RF Host protocols
This chapter presents the protocols used to connect a Tap with a remote device:
- RF protocols are normally used for mobile devices (smartphone, tablets, PC)
- Wired protocols (UART) can be used in production (for mass configuration of Taps).
The RF protocols managed by some IoTize products are:
- NFC (Near Field Communication)
- BLE (Bluetooth Low Energy)
NFC is a convenient way to:
- Select the target system,
- Wake up a 'sleeping' target,
- Launch the associated app (stored in the NFC tag or your Tap),
- Securely initiate pairing authentication and encryption mechanisms.
It is available on most recent Android and the latest iOS mobile devices. The 'NFC only' solution is not very convenient (the short distance must be kept for the whole exchange). It is cheap and fully acceptable for 'one-time' configuration (or an unfrequent usage).
BLE (without NFC)
BLE (Bluetooth Low Energy) is the best way to communicate locally with a device:
- Range is between 20m and 60m,
- Low power solution,
- Available on most mobile devices: Android, iOS and Windows (Windows 10).
- Data transfer rate depends on the mobile device (OS, settings, ...) with a maximum of about 2 kilobytes per second.
NFC can be considered as the 'perfect companion' for BLE and is used:
- To select the correct device,
- To wake up the target system,
- To avoid a permanent radio emission and thus reduce overall consumption,
- To launch (or retrieve) an app,
- To start BLE to continue the communication,
- To secretly exchange the keys required to secure the subsequent BLE exchanges.
The NFC provides a so called 'out of band' channel for BLE.
Wi-Fi is now well-known. If both BLE and Wi-Fi use a 2.4 GHz band, there are several differences:
- Wi-Fi is generally dedicated to TCP-IP,
- Range, data rate (and Power) are higher for Wi-Fi.
Our Wi-Fi modules support two modes:
- 'Access point' (or 'hotspot'), when they can serve several mobile devices. This mode is very similar to BLE.
- 'Station', when they are clients connected to an existing network. This provides a permanent connection to servers if the module is connected to the Internet through a local network.
LoRaWAN is a protocol based on the LoRa (Long Range) technology. LoRa provides another way to connect the module 'almost permanently' to the internet. It requires a network infrastructure (gateway) but this gateway could be quite far away (typically 10-20km). We generally distinguish between private networks (inside a plant for example) and public networks (that work as mobile phone networks).
RF protocol comparison
The following table shows the pros and cons of each solution:
|NFC-only||Secure, convenient for selection and wake-up, cheap, low power (possible energy harvesting)||Must stay in short range|
|NFC-BLE||The cons of each solution are fixed by the combination||No permanent connection (no effective alarm)|
|NFC-WiFi||Permanent connection in station mode (if the network infrastructure provides an internet access)||Consumption and radio waves. The client must be connected to the same network|
|NFC-BLE-LoRa||Good combination to take advantage of the low, medium and long range||The LoRa connection is quite slow (low bitrate)|
The UART port is used in production. You will find more information on UART host protocol here.