Smart meter deployments are high-volume activities and take time and resources to roll out. Typically, projects occur within countries’ boundaries because of the fragmented nature of the utility market along national lines. However, to achieve economies of scale, utility companies and metering service providers are looking to create standardized, global devices.
These need to take account of both national utility regulations and communications regulations, making it impossible to manufacture a single, global device but allowing for regional variants to be created or for variants that can be easily configured for national usage. The metering device itself is just one of the challenges involved in smart meter roll-outs. By definition, a smart meter must be connected so it can transmit data, and therefore connectivity is a mission-critical requirement.
Choice of Connections
There is no one correct answer to the question of which network technology to use to connect smart meters. This is because each deployment has different characteristics. The array of technologies used extends from the private radio mesh networks of the utility companies to low-power wide-area (LPWA) technologies such as LoRaWAN and Sigfox and then on, all the way into the cellular market with narrowband-IoT (NB-IoT) and LTE-M. 2G cellular also exists and is still being used in many markets. Despite the disparity, metering organizations are looking to focus on a limited number of connectivity options, and NB-IoT and LTE-M are set to lead the cellular metering market.
The connectivity decision is increasingly based on the cost, security, coverage, power usage, and the potential throughput of the connectivity. Each of these can cause deployments to succeed or fail and therefore must be carefully balanced against each other to create an optimal solution. From a coverage perspective, near total national coverage is necessary, so that meters in difficult locations such as underground in basements or plant rooms of large buildings can be reached. More than one connectivity solution may be required to achieve this nationally, so different versions of meters may be needed. This is sub-optimal from a cost, manufacturing, and operational perspective, but necessary for ensuring total coverage.
Capacity is also becoming more of a priority as utility companies recognize that they will need to communicate more data, and that their partners will also increase traffic over meter connections. There is a fine balance between provisioning a solution with enough capacity to meet future needs and not spending excessively on capacity that isn’t required. Utility companies are carefully assessing what the operational landscape will look like in a decade and, accordingly, are specifying connectivity that enables them to scale up flexibly in the future.
Another constraint is battery life. With lifespans of two decades or more, utility companies need meters that are power efficient. A truck roll to replace a battery represents a cost that breaks the profitability of a service, so low-power solutions that enable data transmission are attractive.
Why Cellular?
In the past, every metering company that offered connected meters had its own proprietary radio frequency (RF) mesh to enable communications. While these solutions worked adequately, they required meter companies to build their own networks and dedicated equipment.
With cellular data pricing coming down and the scale of metering projects going up, the cost of the module and the whole device with cellular connectivity is coming down. That makes it very attractive for metering deployments, especially because cellular connections come with built-in security, an important requirement given the potential for fraud in the utility sector. Although a range of connectivity options are available to serve smart meters, cellular low-power wide-area (LPWA) networks have a series of advantages to bring to smart meter deployments.
#1: Connection
LPWA was included in the 3GPP standard Release 13 for the machine-to-machine type of communications (mMTC) where these devices don’t have to be connected all the time. This is particularly relevant to the metering space because these devices wake up only once in a while to report data. However, there are scenarios in which some devices communicate more frequently, such as in the case of an emergency or an anomaly.
#2: Power Consumption
Power saving mode (PSM) and extended idle discontinuous reception (eiDRX) capability were put in place to get the best power out of the cellular connectivity. Power consumption has come down significantly to make 10,15, or 20-year deployments possible. These were not possible prior to the 3GPP Release 13 when PSM and eIDRX features didn’t exist with Cat-1 and above categories.
Now, attractive chipsets and modules achieve power consumption that is as low as a microcontroller unit (MCU) can get. Thanks to the ubiquity of network coverage, security, and low-power usage, cellular is becoming the preferred connectivity mode for smart meters. There is a big effort from cellular carriers to encourage adoption because meters will become an additional revenue stream for them.
#3: Range of Use
The investments being made in smart meter infrastructure set the scene for the meter to become an in-building and home hub for other appliances to enable data transmission and a range of applications. Smart meters can provide a service platform for appliances such as dishwashers, fridges, smoke detectors, and access control, many of which will become managed services. There is a clear intent among utility companies to play themselves into this arena, building on their smart metering infrastructure.
Prioritizing Network & Power
Metering companies will need to have the additional network capacity and battery power available to support other partners’ business cases. This is why specifying a powerful module is such an important strategic move. Failure to select modules that don’t offer low-cost, low-power and long-life attributes can mean smart meters will not be able to support additional services and new revenue opportunities are lost. The only other alternative then is a costly upgrade cycle to replace or improve the existing deployed base of smart meters. Few business cases can withstand that so, to be future-ready, a module with all of the capabilities set out above is a prerequisite.
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