Fibocom Shows Satellite IoT Working on Unmodified LTE Modules
Fibocom has published field test results showing its LE270-EU and LE271-GL LTE Cat.1 bis modules connecting to SpaceX’s Direct to Cell satellite network in New Zealand using standard firmware and no satellite-specific hardware modifications. Both modules registered on the network, established IP data sessions and moved data. Under good sky visibility the LE270-EU reached about 2.2 Mbps downlink and the LE271-GL about 2.0 Mbps, both at roughly 0.3 Mbps uplink. The release also reports the figures that matter more for a device designer: indoor throughput falling to around 0.5 Mbps, and an energy cost 1.5 to 1.8 times terrestrial for the same upload.
What the test actually proved
The headline claim is that the test added no satellite hardware. That is the significant part, because the alternative path to satellite IoT has required dedicated satellite modems, antennas and certification, and each of those adds cost, board space and power to a device designed to run for years on a battery.
Direct to Cell works differently from a conventional satellite terminal. SpaceX puts LTE base station capability on low Earth orbit satellites and operates through partnerships with mobile network operators, so a compatible module sees a cell tower that happens to be moving overhead. The physics is ordinary LTE. The geometry, and everything that follows from it, is not.
Fibocom’s result says the ordinary LTE stack in its modules was sufficient to complete registration, establish a session and transfer data. That does not mean Fibocom built the modules for satellites. It means the network accommodated them, which is a different claim and a more useful one for a device maker deciding whether to add satellite capability to an existing design.
The numbers, including the bad ones
The performance figures come with an honesty unusual in this genre. Under outdoor and in-vehicle conditions with good sky visibility, the LE270-EU achieved approximately 2.2 Mbps downlink and the LE271-GL approximately 2.0 Mbps, both delivering around 0.3 Mbps uplink. Network registration took between one and thirty seconds, a range wide enough to suggest it depends heavily on satellite position, and ping response rates ran from 80 to 90 per cent.
That last figure deserves attention. A ping success rate below 100 per cent means one request in five or one in ten does not complete, which for a request-response protocol means retries, and retries cost power and time on a device that has neither to spare in the field.
The indoor result is the one a product manager should read first. Inside a hotel room with obstructed sky, downlink fell to around 0.5 Mbps in some scenarios and ping success to 65 to 70 per cent, with some requests taking noticeably longer. That is not a failure. It describes what direct-to-satellite connectivity does when something blocks the sky, and it sets the boundary for which applications this suits.
The energy penalty is the real constraint
The most useful number in the release is not a throughput figure. Uploading the same file over the satellite link consumed approximately 1.5 to 1.8 times the energy of the same upload over terrestrial cellular, and Fibocom attributes the increase to longer transmission times, higher transmit current and data retransmissions.
For a mains-powered asset tracker that is irrelevant. For a battery-powered sensor in a field, expected to run unattended for years, it is the number that determines the design. A device whose radio budget grows by 50 to 80 per cent on satellite needs a larger battery, a longer reporting interval, or both.
Fibocom’s own guidance follows from that: adjust reporting intervals, buffer data during interruptions and retry when the link returns. Those are sensible recommendations and they describe a device treating satellite as an occasional fallback rather than a primary link, which is probably the correct architecture for most IoT deployments today, and certainly for any device expected to last a decade on one battery.
The coverage constraint
The constraint on Direct to Cell is commercial rather than technical. SpaceX operates the service through mobile network operator partnerships, which means the satellite network appears as a roaming extension of a partner’s terrestrial network rather than as an independent operator. A device in a country without a partner sees nothing, and a device roaming across a border may lose the capability.
That structure shapes what satellite IoT can promise. It is not a global fallback in the way a dedicated satellite constellation is. It is a rural coverage extension in markets where a partner has signed. For an asset tracker operating domestically in a covered market that is sufficient. For a logistics operator moving freight across continents it is not, and the release does not address the distinction.
Why Cat.1 bis is the right test case
LTE Cat.1 bis is worth explaining because it determines who this result applies to. The category sits below higher-throughput LTE variants in data rate and above the narrowband categories in capability, and it has become the default choice for IoT devices needing moderate throughput, mobility and reasonable power consumption at a low module cost.
That makes it the category where satellite fallback matters most. A Cat.1 bis device is typically an asset tracker, a monitor or a meter: it sends small amounts of data at intervals, it runs on a battery, and it often sits exactly where terrestrial coverage is weakest or absent altogether. The 17.7 by 15.8 by 2.4 millimetre form factor and 2.5 microamp power-saving current in these modules are the specifications that make that deployment pattern possible, and neither changes when the link becomes a satellite rather than a tower.
What the link actually needs to carry
What a Cat.1 bis device actually needs from a satellite link is far less than the throughput figures suggest. An asset tracker reports a position, a status and perhaps a sensor reading: a few hundred bytes at an interval of minutes to hours. An agricultural monitor reports soil moisture and temperature on a similar cadence.
At 0.3 Mbps uplink, a device sends a kilobyte in well under a second of transmit time, so throughput is not the constraint. The constraint is the energy that transmit second costs, and the 1.5 to 1.8 times multiplier applies to that second rather than to a continuous session. The release’s figures are more useful than they first appear, because they describe a burst transmission pattern rather than a broadband one.
The commercial implication
The consequence is larger than one vendor’s test. If unmodified Cat.1 bis modules can reach a satellite network, then the installed base of LTE IoT devices becomes a potential satellite market without a hardware refresh, and the addressable population becomes every deployed tracker and meter rather than every future one. That is a different business from selling satellite modems, and it explains why module vendors rather than satellite operators publish these results.
New Zealand is a sensible test location and the release does not say why. It has extensive rural terrain with thin terrestrial coverage, a small population, and an operator market where a satellite partnership is commercially attractive. Those conditions resemble the markets where satellite IoT has a business case, which makes the test more representative than a laboratory result would be and less representative than a multi-market trial.
Where Direct to Cell sits
The alternative approaches to satellite IoT fall into two camps, and Fibocom’s result bears on only one. Dedicated satellite constellations use their own spectrum and modems, which brings global coverage and predictable performance at the cost of new hardware and usually a subscription. Narrowband satellite services offer very low data rates with excellent power characteristics but need their own radios.
Direct to Cell sits between them. It uses existing LTE hardware and existing operator relationships, and it delivers more throughput than narrowband with worse coverage than a dedicated constellation. That is a genuine middle position, and whether it suits satellite IoT depends on two things the industry has not settled: how many operators sign, and how quickly the energy penalty narrows over time.
What is missing
No number of test runs appears, no test duration, and no satellite elevation angles, which are the variables that would let a reader judge whether 2.2 Mbps is typical or favourable. The mobile network operator partner in New Zealand goes unnamed, and Direct to Cell depends on those partnerships. The release gives no pricing or availability date for DTC-ready firmware, and does not say whether the modules required certification beyond standard LTE. Fibocom says it continues to optimize DTC firmware compatibility without saying what still needs fixing.
What to watch
Whether Fibocom publishes the registration-efficiency and connection-resilience improvements it says it is working on, since the one-to-thirty-second registration window is the figure most likely to improve and the one that most affects user experience. Whether the energy penalty narrows, because 1.5 to 1.8 times terrestrial decides whether satellite fallback is viable for battery devices at all. And, whether other module vendors publish comparable results, which would turn a single vendor’s field test into a benchmark the whole module industry could be measured against and a number every device maker could plan to. And whether Direct to Cell coverage expands beyond the operator partnerships that make it work, because a network existing only where a partner holds spectrum is not yet a global fallback for anyone.