Starlink’s LEO Satellites to Deliver 4G and 5G Mobile from Space

The boss of SpaceX, Elon Musk, has confirmed that their Low Earth Orbit (LEO) based Starlink satellites, which normally deliver ultrafast broadband around the world, will soon also enable 4G and 5G based mobile phones to connect directly with their mega constellation. The pledge.. “No More Cell Phone Dead Zones“.

In listening to Musk’s announcement, you’d be forgiven for thinking that this is a brand-new idea and something that only Starlink is doing. But that is incorrect, although they might well be one of the first to make a mass-market commercial product out of it, which people can actually use.

Satellite phones have of course been around for a long time, but they were designed to work with bespoke communication systems and specific satellites in a high (c.35,000km) Geostationary or Geosynchronous orbit. As a result, they tend to be fairly big, clunky and expensive devices – both in terms of hardware and service cost.

However, in recent years we’ve seen various new research and technologies that have helped to pave the way for a different approach (here), which could make it possible to harness the new generation of ultrafast broadband satellites in a much Lower Earth Orbit (LEO – e.g. 500km) to offer a more affordable 4G (LTE) and 5G mobile service – using common standards – over a wide area.

On top of that, the global 3GPP telecommunications standards’ body recently approved Release 17 of the 5G specification, which adds support for Satellite-driven Non-Terrestrial Networks (NTNs). In theory, all of this could make it possible for handset makers (e.g. Samsung) to produce mobile phones that can communicate just as easily with LEO satellites as they can with a terrestrial mobile mast.

A number of satellite operators, such as the British-registered OneWeb, are already developing such solutions, and Starlink is no exception. The company has now hooked up with T-Mobile in the USA to bring this to market and it’s coming sooner than you think.

What are Starlink and T-Mobile offering?

Under the ‘Coverage Above and Beyond‘ (satellite-to-cellular) solution, both companies are initially planning to offer “text coverage” (i.e. text messaging, including SMS, MMS, and “participating messaging apps“) practically everywhere in the continental US, Hawaii, parts of Alaska, Puerto Rico and territorial waters, even outside the signal of T-Mobile’s network. This will use a small slice of their network capacity across a given coverage area (i.e. “2 to 4 Mbits per cell zone“).

The service will be offered starting with a beta in select areas by the end of 2023, after SpaceX’s planned satellite launches. Afterwards, the companies plan to pursue the addition of voice and data (mobile broadband) connectivity, which will be supported by the second generation (V2) of their Starlink satellites with bigger antenna (5 – 6 metres across). The expectation is that these will be sent into space aboard their huge Starship rocket, provided they can get that working in good time (delays in the space industry are not uncommon).

All of this is expected to operate in familiar mid-band spectrum, which in the world of ‘mobile’ communications usually means anything from around 1GHz to 6GHz (e.g. UK mobile operators use various bands like 2.3GHz, 2.6GHz and 3-4GHz etc.).

SpaceX Statement

This satellite-to-cellular service will provide nearly complete coverage anywhere a customer can see the sky—meaning you can continue texting and eventually make a cell phone call even when you leave terrestrial coverage.

We’ve designed our system so that no modifications are required to the cell phone everyone has in their pocket today, and no new firmware, software updates, or apps are needed. As a complementary technology to terrestrial networks, SpaceX can enable mobile network operators to connect more people, fulfill coverage requirements, and create new business opportunities.

Both Starlink and T-Mobile have also expressed their desire to expand ‘Coverage Above and Beyond’ globally, issuing an open invitation to the world’s carriers to collaborate for truly global connectivity. As part of this, T-Mobile has committed to offer reciprocal roaming to those providers working with them to enable this vision.

However, such a service would still need support from other mobile operators in different countries, as well as the nod from national regulators (i.e. spectrum licences may need to be tweaked and the risk of interference with other users of the band thus has to be examined very carefully). Suffice to say, such things can create disputes and delays, so this approach is not without its challenges.

Similarly, handsets may not require any physical changes to work with the new service, but that doesn’t change the fact that such support may still work better when the manufacturers know how best to optimise their hardware and software. Being able to promote such a benefit to customers as a feature is something that could be quite attractive.

One other question mark in all this is the issue of cost. T-Mobile has hinted that the feature may be included for free on their most popular plans, but others might need to pay a small charge for an add-on. Think of this is being a bit like adding roaming support to your plan, albeit a potentially very powerful form of roaming that could one day deliver almost global coverage. That would solve a lot of annoyances.

Finally, we have to consider the potential for making mobile broadband more accessible to those in remote rural areas. Assuming all goes to plan, then Starlink’s new service could have the capability to replace the use of their expensive dish and router equipment, with end-users instead connecting via their existing handset or mobile routers. But performance may not be as good, so we’ll have to see how that one pans out first.

It’s worth noting the UK mobile operators, such as EE (BT), have helped to develop some of the related technologies behind such systems and are already known to be working with OneWeb on future products.