Communications technologies can take time and brainpower. How do they relate to your environmental monitoring? What are the pros and cons of each? Here’s our Simple Guide to Communication Technologies for Environmental Monitoring.
Perhaps the most widely available telecoms protocol, GSM (2G) has been around for almost 25 years. Besides voice, GSM offers SMS which allows for the transmission of up to 160 bytes of information in a single message, with a range of up to around 35km. Messages can be chained together to break data down into transmissible pieces.
However, a single SMS can take several minutes and is not recommended where higher data rates are needed. Also, while there are no plans to turn off 2G in Europe, certain territories will begin shutting down their networks in the coming years with Australia set to go dark this December.
Succeeding mobile technologies have added data links to their voice and SMS offers. This allows devices to achieve data rates high enough to stream high definition video: about 300Mbps in the case of 4G.
These standards have been designed for consumer devices such as smartphones and tablets where a battery life of less than a day is often acceptable. Remote sensing platforms often have to live in the field for months at a time, so power usage is absolutely crucial.
The volume of data is much lower too with a handful of sensors transmitting readings periodically. The power draw to maintain unnecessarily high data rates makes these technologies unsuitable. Besides this, some of these networks may not be available in the most remote locations where many applications in this industry lie.
In January 2015 the formation of the LoRa Alliance was announced with their first open standard released that June. LoRaWAN is billed as a low powered wide area network (LPWAN), one of several launched in recent years. The open-source standard builds on a proprietary radio technology (LoRa) developed by the Semtech Corporation.
The standard allows devices to communicate through a gateway to a central server which then delivers messages to intended recipients. LoRaWAN can provide bitrates from 0.3 to 50kbps, depending on the distance from the gateway, at a range of up to 25km, with user-defined packet sizes in excess of 256 bytes.
Being open-source, users can set up their own gateways, effectively becoming their own service provider. Designed to be low powered and low cost, LoRaWAN is a contender for the title of most widely used Internet of Things network technology, with backing from Cisco, IBM, KPN, Microchip, and Orange.
SigFox is a French company that is partnering with companies in each country to provide the SigFox network. The main rival to LoRaWAN in the LPWAN market, SigFox is a proprietary technology that is provided on a subscription basis, with fees of less than €10 per year per device.
The main difference to LoRaWan is an increased range (claims of up to 150km) and smaller packet size (12 bytes). The significantly smaller packet size may be suitable for individual sensors but platforms measuring a range of parameters such as those in environmental monitoring, this may be an issue.
Weightless is another open-source LPWAN standard, or rather, three standards. Using different frequencies and data rates and offering ranges up to 5km, as well as other features such as AES-128 encryption, Weightless looks to become a viable competitor in the LPWAN market. The three standards are also at various stages of development, with Weightless-N deployed in several European cities, Weightless-W deployed in private networks and Weightless-P as yet unreleased. The Weightless Special Interest Group is certainly one to watch in this growing sector.
Currently being defined by the 3GPP, the mobile telecoms industry body that defines standards such as 3G and 4G, LTE-M is seen as an evolution of 4G (LTE) optimized for the internet of things. Essentially a stripped-down version of the current standard, the rollout of the network may be as simple as a software update to existing mobile base station equipment.
As it is still in development, there are few technical details available although it is expected to have data rates below 100-200kbps and a range of up to 5km. With the backing of industry players, this could quite possibly gain traction very fast.
Another standard in development by the 3GPP is NB-IoT. This is a ground-up approach in contrast to the stripped-back approach of LTE-M. This technology is anticipated to have data rates of about 50kbps and a range similar to that of LTE-M. A combination of proposals put to the 3GPP by Huawei and Ericsson, NB-IoT also has the backing of Qualcomm and Vodafone.
As with LTE-M, NB-IoT is expected to be announced in Release 13 of the 3GPP. At this point development will begin on infrastructure and device hardware and rollout will depend on adoption by national mobile networks. As such, this could still be several years away.
An American startup, WAVIoT produces water and electricity meters communicating over a proprietary network which they also offer as a general M2M solution. At 8-100bps over 50kms, the WAVIoT technology provides the low data, the high range that many IoT applications require. For smaller amounts of data, the range available makes this a very interesting prospect for environmental monitoring.
RPMA is a proprietary LPWAN from a company called Ingenu (formerly On-Ramp). Although technically available globally, Ingenu appears to be targeting the US market. Rather than rolling out a largescale network RPMA is deployed in private networks. RPMA devices can transmit at a relatively high 624kbps at a range of about 15km.
Satellite communications can provide global coverage once there is a clear view of the sky. Both voice and data connections are available through service providers partnered with satellite operators. While satellite is generally a more expensive option, the pervasiveness of service makes it a potential solution in extremely remote locations, making it appealing for environmental data capture.
Only time will tell as to how successfully each standard will get adopted. With each emerging standard, sufficient infrastructure must be rolled out and validation conducted to prove that they can cope with the projected traffic of billions of connected devices in the IoT world. Indeed with each new standard introduced, the legacy of the incumbent standards are questioned, which ultimately is resolved by evaluating the cost-benefit of hardware replacement, power savings, transmissions economics, and range improvement.