Bluetooth® Classic - BR/EDR

Bluetooth® Classic - BR/EDR

Overview of Bluetooth® Classic

Bluetooth® Classic is a frequency-hopping spread spectrum (FHSS) system that streams data in the 2.4 GHz ISM frequency band. The initial target was proving low-power data connection with up to 700 kbit/s in an ad hoc network using protocol stack profiles such as audio, file transfer or streaming. Bluetooth® Classic is implemented in most mobile phones and laptops to enable wireless connectivity between different devices. Most new cars also offer Bluetooth®-enabled in-car entertainment (ICE) system and hands-free calling systems.

In addition to Bluetooth® basic rate (BR), Bluetooth® enhanced data rate (EDR) was introduced with Bluetooth® specification 2.0. EDR provides a faster data rate, supporting up to 2-3 Mbit/s, depending on the used modulation.

Bluetooth® Classic vs. Bluetooth® Low Energy

Bluetooth® Classic radio, or Bluetooth® BR/EDR, supports wireless point-to-point communication. It has become the standard radio used by headphones, wireless speakers and ICE systems as well as for hands-free calling applications. Despite the successful introduction of Bluetooth® Low Energy (Bluetooth® LE) and especially LE Audio, Bluetooth® Classic will play still an important role, with most devices supporting both Bluetooth® Classic and Bluetooth® LE.

Comparison of Bluetooth® BR and EDR
Comparison of Bluetooth® BR and EDR

For the synchronization and header part of the EDR packets, Gaussian frequency shift keying (GFSK) modulation is adopted, where the GFSK modulation is the same used for the basic rate packets with a bandwidth bit period product (BT) of 0.5 and a modulation index between 0.28 and 0.35. The higher modulation schemes of π/4-DQPSK and 8DPSK are used for the data part of EDR packets as shown below.

Bluetooth® BR vs. EDR
Bluetooth® BR vs. EDR

Bluetooth® Classic supports two transport schemes based on:

  • Synchronous communication-oriented links (SCO), which are used for interactive voice communication
  • Asynchronous communications links (ACL), which are used for packet data and audio/video streaming application

Your Bluetooth® test challenges

Bluetooth® device developers use ready-to-go chipsets or modules for easy integration. However, each device design is slightly different. There are several factors in the final design that may influence overall performance: antenna design, power supplies, other wireless communications chips or the final housing. Therefore, it is necessary to test each Bluetooth® device to verify the performance and ensure conformance with the Bluetooth® Special Interest Group (SIG) standards and regulatory requirements. This is especially important because Bluetooth® operates in the unlicensed spectrum and has to work with other radio technologies that use the same spectrum.

Physical layer testing of Bluetooth® Classic devices

There are several RF testing methods for Bluetooth® Classic devices. Testing can be controlled by a vendor-specific control interface, which is often used for fully automated tests in R&D and production. The Bluetooth® SIG standardized test mode is for BR/EDR device compliance testing. This mode enables Bluetooth® transmitter and receiver testing in both conducted and over-the-air (OTA) setups.

Bluetooth® Classic test mode setup for RF qualification
Bluetooth® Classic test mode setup for RF qualification

When testing, the tester and the implementation under test (IUT) form a Bluetooth® piconet, where the tester acts as the central device and has full control over the test sequence via a control interface using the link management protocol (LMP). The IUT acts as peripheral and is set at the beginning via an IUT specific local interface in test mode (TM) for security reasons.

Typical Bluetooth® physical layer test items comprise transmitter tests that cover transmit power, power density spectrum, spurious emission or modulation accuracy, as well as receiver tests for sensitivity or blocking performance.

Example Bluetooth® BR physical layer measurements with the R&S FSW-K8
Example Bluetooth® BR physical layer measurements with the R&S FSW-K8

This is also reflected in the test cases specified by the Bluetooth® SIG for RF qualification as shown on the table below.

RF test suite vs. EDR RF test suite
RF test suite vs. EDR RF test suite

When evaluating the performance of applications such as audio streaming, data transfer or hands-free calling, it is useful to have a fully functional Bluetooth® connection between the tester and DUT along with the possibility of applying related profiles, e.g., A2DP for audio streaming or the hands-free profile (HFP) for interactive speech communication.

High-performance solutions for Bluetooth® Classic testing

Test and measurement solutions from Rohde & Schwarz support Bluetooth® BR, EDR and LE in line with the latest Bluetooth® core specifications for design, certification and production. This is complemented by our comprehensive portfolio for digital design, low-power application and OTA testing.

The R&S®CMW wireless communications test platform supports Bluetooth® up to version 5.x. It covers the Bluetooth® Classic test mode, as specified by Bluetooth® SIG, and offers full stack signaling function and a comprehensive test automation tool.

Bluetooth® test functions are also available for all major Rohde & Schwarz test and measurement instruments, including signal generators and signal analyzers. These products support Bluetooth® as well as other non-cellular and cellular standards.

Want to discuss your specific Bluetooth® test cases with our experts?

Bluetooth® Classic test solutions

R&S®SMBV100B vector signal generator

State-of-the-art signal generation for Bluetooth® BR/EDR and Bluetooth® LE 5.x

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R&S®FSV3000 signal and spectrum analyzer

Fast measurements for Bluetooth® BR/EDR/LE - from R&D all the way to production

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R&S®CMW270 wireless connectivity tester

RF tester approved by the Bluetooth® SIG for Bluetooth® BR/EDR/LE testing up to version 5.4

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R&S®TS8997 regulatory test system for wireless devices

Leading platform for regulatory testing in ISM bands based on ETSI and FCC

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R&S®CMW100 communications manufacturing test set

Ultra-compact non-signaling tester optimized for production lines

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R&S®CMW-Z10 shielded box

Perfect for OTA testing of Bluetooth® devices - excellent shielding effectiveness

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Bluetooth® classic Knowledge+

Application note: From cable replacement to the IoT - Bluetooth® 5.1

Summary of various Bluetooth® technologies with a focus on the physical layer

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Application note: Bluetooth® adaptive frequency hopping on R&S®CMW

Description of adaptive frequency hopping mechanism for improved signaling performance

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Application brochure: Bluetooth® testing with the R&S®CMW

In-depth guide to Bluetooth® technology and testing Bluetooth® devices with the R&S®CMW500

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Application note: Advanced Bluetooth® RF Tests with R&S®CMWrun

Document on the common setups and required configurations for advanced Bluetooth® RF tests

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Application card: Conducted multistandard in-device coexistence testing

Short guide on RF coexistence testing for automotive infotainment systems

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