Document:
SHARKY - User’s Guide
2020/07/20
3. System Overview
3.1.
BLE Technology Overview
Bluetooth Low Energy (BLE) is the main feature of the Bluetooth specification v4.0 released
in December 2009. BLE is a new protocol that allows for long-term operation of Bluetooth
devices that transmit low volumes of data. BLE enables smaller form factors, better power
optimization, and the ability to operate on a small power cell for several years.
The classic Bluetooth specification defines a uniform structure for a wide range of devices
that connect to each other. Bluetooth operates primarily using ad hoc piconets. A master
device controls up to seven slaves per piconet; the slaves communicate with the master
device but they do not communicate with each other. However, a slave device may
participate in one or more piconets, essentially a collection of devices connected via
Bluetooth. A summary of classic Bluetooth topology with multiple piconets, called scatternet,
can be found below.
Figure 1. Bluetooth Scatternet topology
In a BLE topology, the slaves each communicate on a separate physical channel with the
master. Unlike a classic Bluetooth piconet, where all slaves listen for incoming connections
and therefore need to be on constant standby, a BLE slave invites connections and so is in
total control of when to consume power. A BLE master, which is assumed to have less
power constraints, will listen for advertisements and make connections on the back of an
advertisement packet. A diagram of this can be found below.
Doc: UG_MDX-STWBx, Rev 1.6
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