Ookla wrote a recent article that highlights an increasing problem of poor indoor cellular coverage. The article notes that this is a growing problem since the public increasingly relies on cell phone apps.
Indoor cell coverage is growing poorer for several reasons. First, 5G carriers are migrating to higher mid-band frequencies, which don’t penetrate buildings as well as the lower frequencies used in the past. Years ago, cellular networks widely used 700 MHz and 900 MHz frequencies, which had the wonderful property of penetrating almost anything. I remember being amazed a decade ago when I didn’t lose a cell call in an interior elevator of a building. In recent years, I’ve noticed that my cell phone doesn’t work at the back of my neighborhood grocery store – but it did a decade ago. The problem is only going to get worse as cellular carriers migrate more 5G traffic to higher mid-band spectrum bands (3 GHz and higher).
There are also some changes in buildings that make it harder for wireless signals to penetrate. Ookla cites the increasing use of low-E glass, an energy-efficient glass with a microscopic coating that reflects heat and light – and also cellular signals. Ookla says that modern insulation materials, in general, are less friendly to cell signals.
Ookla also lays some of the blame on regulations that completely focus on outdoor cell coverage and has never acknowledged that 80% of cellular traffic originates from indoors (Ookla cites Ericsson for that statistic). The FCC adopted a minimum standard for outdoor cellular speeds of 25/3 Mbps in October 2020 as part of the 5G Fund for Rural America order. Interestingly, at that time, that was a higher speed than the definition of landline broadband that was still stuck at 25/3 Mbps. A few countries like Germany and Ireland require decent indoor cellular speeds for structures like hospitals, busy business districts, and tourist attractions.
There are some solutions to the problem. One would be for regulators to require better cellular speeds to match how people use it. That may sound like an easy fix, but it’s not.
The best way to improve cellular speeds is to use small cell sites that are closer to homes and businesses. A signal from a cell site in a neighborhood will penetrate nearby buildings a lot better than a signal from a tall tower a mile or more away. One of the limiting factors of cellular call strength that doesn’t get mentioned very often is that the power from cell site is restricted and limited. This is done to stop neighboring tall towers from interfering with each other. Stronger signals would penetrate buildings better but would wreak havoc with existing cellular networks.
Some businesses have tackled the problem on their own. Many hotels, hospitals, and business high-rises have invested in a rooftop cellular repeater (which is really a small cell site) that beams a signal down through the building. That strengthens the signal inside a building but nowhere else.
Ookla recommends an interesting solution, which is to embrace a neutral host model of telecommunications. This would have third party companies build, own, and operate cellular infrastructure, which would be leased to multiple service providers on a wholesale basis. Think of this as the open-access version of infrastructure. A neutral host company would build cell sites where they are most needed by the public and lease capacity to all cellular carriers. Unfortunately, that model has not ever been embraced in the U.S. In fact, Crown Castle, which was the predominant company chasing the neutral hosted model, announced in March that it is selling its small cell business and related fiber networks to Zayo and EQT.
Doug: As you know, there are various technical solutions for solving in-building wireless propagation: bi-directional amplifiers (BDAs), distrubuted antenna systems (DAS) and indoor small cells.
The question becomes one of: who pays?
The carriers have funded the large venues – stadiums, airports, and the like but have shied away from widespread deployments. That leaves neutral hosts and property owners to funded IBW deployments in other types of buildings.
But of the 400,000 or so buildings that are candidates for an in-building wireless system, penetration is still in the single digit percentage range.
Or maybe, cellular service is a complementary service to a strong broadband connection powered by fiber. Install a robust network in the home or business that allows the user to enjoy the best of both technologies.
And why we are seeing the three cellular companies investing billions of dollars on fiber networks!
audio calls are very low demand, you don’t need anything fancy fundamentally. A standard low-compression voice call is about 90kbps both ways and is tollerant of upwards of 250ms in the context of a ‘cellular call’. a business voip similar but should be around <100ms which is still well in the realm of a rather mundane home internet service.
carriers just need to fix their wifi calling infrastructure so that works. and/or they need to embrace passpoint/hotspot2.0 more for automatic carrier offload.
That starts to look more and more like the pseudo-carriers like google fi and helium mobile… and I think that sorta scares the big carriers a bit.
Actually, indoor cellular coverage has always been an issue. My explanation to end-users was to think of a cell phone more as a radio, and not a telephone…
When clients complained of inaccessibility at their desk, I would ask, “So how is the radio reception at your desk?” Usually the two were synonymous.
With more towers and more places for cell sites (see Telecom Act of ’96), the issue has been mitigated… but never resolved.
Carriers can help the situation by allowing phones to access cellular networks via WiFi… like one can do in “airplane mode”.
A few of these issues — building materials and frequency — might never be resolved. In order to do so, one needs to repeal a few laws of physics. (LOL!)
P.S. I would imagine that mandating inside-building access (… or similar rules) might run afoul of property rights issues.
It’s always been an issue, but we’re hearing more and more complaints about it and people demanding wifi calling be ‘fixed’ (by us…) because they don’t get good cell service. It feels like it’s gotten much worse and it probably has because of all the ‘FWA’ over cellular soaking up capacity.
We do our best to make wifi calling work, but ultimately we have to tell them that it’s a ‘verizon service’ and they need to ask verizon why it doesn’t work and reinforce that we are not verizon and when verizon blames us they are not being honest. When every single other internet connected device in their home works but wifi calling is sketchy that’s verizon. (or AT&T or TMobile…)
The major carriers should all not only join up with carrier offloading (verizon, I’m looking at you…) but also allow it for home wifi. we see much better results on passpoint offloading than wifi offloading and it’s seamless.
I would second what Daniel says here. WiFi calling is getting harder and harder to keep happy. The clients don’t understand it. And the carriers are insulated by multiple layers of staff from talking to someone that can do anything about it.
As an example, we service a large Cal-Fire site that is remote in the mountains. Cal-Fire has given them all dual SIM phones, Verizon and FirstNet but apparently expects that way up in the mountains where the nearest cell tower is >10 miles away that WiFi calling will “just work”. It doesn’t. They have suggested moving to Starlink from our service solely because of this WiFi calling issue. Problem is they have 8 buildings scattered around in the woods and would either require a terminal at each location which is much more expensive than what we are, or continue using our hybrid fiber/airMax + WiFi to distribute, which would put them back at having WiFi Calling issues most likely.
98% of clients don’t care why it doesn’t work, they just want it to work, and with WiFi Calling the burden on making it work falls on the ISP, not on the carrier. That is not sustainable when the problem is most often in the carrier side of the connection.
As another example, we have a residential client with AT&T cell. If they talk on WiFi calling and move around in their house they phone goes to SOS mode every little bit. That instantly drops the call, every time. They are extremely frustrated. They have solid WiFi in the house, but that isn’t enough.
yes, and I’m more and more convinced that the wifi calling service is underbuilt. We’re seeing issues for periods of time with no other changes at a site, strongly suggesting that wifi calling service itself is an issue.
The problem with making it the ISP’s issue to solve is that a) they can’t and b) labor isn’t free. It really must drive a price hike somewhere in the process for someone and that should be the cell carriers themselves.
You don’t see amazon or google blaming your ISP, they fix their problem and they make it as robust as possible. cell carriers should be pressured to the do same.
I think the problem with the traditional carriers is they think of WiFi calling as only supplemental coverage to their cellular coverage. They stick with cellular as long as possible and switch to WiFi only when cellular is horrible or impossible.
To Amazon, Google, and even Comcast, WiFi calling is their primary mode and cellular coverage is supplemental to the WIFI coverage. They use WiFi as much as possible and only switch to cellular when WiFi isn’t available.