7 0.9 1.0A 1.0B 1.1 November 2003: release 1.2 November 2004: release 2.0+EDR (EDR or Extended Data Rate) triples the data rate up to about 3 Mb/s Currently (July 2007): release 2.1+EDR Next specification (2Q08) will include ability to utilize additional radio technologies to enable high speed Bluetooth applications.

Probably 3.0 The future 8

9 Versions The 1.2 version, unlike the 1.1, provides a complementary wireless solution to co-exist Bluetooth and Wi-Fi in the 2.4 GHz spectrum without interference between them. uses the technique "Adaptive Frequency Hopping (AFH), which runs a more efficient transmission and a more secure encryption. offers voice quality (Voice Quality - Enhanced Voice Processing) with less noise, and provides a faster configuration of communication with other Bluetooth devices within range of reach. Version 2.0, created to be a separate specification, mainly incorporates the technique "Enhanced Data Rate (EDR) that allows you to improve transmission speeds up to 3Mbps while trying to solve some errors specification 1.2.

10 Release 2.1 Near Field Communication (NFC) Technology NFC may also be used in the new pairing system, enabling a user to hold two devices together at a very short range to complete the pairing process. Lower Power Consumption Reduced power consumption means longer battery life in devices like mice and keyboards. Bluetooth Specification Version 2.1 + EDR can increase battery life by up to five times. Improved Security For pairing scenarios that require user interaction, eavesdropper protection makes a simple six-digit passkey stronger than a 16-digit alphanumberic character random PIN code. Improved pairing also offers "Man in the Middle" protection that in reality eliminates the possibility for an undetected middle man intercepting information.

11 Bluetooth Power Class Table Power Class Max Output Power Max Output Power Expected Range Range in Free Space Class 1 100mW 20dBm 42m 100m Class 2 2.5mW 4dBm 16m 50m Class 3 1mW 0dBm 10m 30m

12 Bluetooth RF (physical layer) The Bluetooth RF (physical layer) operates in the unlicensed ISM band at 2.4GHz. The system employs a frequency hop transceiver to combat interference and fading, and provides many FHSS carriers. RF operation uses a shaped, binary frequency modulation to minimize transceiver complexity. The symbol rate is 1 Megasymbol per second (Msps) supporting the bit rate of 1 Megabit per second (Mbps) or, with Enhanced Data Rate, a gross air bit rate of 2 or 3Mb/s. These modes are known as Basic Rate and Enhanced Data Rate respectively.

13 Bluetooth Network Topology Bluetooth devices have the ability to work as a slave or a master in an ad hoc network. The types of network configurations for Bluetooth devices can be three. Single point-to-point (Piconet): In this topology the network consists of one master and one slave device. Multipoint (Piconet): Such a topology combines one master device and up to seven slave devices in an ad hoc network. Scatternet: A Scatternet is a group of Piconets linked via a slave device in one Piconet which plays master role in other Piconet. M S i) Piconet (Point-to- Point) S S S M S ii) Piconet (Multipoint) Master/Slave M M S S S S iii) Scatternet S The Bluetooth standard does not describe any routing protocol for scatternets and most of the hardware available today has no capability of forming scatternets. Some even lack the ability to communicate between slaves of one piconet or to be a member of two piconets at the same time.

14 Bluetooth Protocol Stack Composed of protocols to allow Bluetooth devices to locate each other and to create, configure and manage both physical and logical links that allow higher layer protocols and applications to pass data through these transport protocols SDP Applications IP RFCOMM Data Transport Protocol Group Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao L2CAP Audio Link Manager Baseband RF

15 Transport Protocol Group (contd.) Radio Frequency (RF) Sending and receiving modulated bit streams Baseband Defines the timing, framing Flow control on the link. Link Manager Managing the connection states. Enforcing Fairness among slaves. Power Management Logical Link Control & Adaptation Protocol Handles multiplexing of higher level protocols Segmentation & reassembly of large packets Device discovery & QoS Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao The Radio, Baseband and Link Manager are on firmware. The higher layers could be in software. The interface is then through the Host Controller (firmware and driver). The HCI interfaces defined for Bluetooth are UART, RS232 and USB. BLUETOOTH SPECIFICATION, Core Version 1.1 page 543

16 Middleware Protocol Group Additional transport protocols to allow existing and new applications to operate over Bluetooth. Packet based telephony control signaling protocol also present. Also includes Service Discovery Protocol. SDP Applications IP RFCOMM Middleware Protocol Group Service Discovery Protocol (SDP) Means for applications to discover device info, services and its characteristics. TCP/IP Network Protocols for packet data communication, routing RFCOMM Cable replacement protocol, emulation of serial ports over wireless network Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao Data L2CAP Audio Link Manager Baseband RF

17 Application Group Application Group Consists of Bluetooth aware as well as un-aware applications. SDP Applications IP RFCOMM Data Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao L2CAP Audio Link Manager Baseband RF

18 Bluetooth stack: short version Applications RFCOMM SDP L2CAP HCI Link Manager Baseband RF

19 End to End Overview of Lower Software Layers to Transfer Data BLUETOOTH SPECIFICATION, Core Version 1.1 page 544

20 Time-Division Duplex Scheme Bluetooth devices use a Time-Division Duplex (TDD) scheme Channel is divided into consecutive slots (each 625 s) One packet can be transmitted per slot Subsequent slots are alternatively used for transmitting and receiving Strict alternation of slots b/t the master and the slaves Master can send packets to a slave only in EVEN slots Slave can send packets to the master only in the ODD slots Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao

21 Frequency Hop Spread-Spectrum Bluetooth channel is represented by a pseudo random hopping sequence through the entire 79 RF frequencies Nominal hop rate of 1600 hops per second Channel Spacing is 1 MHz Area USA Europe Spain France Japan Frequency Band (GHz) 2.400-2.4835 2.400-2.4835 2.445-2.475 2.4465-2.4835 2.471-2.497 Bluetooth Channels 79 79 23 23 23 Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao

22 SCO (Synchronous Connection-Oriented) payload types Bluetooth offers two types of links: Synchronous connection-oriented link for classical telephone (voice) connections: HV (High quality Voice), DV (Data and Voice) Asynchronous connectionless link for typical data applications: DM1 (Data Medium rate) and DH3 (Data High rate) with 3 slots payload (30) HV1 audio (10) FEC (20) HV2 audio (20) FEC (10) HV3 DV audio (10) audio (30) header (1) payload (0-9) 2/3 FEC CRC (2) (bytes)

23 ACL (Asynchronous connectionless Link) Payload types payload (0-343) header (1/2) payload (0-339) CRC (2) DM1 header (1) payload (0-17) 2/3 FEC CRC (2) DH1 header (1) payload (0-27) CRC (2) (bytes) DM3 DH3 header (2) payload (0-121) 2/3 FEC header (2) payload (0-183) CRC (2) CRC (2) DM5 header (2) payload (0-224) 2/3 FEC CRC (2) DH5 AUX1 header (2) payload (0-339) header (1) payload (0-29) CRC (2)

24 Baseband data rates ACL 1 slot 3 slot 5 slot SCO Payload User Symmetric Asymmetric Header Payload max. Rate max. Rate [kbit/s] Type [byte] [byte] FEC CRC [kbit/s] Forward Reverse DM1 1 0-17 2/3 yes 108.8 108.8 108.8 DH1 1 0-27 no yes 172.8 172.8 172.8 DM3 2 0-121 2/3 yes 258.1 387.2 54.4 DH3 2 0-183 no yes 390.4 585.6 86.4 DM5 2 0-224 2/3 yes 286.7 477.8 36.3 DH5 2 0-339 no yes 433.9 723.2 57.6 AUX1 1 0-29 no no 185.6 185.6 185.6 HV1 na 10 1/3 no 64.0 HV2 na 20 2/3 no 64.0 HV3 na 30 no no 64.0 DV 1 D 10+(0-9) D 2/3 D yes D 64.0+57.6 D Data Medium/High rate, High-quality Voice, Data and Voice

25 Multi-slot packets f n f n+1 f n+2 f n+3 f n+4 f n+5 Single slot Three slot Five slot

Symmetric single slot 26 f n f n+1 f n+2 f n+3 f n+4 f n+5 f n+6 f n+7 f n+8 f n+9 f n+10 f n+11 f n+12 Master Slave

27 Mixed Link Example MASTER SCO ACL SCO ACL ACL SCO SCO ACL SLAVE 1 SLAVE 2 SLAVE 3

28 Polling on ACL links Slave is allowed to send only after it has been polled. Master polls slave at least Npoll slots (negotiated). Master may send at will. Polling algorithm is proprietary. POLL Data Master Data Slave Slot time TDD frame

29 Bluetooth Connection States There are four Connection states on Bluetooth Radio: Active: Both master and slave participate actively on the channel by transmitting or receiving the packets (A,B,E,F,H) Sniff: In this mode slave rather than listening on every slot for master's message for that slave, sniffs on specified time slots for its messages. Hence the slave can go to sleep in the free slots thus saving power (C) Hold: In this mode, a device can temporarily not support ACL packets and go to low power sleep mode to make the channel available for things like paging, scanning etc (G) Park: Slave stays synchronized but not participating in the Piconet, then the device is given a Parking Member Address (PMA) and it loses its Active Member Address (AMA) (D,I) I A HB Master H E G Bluetooth Connection States C CF D

30 Hold mode In Hold mode a slave is required to temporarily halt transmission Hold mode is typically used when a Master is establishing a link with a new device Hold time t LMP Hold t

31 Sniff mode In Sniff mode a slave enters a low duty cycle mode of operation but is still an active member of the piconet Master can only transmit after sniff interval Sniff time Sniff time t LMP Sniff t

32 Park mode In Park mode a slave enters a low duty cycle mode of operation and is no longer an active member of the piconet Park time Park time t LMP Park Beacon Beacon t

33 Bluetooth Forming a Piconet Inquiry: Inquiry is used to find the identity of the Bluetooth devices in the close range. Inquiry Scan: In this state, devices are listening for inquiries from other devices. Inquiry Response: The slave responds with a packet that contains the slave's device access code, native clock and some other slave information. Page: Master sends page messages by transmitting slave's device access code (DAC) in different hop channels. Page Scan: The slave listens at a single hop frequency (derived from its page hopping sequence) in this scan window. Slave Response: Slave responds to master's page message Master Response: Master reaches this substate after it receives slave's response to its page message for it. Master Slave Inquiry Page Master Response Connection 1 4 7 2 3 5 6 Inquiry Scan Inquiry Response Page Scan Slave Response Connection Forming a Piconet Procedures

34 Connection State Machine Inquiry Page Standby Connected Transmit data Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao Park Hold Sniff

35 SDP - Service Discovery Focus Service discovery within Bluetooth environment Optimized for dynamic nature of Bluetooth Services offered by or through Bluetooth devices Some Bluetooth SDP Requirements (partial list) Search for services based upon service attributes and service classes Browse for services without a priori knowledge of services Suitable for use on limited-complexity devices Enable caching of service information How it works? Establish L2CAP connection to remote device Query for services Search for specific class of service, or Browse for services Retrieve attributes that detail how to connect to the service Establish a separate (non-sdp) connection to use the service

36 L2CAP packet format L2CAP 16 16 0-65,535 bits Length DCID Payload 72 54 bits Baseband Access Code Header Payload Header Payload CRC

37 Packet Structure 72 bits 54 bits 0-2745 bits 220µs Control packets ID* Null Poll FHS DM1 Access Code Header Payload Guard Voice HV1 HV2 HV3 DV Data/voice packets (136 bits) DM1 DM3 DM5 data DH1 DH3 DH5 (2712 bits) No retries No CRC FEC (optional) Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao Header Data ARQ CRC FEC (optional) CRC

Bluez 38

Interference test 39

Inquiry time 40

Throughput 41

42 Higher protocol layers (1) The operation of higher protocol layers is outside the scope of the IEEE 802.15.1 standard (but included in the Bluetooth SIG standards). The usage of these protocols depends on the specific Bluetooth profile in question. A large number of Bluetooth profiles have been defined. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

43 Higher protocol layers (2) The radio frequency communication protocol RFCOMM enables the replacement of serial port cables (carrying RS-232 control signals such as TxD, RxD, CTS, RTS, etc.) with wireless connections. Several tens of serial ports can be multiplexed into one Bluetooth device. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

44 Higher protocol layers (3) TCP/IP based applications, for instance information transfer using the Wireless Application Protocol (WAP), can be extended to Bluetooth devices by using the Point-to-Point Protocol (PPP) on top of RFCOMM. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

45 Higher protocol layers (4) The Object Exchange Protocol (OBEX) is a session-level protocol for the exchange of objects. This protocol can be used for example for phonebook, calendar or messaging synchronisation, or for file transfer between connected devices. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

46 Higher protocol layers (5) The telephony control specification - binary (TCS BIN) protocol defines the call-control signalling for the establishment of speech and data calls between Bluetooth devices. In addition, it defines mobility management procedures for handling groups of Bluetooth devices. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

47 Higher protocol layers (6) The Service Discovery Protocol (SDP) can be used to access a specific device (such as a digital camera) and retrieve its capabilities, or to access a specific application (such as a print job) and find devices that support this application. OBEX TCP/IP/PPP RS-232 emulation TCS BIN SDP RFCOMM L2CAP layer

48 Usage models A number of usage models are defined in Bluetooth profile documents. A usage model is described by a set of protocols that implement a particular Bluetooth-based application. Some examples are shown on the following slides: File transfer LAN access Wireless headset Cordless (three-in-one) phone.

49 File transfer application Using the file transfer profile: A Bluetooth device can browse the file system of another Bluetooth device, can manipulate objects (e.g. delete objects) on another Bluetooth device, or - as the name implies - files can be transferred between Bluetooth devices. File transfer application OBEX SDP RFCOMM L2CAP

50 LAN access application Using the LAN profile: A Bluetooth device can access LAN services using (for instance) the TCP/IP protocol stack over Point-to- Point Protocol (PPP). Once connected, the device functions as if it were directly connected (wired) to the LAN. LAN access application TCP/IP (e.g.) PPP SDP RFCOMM L2CAP

51 Wireless headset application Using the headset profile: According to this usage model, the Bluetooth-capable headset can be connected wirelessly to a PC or mobile phone, offering a fullduplex audio input Headset application and output mechanism. This usage model is known as the ultimate headset. RFCOMM L2CAP SDP Audio

52 Cordless (three-in-one) phone application Using the cordless telephone profile: A Bluetooth device using this profile can set up phone calls to users in the PSTN (e.g. behind a PC acting as voice base station) or receive calls from the PSTN. Bluetooth devices implementing this profile can also communicate directly with each other. TCS BIN Cordless phone application L2CAP SDP Audio

53 Future of Bluetooth Wireless Technology Expect to ship 2 Billion devices in 2011 Ultra Low Power devices Suitability for high speed applications for digital imaging, music, and video transfer Improved interoperability Bluetooth Wireless Experience Bluetooth Alternate MAC/PHY Approach Bluetooth link used to discover peer device, authenticate, discover capabilities (e.g., 802.11), and initiate operation 802.11 link enabled and used when higher performance required 802.11 link idled when operation completed

54 802.11 Alternate MAC/PHY (AMP) Bluetooth/802.11 combo chips on the market Both technologies in the mobile device Bluetooth in ~50% of mobile phones (500M in 2007) 802.11 only in 20M mobile phones in 2007 Leverage 802.11 in AMP Enable high-speed use cases Create market that will increase Bluetooth+802.11 in mobile devices to more than 50% of TAM by 2010 (~600M devices) Bluetooth market 1B/year by 2009 Current 802.11 market projection only 500M/year by 2009 Linkage with Bluetooth could double 802.11 market by 2010