Bluetooth Radio ScopeBluetooth devices operate in the unlicensed 2.4 GHz ISM (Industrial Scientific Medical) band. A frequency hop transceiver is applied to combat interference and fading. Two modulation modes are defined. A mandatory mode, called Basic Rate, uses a shaped, binary FM modulation to minimize transceiver complexity. An optional mode, called Enhanced Data Rate, uses PSK modulation and has two variants: π/4-DQPSK and 8DPSK. The symbol rate for all modulation schemes is 1 Ms/s. The gross air data rate is 1 Mbps for Basic Rate, 2 Mbps for Enhanced Data Rate using π/4-DQPSK and 3 Mbps for Enhanced Data Rate using 8DPSK. For full duplex transmission, a Time Division Duplex (TDD) scheme is used in both modes. This specification defines the requirements for a Bluetooth radio for the Basic Rate and Enhanced Data Rate modes. Frequency Bands and Channel ArrangementThe Bluetooth system operates in the 2.4 GHz ISM band. This frequency band is 2400 - 2483.5 MHz. The 79 RF channels are ordered from channel number 0-78 and are spaced 1 MHz beginning at 2402 GHz. | Regulatory Range | RF Channels | | .400-2.4835 GHz | f=+k MHz, k=0,…,78 |
In order to comply with out-of-band regulations in each country, a guard band is used at the lower and upper band edge.
| Lower Guard Band | Upper Guard Band | | 2 MHz | 3.5 MHz |
Transmitter Characteristics
Power
Class | Maximum Output
Power (Pmax) | Nominal
Output Power | Minimum
Output Power* | Power Control | | 1 | 100 mW (20 dBm) | N/A | 1 mW (0 dBm) | Pmin<+4 dBm to Pmax
Optional: Pmin** to Pmax | | 2 | 2.5 mW (4 dBm) | 1 mW (0 dBm) | 0.25 mW (-6 dBm) | Optional:
Pmin** to Pmax | | 3 | 1 mW (0 dBm) | N/A | N/A | Optional:
Pmin2** to Pmax |
1. * Minimum output power at maximum power setting.
** The lower power limit Pmin<-30dBm is suggested but is not mandatory, and may be chosen according to application needs.
Power class 1 devices implement power control. The power control is used for limiting the transmitted power over +4 dBm. Power control capability under +4 dBm is optional and could be used for optimizing the power consumption and overall interference level.
Devices with power control capability optimizes the output power in a physical link with LMP commands (see Link Manager Protocol). It is done by measuring RSSI and reporting back if the transmission power shall be increased or decreased if possible.
Modulation CharacteristicsThe Modulation is GFSK (Gaussian Frequency Shift Keying) with a bandwidthbit period product BT=0.5. Spurious EmissionsIn-band spurious emissions shall be measured with a frequency hopping radio transmitting on one RF channel and receiving on a second RF channel; this means that the synthesizer may change RF channels between reception and transmission, but always returns to the same transmit RF channel. There will be no reference in this document to out of ISM band spurious emissions; the equipment manufacturer is responsible for compliance in the intended country of use. Radio Frequency ToleranceThe transmitted initial center frequency shall be within ±75 kHz from Fc. Enhanced Data RateA key characteristic of the Enhanced Data Rate mode is that the modulation scheme is changed within the packet. The access code and packet header, as defined in Table 6.1 in the Baseband Specification, are transmitted with the Basic Rate 1 Mbps GFSK modulation scheme, whereas the subsequent synchronization sequence, payload, and trailer sequence are transmitted using the Enhanced Data Rate PSK modulation scheme. EDR Modulation CharacteristicsDuring access code and packet header transmission the Basic Rate GFSK modulation scheme is used. During the transmission of the synchronization sequence, payload, and trailer sequence a PSK type of modulation with a data rate of 2 Mbps or optionally 3 Mbps is used. Receiver Characteristics
Sensitivity LevelThe actual sensitivity level is defined as the input level for which a raw bit error rate (BER) of 0.1% is met. The receiver sensitivity shall be below or equal to –70 dBm with any Bluetooth transmitter Interference PerformanceThe interference performance on Co-channel and adjacent 1 MHz and 2 MHz shall be measured with the wanted signal 10 dB over the reference sensitivity level. For interference performance on all other RF channels the wanted signal shall be 3 dB over the reference sensitivity level. Out-of-Band BlockingThe out-of-band suppression (or rejection) shall be measured with the wanted signal 3 dB over the reference sensitivity level. The interfering signal shall be a continuous wave signal. The BER shall be ≤ 0.1%. Intermodulation CharacteristicsThe reference sensitivity performance, BER = 0.1%, shall be met under the following conditions: - The wanted signal shall be at frequency f0 with a power level 6 dB over the reference sensitivity level.
- A static sine wave signal shall be at a frequency f1 with a power level of –39 dBm.
- A Bluetooth modulated signal (see Section 4.1.7 on page 43) shall be at f2 with a power level of -39 dBm.
Enhanced Data Rate
EDR Actual Sensitivity LevelThe actual sensitivity level shall be defined as the input level for which a raw bit error rate (BER) of 0.01% is met. The requirement for a Bluetooth π/4-DQPSK and 8DPSK Enhanced Data Rate receiver shall be an actual sensitivity level of –70 dBm or better. The receiver shall achieve the –70 dBm sensitivity level with any Bluetooth transmitter compliant to the Enhanced Data Rate transmitter
specification. EDR BER Floor Performance
The receiver shall achieve a BER less than 0.001% at 10 dB above the reference sensitivity level. Interference PerformanceThe interference performance for co-channel and adjacent 1 MHz and 2 MHz channels shall be measured with the wanted signal 10 dB above the reference sensitivity level. On all other frequencies the wanted signal shall be 3 dB above the reference sensitivity level.
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