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6.3 Core Technology Architectures

Modern Bluetooth is not a single technology but a combination of three distinct architectures designed for different use cases. A device can implement one or more of these.

3.1 Bluetooth Classic (BR/EDR)

This is the original Bluetooth protocol, designed for continuous, point-to-point data streaming.

  • Primary Use Case: Audio streaming and data transfer where throughput is more important than power consumption.

  • Topology: It forms a piconet, where a single master device can connect to up to seven active slave devices. The communication is connection-oriented.

  • Strengths: High data throughput (up to 3 Mbps) ideal for high-quality audio or file transfers.

  • Weaknesses: Higher power consumption, making it unsuitable for battery-powered IoT devices.

  • Example Applications: Wireless headphones, speakers, in-car audio systems, legacy file transfers.

3.2 Bluetooth Low Energy (BLE)

BLE was introduced in Bluetooth 4.0 and is the dominant technology for the Internet of Things.

  • Primary Use Case: Short bursts of data from low-power, battery-operated devices.

  • Topology: A central device (like a smartphone) can connect to many peripheral devices (like sensors). It operates by advertising its presence and can form fast, temporary connections to transfer data.

  • Strengths: Extremely low power consumption, allowing for multi-year battery life. Very fast connection setup time.

  • Weaknesses: Lower data throughput than Classic, not designed for continuous streaming.

  • Example Applications: Fitness trackers, smartwatches, environmental sensors, proximity beacons, smart home devices.

3.3 Bluetooth Mesh

Bluetooth Mesh is not a separate radio technology; it's a networking protocol that operates on top of the BLE radio.

  • Primary Use Case: Large-scale device networks requiring reliable, building-wide coverage.

  • Topology: A true mesh network. Devices (or nodes) can relay messages for other nodes, extending the range of the network far beyond the reach of a single device. This creates a many-to-many communication system.

  • Strengths: Enormous scalability (up to 32,000 nodes), high reliability (no single point of failure), and extended range.

  • Weaknesses: Higher latency than a direct BLE connection and is not suitable for high-throughput or streaming applications.

  • Example Applications: Smart lighting systems in commercial buildings, industrial sensor networks for predictive maintenance, asset tracking across a large facility.

3.4 Key Differences: A Summary

Feature Bluetooth Classic (BR/EDR) Bluetooth Low Energy (BLE) Bluetooth Mesh
Primary Use Case Audio Streaming, File Transfer IoT Sensors, Wearables, Beacons Large-Scale Control Networks
Throughput Medium-High (~2.1 Mbps) Low-Medium (~1-2 Mbps) Low
Power Consumption Medium Very Low Low (node-dependent)
Topology Piconet (Master-Slave) Star (Central-Peripheral) Mesh (Node-to-Node)
Connection Time Slower (~100ms) Very Fast (<3ms) N/A (Always on or advertising)
Number of Devices 1 Master to 7 Slaves 1 Central to Many Peripherals Thousands of Nodes in a Network
Example Wireless Headphones Heart Rate Monitor Smart Building Lighting
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