We get a lot of questions about our technology. How does it work? How can I take it to use? How does it compare to other technologies? We put together a series of blogs to help you out.
In this first blog we answer questions on hardware and especially in relations to Bluetooth Low Energy (BLE) hardware.
Does Wirepas support BLE?
Wirepas Mesh does run on BLE chips, such as the nRF52 product family from Nordic Semiconductor and the EFR32 product family from Silicon labs. We share the same physical layer as the BLE hardware. However, Wirepas Mesh overwrites the Bluetooth firmware, still keeping the ability to transmit and receive BLE Beacon messages.
Is this a BLE Mesh?
This is a great question. To put it simply, it is not. It’s something much more advanced.
Unlike most mesh connectivity technologies, BLE Mesh does not use routing. It is a so-called flooding mesh, based on repeaters that repeat messages they hear from devices in the network. And those repeaters need to be mains powered as they consume a lot of power.
These limitations are acceptable for example for pure wireless lighting control where devices are mains powered and switch command is broadcast to all devices, but they make it completely unsuitable for sensor networks bigger than 100 devices. Let’s explain.
BLE has an inbuilt BLE Beacon advertisement, designed for devices to find each other, and make a pair. This same pairing functionality has been repurposed in the BLE Mesh: there are devices that are advertising beacons like low power sensors and devices receiving and repeating beacon messages including data. To ensure the message is heard at least by someone, the devices repeat the same message typically three times in three channels. In the end, data might also reach a gateway.
When there are many BLE mesh repeater devices in one building, they all impact interference to others. Why? Because communication is not synchronized, and devices are transmitting at the same time. This is a bit like when many people shout words in the room simultaneously, you might pick up a word here and there.
The problem increases in use cases like occupancy sensoring. Sensors need to transmit movement data over the network. There is no routing, sensor transmit BLE beacon opportunistically with full power to maximize possibility to repeaters to receive a signal. In case there are 1000 repeaters in the network, basically all of these devices will receive this one sensor message at least once. One BLE beacon transmission is becoming thousands of transmissions. When there are 100 sensors transmitting data continuously, it means over 100.000 repeats to deliver one change of a status of each sensor. The more messages, the more interference and lower the throughput.
BLE Mesh was never designed for these kind of use cases. With careful design, it is possible to have less repeaters in the network and limit hop count per message when beacon message is not travelling to all 1000 repeaters in the networks. Hop count limit leads to islands of devices which all need to have their own gateway. These methods require network planning.
With Wirepas Mesh, the firmware has both adaptive routing and adaptive flooding. This means that the network itself is intelligent to make the right decisions how to carry the message through the network to the gateway. And it can handle tens of thousands of devices in one network without any issue.
In battery operated sensor networks each device extending the coverage also means that there is no wired or additional wireless infrastructure required with the Wirepas Mesh. This is a big difference to a BLE Mesh where the continuous BLE beacon scanning demands mains power for the repeaters. In BLE Mesh you need to build infrastructure to include mains powered repeaters which is costly.
Can I run Wirepas on my existing device?
Wirepas Mesh runs on BLE chips. Your hardware is compatible with Wirepas Mesh if your product includes any of the following System on Chip (SoC) components:
- The nRF52 product family from Nordic semiconductor including chips nRF52832, nRF52840 or nRF52833.
- The EFR32 product family from Silicon labs including components EFR32BG12, EFR32bg21 or EFR32bg22.
There is a great variety of wireless modules including SoC components compatible with Wirepas Mesh. You can find them all on the Wirepas partner product site.
On top of this, a low power operation requires a 32kHz crystal to maintain high accuracy of the communication. The low latency mode of Wirepas Mesh designed for mains powered applications like LED drivers, do not require a 32kHz crystal. In case your product does not include the chips or modules we would recommend you consider redesigning a new hardware version.
From an application software point of view, your application today is most probably developed with the silicon vendor Software Development Kit (SDK). This means that you would need to port your application on the Wirepas SDK. For more information on that, please visit the Wirepas GitHub.
In the next ‘you ask – we answer’ blog we will answer technical questions on the Wirepas performance.