[Bt_books] "Low-power Bluetooth Development Authority Guide" notes (to Be continued)

Brief

This book is from the CSR Bluetooth protocol architect, is the Bluetooth domain Daniel's work, but overall it seems that the book is relatively simple. Summary Basic Concepts Bluetooth Concept

The basic idea of low power consumption is that the connection is transient, and when you need to do something or check it, you can quickly create a connection, finish what you want to do, and then disconnect.
Low power Bluetooth can establish a connection, send data, and gracefully disconnect within approximately 3ms. Load Balancing

Using a single machine to respond to a millions of per day request can result in overload or even service failure. The workaround is to use many of the same servers that have access to the same information. There is also a way to resolve the same domain name to different IP addresses to tell different clients, so that the load evenly distributed on top of each server. Low power Bluetooth architecture

The introduction of this book is still very easy to understand. The low power consumption Bluetooth architecture is divided into three basic parts:
-Controller: Usually a physical device that sends and receives radio signals and knows how to translate these signals into packets carrying information;
-Host: Usually a software stack that manages how the two devices communicate and how to use the radio to provide several different services at the same time;
-Application: Application section, using the software stack to implement user instances. Link Layer

Link Layer, which is the most complex part of BLE, is responsible for broadcasting, scanning, establishing and maintaining connections, and ensuring that packets are organized in the right way, correctly computed checksum values, and cryptographic sequences. It defines three basic concepts: Channel, message, process. HCI Layer

Actually consists of two separate parts:
-Logical interface: Defines command and event and its associated behavior;
-Physical Interface: Defines how command and event and data are transmitted through different connection technologies (USB, SDIO, UART). L2CAP Layer

Fixed channel used: Signaling channel (signal channel), Security Manager channel (SMP), Property Protocol channel (ATT). Controller Link Layer

The link layer is the most complex part of the BLE. Data Whitening

The BLE data is bleached, and the reason is that when the frequency shift keying (FSK) has a poor ability to accept the same bits continuously, albinism reduces the length of the same continuous bit.