|Technical Summary of Bluetooth|
Bluetooth radios operate in the unlicensed ISM band at 2.4 GHz. A frequency hop
transceiver is applied to combat interference and fading. A shaped, binary FM
modulation is applied to minimize transceiver complexity. The gross data rate is
1Mb/s. A Time-Division Duplex scheme is used for full-duplex transmission.
The Bluetooth baseband protocol is a combination of circuit and packet switching.
Slots can be reserved for synchronous packets. Each packet is transmitted in a
different hop frequency. A packet nominally covers a single slot, but can be extended
to cover up to five slots. Bluetooth can support an asynchronous data channel, up to
three simultaneous synchronous voice channels, or a channel which simultaneously
supports asynchronous data and synchronous voice. Each voice channel supports
64 kb/s synchronous (voice) link. The asynchronous channel can support an
asymmetric link of maximally 721 kb/s in either direction while permitting 57.6 kb/s
in the return direction, or a 432.6 kb/s symmetric link.
The Bluetooth air interface is based on a nominal antenna power of 0dBm. The air
interface complies with the FCC rules for the ISM band at power levels up to 0dBm.
Spectrum spreading has been added to facilitate optional operation at power levels
up to 100 mW worldwide. Spectrum spreading is accomplished by frequency
hopping in 79 hops displaced by 1 MHz, starting at 2.402 GHz and stopping at 2.480
GHz. Due to local regulations the bandwidth is reduced in Japan, France and Spain.
This is handled by an internal software switch. The maximum frequency hopping rate
is 1600 hops/s. The nominal link range is 10 centimeters to 10 meters, but can be
extended to more than 100 meters by increasing the transmit power.
- RX sensitivity: -70dBm
- IP3: -16dBm
- CP1dB: -26dBm
- Double-sided IF bandwidth: 1.0MHz
- C/Ico-channel (0.1% BER): 11dB
- C/I1MHz (0.1% BER): -8dB
- C/I 2MHz (0.1% BER): -40dB
- C/IAWGN (0.1% BER): 18dB
- In-band image rejection: 20dB
- Antenna diversity: not required
- TX power:
- nominal: 0dBm
- optional range:-30 - +20dBm
- Modulation index (no ISI): 0.28-0.35
- TX carrier offset: <75kHz
- TX carrier drift in slot: TBD
- Adjacent channel power (1MHz): -20dBm
- Out of band spuriousness: 50dB
- Power control requirements:
- optional range: -30 - +20dB
- Frequency Sources
- Reference timer accuracy: 20ppm
- L500kHz: -89dBc/Hz
- L 2MHz: -121dBc/Hz
- Channel-switching time: 220us
- TX/RX turnaround time: 220us