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Bluetooth ad-hoc piconets

Bluetooth ad-hoc piconets. Bluetooth - original. A cable replacement technology 1 Mb/s symbol rate Range 10+ meters Single chip radio + baseband at low power & low price point. Why not use Wireless LANs? - power - cost. What does Bluetooth do for you?. Cable Replacement. Landline.

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Bluetooth ad-hoc piconets

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  1. Bluetoothad-hoc piconets Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.1

  2. Bluetooth - original • A cable replacement technology • 1 Mb/s symbol rate • Range 10+ meters • Single chip radio + baseband • at low power & low price point Why not use Wireless LANs? - power - cost Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.2

  3. What does Bluetooth do for you? Cable Replacement Landline Data/Voice Access Points Personal Ad-hoc Networks “Usage Models” Class Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.3

  4. Bluetooth Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.4

  5. Who is Bluetooth? Harald Blaatand “Bluetooth” II King of Denmark 940-981 • Son of Gorm the Old (King of Denmark) and Thyra Danebod (daughter of King Ethelred of England) This is one of two Runic stones erected in his capital city of Jelling (central Jutland) • This is the front of the stone depicting the chivalry of Harald • Harald controlled Denmark and Norway • Harald thinks mobile PCs and cellular phones should seamlessly communicate Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.5

  6. Bluetooth Working Group History February 1998: The Bluetooth SIG is formed • promoter company group: Ericsson, IBM, Intel, Nokia, Toshiba May 1998: Public announcement of the Bluetooth SIG December 1999: The promoter group increases to 9 • 3Com, Lucent, Microsoft, Motorola November 1999: IEEE802.15 was formed to promote WPANs WPAN: Wireless Personal Area Networks July 2009: There are 10000+ adopters Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.6

  7. Bluetooth Protocol Stack Applications IP SDP RFCOMM Control Data Audio L2CAP Link Manager Single chip with RS-232, USB, or PC card interface Baseband RF Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.7

  8. Bluetooth Radio Specification Applications IP SDP RFCOMM Control Data Audio L2CAP Link Manager Baseband RF Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.8

  9. Radio Spectrum l 12cm 5cm 83.5 Mhz 125 Mhz 2.4 Ghz 5.725 Ghz 2.4835 Ghz 5.785 Ghz 802.11a HiperLan2 802.11b/g Bluetooth Microwave oven Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.9

  10. Bluetooth Radio Link 1Mhz . . . 79 1 2 3 83.5 Mhz • frequency hopping spread spectrum • 2.402 GHz + k MHz, k=0, …, 78 • 1,600 hops per second • GFSK modulation • 1 Mb/s symbol rate • transmit power • 0 dbm (up to 20dbm with power control) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.10

  11. Reliability The hostile ISM band is managed by: Frequency hopping Adaptive power control Short data packets Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.11

  12. Bluetooth Baseband Applications IP SDP RFCOMM Control Data Audio L2CAP Link Manager Baseband RF Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.12

  13. Bluetooth Physical Link m s m • Piconet • Master can connect to 7 slaves • Each piconet has max capacity (1 Mbps) s s s • Point to point link • master - slave relationship • radios can function as masters or slaves Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.13

  14. Piconet Collection of devices connected in an ad hoc fashion One unit acts as master and the others as slaves for the lifetime of the piconet Master determines hopping pattern, slaves have to synchronize Each piconet has a unique hopping pattern Participation in a piconet = synchronization to hopping sequence Each piconet has one master and up to 7 simultaneous slaves (> 200 could be parked) P S S M P SB S P SB M=Master S=Slave P=Parked (can be reactivated within some milliseconds) SB=Standby (not active at all) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.14

  15. Forming a piconet • All devices in a piconet hop together • Master gives slaves its clock and device ID • Hopping pattern: determined by device ID (48 bit, unique worldwide) • Phase in hopping pattern determined by clock • Addressing • Active Member Address (AMA, 3 bit) • Parked Member Address (PMA, 8 bit)    P  S SB  SB  S   SB   M P SB SB    SB  S   SB SB  P  SB SB SB Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.15

  16. Link types ACL – Asynchronous Connection Less Used for all data communication and signalling. A device may keep multiple ACL connections. SCO – Synchrounous Connection Oriented Used for synchrounous voice transmission (Point to Point). Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.16

  17. Bluetooth Packet Format 54 bits 72 bits 0 - 2744 bits Access code Header Payload • Access code: • Synchronization. • Identification. • Header: • AM-ADDR: MAC-address • Type: payload type • Flow: flow control • ARQ: fast retransmit • HEC header Voice Data CRC No CRC No retries ARQ FEC (optional) FEC (optional) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.17

  18. Bluetooth Channel FH/TDD Hopping pattern is decided by the master f4 f1 f5 f3 f2 f6 m s1 s2 625 µsec 1600 hops/sec Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.18

  19. Multislot Packets Data rate depends on type of packet FH/TDD f1 f5 f4 f6 m s1 s2 625 µsec Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.19

  20. Data Packet Types for ACL DM1 108.8 108.8 108.8 258.1 387.2 54.4 DM3 286.7 477.8 36.3 DM5 172.8 172.8 172.8 DH1 390.4 585.6 86.4 DH3 433.9 723.2 57.6 DH5 Symmetric Asymmetric kbps 2/3 FEC Symmetric Asymmetric No FEC kbps Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.20

  21. Link types SCO – Synchrounous Connection Oriented Used for synchrounous voice transmission (Classic telephone (voice)). Connections require symmetrical, circuit switched, point-to-point connections The master reserves two consecutive slots (forward and return slots) at fixed intervals. Using an SCO link, three different types of single-slot packets can be used payload (30) HV1 audio (10) FEC (20) HV2 audio (20) FEC (10) HV3 audio (30) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.21

  22. Physical Link Types ACL SCO ACL SCO ACL ACL SCO SCO ACL SCO SCO ACL • Synchronous Connection Oriented (SCO) Link • slot reservation at fixed intervals • Asynchronous Connection-less (ACL) Link • Polling access method m s1 s2 Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.22

  23. Robustness Slow frequency hopping with hopping patterns determined by a master • Protection from interference on certain frequencies • Separation from other piconets (FH-CDMA) Retransmission • ACL only, very fast Forward Error Correction • SCO and ACL Error in payload (not header!) NAK ACK A C C F H MASTER SLAVE 1 B D E SLAVE 2 G G Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.23

  24. Link Manager Protocol (LMP) Applications IP SDP RFCOMM Control Data Audio L2CAP Link Manager Baseband RF • Setup and management • of Baseband connections • Piconet Management • Link Configuration • Security Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.24

  25. L2CAP Applications IP SDP RFCOMM Audio L2CAP Link Manager Baseband RF Logical Link Control and Adaptation Protocol Data • L2CAP provides • Protocol multiplexing • Segmentation and Re-assembly • Quality of service negotiation Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.25

  26. Profiles Represent default solutions for a certain usage model • Vertical slice through the protocol stack • Basis for interoperability Generic Access Profile Service Discovery Application Profile Cordless Telephony Profile Intercom Profile Serial Port Profile Headset Profile Dial-up Networking Profile Fax Profile LAN Access Profile Generic Object Exchange Profile Object Push Profile File Transfer Profile Synchronization Profile Applications Protocols Profiles Additional Profiles Advanced Audio Distribution PAN Audio Video Remote Control Basic Printing Basic Imaging Extended Service Discovery Generic Audio Video Distribution Hands Free Hardcopy Cable Replacement Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.26

  27. Scatternet Slave 2 Slave 1 Master Slave 3 Master 2 Slave 4/ Master 3 Slave 5 • Scatternet • A set of inter-connected piconets • Some devices participate in more than one piconet • Called Bridging node. • A Bridging nodemay be slave in several piconets but only master in one of its piconets • A Bridging node may only participate in one piconet at a time • Bluetooth unit only has one transceiver • Different frequency hop sequences used for each piconet • Has to switch between piconets on a time division basis • Scatternet scheduling • The task of controlling the presence of Bridging nodes in different piconets Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.27

  28. Scatternet Example PDA mouse Cordless headset Cell phone Cell phone PDA Cell phone Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.28

  29. End Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.29

  30. Example: Power consumption/CSR BlueCore2 Typical Average Current Consumption (1) VDD=1.8V Temperature = 20°C Mode SCO connection HV3 (1s interval Sniff Mode) (Slave) 26.0 mA SCO connection HV3 (1s interval Sniff Mode) (Master) 26.0 mA SCO connection HV1 (Slave) 53.0 mA SCO connection HV1 (Master) 53.0 mA ACL data transfer 115.2kbps UART (Master) 15.5 mA ACL data transfer 720kbps USB (Slave) 53.0 mA ACL data transfer 720kbps USB (Master) 53.0 mA ACL connection, Sniff Mode 40ms interval, 38.4kbps UART 4.0 mA ACL connection, Sniff Mode 1.28s interval, 38.4kbps UART 0.5 mA Parked Slave, 1.28s beacon interval, 38.4kbps UART 0.6 mA Standby Mode (Connected to host, no RF activity) 47.0 µA Deep Sleep Mode(2) 20.0 µA Notes: (1) Current consumption is the sum of both BC212015A and the flash. (2) Current consumption is for the BC212015A device only. (More: www.csr.com ) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.30

  31. Baseband • Piconet/channel definition • Low-level packet definition • Access code • Channel, device access, e.g., derived from master • Packet header • 1/3-FEC, active member address (broadcast + 7 slaves), link type, alternating bit ARQ/SEQ, checksum 68(72) 54 0-2745 bits access code packet header payload 4 64 (4) 3 4 1 1 1 8 bits preamble sync. (trailer) AM address type flow ARQN SEQN HEC Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.31

  32. ACL 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) Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/ MC SS02 7.32

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