How much do you know about Bluetooth's core technologies such as system, protocol, and architecture?

Jacktang

How much do you know about Bluetooth's core technologies such as system, protocol, and architecture? [Copy link]

Bluetooth system composition

1. Radio unit (Radio): responsible for sending and receiving data and voice, characterized by short distance and low power consumption. Bluetooth antennas are generally small in size and light in weight, and are microstrip antennas. 2. Baseband or link control unit (LinkController): performs mutual conversion between RF signals and digital or voice signals, and implements baseband protocols and other underlying connection procedures. 3. Link management unit (LinkManager): responsible for managing the communication between Bluetooth devices, and implementing operations such as link establishment, verification, and link configuration. 4. Bluetooth software protocol implementation: as shown in the purple part of the above figure, we will explain this in detail later. Related specifications for low-power Bluetooth

Bluetooth protocol composition 1. Bluetooth protocol architecture

The protocols in the Bluetooth protocol system are divided into four layers according to the degree of attention of SIG:

1. Core protocols: BaseBand, LMP, L2CAP, SDP; 2. Cable replacement protocol: RFCOMM; 3. Telephone transmission control protocol: TCS-Binary, AT command set; 4. Optional protocols: PPP, UDP/TCP/IP, OBEX, WAP, vCard, vCal, IrMC, WAE. In addition to the above protocol layers, the specification also defines the host controller interface (HCI), which provides a command interface for the baseband controller, connection manager, hardware status and control registers. In Figure 1, HCI is located at the lower layer of L2CAP, but HCI can also be located at the upper layer of L2CAP. The Bluetooth core protocol consists of Bluetooth-specific protocols developed by the SIG. Most Bluetooth devices require the core protocol (plus the wireless part), while other protocols are determined according to the needs of the application. In short, the cable replacement protocol, telephone control protocol and adopted protocol constitute application-oriented protocols based on the core protocol. The Bluetooth protocol stack allows for multiple methods, including RFCOMM and Object Exchange (OBEX), to send and receive files between devices. If you want to send and receive streaming data (and want to take a traditional serial port application and add Bluetooth support to it), then RFCOMM is better. Conversely, if you want to send object data along with context and metadata about the payload, then OBEX is best. The Bluetooth application activity diagram is as follows

wtuedu

I've learned it! But which version is this?

star_66666

I don't know much, come and learn

懒猫爱飞

Thanks for sharing. This should be the classic version. The Bluetooth used in smart consumer electronics now is generally low-power Bluetooth (BLE)