Ebook

Chapter 5

Bluetooth Connectivity

Bluetooth® is a wireless technology used for exchanging data between devices over short distances. The Bluetooth standard is maintained by the Bluetooth Special Interest Group (SIG).

The Bluetooth Classic standard specifies two PHY modes: Basic Rate (BR) and Enhanced Data Rate (EDR). In addition, the more recent Bluetooth Low Energy (LE) standard focuses on applications in the healthcare, fitness, security, smart building, and home entertainment industries. Bluetooth design challenges exist in the areas of transceiver chip design, coexistence modeling, mesh networking performance, RF design, and localization performance.

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Waveform Generation and Link Simulation

To enable transceiver testing, Bluetooth engineers must have standards-based waveforms available. MathWorks Bluetooth® Toolbox provides waveform generation capabilities for all possible Bluetooth variants, whether BR, EDR, or LE.

Bluetooth LE Waveform Generation and Visualization

Those same Bluetooth engineers must also assess BER/PER performance of end-to-end links in the presence of RF impairments and interference. They must also account for path loss in office, factory, and outdoor environments.

End-to-End Bluetooth LE PHY Simulation Using Path Loss Model, RF Impairments, and AWGN
Visualization of Bluetooth LE waveform, showing spectral analysis, constellation diagram, and eye diagram.

App-based Bluetooth LE waveform generation.

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Coexistence Modeling

Since Bluetooth and WLAN systems operate in the same 2.4 GHz frequency band, they must coexist with each other. Bluetooth designers must develop adaptive frequency hopping (AFH) algorithms that can avoid interference from the much wider bandwidth WLAN signals. To effectively model these systems, they must simulate both the physical layer and the MAC layer.

Noncollaborative Bluetooth LE Coexistence with WLAN Signal Interference

Also, when Bluetooth systems include more than one peripheral node, the central node must schedule network communications to optimize quality of service (QoS) metrics like aggregate throughput, latency, and packet delivery ratio.

Spectrum and spectrogram of Bluetooth-WLAN coexistence prior to Bluetooth adaptive frequency hopping.

Spectral view of Bluetooth-WLAN coexistence.

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Localization

Bluetooth is now one of many wireless technologies that can provide localization, or positioning, services. It competes with 5G, WLAN, and ultra-wideband (UWB) in this arena. Localization solution providers must compare the performance of these disparate systems to make the choice most suited to their use case. Bluetooth device manufacturers must choose appropriate antenna arrays to implement triangulation solutions with angle of departure (AoD) and angle of arrival (AoA) techniques.

Bluetooth LE Direction Finding for Tracking Node Position
Bluetooth LE localization results with three locator nodes and angle of arrival processing.

Bluetooth LE positioning with direction finding.

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