BLE Advertising is one of the most important aspects of Bluetooth Low Energy. Understanding how to properly use advertisements can help you lower your power consumption, speed up your connections, and improve reliability. We’re going to go over how they work and how to use them.
Bluetooth Smart has two ways of communicating. The first one is using advertisements, where a BLE peripheral device broadcasts packets to every device around it. The receiving device can then act on this information or connect to receive more information. The second way to communicate is to receive packets using a connection, where both the peripheral and central send packets. We will focus on advertisement for several reasons:
- You can’t create a connection between two devices without using advertisements. Defining the data and format of advertisement packets is usually the first thing you work on when developing a BLE device.
- A large number of BLE products sleep most of the time, waking up only to advertise and connect when needed. This means advertisements have a big impact on power consumption.
- Users want responsive products, and the advertising interval is critical in quick connections.
Advertising is by design unidirectional. A Central device can’t send any data to the Peripheral device without a connection. But a single peripheral can advertise to multiple masters in the area.