How to implement a low-power WAN to support the IoT

Continuity of operations

Shane Rooney, executive director at industry body GSMA, says his organisation recommends that enterprises use licensed spectrum LPWAN as “it is the only way to ensure the continuity of their business operations”.

“Mobile operators have been providing trusted and secure machine to machine [M2M] and IoT solutions for years and the LPWAN standards LTE-M and NB-IoT provide the same attributes,” he says. “An enterprise needs to ensure that its partner will need to be around in five to 10 years’ time, so, in summary, what needs to be considered is trust, security, reliability, availability and experience.”

Rooney says newer LPWAN technologies are cheaper, provide better coverage and use a lot less power. “A utilities company with meters in basements may not have been able to get coverage previously or have had to send someone to change the battery every six months,” he says. “There is an immediate cost saving for them if they were to use LPWAN.”

According to Robin Kent, director of European operations at Adax, NB-IoT is the answer. “It vastly improves indoor coverage, supports a massive number of low-throughput devices, provides low delay sensitivity, ultra-low device cost, low device power consumption and optimised network architecture,” he says.

“Based on 3GPP standards and operating in a licensed spectrum, it ensures stability, reliability and security in the future. NB-IoT trialling is taking place, with pre-commercial launches planned later this year and commercial launches scheduled to take place globally in 2017, according to the GSMA, which says it will address the LPWAN IoT market opportunity using licensed spectrum with the intent to launch commercial solutions in 2016/17,” he adds.

Implementation process

Implementing LPWAN will depend on the use case and whether it is a fresh project or replacing an existing infrastructure.

“Cellular connectivity is widely available globally and mobile operators are building on top of this existing infrastructure to provide better and deeper coverage for IoT applications using the new technologies,” says Rooney.

According to Nigel Upton, director and general manager of IoT at Hewlett-Packard Enterprise (HPE), when implementing LPWAN to support an IoT project, it is a matter of picking out which use cases to go after.

Enterprises should be looking at what they are trying to get out of it, says Upton. “That’s a key question with IoT – what am I trying to get out of it, and therefore what sort of devices do I need to bring on board, and how do I make sure I test it correctly?”

Take responsibility

In such deployments, enterprises want somebody to take responsibility and accountability for the complete end-to-end system.

“When we first started this journey, we would come at it from our platform side and customers would say, great, but who’s going to source the devices, manage the connectivity, and so on, because a lot of them just don’t want to put this together piecemeal,” says Upton.

Once the use case and business reason have been established, the next job is to plan network requirements, followed by radio planning. “This is a specialist skill for LPWAN, and expertise in other radio technology does not guarantee success in LPWAN,” says Matt Bacon, marketing and communications director at Actility.

After that, the next step is usually a proof of concept (PoC), a small-scale but fully functional deployment. “There are usually lessons to be learned from the PoC,” says Bacon. “After the PoC has proved successful, you scale up, defining the full-scale solutions and services you are going to deploy.”

This should then lead on to rolling out the full-scale network, deploying the gateways and installing or integrating the network management software, provisioning all the sensors and devices onto the network, and integrating and ensuring the flow of data from devices to applications.

“Finally, once the whole thing is up and running, you need to be ready to manage your service and network operationally,” says Bacon.

Pitfalls and problems

When rolling out an IoT project, the key challenge is to get the business model right through services, because these deployments are capital-intensive with long payback periods.

“This has to be considered in the planning stage of the deployment, and all parties involved must reach a coherent long-term agreement with clear prioritisation and compromises where needed,” says VS Shridhar, senior vice-president and head of the IoT business unit at Tata Communications.

“Connected devices are the mainstay of smart cities and their high-power consumption is a critical issue – which is where LPWAN comes in,” he adds.

HPE’s Upton says a lot of devices deployed in the field are not that complex – it is more down to how you use it, understanding what customers want, and managing expectations.

“Having lots of not-very-complex devices can actually allow you to generate a huge amount of data, probably more useful data than having one or two complex devices,” he says.

With many sensors deployed on a network, enterprises will get a huge amount of data back, says Upton. “Understanding what we are going to do with it is going to be a challenge moving forward.”

Upton says device longevity is an important point here. “People talk about devices lasting 10 years, but that’s not a certainty and we need to think about the consequences of devices dropping off networks if and as they fail,” he says.

In theory, the battery in one of these devices might last 10 years, but if it is buried in the ground, the effect of moisture and temperature will have an impact.

“I suspect that people are quite interested in looking at battery technology here and how it is evolving to make all this a little more reliable, because if, for instance, you bury a sensor in concrete, you’re not digging it out again,” says Upton.

Getting enough range for an IoT project, especially when devices can be sited kilometres apart, can be a major problem. A popular way to improve range is to use relay stations, whereby traffic is relayed over greater distances to a maximum of two hops. Ken Munro, a partner at ethical hacking company Pen Test Partners, says it is not yet clear who will “own” the relay and who will have access to the traffic.

“This will depend very much on the implementation,” he says. “Is the relay acting simply as a switch and forwarding packets, or is it doing more? This is also a consideration when it comes to selecting which standard to back.”

Another problem to consider when implementing IoT projects is frequency access. In some countries, the 900MHz spectrum is not commercially available. “That is an issue if you’re an international company looking to use a single solution,” says Munro.

Future developments

Bacon says that over the next 12 to 18 months, the industry will see increasing availability of public LPWAN networks. “More and more LoRaWAN networks are operational globally, and towards the end of that window, we will start to see initial availability of commercial NB-IoT networks from operators,” he says.

It should also be noted that as the cost of end devices and radios comes down, there will be a shift from buying sensors to having them embedded in the manufacturing process.

“If you think about something like a bicycle or a backpack, it’s now becoming much more feasible to embed things like tracking sensor devices in the manufacturing process of the product, rather than adding it in as an afterthought,” says Upton.