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Comment by jsjohnst | Hacker News Reader

I’ve done a lot of prototyping with LTE, GPRS, LTE-M, and NB-LTE chipsets (along with having previously worked for a Bluetooth tracker company) and I think this article is making a false conclusion. The terrible battery life of these example products is much more caused by the power devouring GPS or a lack of adequate battery capacity in these products than by the LTE-M chipset.

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If you think so, you've to state what the power use was of the chipsets you've used.

For example the well-known nRF51: https://devzone.nordicsemi.com/f/nordic-q-a/1657/how-to-mini.... It can be as low as 20 uA. Between advertisements 4 uA.

Er, what relevance does BLE power consumption have to LTE-M, NBIOT, etc.?

Mmm. That's the thesis of the article?

"This mobile tracker is seemingly designed to resemble a popular Bluetooth tracker and sports a LTE-M radio and GPS receiver. But as mentioned here and here, a leopard can’t change its spots."

They try to be as low power as a Bluetooth tracker, but they just can't. It will never be actually low power.

One (or a few) crappily implemented products doesn’t prove a point to me. As I’m bound by NDA on my prototypes, but I’ll do a little digging for public info I can share.

BLE was included to demonstrate that the convention for "low power" IoT devices is usually expressed in terms of years (of battery life). This is not saying BLE is a LPWAN, but in the minds of customers the expectation, like for LoRa, Sigfox, or active RFID, low power means years of battery life.

Show me a BLE device that has years (plural) of battery life.

https://www.blueupbeacons.com/index.php?page=maxi

On two AA batteries, 10 years. It's plural.

Ok, I partially stand corrected. But let’s get a few facts straight. First, the default config battery life is 4 years, not 10. Anybody can make a device that’s not useful for the intended purpose last forever. That said, the default config is a very reasonable 400ms IBeacon with Nordic chipset and transmit power of -8dbm. The important thing to note is that it’s using 2600mAh AA batteries. That’s not your off the shelf AA, but a very high power version of the AA (roughly 2.6x more energy each). Another important thing to note is it doesn’t do any sensor reading or two way communications, it’s just doing a blip of radio broadcast 2.5x a second. Still true BLE, yes, but also very much comparing apples and oranges to an LTE-M chipset and literally anything you’d do with it.

its down to duty cycle. That figure is the average consumption. I can make most chipsets consume 20uA, its trivial, just don't take them out of hibernation.

LTE-M is a high(well couple of kilobytes per second) bandwidth, full duplex, high duty cycle transport layer. Not only that, its relatively long distance (well kinda)

Bluetooth is short range < 30m, and at high bandwidth shorter range. yes it can be full duplex, but not at low power (I've not validated that claim though) The BLE beacons don't emit a location every 4 seconds, they also don't have a GPS on all the time eating 35mah.

Lora has a maximum duty cycle of something like 5% (ie it has to be not transmitting 95% of the time) not only that, its not designed for realtime two way communications, It's niche is a sensor reporting the state of a sensor every n minutes.

You won't be able to achieve the BLE figures with cellular technology. (Even without GPS. )

You just basically say so by explaining how much higher the bandwidth is.

The thesis of the author of this article still stands. It's not just GPS.

I can, if I don't turn it on, which is where the 20uA figure comes from, keeping the device in hibernation

Exactly. Duty cycle is something we had to be very aggressive about even on the BLE side.

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