LoRa 443MHz benefits
Specification:
LoRa modulation is used
- Multicast/broadcast
- Configurable confirmation modes: with or without ACK
- Configurable bandwidth: 125kHz (lower data rate, longer range) – 500 kHz (higher data rate, shorter range)
- Configurable spreading factor: SF7 (higher data rate, shorter range) – SF12 (lower data rate, longer range)
- Configurable TX power: 2 dBm – 17dBm
- Configurable channels: 15 frequencies, 8 non-overlapping when 125kHz bandwidth is used
- Protocol is optimized for using LoRa without batteries
- Fully European technology – the standard, ICs, final solution
- Filtering possibility for LoRa telegrams
- Listen before talk mechanism for collision avoidance
- Optional statistics data for each received telegram: physical address, RSSI and TX power
- Simultaneous wired and wireless connections (wired – for security sensitive operations to avoid sniffing, brute-force etc.). Transparent bridge mode
- No single point of failure compared to other widely used client-server technologies e.g. LoRaWAN
Data rates
- Best case: SF7 / 500 kHz = 16ms per message (22 kbps)
- Default: SF7 / 125 kHz = 62ms per message (5.5kbps)
- Worst case: SF12 / 125 kHz = 1300ms per message (0.3 kbps)
- 2x increase in bandwidth provides 2x less air time
- SF+1 takes approximately 2x more air time compared to previous SF
Why 443MHz?
- 4x longer distance than 868 MHz
- 433 MHz is less crowded than 868 MHz used by other technologies like Zwave, EnOcean etc.
- Much lower mobile network interference
- Much better wall penetration
- Lower signal dissipation in atmosphere – less energy is needed for transmission of the same amount of data compared to 868 MHz (increasing the frequency by 2x increases losses by 4x)
Universal technology
- Most other technologies are not universal and are designed for either long-range LPWAN networks or short range e.g. BLE
- Type of priority – range, bit rate, energy (battery drain) can be freely adjusted depending on project needs
- Statistics data can be used to check signal levels. Channel Energy reserve is always known and can be increased by lowering bandwidth, increasing spreading factor or increasing TX power
Visual indicators
- Each device has LED indicators for RX/TX activity. This is very important for installers to be able to perform diagnostics without additional tools
- Statistics application provides a visual representation of signal levels for all received radio telegrams
Security based on ChaCha20
- More advanced than AES128 encryption
- The implementation reference for ChaCha20 has been published in RFC 7539; proposed standardization of its use in TLS is published as RFC 7905; use of ChaCha20 in IKE and IPsec have been proposed for standardization in RFC 7634
- Widely used in operating systems, VPN protocols and Internet security (e.g. Google’s implementation secures https (TLS/SSL) traffic between the Chrome browser on Android phones and Google’s websites)
- https://en.wikipedia.org/wiki/Salsa20
Regulatory compliance
Nonspecific short range device allowance in Europe*
| Frequency Band | ERP | Duty Cycle | Channel Bandwidth |
|---|---|---|---|
| 433.05-434.79 MHz | +10dBm | <10% | No limits |
| 433.05-434.79 MHz | 0dBm | No limits | No limits |
| 433.05-434.79 MHz | +10dBm | No limits | <25kHz |
* http://www.ti.com/lit/an/swra048/swra048.pdf