LTE Cat M1 and NB-IoT - the solutions for gas, water and heat metering?

New low power wide area communications promise long battery life, lower cost and better reliability for gas, water and heat utility applications.

With the requirements for smart electric metering well understood and rollouts in the most developed regions of the United States, Europe and Asia well under way, the focus is now shifting.

Driven by the need for more sustainable use of resources and advances in technologies, other utilities including gas, water and heat are looking increasingly to smart metering and other smart applications as they build out their internet of things (IoT).

Gas, water and heat smart metering

However, the communications requirements for these utility deployments are different, and mainly for one key reason.

Unlike smart electric meters that can draw on the grid for their power requirements, smart meters for the other utilities need batteries. And because of the high costs involved in replacement, the batteries are required to have a lifetime in the field of at least 10 years and more.

Another consideration is the level of communications that is required between the meters and the utility. With gas, water and heat, the focus is primarily on data collection and use cases such as leak monitoring, which are both less data intensive and real-time dependent than for example demand management or grid monitoring via smart electric metering.

The other potentially different issue is the location of the meters, which is often within the building, perhaps in a basement or at least within a concreted area.

“Modern smart metering systems must have a high degree of reliability, with the end target to achieve a 100% readout,” says Ludger Boeggering, Senior Professional Product Strategy at wireless technology provider u-blox.

Open standards are a key requirement as in most cases a mix of communications solutions are used – and that is anyway what utilities demand, so that they have a choice of suppliers and aren’t dependent on just one.

“Implementing a smart metering system is a major investment for a utility. Selecting the best fitting communication technology can result in significant savings, both in the deployment and in operation.”

LPWA communications

Up to now gas, water and heat metering solutions have had to rely on complex, costly and power hungry installations either with gateways or concentrators based on mobile 2G or 3G for communications or with meshed radio systems.

But the emergence of new low power wide area (LPWA) solutions based on 4G is now changing the use case for these utilities.

In general LPWA options are split into two proprietary LPWA technologies, such as SigFox and LoRa, which typically operate on unlicensed spectrum, and the forthcoming 3GPP standardised cellular IoT technologies operating on licensed spectrum.

These 3GPP technologies, which are optimised for the widely varying requirements of the IoT, are termed LTE Cat NB1 (or narrowband IoT, NB-IoT) and LTE Cat M1 (or enhanced machine type communications, eMTC).

These combine the advantage of using a common available infrastructure with low power consumption, low device cost. low deployment cost, deep in-building penetration and a massive number of simultaneously operating units.  

Boeggering comments that today, the main focus on LTE Cat NB1 is from the mobile operators in Europe and Asia Pacific, whereas LTE Cat M1 is being advanced in the US. However, he believes that in the long term, both should become widely available.

“Cat NB1 and Cat M1 will start becoming available in the respective regions during 2018, but with their different features, we anticipate that both must be implemented eventually to meet the differing use cases of the utilities and other users.”

LTE Cat NB1 vs Cat M1

The key differences between LTE Cat NB1 and LTE Cat M1 are to do with the latencies, bandwidths and ranges they offer and their power requirements (see table).

Comparison of features of LTE Cat M1 and LTE Cat NB1

In broad terms, LTE Cat M1 offers lower latency and greater bandwidth for data handling, while LTE Cat NB1 offers greater building penetration and meter battery lifetime – and both offer these advantages over technologies such as GPRS, CDMA or UMTS, Boeggering says.

“For example, LTE Cat M1 is more suitable for control applications in the grid requiring a lot of utility interaction, whereas LTE Cat NB1 is more suitable for lower frequency meter reading as well as being more cost-effective in terms of its technical design and implementation.”

With these differences, Boeggering anticipates that utilities could utilise the different solutions for different categories of customers.

“My view is that for smart gas, water and heat metering, LTE Cat NB1 will become the technology of choice, especially for residential applications.”

He adds: “In the industrial sector, the requirements are likely to be more sophisticated. For example, LTE Cat M1 would be more suitable for higher read rates and the greater power requirements from the larger capacity batteries typically used.”

LTE Cat NB1 and LTE Cat M1 demonstrated

With the development of the LPWA LTE Cat NB1 and LTE Cat M1 well under way, Boeggering says that u-blox has been involved from the beginning and already supports more than 700 trials in EMEA and countries including the United States, Australia, Chile and China among others in Asia.

Early vendor adopters of LTE Cat NB1 include Kamstrup and Diehl Metering, with several trials under way in Spain where Vodafone is spotlighting the technology. The largest and most advanced of these is with Aguas de Valencia, which is trialling automated meter reading with several thousand water end points.

In the United States, Verizon was the first telecom provider into the market with LTE Cat M1 but subsequently other providers including AT&T are also advancing the technology and trials with major meter vendors are starting to get under way.

In Australia, both LTE Cat NB1 and LTE Cat M1 are being rolled out by different telecoms operators, with the former the more advanced. Among trials there, a Melbourne utility is testing LTE Cat NB1 with Vodafone for monitoring and management of its sewer network.

Clearly at this stage at least, utility choice between the cellular LPWA technologies will be mostly application dependent, unless the utility opts for a potentially more costly and risk prone own infrastructure.

“For certain applications an own network makes sense but in most cases there are advantages to using the licensed spectrum based public mobile networks,” says Boeggering.

He concludes: “Whatever choice one makes, the key is to ensure that the solution meets your use case requirements and is based on technology that meets the highest demands for robustness, reliability, quality and long term availability. LTE Cat M1 and NB-IoT both come with the best preconditions to fulfill the challenging requirements of the energy market.”

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