ANT +

Today, the two main dominant trends are the development of wearable electronics and the Internet of things. Fitness trackers and smart watches are conquering the world, and completely ordinary and simple in their purpose household devices acquire unprecedented opportunities and their own IP. Previously, the fact of connecting to a network attracted us, and the development of gadgets was subordinated to the idea of ​​improving communication methods. Today, a new era is beginning: we are turning into centers of tiny networks named after ourselves. We begin to surround ourselves with devices that register our physical condition, movement in space and type of activity, creating round-the-clock logs of our being. Our homes are gradually being filled with appliances and devices that can (and should) be controlled remotely and centrally. As a result, the smartphone will become increasingly important as a center, where information flows from various trackers, sensors, smart bulbs and other numerous high-tech satellites. Obviously, in these conditions a certain generally accepted communication protocol is needed. And one of the most promising applicants for this role is the ANT + protocol implemented in YotaPhone 2.

What is ANT +

This is a proprietary protocol designed to communicate with sensors in the near field. Mainly:

• heart rate sensors
• speed sensors
• pedometers
• calorie counters
• blood pressure sensors
• Libra,
• temperature sensors and much more.

For this, a mobile device (smartphone, tablet, smartwatch, cycle computer, etc.) must be equipped with a wireless module that supports transmission via ANT + protocol. In YotaPhone, the WCN3680 chip from Qualcomm is responsible for this. Data is transmitted at a frequency of 2.4 GHz, in the ISM band (Industrial, Scientific, Medical - industrial, scientific, medical), while using the same bandwidth as that of Bluetooth. The communication radius of the ANT + protocol is an average of 30 m.

ANT + is an adaptive synchronous protocol. An ANT + network consists of logical connections between two nodes. Within each connection, one node is master, and the other is slave. However, the same slave can be master with respect to another node with which it makes a different logical connection. In an ANT network, any node can connect to any node.



The logic of the ANT protocol in Android:

Comparison with Bluetooth

Given the overall frequency and bandwidth, what is the difference between ANT + and Bluetooth?

• Different package structure.
• Different number of channels: ANT + - 83 (WCN3680 chip supports 79), Bluetooth Low Energy - 40.
• Different channel spacing: ANT + - 1 Hz, Bluetooth LE - 2 Hz.
• Different reception ranges: ANT + - 30 m, Bluetooth LE - 50 m.

However, all these differences do not answer the question: why is ANT + needed if there is Bluetooth? It's all about power consumption. In this regard, ANT + shows good results: some mobile devices can work for about a year on a single battery charge. If you compare ANT + and Bluetooth Smart, then:

• They have the same energy consumption in sleep and active modes.
• ANT + consumes less when advertising a service.
• ANT + consumes less when scanning and initiating a communication session.
• ANT + requires fewer transactions for each phase of the communication session.
• When sending one data volume, ANT + sends less additional information.

The energy savings for each of these items are not great, but in total there is more than a significant difference: ANT + is 25-50% more energy efficient than Bluetooth Smart.

This protocol also has a number of other advantages. For example, due to the different network topology, ANT + allows you to implement much more custom connection scenarios. In addition, the ANT + service for Android allows you to simultaneously run several independent applications using the same communication module.

Conclusion

Despite the propriety of the protocol itself, the number and composition of external devices connecting to the gadget is unlimited. Is that the number of radio frequency channels. That is, you can simultaneously receive information from a variety of sensors, depending on the task at hand. At the moment, this mainly applies to sports and physical activity, but with the development of the Internet of things, we can expect a significant expansion of the range of connected devices. For example, now ANT + allows you to control music playback, receive information from gas and torque sensors on a motorcycle, as well as navigation data from GPS devices.