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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. IEEE 802.15 Working Group for WPAN.

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Redes Inalámbricas – Tema 2.B Wireless PANs: Bluetooth

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  1. Redes Inalámbricas – Tema 2.BWireless PANs: Bluetooth Bluetooh Acknowledgments: Foo Chun Choong, Ericsson Research / Cyberlab Singapore, and Open Source Software Lab, ECE Dept, NUS

  2. IEEE 802.15 Working Group for WPAN • IEEE Std802.15.1™-2002 - 1Mb/s WPAN/Bluetooth v1.x derivativework • 802.15.2™- RecommendedPracticeforCoexistence in UnlicensedBands • 802.15.3™ - 20+ Mb/s HighRate WPAN for Multimedia and Digital Imaging • 802.15.3a™ - 110+ Mb/s HigherRateAlternative PHY for 802.15.3 • 802.15.4™ - 200 kb/s maxforinteractivetoys, sensor and automationneeds 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. HEADSET PRINTING TRANSFER MUSIC HID 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. • http://bluetooth.com/Bluetooth/Press/SIG/Bluetooth_SIG_LAUNCHES_NEW_PROGRAM_FOR_ENHANCED_VISIBILITY_OF_IBLUETOOTHI_FUNCTIONALITY.htm

  5. 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 • July 2007: release 2.1+EDR • April 2009: release 3.0+HS

  6. 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.

  7. 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.

  8. Release 3.0 • It supports theoretical data transfer speeds of up to 24 Mbit/s. • Its main new feature is AMP (Alternate MAC/PHY), the addition of 802.11 as a high speed transport. • Two technologies had been anticipated for AMP: 802.11 and UWB, but UWB is missing from the specification. • Alternate MAC/PHY • Enables the use of alternative MAC and PHYs for transporting Bluetooth profile data. The Bluetooth Radio is still used for device discovery, initial connection and profile configuration, however when lots of data needs to be sent, the high speed alternate MAC PHY (802.11, typically associated with Wi-Fi) will be used to transport the data. • And also: • Unicast connectionless data • Read encryption key size • Enhanced Power Control

  9. Bluetooth Power Class Table

  10. M M M Master/Slave S M S S S S S S S S S i) Piconet (Point-to-Point) ii) Piconet (Multipoint) iii) Scatternet 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. 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.

  11. BLUETOOTH SPECIFICATION, Core Version 1.1 page 543 Bluetooth Protocol Stack: Transport Protocol Group • 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 (L2CAP) • Handles multiplexing of higher level protocols • Segmentation & reassembly of large packets • Device discovery & QoS • 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. Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao

  12. IP Control Data Middleware Protocol Group Bluetooth Protocol Stack: 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. Applications SDP RFCOMM Audio L2CAP • 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 Link Manager Baseband RF Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao

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

  14. 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 audio (30) DV audio (10) header (1) payload (0-9) 2/3 FEC CRC (2) (bytes)

  15. 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 header (2) payload (0-121) 2/3 FEC CRC (2) DH3 header (2) payload (0-183) CRC (2) DM5 header (2) payload (0-224) 2/3 FEC CRC (2) DH5 header (2) payload (0-339) CRC (2) AUX1 header (1) payload (0-29)

  16. Channel access • 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

  17. fn fn+1 fn+2 fn+3 fn+4 fn+5 Multi-slot packets Single slot Three slot Five slot

  18. SCO ACL SCO ACL SCO SCO ACL ACL Mixed Link Example MASTER SLAVE 1 SLAVE 2 SLAVE 3

  19. Throughput

  20. A B H C Master D H E I G C F 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) Bluetooth Connection States

  21. Master Slave Inquiry 1 Inquiry Scan 2 Inquiry Response 3 Page 4 Page Scan 5 Slave Response 6 Master Response 7 Connection Connection 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. Forming a Piconet Procedures

  22. Inquiry time

  23. 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

  24. Bluez

  25. 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.

  26. 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

  27. 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 (e.g.) TCP/IP SDP PPP RFCOMM L2CAP

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

  29. Cordless (three-in-one) phone application Using the cordless telephoneprofile: 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. Cordless phone application TCS BIN SDP Audio L2CAP

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