Power consumption of ANT/ANT+ compared to other wireless sensor network technologies

Question

ANT/ANT+ is a proprietary but open access multicast wireless sensor network technology. It's data rate and the resulting application throughput of 20 to 60 kBit/s is significantly reduced compared to its competitors, i.e. Bluetooth and ZigBee. For applications that get along with that restriction and a physical range that is comparable to other wireless network systems it might well be an interesting alternative. It would seem that it is primarily used by sports and fitness sensors by a number of manufacturers.

This Wikipedia page states that:

Geräte benötigen beim Empfang oder Senden weniger als 50 mW Leistung. Da sie die meiste Zeit im Sleep-Mode verharren, ist die Gesamtstromaufnahme gering.

Which roughly translates to:

Devices require less than 50 mW of power when receiving or transmitting. Since they remain in sleep mode for most of the time, the total current consumption is low.

It focuses on ANT being specifically well suited for low power sensor networks with less than 50 mW of power consumption during transmissions and being in sleep mode most of the time.

However, one would expect any battery powered appliance (and even more so devices powered by energy harvesting) making heavy use of deep sleep modes during times of inactivity. I wonder how a "real life" sensor network using ANT would compete against other technologies such as Bluetooth low energy in terms of power consumption?

Answer 1

The ant website has a power estimator which suggests an active 4800 baud connection requires less than 100 uA from a coin cell. I'm not too sure I trust the numbers there though, they look rather optimistic. The page does link some transmit IC data sheets though.

According to this digikey article, the energy per bit is similar between ANT+ and BLE, but I infer reading between the lines that BLE might have a slightly higher protocol overhead for light use than ANT+.

It is likely that other factors will be just as significant in selecting the protocol than just power budget in this case.

Answer 2

The reason you see such a difference between ANT and BLE is the use case is very different for ANT. Sports use cases are looking for data from a "UDP" type of view where they just want the most recent information and don't need to send much information but they need to send it often.

For example, BLE can behave similar to a message based system (as is Zigbee) where you only transmit if you have something to say, ANT does not do that. ANT transmits on period, and if you have nothing new to send, then the radio will send the last message again.

Therefore I would recommend using the radio that best suits your use-case to get the best power consumption.

Note: also ANT+ is simply an application layer overtop of ANT and has little to no effect on power consumption except for defining channel configuration.