Category Archives: IEEE Spectrum

CubeSat Operators Launch an IoT Space Race

A rocket carrying CubeSats launched into Earth orbit two years ago, on 22 March 2021. Two of those CubeSats represented competing approaches to bringing the Internet of Things (IoT) to space. One, operated by Lacuna Space, uses a protocol called LoRaWAN, a long-range, low-power protocol owned by Semtech. The other, owned by Sateliot, uses the narrowband IoT protocol, following in the footsteps of OQ Technology, which launched a similar IoT satellite demonstration in 2019. And separately, in late 2022, the cellular industry standard-setter 3GPP incorporated satellite-based 5G into standard cellular service with its release 17.

In other words, there is now an IoT space race.

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In addition to Lacuna and Sateliot, OQ Technology is also nipping at the heels of satellite telecom incumbents such as IridiumOrbcomm, and Inmarsat for a share of the growing satellite-IoT subscriber market. OQ Technology has three satellites in low Earth orbit and plans to launch seven more this year, says OQ Technology’s chief innovation officer, Prasanna Nagarajan. OQ has paying customers in the oil and gas, agriculture, and transport logistics industries.

Sateliot, based in Barcelona, has the satellite it launched in 2021 in orbit and plans to launch four more this year, says Sateliot’s business development manager, Paula Caudet. The company is inviting early adopters to sample its service for free this year while it builds more coverage. “Certain use cases are fine with flybys every few hours, such as agricultural sensors,” Caudet says.

OQ Technology claims it will launch enough satellites to offer at least hourly coverage by 2024 and near-real-time coverage later that year. Sateliot is also aiming for better-than-hourly coverage sometime in 2024 and near-real-time coverage in 2025.

Incumbent satellite operators are already offering IoT coverage, but so far they require specific IoT hardware tuned to their spectrum bands and protocols. Insurgent companies that make use of the 3GPP release 17 standard will be able to offer satellite connectivity to devices originally designed to connect only to cellular towers.

New companies also see an opportunity to offer lower, more attractive pricing. “Legacy satellite providers were charging maybe [US] $100 for a few kilobits of data, and customers are not willing to pay so much for IoT,” says Nagarajan. “There seemed to be a huge market gap.” Another company, Swarm, which is a subsidiary of SpaceX, offers low-bandwidth connectivityvia proprietary devices to its tiny satellites for $5 per month.

Thanks to shared launch infrastructure and cheaper IoT-compatible modules and satellites, new firms can compete with companies that have had satellites in orbit for decades. More and more hardware and services are available on an off-the-shelf basis. “An IoT-standard module is maybe 8 or 10 euros, versus 300 euros for satellite-specific modules,” says Caudet.

In fact, Sateliot contracted the construction of its first satellite to Open Cosmos. Open Cosmos mission manager Jordi Castellví says that CubeSat subsystems and certain specialized services are now available online from suppliers including AlénSpaceCubeSatShopEnduroSat, and Isispace, among others.

By building constellations of hundreds of satellites with IoT modules in low Earth orbit, IoT-satellite companies will be able to save money on hardware and still detect the faint signals from IoT gateways or even individual IoT sensors, such as those aboard shipping containers packed onto cargo ships at sea. They won’t move as much data as voice and broadband offerings in the works from AST SpaceMobile and Lynk Global’s larger and more complex satellites, for example, but they may be able to meet growing demand for narrowband applications.

OQ Technology has its own licensed spectrum and can operate as an independent network operator for IoT users with the latest 3GPP release—although at first most users might not have direct contact with such providers; both Sateliot and OQ Technology have partnered with existing mobile-network operators to offer a sort of global IoT roaming package. For example, while a cargo ship is in port, a customer’s onboard IoT device will transmit via the local cellular network. Farther out at sea, the device will switch to transmitting to satellites overhead. “The next step is being able to integrate cellular and satellite services,” Caudet says.

This post was updated on 28 March to clarify the planned launch schedules and coverage schedules for OQ Technology and Sateliot.

First published by IEEE Spectrum: [html].

No More ‘No Service.’

IN 2023, YOU OR someone you know will be able to send a text message through space. Late in 2022, hardware behemoths Huawei and Applereleased cellular telephones capable of texting on traditional satellite-communications networks. A pair of ambitious startups, AST SpaceMobile and Lynk Global, also started building new low Earth orbit (LEO) satellite networksdesigned to reach conventional 5G cellphones outside terrestrial coverage.

“Offering direct satellite access to smartphones without modifications would allow access to billions of devices worldwide,” says Symeon Chatzinotas, the head of the University of Luxembourg’s SigCom research group.

Read more: No More ‘No Service.’

Users looking to connect via satellite won’t need the bulky, expensive commercial satphones that have been available since the late 1990s—but they also won’t have conventional calling or high-bandwidth data streaming just yet. Satellite connections are still plenty useful, though. To begin with, people could use texting to signal for help if need be, no matter where they are, as long as they have a clear view of the sky. That is, their mobile phones will have capabilities similar to existing pocket devices like Garmin’s inReach communicator.

Huawei has not said when its service will begin working, but Apple’s partnership with Globalstar, dubbed Emergency SOS via satellite, has been operational since November 2022. As of this writing, Lynk Global has agreements with 23 telecom providers to begin commercial operations in 2023. AST SpaceMobile says it plans to launch its first five commercial satellites late in 2023, has agreements or understandings with more than 25 telecom providers around the world, and should begin commercial operations in 2024.

A man in a green shirt is finishing placing a 4 by 4 array of golden circles on a post in a room with a floor, ceiling, and walls covered in blue pyramids.An AST SpaceMobile employee sets up a test unit of the BlueWalker 3 satellite’s modular antenna array; the final array includes 148 such units. AST SPACEMOBILE

Splashy announcements of satellite-cellular connectivity from Apple, Starlink, and T-Mobile in the third quarter of 2022 promoted the idea of anywhere, any-kind connectivity. The first services won’t be that slick, though. Apple and Huawei will both connect initially to older satellites in higher orbits, for which it could take more than 10 minutes to establish a connection. Even the newer LEO networks, such as Lynk Global’s, currently advertise satellite texting but are not yet promising the higher-capacity link that a voice or video call would require.

AST SpaceMobile says that as the company adds satellites, it will be up to its mobile-network-operator (MNO) partners to decide whether to market the bandwidth in small increments to many users for texting or voice-only calls or to offer data-heavy services to select users. Lynk doesn’t mind its competitors’ aspirational advertising campaigns, says Lynk Global CEO Charles Miller: “They educated the market. It’s only going to make people want more.”

The tech that’s moving cell towers into space

A phone screen display mockup. At the top of the screen, a black box says \u201ckeep point at satellite to send and receive\u201d with a progress bar slightly filled below it. Below the box, a text message exchange gives more detailed instructions on how to use the service.This mock-up shows the app for Apple’s Emergency SOS via satellite, which enables emergency texting in areas with no terrestrial coverage. APPLE

These new offerings are possible thanks to a handful of advances that are now maturing. Advances include the declining cost of satellite manufacturing and the shrinking size of satellites themselves, making it affordable to build many more satellites than in the past. And with many more of them, it’s possible to put the satellites into lower orbits, between 300 to 600 kilometers above Earth, where each covers less ground. But closer satellites allow handsets with less power to reach them.

Another improvement is in software-defined radios—chips that can transmit and receive on different wavelengths modulated by software running aboard the satellite. In the past, sending and receiving such a wide range of different wavelengths required distinct hardware. Digital signal processing enables these chips to do the work of a complicated array of hardware. “Software-defined radio means the phased-array antennas can do frequency hopping as we switch from country to country,” Miller says. That technology makes it viable to pack more antenna capability into less space—Lynk will start with relatively small 1-square-meter antennas, but it plans to install bigger, more effective ones on its satellites in the future.

AST SpaceMobile chief strategy officer Scott Wisniewski says larger antennas are a big part of AST’s strategy: “We think that’s very important to communicate with low-power, low-signal-strength phones.” AST plans to deploy antennas up to around 400 m2, which would be the largest commercial telecom arrays in LEO.

AST SPACEMOBILE 5 Block 1 Bluebirds~170 satellites550-700 km First commercial service in 2024Block 1 Bluebirds: 
64 m2antennas Block 2 Bluebirds: 128 m2antennas 
LYNK GLOBAL 12 satellites5,110 satellites500 km2027First generation: 
1 m2satellites Second generation: 
4 m2satellites 

Even so, having phones communicate with satellites rather than cell towers is tricky because of the much larger signal delays. “Everything about a phone is built around time-synching on the order of 5 to 10 milliseconds,” Wisniewski says. “That works just fine with a tower that’s a quarter mile away, 3 miles away even, but not for orbit.” AST is developing hardware solutions with Nokia and Rakuten that tell the core network how to wait longer for satellite signals.

In 2023, Apple and Huawei will be testing how much use they can get from older communications satellites through their flagship handsets, equipped with new chips. Meanwhile, if things go according to Lynk Global’s plan, by spring of 2023 the company will be offering commercial service to its MNO partners. AST may have its first commercial satellites in space but would still be testing and configuring them.

Network operators “historically asked ‘How is this possible?’” Wisniewski says. “Lately it’s more about ‘How can we use this best, when can we use this, what’s the best market strategy for each market?’” For people living in certain countries, 2023 could be the year when they are no longer troubled by the words “No Service.” 

First published by IEEE Spectrum: [html]

Apple Kicks Off the Cell-Calls-From-Space Race

The race to deliver cellular calls from space passes two milestones this month and saw one major announcement last month. First, Apple will offer emergency satellite messaging on two of its latest iPhone models, the company announced on Wednesday. Second, AST SpaceMobile plans a launch on Saturday, 10 September, of an experimental satellite to test full-fledged satellite 5G service. In addition, T-Mobile USA and SpaceX intend to offer their own messaging and limited data service via the second generation of SpaceX’s Starlink satellite constellation, as the two companies announced on 25 August

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As China’s Quantum-Encrypting Satellites Shrink, Their Networking Abilities Grow

The orbiting Tiangong-2 space lab has transmitted quantum-encryption keys to four ground stations, researchers reported on 18 August. The same network of ground stations is also able to receive quantum keys from the orbiting Micius satellite, which is in a much higher orbit, using the space station as a repeater. It comes just after the late July launch of Jinan 1, China’s second quantum-encrypting satellite, by the University of Science and Technology of China. USTC told the Xinhua News Agency that the new satellite is one-sixth the mass of its 2016 predecessor.

“The launch is significant,” says physicist Paul Kwiat of the University of Illinois in Urbana-Champaign, because it means the team are starting to build, not just plan, a quantum network. USTC researchers did not reply to IEEE Spectrum’s request for comments.

In quantum-key distribution (QKD), the quantum states of a single photon, such as polarization, encode and distribute random information that can be used to encrypt a classical message. Because it is impossible to copy the quantum state without changing it, senders and recipients can verify that their transmission got through without tampering or reading by third parties. In some scenarios it involves sending just one well-described photon at a time, but single photons are difficult to produce, and in this case, researchers used an attenuated laser to send small pulses that might also come out a couple of photons at a time, or not at all.

The USTC research team, led by Jian-Wei Pan, had already established quantum-key distribution from Micius to a single ground station in 2017, not long after the 2016 launch of the satellite. The work that Pan and colleagues reported this month, but which took place in 2018 and 2019, is a necessary step for building a constellation of quantum-encryption-compatible satellites across a range of orbits, to ensure more secure long-distance communications.

Several other research groups have transmitted quantum keys, and others are now building microsatellites for the same purpose. However, the U.S. National Security Agency’s site about QKD lists several technical limitations, such as requiring an initial verification of the counterparty’s identity, the need for special equipment, the cost, and the risk of hardware-based security vulnerabilities. In the absence of fixes, the NSA does not anticipate approving QKD for national security communications.

However, attenuated laser pulses are just one way of implementing QKD. Another is to use quantum entanglement, by which a pair of photons will behave the same way, even at a distance, when someone measures one of their quantum properties. In earlier experiments, Pan and colleagues also reported using quantum entanglement for QKD and mixing satellite and fiber-optic links to establish a mixed-modality QKD network spanning almost 5,000 kilometers.

“A quantum network with entangled nodes is the thing that would be really interesting, enabling distributed quantum computing and sensing, but that’s a hard thing to make. Being able to do QKD is a necessary but not sufficient first step,” Kwiat says. The USTC experiments are a chance to establish many technical abilities, such as the precise control of the pulse duration and direction of the lasers involved, or the ability to accurately transfer and measure the quantum signals to the standard necessary for a more complex quantum network.

That is a step ahead of the many other QKD efforts made so far on laboratory benchtops, over ground-to-ground cables, or aboard balloons or aircraft. “You have to do things very differently if you’re not allowed to fiddle with something once it’s launched into space,” Kwiat says.

The U.S. CHIPS and Science Act of 2022, signed on 9 August, allocated more than US $153 million a year for quantum computing and networks. While that’s unlikely to drive more American work toward an end goal of QKD, Kwiat says, “maybe we do it on the way to these more interesting applications.”