Understanding ANT+ Technology: Basics and Applications

This page covers the basic features of ANT+ technology. It explores the ANT and ANT+ network concepts used in M2M and IoT (Internet of Things) applications. ANT is an open-access multicast WSN (Wireless Sensor Network) technology designed, developed, and marketed by ANT Wireless.

It operates in the 2.4 GHz ISM band and is known for its ultra-low power consumption.

ANT+ is the successor to the basic ANT protocol, enhanced with interoperability functionality.

ANT+ is promoted and maintained by the ANT+ Alliance.

ANT+ leverages the benefits of readily available low-power and low-cost transceiver devices.

It supports various network configurations, including peer-to-peer, tree, star, and mesh topologies, as well as network-to-network connections.

It boasts fast over-the-air transfer rates.

ANT and ANT+ network basics in M2M, IoT

ANT Network Basics

An ANT network consists of nodes and channels.

• ANT Nodes: Physical devices
• ANT Channels: Communication channels

Unlike most synchronous networks, which rely on a central node as the master of all nodes, ANT allows master and slave devices to be defined on a per-channel basis.

This means a node can be the master of one channel and the slave of another, providing greater flexibility in the network. A basic ANT channel comprises two nodes: a master and a slave.

The master defines the channel and controls the timings and transmissions.

Let’s break down the communication process within an ANT network:

• Master Transmission: The master must transmit during every channel period.
• Data Repetition: If there’s no new data to transmit, the master simply broadcasts the previous data by default.
• Slave Search and Synchronization: Slave devices, upon opening their channel, immediately begin searching for the master. Once found, the slave stops searching and synchronizes to the master’s transmissions, receiving data every channel period.
• Drift Correction: The slave detects any drift and adjusts its phase to maintain perfect synchronization with the master.
• Collision Avoidance: Similarly, the master device can detect transmissions from other masters in the same space and adjusts its phase to avoid collisions.
• Timing Adjustment: The slave will also detect shifts and adjust its timings to match the master.

This mechanism allows ANT to achieve synchronization and coexistence.

An ANT packet consists of 8 bytes, excluding overhead.

Data is always exchanged from master to slave during each channel period in unidirectional mode.

Slave devices can optionally support data transfer from slave to master in bidirectional mode.

ANT+ utilizes device profiles that specify data formats, channel parameters, and the network key.

Examples of ANT+ device profiles include:

• Heart rate monitor
• Speed and distance monitors
• Bike speed and cadence sensors
• Bike power sensor
• Weight scale (e.g., tracking BMI and percent body fat)
• Fitness equipment data sensors
• Temperature sensor