LoRa Network Server

When asking what is LoRa, you may get several different answer. One thinks it's  essentially the LoRa modulation, giving the extraordinary radio performance. Other one says it's the LoRaWAN protocol, as that is the only well specified part of the system. Third one may consider it's all about the Network Server where all the network management functionality is implemented.

LoRa network architecture. Source: Semtech 

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In LoRa networks, especially when considering public network approach, the Network Server plays central role. Gateway is intended to be a simple packet forwarder and thus being inexpensive part of the system. At the moment there are three network server providers:

• Actility ThingPark  
• IBM LRSC
• Orbiwise UbiQ

Actility is perhaps the leading supplier with most commercial deployments in place at the moment. Espotel recently joined Actility's certification program in order to ensure end-devices are compatible with the ThinkPark back-end.

LoRaWAN certification acknowledged by the LoRa Alliance guarantees interoperability of end-devices with any gateway manufacturer. However, LoRa Alliance  does not specify the interface towards Network Server, thus it is implementation specific. That's why different back-end providers may have their own certification programs, like Actility does.

Kerlink outdoor gateway and LoRaMote test device with IMST LoRa module
as part of ThinkPark certification program content.

The test network is very easy to set up. The supplied gateway is pre-configured to ThingPark and requires no user configuration at deployment, just blug & play. Power-over-Ethernet with provided power injector makes cable installation easy. Only internet connectivity is required. There also exists variant with cellular data modem instead of Ethernet.

Screenshot of ThingPark DeviceManager web interface.

Edit 2015-8-26:
According to the feedback I have received, there are several other Network service providers emerged, including Lace, Loriot, Senetco, and The Things Network. I consider that as positive sign, meaning there are many parties who believe in LoRa technology. The ecosystem is stronger all the time.

Lora Network Coverage

Espotel LoRa network covers most of Espoo populated area with cell diameter of 20 km. Tested performance exceeds initial estimation.

Once the gateway passed solar powered test period, it was erected to it's final position at the highest point at roof-top of Espotel HQ, some 6 meters higher than previously in a more difficult to reach location some 15-20 meters above the ground.

Now more comprehensive network coverage test was performed. The testing focused on uplink performance. Results with distances from the gateway:

• 10 km - Stationary nodes in good position with proper antenna
• 7.5 km - Vehicle mount with external antenna
• 5 km - Indoor coverage with dipole antenna
• 2.5 km - Indoor coverage with integrated antenna

Espotel LoRa network coverage.

The network covers majority of the city of Espoo with more than 90% of it's population. Communication is possibly also in western parts of Helsinki downtown and from tall buildings further away. The map indicates circles with radius of 10km, 7.5km, 5km and 2.5km. 

868 MHz half-wave dipole antenna with magnetic mount at car roof-top.

Testing was performed using standard type 868 MHz half-wave dipole antenna mounted at vehicle roof-top with magnetic mount. Multitech mDot Lora-module was used with default parameter configuration.

Within distance from 7,5 to 10 km it was possible to communicate from car to the gateway every now and then, but in practice the reasonable maximum distance is about 7,5 km due to increased packet-loss ratio while distance increases.

Espotel engineer installing the gateway in it's new location.

First LoRa network now open

Espotel has released first open LoRa network in Finland for developers' and hackers' use.

The first gateway is located at the roof of Espotel HQ in southern Espoo.The network is intended for promoting LoRa RF technology and is open and free of charge for all development and test purposes. The gateway will be open for limited period of time and closed down when commercial public networks are available or winter blocks the energy source of the gateway, which ever comes first.

Solar powered LoRa gateway at the roof of Espotel HQ.

The gateway is solar powered in order to emphasis the low power nature of LoRa RF technology. The gateway has solar cell with 50W nominal power and 75 Ah battery that provides run time of one week without sun. That's necessary as the weather in Finland is often cloudy and there may be number of rainy days in a row.

At the moment the gateway is not at the highest possible location but in easy to access location, due to test run period ongoing to see whether the solar cell capacity is high enough. Even if the sun may shine in Finland up to 24h per day at Summer time, it's most of the time shining from wrong direction to the panel. Motorized panel with 360 degree rotation capability would be needed to utilize the full potential of mid-night sun.

I performed the first signal strength test Today while driving home from the office. With LoRa node in my car, I got signal transmitted some 6 km away from the gateway. The node had +14dBm TX power and quarter-wave dipole antenna. Once the gateway antenna will be erected some 5 more meters after solar cell test run, the initially expected 7 km range is most likely. More detailed network coverage map will be published later.

Location of gateway and most distant location from where signal was detected. 7km radius is marked with blue circle.

The gateway is connected to the internet with 3G/4G cellular data modem, and delivers all received data to IBM IoT Foundation and further to Bluemix. From there the data is available either with WebSocket, HTTP or MQTT interface. Tell me your device details and I'll give you access to your data. Currently only upstream data is supported for simplicity sake.

The gateway conforms with LoRaWAN 1.0 specification and LoRa devices are required to do so. Network key, application key and encryption are not defined, all devices and connections are accepted. If you have a cool project in mind, we may even sponsor you some LoRa hardware. Just contact me by email.

Happy hacking!

Driving global success of the LoRaWAN protocol

LoRaWAN 1.0 draft specification has passed the review period within LoRa Alliance, making it one step closer to ratification. As a LoRa Alliance member and in order to increase public awareness of LoRa RF technology, Espotel will launch an IoT campaign for the rest of the year.

Weatherproof LoRa gateway with Multitech Conduit
in a box and improved 868 MHz antenna.

An open and free of charge LoRa gateway located at the roof of  Espotel HQ in Espoo Finland will play central role within the campaign. The gateway is implemented with Multitech MultiConnect Conduit IoT Gateway with LoRa extension, located inside an IP65 classified plastic chassis for weather resistance and connected to Taoglas Omni-directional Outdoor 868 MHz ISM-band dipole antenna. Multitech Conduit gateway and mDot LoRa module conform with the LoRaWAN 1.0 protocol specification.

Expected network coverage spans over the southern part of the city of Espoo, including Aalto University campus in Otaniemi.

Expected coverage of the Espotel open LoRa network.

Espotel will organize and sponsor events like hackathons and other developer-oriented activities in order to provide hands-on experiences with capabilities of the radio technology. ARM mbed development environment makes it easy to start implementing custom applications. As the official ARM mbed Ecosystem partner, Espotel is committed to leverage mbed technology and bring platform support to the environment.

Example device RaspberryPi2 retrofitted with Multitech mDot LoRa module.

Together with technology partners like IBM, Multitech and Semtech, Espotel will organize business events to increase awareness of benefits of LoRa technology among decision makers and influencers within different industries.

Within the LoRa Alliance, Espotel is actively driving LoRaWAN conformance certification process, and intents to be become an Alliance acknowledged LoRaWAN conformance certification house. This is natural extension to the test and certification services provided by Espotel's accredited laboratory facilities in Finland.

This short video (2:33) gives a nice overview of our laboratory facilities. Our reference customer design, Enevo smart waste sensor is acting as a case example of testing service:
https://www.youtube.com/watch?v=JaU-J7Im144

LoRa Gateway with ARM mbed and IBM cloud support

Early review of the new IOT Gateway from Multitech, making IOT implementations yet another step faster and easier.

MultiConnect Conduit is soon to be available new IOT gateway from Multitech Systems inc. The gateway has high performance 7-band cellular data modem for internet connectivity in global operation.

Multitech Conduit IOT gateway and LoRa mDot module from Multitech.

Due to my deep interest to LoRa RF technology, I just got an early engineering sample with 868 MHz LoRa extension module for evaluation use. This is one of the very first Conduit units in Europe. Multitech also provides mDot modules for end device implementation. Espotel already uses LoRa mDots in a customer pilot project. The reason why Espotel has selected Multitech as it's LoRa gateway supplier is that both companies are in close co-operation with ARM and IBM, and members of LoRa Alliance.

Conduit runs developer-friendly Linux operating system with support for many different programming languages, including C/C++, Python, Ruby, Pearl, C#, Java, Node.js and Node-RED.
Node-RED is a cool graphical tool to define data paths and integrations. Database, web server and other services on-board makes it possible to implement stand-alone applications without mandatory need for other back-end or cloud at all.

Conduit has compact form factor with dimensions of 13 x 10 x 4,5cm. Two expansion slots together with integrated cellular data modem, GPS, Ethernet, and USB host makes it versatile for many different kind of IOT applications. Initial set of mCard expansion cards include RS-232/485, GPIO and LoRa RF. The USB host port enables use of Wifi, Bluetooth, BLE and other dongles as well as external storage and extended connectivity.

Multitech provides readily available integration with IBM Bluemix via IOT Foundation using MQTT protocol with secure connectivity and safe data storage. Bluemix is handy environment for rapid prototyping and integrations, spanning up to production use as well. Node-RED is one of the programming options in Bluemix as well.

mDot is a new intelligent RF module from Multitech. It is available in two versions; Xbee compatible form factor with pin headers, or surface mount PCB. LoRa variant of mDot contains LoRa RF chip from Semtech and STM32 microcontroller from ST for application software. The controller is freely programmable by user and there is no need for additional MCU. This makes it cost efficient alternative, as a comparison; Microchip's LoRa module has a network controller inside, but requires an external application controller outside, which affects the overall BOM cost structure of a device.

In ARM mbed Ecosystem, Multitech has provided mDot platform support for mbed environment. Free and open source software stack is available via mbed developer site. Free mbed IDE, compiler and repository in cloud makes it easy and straightforward to start development. For more demanding development there is option to deploy the build environment in Eclipse IDE.

With free mDot library and LoRaMAC implementation, plug & play connectivity with Conduit is provided. Multitech provides number of readily available example implementations in mbed team repository which makes it easy to start development. LoRaMAC and mbed can be used with other processors as well, not limited to Multitech modules, like I did with Freescale FRDM-LK25Z board reported in my previous blog posting.

Conlusions
With readily available mbed and Bluemix integration, developer can set up the full chain from device to cloud in matter of hours, not days or weeks or months. This is definitely a significant productivity improvement over the traditional approach.

From now on, I'd feel it silly to start implementing device side code from scratch, manually installing back-end services a top of virtual server, and so on.  When teams can focus on what brings the true value to the customer or user, they are able to fail fast - not after months of development - to get immediate feedback whether the idea works or not. As an investor I'd love this approach.

That's the great value prop of the new IOT era - make me able to fail faster than ever before.

Real-life performance of the LoRa radio

Numbers put in datasheet is one thing, but experimenting the performance in real environment gives you the confidence. According to our experiments, LoRa really does outperform other competing RF technologies.

Today I performed some RF link length and performance testing in customers premises in production facilities. The purpose was to detect the limits of different frequencies and radio technologies commonly used in Wireless Sensor Networks, which means low power and low cost. Testing was limited to license-free IMS bands with transmit power within legal limits. Protocol issues were not covered in this experiment since the purpose was to set theoretical limits of any radio.

National Instruments Finland kindly supported us by supplying necessary wireless measurement instruments: NI PXI FlexRIO SDR (Software Defined Radio) which acted as a base station, and NI USRP (Universal Software Radio Peripheral) which was used as mobile station together with laptop running LabVIEW.

RF testing ongoing: measurement man at the left,
USRP in the middle, and PXI FlexRIO on the right.

The test environment consist of 160m long warehouse with interconnected manufacturing and office spaces. All in all rather complex building with many concrete walls, number of metal plated walls, metal fire doors, and plenty of metal structures inside. Mobile phones didn't work in many spots and Wifi had very limited coverage. Definitely difficult environment for any radio, just like real industrial deployment sites tends to be.

Typical narrowband tranceiver have receiving sensitivity of -110dBm, thus we decided to map the border where typical radio can not detect signal from noise. Test results of 434MHz, 868MHz and 2.4 GHz didn't surprised much. 2.4 GHz achieved 80m link length with direct line of sights. It couldn't penetrate through the first concrete wall.

434 and 868 MHz had very similar performance to each other. Almost the whole building complex was covered with recognizable signal. Only at the other end of the building in a completely metal covered hall with tiny windows in doors the signal was completely lost.  434 MHz benefits from open doors, even if they are not within the direct line in between transmitter and receivers. This indicates the lower frequency reflects from structures better and can bounce within the labyrinth, whereas the higher frequency tends to travel more straightforward though obstacles. When fire doors were closed, there was no significant difference in performance.

Then we compared the results of narrowband RF with spread spectrum LoRa radio. We changed from NI equipment to actual LoRa hardware, as generating the spread spectrum signal with software radio would be way too complex and effort consuming exercise for the purpose of this test. ARM mbed-enabled SX1276 LoRa development board from Semtech and FRDM-KL25Z MCU development board from Freescale was used instead.

LoRa RF test equipment for 434 and 868 MHz with battery pack.

In this experiment, we did not only measured carrier signal strength, but two-way packet communication over LoRaMac was used. Other radio unit was located in the same spot with the original base station. With this setup, we couldn't identify the limits of the connectivity, as we got packets through in all over the building, even in most difficult locations.

We went event to a bomb shelter in the basement of the office wing, with heavy steel-reinforced concrete walls and blast doors. There was no problems with signal when doors were closed. We event put the radio into a all-metal locker in the bomb shelter and locked the door. Still the signal passed happily, obviously through the small ventilation holes of the locker, and through all the concrete walls up to ground and into next wing of the building.

Really incredible result!

At last we moved the base station into most distant location within the building at the end of the warehouse hall. Now we managed to create challenging enough conditions for the radio. To block the signal, several concrete walls, metal fire doors and dozen or so metallic warehouse shelves were needed. Performance of 434MHz and 868MHz Lora was similar to each other, just like recognized in narrowband Sub-GHz tests.

The conclusion: We did not quite reach the promised 150-160 dB link budget advertised by LoRa datasheets and marketing material. However, we did got 145 dB link budget in a real and challenging environment. It really does outperform any competing technologies, not only in paper but in practice as well, with actual two-way data link established.

The test was performed with two LoRa end-nodes. I'm really waiting for a possibility to repeat the experiment with real LoRa-gateway having a LoRa concentrator chip in place. LoRa Alliance was publish at the beginning of January 2015, thus it is still pretty new technology.

Internet of Testing

Internet of Testing is all about productivity improvement. Market leading test and measurement technology from NI integrated with leading Cloud technology from IBM makes at all possible.

"LabVIEW - Improving the Productivity of Engineers and Scientists". is the main value proposition of National Instruments, as stated on their web site. LabVIEW is great tool for test and measurement of all kinds of physical phenomena. Robustness of the technology makes it good for most demanding live monitoring and automation control applications.

The real value comes from the high productivity of software development with graphical LabVIEW programming language. Graphical presentation makes LabVIEW program easy and intuitive to understand, but the value lies in the great amount of readily available mathematical algorithms, instrument drivers, communication interfaces, and user interface elements.

LabVIEW program can run in a PC (Win, Mac, Linux) or in a measurement instrument (RT-Target) like myRIO, CompactRIO,SingleBoard RIO, System-on-Module RIO, etc.  However, so far LabVIEW has provided limited support for remote operations and distributed architecture. But now the situation has changed.

Internet of Things Foundation is a IBM cloud-hosted service for collecting, storing, and integrating data of Things. IoT Foundation provides ready and direct integration to Bluemix, it's like one of the Bluemix APIs. When talking of Bluemix, we're yet again talking about productivity improvement, which is the main value proposition of PaaS (Platform as a Service).

When combining these two technologies, we get productivity square two. And that's the big thing!

LabVIEW recipe for IOT Foundation

Espotel has contributed my work to the open source community. It's a recipe how to connect any LabVIEW program, running either in a PC or in a measurement instrument, to IOT Foundation cloud fast and easily. It's a simple LabVIEW library which can be included in any LabVIEW project.

Example usage of the LabVIEW library for IOT Foundation

IOT Foundation uses MQTT for data transfer. It's fast, reliable, lightweight and secure messaging protocol intended for M2M and IoT applications. The LabVIEW library consists of three main elements:

• Open MQTT connection to IOT Foundation
• Publish (transfer) data over MQTT to IOT Foundation
• Close MQTT connection to IOT Foundation

The library contains one more element for reading device credentials from a file. IOT Foundation provides secure device registration, authentication and data transfer mechanism, based on credentials. Storing credentials is a file makes it possible to use the library in any stand-alone instruments without local user interface.


Applications:

• Remote real-time LabVIEW or HTML user interfaces
• Remote measurement and distributed testing
• Condition monitoring