In an experience that is probably familiar to everybody, in the last few months I’ve found myself unable to get a cell signal in places I routinely visit. At the pharmacy, the only cell coverage I could find was directly next to the front windows. I went to my doctor and found I couldn’t get any reception while biding my time in a waiting room. There was no signal in the back half of the grocery store.

I know my experience is not unique, and I regularly see other people grumbling in these locations about the lack of cell signal. It seems extraordinary in today’s world, where people want nearly ubiquitous cellular coverage, to find so many places with poor or no cell coverage indoors.

My first reaction to this was surprise, since my cellphone data speeds are easily ten times faster than they were a decade ago. The fact that I can’t receive indoor cellular coverage is a reminder that cell reception is due a lot more to the power of the signal rather than the speeds being delivered.

There are several reasons why indoor cell coverage is getting worse. One big reason is that cell carriers have been migrating to higher frequencies. Years ago, cellular networks widely used frequencies like 700 MHz and 900 MHz, which were able to easily penetrate buildings. The higher frequencies used today do a much worse job of penetrating buildings. A second reason is that the building materials used in newer or upgraded buildings deflect a lot of the cell signal. Modern insulation materials are generally less friendly to cell signals. Ookla recently documented that low-E glass, which is used to reflect heat in many new buildings, reflects cell signals along with reflecting heat. The bottom line is that you aren’t imagining it if you notice that indoor cell coverage isn’t as good as it was in the past.

There are several possible fixes for this, but they aren’t cheap and aren’t widely deployed. One is for businesses to invest in a cellular repeater to put on the roof to aim downward to provide better cell coverage inside the building. Cell carriers have been pushing this technology for years, and many hotels, convention centers, and office buildings are willing to pay for the capital costs and recurring fees to provide better cell indoor coverage. But groceries, hardware stores, doctors’ offices, and pharmacies aren’t willing to make this kind of investment.

Another alternative is to provide free public WiFi inside large buildings. Many businesses where customers spend significant time do this today. A large percentage of the restaurants I visit have WiFi for customers, but most require a customer to find the password and log in, something I’m rarely willing to do during a quick trip to the grocery or pharmacy. Very few stores offer WiFi that doesn’t require a password.

There has been talk for years of implementing Hotspot 2.0, a technology that allows a subscriber to automatically connect to any WiFi router that is part of a larger Hotspot 2.0 network. Every year we hear of a few smaller cities or ISPs that put together this kind of network. However, the idea has never gotten enough traction to bring it to larger markets. I’m sure the issue is figuring out a way to monetize the effort to cover the costs of implementing it.

Another new concept for improving indoor coverage is to allow access to a neutral 5G host. This would involve a third-party infrastructure provider to build, own, and operate shared cellular infrastructure for buildings that can be used by any cellular carrier. The neutral 5G host would likely want some up-front money from building owners, but would expect to also charge the cell carriers for the extra reach provided to their networks.

One interesting technology solution is the use of small cellular repeaters that would work in conjunction with a neutral host. Ericsson markets a repeater called the Radio Dot, shown at the top of this blog. Repeaters can be distributed throughout a building to make sure the cell signal reaches all needed spaces, much like is done with WiFi extenders.