Frequently Asked Questions
DevEUI is a 64-bit number. It is the unique ID of the end-device.
AppEUI is a 64-bit number. It is the unique ID of the application server and is the destination of the messages sent by the end-devices. It must be unique so that the end-device knows where to send its messages. The AppEUI can be linked to either a single application (unique customer) or to several applications. In this last case, the manufacturer must re-route the messages to its end customers by using the DevEUI.
How to get them:
DevEUI key is linked to the end-device, this means end-device manufacturers should contact the IEEE to get a range of unique identifiers.
AppEUI is usually provided to the end-device manufacturers by the solution providers.
AppKey is a 128-bit key which is used to secure the communication between the source of the message (the end-device) and the destination of the message (the join server). This key is unique for each device and must be know by both sides. It is at the heart of the security and must only be known by the device and the join server. AppKey is never sent over the air and must remain secured over the lifetime of the end-device.
How to get it:
AppKey is typically a randomly-generated number that is programmed into the end-device and simultaneously communicated to the join server, so that it can authenticate the messages from the end-device.
There are currently no signs that this frequency band is being harmonized in Europe, so for now we are sticking to the 865-870 MHz frequency band.
There are some technical differences between LoRaWAN and alternative LPWAN technologies which enable a much broader set of applications to be addressed from a bi-directional connectivity, adaptive data rate and end point class perspective, but the key differentiator is the ecosystem, the Certification Program and standardization. If you look at successful technology adoption over the past 10 years all have followed this model. Having different business models, competition, and a diverse ecosystem with industry leaders is the only way to scale volume and deployments. An open standard is also a proven strategy to get acceptance and wide deployment versus proprietary technology, the choice of the various network components; gateways, end-devices, cloud network servers along with chips, development kits and end products from many different suppliers offers a low risk strategy for potential operators or end users.
Last but not least LoRaWAN protects data and privacy like no other LPWAN, it is the most secure solution available in the market with AES 128 encryption on multiple levels for all data from sensor to application server and back.
There is no such concept as a LoRa gateway or LoRaWAN gateway. A LoRa gateway can be connected to a LoRaWAN network server, in other words a server running LoRaWAN protocol, or to another server running another protocol. In fact, only gateways with eight channels or more are considered LoRaWAN-capable.
If I set the LoRa spreading factor to 7 and bandwidth to 500 kHz, could Channel Activity Detection (CAD) detect the preamble of a LoRa signal with spreading factor set to 7 and bandwidth to 125 kHz?
No, it may marginally pick up, but in principle the bandwidth and spreading factor must be coherent for the Channel Activity Detection (CAD) to work.
The following data shows the impedance of the two antennas on the SX1280 development kit, with the impedance matching. Here we see in excess of 16 dB of return loss which is good for a portable antenna.
The figure below shows a representation of the antenna system diversity performance, based upon the measured antenna S Parameters. (Based upon the method of Blanch et al). Here the red threshold indicates poor diversity performance, black acceptable diversity performance and green good, i.e. useful, antenna diversity performance.
The final plots show the simulated radiation patterns of the two diversity antennas. The pattern corresponding to the highlighted antenna (with the pattern in the same orientation as the board image).
Semtech provides full API documentation on the core elements of the solution such as the decryption and the solver. This makes it simple to provide the fully integrated scalable solution.
Final validation of a product will often require certified approval from an international or regional regulation office (typically ETSI, FCC or ARIB depending on the region).
One of the tests required is the Continuous Wave radio test (also called Tx-Cw) which is described in another article.
Another test requires setting the radio in continuous modulated signal to measure the spectral occupation taken by the radio signal when transmitting packets. To this aim, it is often required for the radio to transmit pseudo-random binary PN9 or PN15 payloads. There is no easy way to perform this test and the only solution is to create the payloads on the companion MCU and then send the packets one by one, with a different PNx sequence generated from the MCU. Here, care must be taken in the time between packets which will have an influence on the spurious emissions generated by the PA ramp-up and down in quick succession.
What does the software solution consist of, what files are included and what checks are run on the source code ?
Source code lists are available to licensees. Other items made available are test routines, procedures and scripts for hardware and software. Test results are provided within the test reports provided to the licensee.
There is not a lot of field data available on different types of antenna yet. All field trials to-date have been conducted with 5dBi omni-directional antennas. Trials have been executed with the two diversity antennas placed in different polarizations and it was found that two vertical antennae spaced at one meter horizontally were significantly better than placing one horizontally and one vertically. No data is available on using sectored antenna with LoRa location at this time.
The idea behind this test is to measure the output power of a single frequency carrier and measure the potential spurs around this frequency.This test is required for the EN300.220 ETSI validation.
On most of the Semtech FSK transmitters, the simplest way to perform this test is to set the Frequency Deviation of a standard modulated FSK signal to 0 Hz.
The first step is to set the frequency of the continuous wave, as a second step, you will need to set the PA Output (RFO or PA Boost depending on your chipset and implementation). The third step is to set the frequency deviation to 0 .To finish, you need to set the radio in continuous transmit mode. Using a spectrum analyser, you should observe a clean carrier at the frequency entered.
Alternatively, for the SX127x, it is also possible to digitally create a continuous waveform using the internal radio modulator.This method is slightly more obscure as it is using some undocumented registers of the radio.To simplify the work, we have implemented example code for the SX1272 and the SX1276 which are given with the software release for the chipsets.
The examples are located here.
No, LoRa devices can be used like any other RF transceiver in existing applications with custom proprietary protocols. However, using LoRaWAN will significantly improve time to market. The stack, having similarities to 802.15.4, is FCC and ETSI compliant and offers all the security needed by a modern RF protocols (network key, unique Id for each end point, AES128 encryption… ). LoRaWAN also offers the possibility to be used in private AND public networks.
I have an existing RS-232/cellular/ZigBee-based system. Can I just plug in a LoRa Module and get the extra range?
There are changes required at the host interface and specifications for transmitting data in a LoRa system that require changes to the host system software, but with fully integrated modems available in the eco-system, and their well-defined host controller interface, it is actually quite seamless.
The “JoinAccept” message is decrypted by the Application Server (AS) and not the Network Server (NS).
The AS is allowed to see the end-device application data but the NS is not.
The AS exchanges key information with the end-device through the NS (the NS forwards the messages but doesn’t understand them).
At the end of the exchange, when the session keys have been calculated, the AS gives the network session key to the NS.
In Europe LBT+AFA ( Listen-Before-Talk + Adaptive-Frequency-Agility ) is not desired or implemented, however in certain regions LBT is mandated.
The reference design now implements LBT, specifically to be in compliance with regulations in Korea and Japan.
LoRaWAN data rates range for LoRa between 0.3 kbps to 11 kbps, and one GFSK data rate at 50 kbps for Europe. In North America, the minimum data rate is 0.9 kpbs due to FCC rules. To maximize both battery life of the end-devices and overall network capacity, the LoRaWAN network server is managing the data rate and RF output power for each end-device individually by means of an adaptive data rate (ADR) algorithm. The ADR is critical for a high performance network and it enables scalability. A network can be deployed with a minimal investment in infrastructure, and as capacity is needed, more gateways can be deployed and the ADR will shift the data rates higher which will scale the network capacity.
No, LoRaWAN as a protocol is strictly for wide area networks, but LoRa as a lower-level physical layer technology (PHY) can be used in all sorts of applications outside of wide area.
LoRaWAN certification ensures interoperability and compliance with LoRaWAN networks and will be requested by LoRaWAN network carriers. It also entitles the use of the LoRa Alliance Certified logo.
Currently the certification program is for Class A devices at EU region 863-870MHz band.
The certification program for Class B, Class C and Gateway devices has not yet been opened.
The certification program for regions that do not use the EU ISM Band is also still under development. However you may contact Espotel if you are interested in pre-certification testing for devices that do not yet have a certification program.