Bluetooth

Idea

 Universal radio interface for ad-hoc wireless connectivity

 Interconnecting computer and peripherals, handheld devices, PDAs, cell  phones – replacement of IrDA

 Embedded in other devices, goal: 5€/device (2005: 40€/USB bluetooth)

 Short range (10 m), low power consumption, license-free 2.45 GHz ISM

 Voice and data transmission, approx. 1 Mbit/s gross data rate

Characteristics

2.4 GHz ISM band, 79 (23) RF channels, 1 MHz carrier spacing FHSS and TDD

Voice link – SCO (Synchronous Connection Oriented)

 Channel 0: 2402 MHz ... channel 78: 2480 MHz

 G-FSK modulation, 1-100 mW transmit power

 Frequency hopping with 1600 hops/s

 Hopping sequence in a pseudo random fashion, determined by a master

 Time division duplex for send/receive separation

 FEC (forward error correction), no retransmission, 64 kbit/s duplex, point-to-point, circuit switched

Data link – ACL (Asynchronous ConnectionLess)

Asynchronous, fast acknowledge, point-to-multipoint, up to 433.9 kbit/s symmetric or 723.2/57.6 kbit/s asymmetric, packet switched

Topology and Overlapping piconets (stars) forming a scatternet