A catch-up with the Wi-SUN Alliance, spanning updates to the utility sector and its low-power mesh protocol, found renewed momentum for standards-based smart metering. However, a wildcard on the horizon could sow immense disruption among the sub-GHz players, despite an outpouring of complaints to the FCC regarding the controversial proposal.
If the FCC listens to reason, this should all blow over, but given the turbulent political climate, formerly safe bets are now questionable. So, will the IoT be rocked by upheaval in the 900 MHz band? Hopefully not.
For now though, on the metering front, the Wi-SUN Alliance is the industry body that oversees the namesake Wi-SUN protocol – an IEE 802.15.4g-based low-power wireless mesh technology, favored by utilities and increasingly smart cities. It has been plugging away in this IoT space for years, since 2012, and has survived that infamous IoT hype-cycle.
The backdrop to the interview was the announcement that the first companies have now achieved certification of the new Global Field-Area Network (FAN) 1.1 specification. Few names will be familiar to Wireless Watch readers, bar silicon providers Renesas and Silicon Labs, and perhaps Landis+Gyr – a meter and utility infrastructure provider. The other firms are Exegin Technologies, Kyoto University, Nagano Japan Radio co., Nissin Systems, and VertexCom.
The 1.1 update has increased the potential bitrate of Wi-SUN to 2.4 Mbps, and its OFDM modulation scheme can be tuned to a very low bitrate, to achieve better battery life. To this end, v1.1 allows utilities and smart cities to create a single network that has a dynamic mix of devices, with the highest rates being used for high-volume data and backhaul.
Alliance CEO Phil Beecher pointed to National Grid in Massachusetts as an example of a blended network – comprising some 4 million electricity meters and 2 million gas meters and methane detectors – joined up using the same network management system (NMS), with the electricity meters acting as backhaul nodes for the gas meters, thanks to their native power supply.
Miami was another highlighted example, where around 500,000 lights are connected. In such a network, you need to leverage the dynamic routing in the Wi-SUN standard, to avoid single links being overloaded – especially when you factor in additional connections from traffic signals, garbage can fill level sensors, and the proximity sensors for triggering light dimming. Suddenly, 2.4 Mbps can be strained.
“With OFDM and the lower data rate, those are a real challenge for LoRaWAN now. We can support these mixed technology networks with higher data rates for things like street lighting and lower power sensors for the lights, with much better spectral efficiency,” said Beecher.
On this point, we asked about the overlap between LoRaWAN and Wi-SUN in the bidding process for contracts. “No, we don’t see LoRaWAN much these days. A number of utilities did deploy LoRa with high expectations, but are now backtracking. I don’t like badmouthing, but that ecosystem really oversold its capabilities, and that’s certainly come back to bite them. People are coming back to Wi-SUN,” said Beecher.
The covid pandemic’s supply chain problems also helped return people to the fold, said Beecher. “Wi-SUN FAN was up against a number of proprietary mesh technologies, but when those issues hit, utilities could not buy meters from their preferred suppliers, and didn’t have an alternative,” noted Beecher, saying that the interoperability of the Wi-SUN standard is now a major selling point.
“Around that same time, we faced a lot of skepticism coming out of the Latin American utilities, especially in Brazil, where they were convinced that Wi-SUN was non-interoperable. So, we held a plugfest with nine of our member companies, in a live demonstration network, where utilities representing around 80% of Brazilian homes attended, to show that it does work. Our thirty minutes of allotted Q&A after the demonstration ran to over an hour and a half, and we’re planning to hold a similar plugfest for North America in August,” said Beecher.
India and Wirepas
Beecher said that Wi-SUN encountered Wirepas a lot in India. “It’s a thorn in the side for sure, and has similar problems in terms of non-standard technologies as Semtech does with LoRa. We believe Wirepas has been badmouthing Wi-SUN in India, telling users that it cannot meet the Indian SLA requirements, but that is not actually true. There are places where Wi-SUN forms a network faster, but we’re using certificate-based security, so you cannot really compare like for like here,” said Beecher.
“That said, I do know that some of the early Wi-SUN implementations in India were not very good, but that’s the nature of standards. Someone can build a bad standards-based stack, and the whole technology can be tarred,” said Beecher, recalling the early days of Bluetooth, where poor implementations dragged the whole technology down.
In India, the Bureau of Indian Standards has adopted Wi-SUN FAN, and launched an Indian certification program earlier this year. Regional neighbor China is somewhat walled off to the likes of Wi-SUN, noted Beecher.
“Most of the state grid is on powerline metering, but we do have a lot of Chinese member companies. They are geared towards the export market, particularly in Latin America. It’s difficult to tell what’s going on in China, but there is spectrum available in the 780 MHz range. You need to be on the ground to know what’s going on there, really,” said Beecher.
AMI 2.0
On wider trends, Beecher noted that AMI 2.0 (the second generation of the Automated Metering Infrastructure trend) is generating a lot of noise, but that there is still a lot of work to be done. Itron, a major vendor, was highlighted, in examining how Wi-SUN and cellular fit together.
“You don’t necessarily want to put cellular into every single smart meter. While there does seem to be a migration away from LTE Cat-NB to Cat-M, you still can’t necessarily achieve the data rate and power consumption resilience in cellular that you need for metering,” advised Beecher.
“There is some scope for 450 MHz cellular,” said Beecher, referring to a recent trend with its own industry alliance, “but het-gen networks are still advantageous. I had a chat recently with a company that did LoRa meters with cellular backhaul, which is now looking to reduce cellular usage by using Wi-SUN, as the opex is too much. They are generating 250 GB of data per month, paying per byte, and so that has become very expensive in that urban setting, where you don’t really need cellular.”
“But AMI 2.0 is more thinking about achieving the sort of maturity that utilities were talking about five years ago – adding renewables, having real-time data, and some form of edge processing. If you look at meters like Landis+Gyr’s Revelo, you can see how you can put some intelligence into the meter. It has WiFi for domestic use, and allows users to download applications to the meter, for the utility to then sell as value-added services,” said Beecher.
“But you also need to look at things like TEPCO in Japan, which is just about to start a 10-year meter renewal cycle – moving from 15-minute reads to 5-minute reads, on around 25 million meters. The important thing there is to process data as near to the edge as possible, as you don’t want to send all that data back to the cloud,” warned Beecher.
And so, we had to ask if the MNOs had a role to play. “I think the MNOs, especially in North America, are struggling to make any money in the IoT, and there is also a lot of skepticism from utilities that have been promise 10-year battery lives. With AMI 2.0, there is actually a bit of a drive towards private cellular, rather than using the MNO, and 5G is simply too high on the energy consumption front for utilities,” said Beecher.
Beecher said smaller municipalities might be better targets for MNOs, focusing on cities that might not want to run their own Wi-SUN networks. Cellular is used all the time for backhaul, in the larger Wi-SUN deployments, where a customer will run their own network, but smaller users might not want that additional work.”
“MNOs have tried to break into the utility space, but I’m not sure how successful they can be. The very large utilities, especially in the Americas, have already been bitten by GPRS, so now they generally manage their own networks or have someone like Itron or Landis+Gyr provide the NMS. It comes back to how MNOs can make money on just a few bytes of data per meter per month,” concluded Beecher.
NextNav’s FCC disruption
As for potential headaches on the near horizon, Beecher concluded that progress is good for Wi-SUN – which has north of 130 million connections globally now. However, on the spectrum front, a proposal from NextNav has set alarm bells ringing in the industry.
Here, NextNav wants to provide Positioning, Navigation, and Timing (PNT), and wants the FCC to “reconfigure” the 900-928 MHz band, to allow NextNav to create a “terrestrial 3D PNT network to complement and back up GPS.” It believes 15 MHz of this band could be allocated for 5G operations, “while appropriately protecting incumbent operations.”
Unsurprisingly, there have been a raft of comments, in response to the FCC’s call for input. The Wi-SUN Alliance’s comment notes that the proposal would require “radically changing the deployed environment with a proposal such as NextNav’s will require expensive network re-design, re-positioning of existing field assets, and addition of new field assets in order to maintain required performance and safety,” and asserts that NextNav has misled the FCC by misrepresenting how functions like forward-error correction and frequency hopping could (or rather cannot) be applied to these sorts of networks.
The Wi-Fi Alliance has objected, saying NextNav has still not demonstrated how it could ensure coexistence with WiFi HaLow (IEEE 802.11ah) devices operating in that band. The Z-Wave Alliance says that NextNav’s study “is undermined by significant omissions and a lack of real-world data,” while the LoRa Alliance stresses that “their assumptions and technical analysis do not accurately reflect real-world conditions.”
Given the current state of the FCC, which has only just had its spectrum auction authority reinstated by the extremely controversial budget bill, the political lobbying will be fraught. Of the 1900+ items, we could not find a comment that supported NextNav’s proposal, but under the current administration, it is by no means certain that the FCC will take this feedback on board.
NextNav has published a few somewhat sycophantic statements of support for new commissioner Carr, and its CEO Mariam Sorond has previously served on the FCC’s Technological Advisory Council.
NextNav’s share price has been on something of a run recently, and it closed a $190 million senior notes financing round in March, led by M-Cor Holdings. Goldman Sachs, Oak Investment Partners, and Fortress are notable investors.