LoRa under cover

This time we put LoRa underground, reading water meter 2 meters below the surface. Other technologies including cellular data and 2.4GHz had already proven to fail with this task. Let LoRa proof its capabilities.

Well located at parking lot.

It this test, a water meter is located in an infrastructure well located at parking lot. The well has heavy cast iron lid and also all-metal collar for depth of 25 cm. Walls of the well are made with concrete rings. The water meter is at the bottom of the well, approx. 2 meters in depth. 

Water meter at the bottom of the well.

We build a demo setup with Multitech Conduit LoRa gateway, and mDot integrated with Raspberry Pi and M-BUS master interface, all put in an IP-classified plastic box. The box is well over-sized, but there is good space for battery. The LoRa transmitter in the "shoe-box" is interfaced with the meter over wired M-BUS. RF transmit power is 14dBm and spreading factor 12.

LoRa transmitter and gateway.

The transmitter was located next to the meter at the bottom of the well. The LoRa gateway was located in a meeting room inside a nearby building. The line of sight between meeting room and the well was blocked by a storage wing covered by metal plates.

Building where the gateway was located.

Distance of the well and the building is approx 25 meters. For realistic condition, the lid was closed tightly and a van was parked above the well. In the direct line between transmitter and receiver, there is several meters of soil, metal cage, brick wall and concrete floor.

Diagram of the test setup

And the results? Excellent!

Received signal strength is approx. -105dBm, which gives wide margin left. The gateway could be located much further away. We also tested signal coverate inside the office building and got it all covered from the same gateway location, 100 meters through several steel reinforced concrete floors and brick walls.

What's the meaning of all this? In an automated meter reading application, whether water, electricity or other types of meters or sensors, even a large complex with outdoor environment and difficult locations like basements and underground locations, it all can be covered with a single gateway located pretty freely in most convenient location. Outdoor wall installation or other difficult to reach position is not necessary.

This time we didn't tested the maximum distance from the well where the signal can be detected, as the results were good enough for the purpose of the trial.

New challengers entering IoT connectivity market

IoT connectivity market is far from mature. New challengers are popping up every now and then. The latest was announced Today, when Intel, Nokia and Ericsson released their co-op in a new mobile radio technology called Narrow-Band (NB) LTE-M for Low Power Wide Area IoT communication.

Like the name says, NB LTE-M is narrow-band version of the LTE-M. NB uses 200 kHz band where as the normal LTE-M consumes 1.4MHz. Both versions can co-exists without interfering each others. The purpose of the narrower band is to reduce end-device power consumption and cost. Intel says it will launch low-cost and low-power chips for IoT market using the new technology. What does that mean in numbers remains to be seen.

LPWA IoT Connectivity Overview
Nokia White Paper - LTE-M – Optimizing LTE for the Internet of Things

Technologies listed in the comparison above are all intended for public networks. LoRa is the only one which is available for private network applications also. That means you can set up a LoRa gateway of your own just like using WiFi. Sigfox is closed and propriterary technology, and use of licensed frequency bands means you got to be an operator to get the license in hand.

The greatest weakness of LoRa technology is the use of unlicensed frequency band. In Europe, the duty-cycle limitation is only 1%. That's regulatory not technology limitation. It does not affect much the downlink or uplink of many IoT applications, but over-the-air firmware updates are very difficult, next to impossible. It would take awfully long time to transfer any reasonable sized firmware. Perhaps some clever delta (diff) technology for patching the device firmware image could work.

 The above comparison is missing energy consumption. It seems to be difficult to find comparable numbers for real energy (J) consumption per delivered payload with different technologies. Mobile data suffers from significant overhead in terms of channel opening, handshaking, etc. Most of the energy is consumed by other functions than transmitting/receiving the actual payload data. As an opposite, LoRa introduces very low overhead. Any technology can provide battery life of over 10 years, it's only question of how much batteries you need.

LoRa is available as of Today. For LTE-M, first device and network manufacturers must introduce new products, then operators must upgrade their base stations. I don't believe LTE-M is really in place next year. Once it's there, the deployment of the technology will be fast for sure.

No convergence of IoT connectivity technologies is visible within the foreseeable future. There are different use cases for different types of radios. Main categories are short range radios (Bluetooth, Wifi, etc), Low Power Wide Area (LoRa, UNB), and cellular data. They have all different nature and no single technology will rule them all.

Conduit LoRa gateway and Espotel LoRa device supporting ThingPark

Multitech MultiConnect Conduit is latest LoRa gateway supporting Actility's ThingPark LoRa Network Server. I just got one of the very first setups.

Conduit gateway connected to ThingPark.

Recently Actility and Multitech created a custom firmware for Conduit to provide connectivity to ThingPark backend. Thanks to that, now there exists cost-efficient alternative gateway available for LoRa networks operated with ThingPark network management solution. Conduit may improve indoor coverage of public LoRa networks, or it can be used in private network installations. Later this year Multitech will introduce outdoor installation kit with IP-classified chassis and optional solar power pack.

Multitech and Kerlink gateways listed in my ThingPark account.

Espotel recently joined Actility's ThingPark certification program. The aim is to provide end-devices compliant with the ThinkPark network management solution. Espotel is now finalizing it's own LoRa reference design, nickname "ELMO" (Espotel LoRa Modem), which is Arduino form-factor compatible prototyping device.

Espotel LoRa Modem "ELMO"

ELMO will be LoRaWAN certified and tested against Actility's requirements. Right at the moment our engineers are working to introduce ELMO as public platform in ARM mbed development environment.

ELMO has dual Arduino-pinheaders. This enables function as a master or slave. ELMO can be used as LoRa-shield for external MCU boards, like STM32-Nucleo, Freescale FRDM, or Arduino. ELMO also supports integration of application software and protocol stack into one and running them both directly in ELMO's own MCU without external MCU needed. In both scenarios, 3rd party shields can be used to provide additional interfaces and sensors.

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