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Prof. Dr.-Ing. Jochen Schiller, SS027.1 Bluetooth ad-hoc piconets.

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Presentation on theme: "Prof. Dr.-Ing. Jochen Schiller, SS027.1 Bluetooth ad-hoc piconets."— Presentation transcript:

1 Prof. Dr.-Ing. Jochen Schiller, SS027.1 Bluetooth ad-hoc piconets

2 Prof. Dr.-Ing. Jochen Schiller, SS027.2 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

3 Prof. Dr.-Ing. Jochen Schiller, SS027.3 What does Bluetooth do for you? Personal Ad- hoc Networks Cable Replacement Usage Models Class

4 Prof. Dr.-Ing. Jochen Schiller, SS027.4 Bluetooth

5 Prof. Dr.-Ing. Jochen Schiller, SS027.5 Who is Bluetooth? Harald Blaatand Bluetooth II King of Denmark 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

6 Prof. Dr.-Ing. Jochen Schiller, SS027.6 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: IEEE was formed to promote WPANs WPAN: Wireless Personal Area Networks July 2009: There are adopters

7 Prof. Dr.-Ing. Jochen Schiller, SS027.7 Bluetooth Protocol Stack RF Baseband Audio Link ManagerL2CAP Data SDP RFCOMM IP Single chip with RS-232, USB, or PC card interface Control Applications

8 Prof. Dr.-Ing. Jochen Schiller, SS027.8 Bluetooth Radio Specification RF Baseband Audio Link Manager L2CAP Data Control SDP RFCOMM IP Applications

9 Prof. Dr.-Ing. Jochen Schiller, SS027.9 Radio Spectrum 125 Mhz Ghz Ghz a HiperLan Mhz 2.4 Ghz Ghz b/g Bluetooth Microwave oven 12cm 5cm

10 Prof. Dr.-Ing. Jochen Schiller, SS Bluetooth Radio Link 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)... 1Mhz Mhz

11 Prof. Dr.-Ing. Jochen Schiller, SS Reliability The hostile ISM band is managed by: 1. Frequency hopping 2. Adaptive power control 3. Short data packets

12 Prof. Dr.-Ing. Jochen Schiller, SS Bluetooth Baseband RF Baseband Audio Link Manager L2CAP Data Control SDP RFCOMM IP Applications

13 Prof. Dr.-Ing. Jochen Schiller, SS Bluetooth Physical Link Point to point link – master - slave relationship – radios can function as masters or slaves ms s s m s Piconet –Master can connect to 7 slaves –Each piconet has max capacity (1 Mbps)

14 Prof. Dr.-Ing. Jochen Schiller, SS 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) M=Master S=Slave P=Parked (can be reactivated within some milliseconds) SB=Standby (not active at all) M S P SB S S P P

15 Prof. Dr.-Ing. Jochen Schiller, SS 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) SB M S P S S P P

16 Prof. Dr.-Ing. Jochen Schiller, SS 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).

17 Prof. Dr.-Ing. Jochen Schiller, SS Access code: –Synchronization. –Identification. Header: –AM-ADDR: MAC-address –Type: payload type –Flow: flow control –ARQ: fast retransmit –HEC Bluetooth Packet Format 72 bits 54 bits bits Access code Header Payload DataVoice CRC No CRC No retries header ARQ FEC (optional)

18 Prof. Dr.-Ing. Jochen Schiller, SS Bluetooth Channel m s1s1 s2s2 625 µsec f1 f2 f3 f hops/sec f5 f6 FH/TDD Hopping pattern is decided by the master

19 Prof. Dr.-Ing. Jochen Schiller, SS Multislot Packets m s1s1 s2s2 625 µsec f1 f4 f5 f6 FH/TDD Data rate depends on type of packet

20 Prof. Dr.-Ing. Jochen Schiller, SS Data Packet Types for ACL DM1 DM3 DM5 DH1 DH3 DH5 2/3 FEC No FEC SymmetricAsymmetric SymmetricAsymmetric kbps

21 Prof. Dr.-Ing. Jochen Schiller, SS 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) audio (30) audio (10) HV3 HV2 HV1 FEC (20) audio (20)FEC (10)

22 Prof. Dr.-Ing. Jochen Schiller, SS Physical Link Types m s1s1 s2s2 SCO Synchronous Connection Oriented (SCO) Link –slot reservation at fixed intervals Asynchronous Connection-less (ACL) Link –Polling access method SCO ACL

23 Prof. Dr.-Ing. Jochen Schiller, SS 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 MASTER SLAVE 1 SLAVE 2 ACCHF GG BDE NAKACK Error in payload (not header!)

24 Prof. Dr.-Ing. Jochen Schiller, SS Link Manager Protocol (LMP) RF Baseband Audio Link Manager L2CAP Data Control SDP RFCOMM IP Applications Setup and management of Baseband connections Piconet Management Link Configuration Security

25 Prof. Dr.-Ing. Jochen Schiller, SS L2CAP Logical Link Control and Adaptation Protocol L2CAP provides Protocol multiplexing Segmentation and Re-assembly Quality of service negotiation RF Baseband Audio Link ManagerL2CAP Data SDP RFCOMM IP Applications

26 Prof. Dr.-Ing. Jochen Schiller, SS 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 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 Profiles Protocols Applications

27 Prof. Dr.-Ing. Jochen Schiller, SS Scatternet –A set of inter-connected piconets –Some devices participate in more than one piconet –Called Bridging node. –A Bridging node may 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 Master Slave 1 Slave 2 Slave 3 Master 2 Slave 4/ Master 3 Slave 5

28 Prof. Dr.-Ing. Jochen Schiller, SS Scatternet Example PDA Cell phone Cordles s headset Cell phone PDA Cell phone mouse

29 Prof. Dr.-Ing. Jochen Schiller, SS End

30 Prof. Dr.-Ing. Jochen Schiller, SS 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

31 Prof. Dr.-Ing. Jochen Schiller, SS 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 access codepacket headerpayload 68(72) bits AM addresstypeflowARQNSEQNHEC bits preamblesync.(trailer) 464(4)

32 Prof. Dr.-Ing. Jochen Schiller, SS ACL Payload types payload (0-343) header (1/2)payload (0-339)CRC (2) header (1)payload (0-17)2/3 FEC header (1)payload (0-27) header (2)payload (0-121)2/3 FEC header (2)payload (0-183) header (2)payload (0-224)2/3 FEC header (2)payload (0-339) DH5 DM5 DH3 DM3 DH1 DM1 CRC (2) (bytes)


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