Bluetooth® Classic is implemented in most mobile phones and laptops to enable wireless headset connectivity or connectivity between mobile phones and other devices for synchronization. Most new cars already offer Bluetooth® enabled in-car entertainment (ICE) systems and handsfree calling systems.
Bluetooth® is a frequency hopping spread spectrum system that works in the internationally available ISM bands at 2.4 GHz. The initial goal of Bluetooth® Classic is a data connection up to 700 kbit/s in an ad hoc network. The data connection is based on a protocol stack profile such as audio, file transfer or streaming that allows a complete single-device design. Bluetooth® specification 2.0 implemented an enhanced data rate (EDR) of up to 3 Mbit/s.
| Basic rate | Extended data rate | |
|---|---|---|
| Spectrum | 2.4 GHz ISM band | 2.4 GHz ISM band |
| Number of channels | 79 | 79 |
| Channel spacing | 1 MHz | 1 MHz |
| Interference avoidance | Adaptive frequency hopping spread spectrum (1600 hops/s over max. 79 channels) | Adaptive frequency hopping spread spectrum (1600 hops/s over max. 79 channels) |
| Error detection/correction | FEC | FEC |
| Advertizing | Advertizing sequence | Advertizing sequence |
| Audio support | YES (advanced audio distribution profile, handsfree profile, handsfree audio gateway profile) | YES (advanced audio distribution profile, handsfree profile, handsfree audio gateway profile) |
| Header modulation | GFSK (160 kHz deviation) | GFSK (160 kHz deviation) |
| Data modulation | GFSK (160 kHz deviation) | π/4-DQPSK or 8DPSK |
| Max. data rate | 1 Mbit/s | 3 Mbit/s |
Developers of Bluetooth® enabled devices use ready-to-go chipsets or modules for easy integration of Bluetooth® connectivity into their device. However, each device design is slightly different. There are several factors in the final design that may influence the overall communications performance, such as antenna design, power supplies, other wireless communications chips or the final housing.
Therefore, it is necessary to test each Bluetooth® enabled device to verify the required performance and to ensure conformance with Bluetooth® SIG standards and regulatory requirements, especially since Bluetooth® operates in the unlicensed spectrum and has to interwork with other radio technologies using the same spectrum. Testing of Bluetooth® RF performance and quality can be quite easy.
Test setup for Bluetooth® Classic audio testing in signaling mode with the R&S®CMW wireless communication tester
