Tag Archives: cellular roaming

How’s Your Cellular Coverage?

The FCC recently announced that it is ready to launch its 5G Fund, which will provide $9 billion to bring better 5G cellular coverage to rural America. The FCC will be choosing the areas that are eligible for the 5G Fund using mapping data it collects from cellular carriers of where they claim to serve. An area is considered as served for purposes of the 5G Fund if at least one carrier is providing 5G cellular coverage with a speed of at least 7/1 Mbps.

That requirement for a specific speed should sound familiar, because for broadband grants, an area is considered covered if at least one ISP offers a speed of 100/20 Mbps.  But there is one big difference between broadband coverage and cellular coverage – the mobility issue.

If the FCC broadband maps are accurate and one ISP really can deliver a broadband speed of at least 100/20 Mbps – then the FCC has deemed that customers to have an option to buy broadband. But cellular coverage is very different. People don’t necessarily choose a cellular carrier because the speeds are good at their home. They also care about the coverage when they are commuting, shopping, going to school, etc.

Most rural county seats or other sizable towns have several cellular carriers with good coverage in and around the towns. When I hear complaints about lack of rural cellular coverage, this often translates to mean that people who live in towns lose coverage when they drive into rural areas. When I look in detail at specific counties, I find many examples where the carriers that claim coverage in the rural areas are not the same carriers that most people in the towns are using.

When I look at the FCC cellular maps in my county, I find large areas where only one carrier claims coverage. The FCC maps show that in my county, there are pockets where only T-Mobile, UScellular, or Verizon claim service. If I cross a little further into the next county, I find large rural areas where the only carrier with claimed coverage is Dish.

This creates a dilemma that is not recognized in the FCC’s definition of cellular coverage. The reality is that delivery drivers, real estate agents, commuters, and anybody else who regularly moves between the city and rural areas must subscribe to multiple carriers to guarantee a working cellular signal. I subscribe to AT&T since, in my hilly city, Verizon and others have a dead zone at my house. But AT&T has the least amount of rural coverage in the county, and so my AT&T phone gets no signal when I travel outside the city. And when I say outside, I usually lose coverage with AT&T within a few short miles outside of town.

Earlier this year I interviewed a real estate agent who works in a rural county in Illinois. She has to carry phones subscribed to four different carriers in order to be able to have coverage at the various homes she is trying to sell. I’ve heard similar stories from many people who travel during the day such as delivery drivers and social workers.

This creates a big real life conundrum. According to the FCC maps there are no large areas of my county that don’t have at least one cellular carrier that claims coverage. This county is not going to get any new cell towers from the 5G fund. And yet everybody I know says they have poor cell coverage outside the city. No matter which carrier they use at their home, they quickly drive to areas outside the city where that carrier doesn’t work.

I understand that this issue is probably worse in hilly Appalachia where I live since there are dead zones everywhere caused by the hills. But this issue appears everywhere. I was working in a rural Minnesota County in a flat farming area where half the county can only get AT&T at home and the other half can get Verizon. This means a hassle and havoc for anybody who travels between the two areas.

What I am describing is the natural consequence of cellular signals that only carry for a limited distance from any tower. In my county, somebody who works around my county needs to be able to connect at times to AT&T, Verizon, T-Mobile, and Uscellular. The only way to do that is to have four phones or else pay huge fees for roaming.

I love the idea of the FCC’s 5G Plan since it will bring cellular coverage to areas where no carrier serves. But the 5G Plan is not going to solve the general public feeling that rural cellular coverage is terrible. I think that what is needed is for the FCC to implement roaming fees and policies that make it reasonably affordable to use your cellphone when you drive into an area served by somebody other than your home carrier.

Massive MIMO

One of the technologies that will bolster 5G cellular is the use of massive MIMO (multiple-input, multiple-output) antenna arrays. Massive MIMO is an extension of smaller MIMO antennas that have been use for several years. For example, home WiFi routers now routinely use multiple antennas to allow for easier connections to multiple devices. Basic forms of the MIMO technology have been deployed in LTE cell sites for several years.

Massive MIMO differs from current technology by the use of big arrays of antennas. For example, Sprint, along with Nokia demonstrated a massive MIMO transmitter in 2017 that used 128 antennas, with 64 for receive and 64 for transmit. Sprint is in the process of deploying a much smaller array in cell sites using the 2.5 GHz spectrum.

Massive MIMO can be used in two different ways. First, multiple transmitter antennas can be focused together to reach a single customer (who also needs to have multiple receivers) to increase throughput. In the Sprint trial mentioned above Sprint and Nokia were able to achieve a 300 Mbps connection to a beefed-up cellphone. That’s a lot more bandwidth than can be achieved from one transmitter, which at the most could deliver whatever bandwidth is possible on the channel of spectrum being used.

The extra bandwidth is achieved in two ways. First, using multiple transmitters means that multiple channels of the same frequency can be sent simultaneously to the same receiving device. Both the transmitter and receiver must have the sophisticated and powerful computing power to coordinate and combine the multiple signals.

The bandwidth is also boosted by what’s called precoding or beamforming. This technology coordinates the signals from multiple transmitters to maximize the received signal gain and to reduce what is called the multipath fading effect. In simple terms the beamforming technology sets the power level and gain for each separate antenna to maximize the data throughput. Every frequency and its channel operates a little differently and beamforming favors the channels and frequency with the best operating capabilities in a given environment. Beamforming also allows for the cellular signal to be concentrated in a portion of the receiving area – to create a ‘beam’. This is not the same kind of highly concentrated beam that is used in microwave transmitters, but the concentration of the radio signals into the general area of the customer means a more efficient delivery of data packets.

The cellular companies, though, are focused on the second use of MIMO – the ability to connect to more devices simultaneously. One of the key parameters of the 5G cellular specifications is the ability of a cell site to make up to 100,000 simultaneous connections. The carriers envision 5G is the platform for the Internet of Things and want to use cellular bandwidth to connect to the many sensors envisioned in our near-future world. This first generation of massive MIMO won’t bump cell sites to 100,000 connections, but it’s a first step at increasing the number of connections.

Massive MIMO is also going to facilitate the coordination of signals from multiple cell sites. Today’s cellular networks are based upon a roaming architecture. That means that a cellphone or any other device that wants a cellular connection will grab the strongest available cellular signal. That’s normally the closest cell site but could be a more distant one if the nearest site is busy. With roaming a cellular connection is handed from one cell site to the next for a customer that is moving through cellular coverage areas.

One of the key aspects of 5G is that it will allow multiple cell sites to connect to a single customer when necessary. That might mean combining the signal from a MIMO antenna in two neighboring cell sites. In most places today this is not particularly useful since cell sites today tend to be fairly far apart. But as we migrate to smaller cells the chances of a customer being in range of multiple cell sites increases. The combining of cell sites could be useful when a customer wants a big burst of data, and coordinating the MIMO signals between neighboring cell sites can temporarily give a customer the extra needed bandwidth. That kind of coordination will require sophisticated operating systems at cell sites and is certainly an area that the cellular manufacturers are now working on in their labs.

When Customers Use Their Data

In a recent disturbing announcement ,Verizon Wireless will be disconnecting service to 8,500 rural customers this month for using too much data on their cellphones. The customers are scattered around 13 states and are a mix those with both unlimited and limited data plans.

Verizon justifies this because these customers are using data where Verizon has no direct cell towers, meaning that these customers are roaming on cellular data networks owned by somebody else. Since Verizon pays for roaming the company say that these customers are costing them more in roaming charges than what the company collects in monthly subscription fees.

Verizon may well have a good business case for discontinuing these particular data customers if they are losing money on each customer. But the act of disconnecting them opens up a lot of questions and ought to be a concern to cellular customers everywhere.

This immediately raises the question of ‘carrier of last resort’. This is a basic principle of utility regulation that says that utilities, such as traditional incumbent telephone companies, must reasonably connect to everybody within their service territory. Obviously cellular customers don’t fall under this umbrella since the industry is competitive and none of the cellular companies have assigned territories.

But the lines between cellular companies and telcos are blurring. As AT&T and Verizon take down rural copper they are offering customers a wireless alternative. But in doing so they are shifting these customers from being served by a regulated telco to a cellular company that doesn’t have any carrier of last resort obligations. And that means that once converted to cellular that Verizon or AT&T would be free to then cut these customers loose at any time and for any reason. That should scare anybody that loses their rural copper lines.

Secondly, this raises the whole issue of Title II regulation. In 2015 the FCC declared that broadband is a regulated service, and that includes cellular data. This ruling brought cable companies and wireless companies under the jurisdiction of the FCC as common carriers. And that means that customers in this situation might have grounds for fighting back against what Verizon is doing. The FCC has the jurisdiction to regulate and to intervene in these kinds of situations if they regulate the ISPs as common carriers. But the current FCC is working hard to reverse that ruling and it’s doubtful they would tackle this case even if it was brought before them.

Probably the most disturbing thing about this is that it’s scary for these folks being disconnected. Rural homes do not want to use cellular data as their only broadband connection because it’s some of the most expensive broadband in the world. But many rural homes have no choice since this is their only broadband alternative to do the things they need to do with broadband. While satellite data is available almost everywhere, the incredibly high latency on satellite data means that it can’t be used for things like maintaining a connection to a school server to do homework or to connect to a work server to work at home.

One only has to look at rural cellular networks to understand the dilemma many of these 8,500 households might face. The usable distance for a data connection from a cellular tower is only a few miles at best, much like the circles around a DSL hub. It is not hard to imagine that many of these customers actually live within range of a Verizon tower but still roam on other networks.

Cellular roaming is an interesting thing. Every time you pick up your cellphone to make a voice or data connection, your phone searches for the strongest signal available and grabs it. This means that the phones of rural customers that don’t live right next to a tower must choose between competing weaker signals. Customers in this situation might be connected to a non-Verizon tower without it being obvious to them. Most cellphones have a tiny symbol that warns when users are roaming, but since voice roaming stopped being an issue most of us ignore it. And it’s difficult or impossible on most phones to choose which tower to connect to. Many of these customers being disconnected might have always assumed they actually were using the Verizon network. But largely it’s not something that customers have much control over.

I just discussed yesterday how we are now in limbo when it comes to regulating the broadband practices of the big ISPs. This is a perfect example of that situation because it’s doubtful that the customers being disconnected have any regulatory recourse to what is happening to them. And that bodes poorly to rural broadband customers in general – just one more reason why being a rural broadband customer is scary.