Bluetooth Architecture

Thu Dec 29 15:31:51 CST 2022

Bluetooth Architecture

The HCI architecture for Bluetooth will have the following architectures.

1_HCI-Bluetooth-Architecture

BT Controller: refers to the Bluetooth chip, including BR/EDR chip (Bluetooth 2.1), AMP chip (Bluetooth 3.0), LE chip (Bluetooth 4.0)

BT Host: refers to the Bluetooth protocol stack

HCI architecture for Bluetooth

2_HCI-architecture-for-Bluetooth

The architecture is divided into 4 layers: HW / Transport / HOST / APP.

HW Layer

Here is the Bluetooth chip layer, which contains the following parts.

(1) RF (RADIO): RF layer, the local Bluetooth data sent to the remote device through RF, and receive data from the remote Bluetooth device through RF

(2) BB (BASEBAND): baseband layer, the RF signal and digital or voice signal conversion, to achieve the baseband protocol and other underlying connectivity protocols.

(3) LMP (LINK MANAGER PROTOCOL): link management layer, responsible for managing the communication between Bluetooth devices, to achieve the establishment of the link, verification, link configuration and other operations

(4) HCI (HOST CONTROLLER INTERFACE): host controller interface layer, HCI layer in the chip as well as the protocol stack, the chip level HCI is responsible for the data of the protocol stack to do processing, converted to the chip internal action, and receive data from the remote end, through the HCI reported to the protocol stack.

(5) BLE PHY: the physical layer of BLE

(6) BLE LL: Link layer of BLE

TRANSPORT Layer

Interaction between HOST and CONTROLLER in hardware interface (UART/USB/SDIO)

H2: USB transport

H4: UART transport (is the simplest UART transport, just add a type in front of HCI raw data, as follows HCI has a total of five kinds of HCI data)

● HCI COMMAND: the command sent to the chip by the Bluetooth protocol stack       

● HCI EVENT: the event reported by the Bluetooth chip to the Bluetooth protocol stack       

● HCI ACL: the common data that the Bluetooth protocol stack interacts with the Bluetooth chip in both directions       

● HCI SCO: audio data such as call/speech recognition interacted between Bluetooth chip and Bluetooth stack in both directions       

● HCI ISO (this part is only added in core5.2): the packet format for LE audio

HOST Layer

HOST layer: Bluetooth protocol stack HCI (HOST CONTROLLER INTERFACE): host control layer interface, mainly responsible for sending the data of the protocol stack through the transport to the Bluetooth chip, and accept the data from the Bluetooth chip, the data is mainly divided into HCI COMMAND (HOST->CONTROLLER), HCI EVENT (HOST-CONTROLLER), HCI ACL (HOSTCONTROLLER), HCI SCO.

3_Overview-of-Bluetooth-Lower-Layers



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By HornmicLink_Henry @221229 15:38