BLE - Bluetooth Low Energy

What is BLE?

BLE stands for Bluetooth Low Energy. It is a wireless communication protocol designed for low-power, short-range communication, particularly in battery-operated devices like fitness trackers, smartwatches, sensors, and IoT devices.

Why is BLE useful?

  • Consumes very little power, enabling long battery life.

  • Ideal for intermittent data transmission in IoT and wearable devices.

  • Supports small data payloads and quick connection setup.

  • Widely supported in smartphones, tablets, PCs, and embedded devices.

  • Enables secure communication with features like encryption and authentication.

How it works?

  • BLE devices operate in two roles: Central (e.g., phone) and Peripheral (e.g., fitness tracker).

  • The Peripheral advertises its presence; the Central scans and initiates a connection.

  • Once connected, data is exchanged using the GATT (Generic Attribute Profile).

  • BLE operates in the 2.4 GHz ISM band and uses frequency hopping to reduce interference.

  • It supports secure pairing, encryption, and efficient data transfer using small packets.

Where is BLE used?

  • Wearables (smartwatches, fitness bands).

  • Healthcare devices (heart rate monitors, glucose meters).

  • Smart home products (locks, lights, sensors).

  • Industrial IoT (asset tracking, beacons).

  • Automotive applications (keyless entry, tire pressure monitoring).

Which OSI layer does this protocol belong to?

  • BLE spans multiple OSI layers: * Physical Layer (Layer 1) – radio transmission. * Data Link Layer (Layer 2) – includes the Link Layer and L2CAP. * Application Layer (Layer 7) – where profiles like GATT and services reside.

IS BLE Windows specific?

  • No, BLE is not Windows-specific.

  • It is supported on many platforms including Windows, Android, iOS, macOS, and Linux.

IS BLE Linux Specific?

  • No, BLE is not Linux-specific.

  • However, Linux supports BLE via stacks like BlueZ and is commonly used in embedded devices.

Which Transport Protocol is used by BLE?

  • BLE does not use TCP or UDP.

  • It uses its own lightweight transport protocols, such as: * ATT (Attribute Protocol) * L2CAP (Logical Link Control and Adaptation Protocol)

Which Port is used by BLE?

  • BLE does not use traditional IP ports.

  • It uses channels in the 2.4 GHz frequency band: * 3 advertising channels * 37 data channels

Is BLE using Client server model?

  • Yes, BLE uses a client-server model via the GATT profile: * The Peripheral acts as the GATT server, providing data (like sensor readings). * The Central acts as the GATT client, requesting or subscribing to data.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • rfc details

  • setup

  • setup

  • packet details

  • usecases

  • features

  • Reference links