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Bluetooth. Bluetooth. Basic idea: cable replacement Forget Plug and Play - just Play 1Mbps(Sync), 723kbps(Async) 2.4GHz ISM band 3 voice channels 8 participants in a piconet Introduced by Ericsson Laboratory Bluetooth SIG Serve as the baseline of IEEE 802.15.1 standard for WPAN.
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Bluetooth • Basic idea: cable replacement • Forget Plug and Play - just Play • 1Mbps(Sync), 723kbps(Async) • 2.4GHz ISM band • 3 voice channels • 8 participants in a piconet • Introduced by Ericsson Laboratory • Bluetooth SIG • Serve as the baseline of IEEE 802.15.1 standard for WPAN
Application Examples Bluetooth
Landline Cable Replacement Data/Voice Access Points Personal Ad-hoc Networks Bluetooth Application Domains Bluetooth
Share the same FHS using slotted TDD Ad Hoc Networking Piconet Scatternet
freq 2.402 2.480 master slave time Radio Parameters • FHSS over 79 channels of width 1MHz • 2.402 + k MHz, k = 0, …, 78 • Modulation: GFSK • Transmit power • 0 dBm ~ 20 dBm (provided power control)i.e.) 1 mW ~ 100 mW • Link range: 0.1 ~ 10m, (~100m, 20 dBm) Bluetooth
Slave may transmit in a slot When master has polled the slave (ACL link) When a master sends a broadcast packet in the preceding slot When the slave alrready has a reservation for that slot (SCO link) master t f(2k) f(2k+1) f(2k+2) 0-2745b 72b 54b slave t 625ms packet header payload access code Packet Transmission: FH/TDD Channel Bluetooth
Power management Active mode Sniff mode: slave listens only at fixed interval Hold mode: does not support ACL packets, but performs scanning, paging, inquiring, or attending another piconet Park mode: gives up active member, however, stays synchronized to the channel Links ACL: asynchronous CL link for data comm. Packet switched p-t-p, p-t-mp SCO: synchnonous CO link for voice comm. P-t-p symmetric Support QoS master active slave parked slave standby Operational States
RF Layer Baseband Layer FH selection: (clock, address) FH sequence piconet creation MAC procedures Link Manager Link setup (ACL/SCO) Link control/configuration Power mgmt/Authentication L2CAP HL protocol multiplexing Segmentation/reassembly QoS management RFCOMM: Serial port emulation TCS: telephony control Protocol Stack
L2CAP layer connection-oriented channels and connectionless broadcast to piconet transport services for framed asynchronous and isochronous data Upper baseband layer Link Manager operates LM protocol includes Device Manager and Resource Manager transport services for unframed synchronous and isochronous data Lower baseband layer Link controller operating LC protocol packet assembly/disassembly Bluetooth Architecture Update - Core
Upper Baseband Layer • Link Manager • manages [logical] links • also manages (creates, modifies, destroys) logical channels and physical links • uses the LM protocol to communicate with peer link manager • interacts with device manager and resource controller • Device Manager • scanning, paging and inquiring operations • names, link keys, addresses, other local data • Baseband Resource Manager • contains the scheduler that allocates time to each operation and meets QoS commitments • contains a resource model to check and agree to QoS settings (traffic admittance control)
L2CAP - Functional Block • Channel Manager • manages the creation of L2CAP channels when requested by application creates/modifies/destroys baseband logical links (when required) to support different L2CAP channel types • negotiates QoS requirements with local link manager and remote channel manager • L2CAP Resource Manager • may check submitted traffic conforms to traffic flow specification agreed when channel created • manages potential limited buffering in Bluetooth Controller schedules (orders) PDU submission to baseband
Physical channel Characterized by timing and RF carrier hopping/occupancy Identified additionally by channel access code Physical link Represents a point-to-point RF connection between two devices May be active or parked Physical Channel and Link
Logical Channel Basic transports for data traffic between connected devices Different logical channels have behaviour suitable for data being transported such as flow control, acknowledge/repeat mechanisms and scheduling requirements Identified by LCID (logical channel identifier) field in packet header (p.k.a. AM_ADDR) Logical Link Some logical channels can support more than 1 type of traffic stream ACO can carry LMP and L2CAP logical link traffic may be interleaved subject to shared ARQn schemes Logical links defined to distinguish LMP messages, L2CAP frames (and possibly others in the future) Identified by LLID (logical link identifier) field in payload header (p.k.a. L_CH field) Logical Channel and Link