Bluetooth
PreviousIEEE 1905.1 standard, Convergent Digital Home Network for Heterogeneous TechnologiesNextPiconets
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Access mostly to “transported devices”.
No dominant need for Information Technologies.
No physical access to cabled networks.
No need for large communication rates.
Very low cost system required.
Consumer electronics integration is mandatory.
Target deployment environment: communication of personal devices working together.
Short-range.
Low Power.
Low Cost.
Small numbers of devices.
Sometimes have more “bus-like” characteristics.
PAN Standards
Bluetooth – Industry consortia.
IEEE 802.15.1 – ”Bluetooth” based.
IEEE 802.15.2 – Interoperability and coexistence.
IEEE 802.15.3 – High data rate WPAN (UWB).
IEEE 802.15.4 – Low data rate WPAN (Zigbee,...).
IEEE 802.15.5 – Mesh Networks.
IEEE 802.15.6 – Body Area Network.
Originally for replacing “USB”, not “Ethernet”.
Cable replacement technology.
Later also used as Internet connection, phone, or headset.
Created by Ericsson.
PAN - Personal Area Network.
Up to 1 Mbps connections.
Includes synchronous, asynchronous, voice connections.
Piconet routing.
Small, low-power, short-range, cheap, versatile radios.
Master/slave configuration and scheduling.
Introduced in Bluetooth v2.0 to support faster data transfer.
Supports a data rate up to 3 Mbps.
Using reduced duty cycle control (time radio is ON), EDR can provide lower power consumption.
BT HS was released in April 2009 (in Bluetooth version 3.0+HS).
Bluetooth 3.0+HS provides data transfer speeds of up to 24 Mbps, though not over the Bluetooth link itself:
BT link is used for negotiation and establishment, and the high data rate traffic is carried over a collocated 802.11 link.
HS part of the specification is not mandatory in BT 3.0.
Only devices that display the "+HS" logo actually support Bluetooth over 802.11 high-speed data transfer.
Radio network, on the 2.4 GHz, world-wide!
Airplane friendly!
FH (Frequency Hopping) spread spectrum:
79 (23 - .jp .es .fr) channels (de 2.402GHz - 2.480GHz).
Defines a master that synchronizes everyone to his hop-pattern.
Defines two types of networks:
piconets.
scaternets.
Maximum 8 devices per piconet (1 master + 7 slaves).
Transmission rate: 720 Kb/s (max), assymetrical variable.
Signal broadcast over a seemingly random series of frequencies.
Receiver hops between frequencies in sync with the transmitter.
Each frequency has the bandwidth of the original signal.
Dwell time is the time spent using one frequency.
Spreading code determines the hopping sequence.
Must be shared by the sender and receiver (e.g. standardized).
Eavesdroppers hear unintelligible blips.
Jamming on one frequency affects only a few bits.
Typically a large number of frequencies are used.
Improved resistance to jamming.
Global architecture for low power.
Hold and Park mode: 60 μA current.
Connected device, but not operating.
Device operates after a 2 ms wait process.
In Hold: keeps its AMA (Active Member Address); in Park has to free AMA, and later has to claim it back.
Transmission power ~1mW.
100mW classes also exist.
Standby Current < 0.3 mA.
3 months.
Voice mode: 8-30 mA.
75 hours.
Data mode (medium): 5 mA (0.3-30mA, 20 kbit/s, 25%).
120 hours.
