After more than 20 years as a Switch Engineer and part owner for a major wireless carrier, I still find the most common question I am asked even though I am retired is “Why Don’t I Have Cell Phone Service”. This is really not a very difficult question to answer once you have the understanding of how cell phones work and the different carriers you may have service through.
First let me explain that there are two major types of Digital Phones. One is CDMA which is the main service carriers like Verizon and Sprint use and then there’s GSM which is what AT&T and T-Mobile use. There are a few others but they are not as widely used in the industry at this time. These two digital technologies operate totally different from each other and are not compatible with each other. In other words at this time you cannot use a Verizon phone on a AT&T system and vice versa.
Now let’s say you are standing next to your friend and he has phone service and you do not. Most likely one of you has a CDMA phone and the other is a GSM phone. Let’s say Friend “A” is on AT&T and Friend “B” is on Verizon. Since these digital technologies are not compatible at this time then it would require both carriers to have a Cell Site system in the general area as to where you are. Keep in mind in a perfect world (Flat with no trees) a cell site will talk on average about 20 air miles. So you will both need to be within that distance to the cell tower. As we all know it’s not a perfect world so expect anywhere from 10 to 15 miles in Rural country and up to 5 miles in Urban. That is the basics of the causes. Now let me explain why there isn’t always a tower where people think there should be one.
Below I will be listing some numbers. These numbers are for reference only and will be adjusted by each carrier based on their business model. But the numbers I use are very close to what they may use.
First thing that will determine if a carrier places a cell tower in a general area is how much revenue they can generate and what is the total payback of the site. This means how many calls will be made and how many years it will take for the site to break even between build and maintenance costs and revenue. On most systems they shoot for a 24 to 48 month payback. They also look at things such as population and road traffic. They will need to see if they can get on average about 2000 customers in the area. Thus based on the population and the number of other carriers in the area this can become quite difficult in small populated areas. The Average cost for a cell site is about $750K. This includes everything from a tower to equipment and man power to get it up and running from scratch.
Let’s say a carrier can now justify a tower in a particular area. The next biggest hurdle they run into is local governments and the citizens themselves. Everyone wants Cell Phone service but no one wants a tower in the area where they can see it and take away from their view. Most people want their cake and eat it too. Also a lot of local Governments have instituted a ban on new towers and thus this makes it even more difficult. Then of course you have things like the FAA if you are near an Airport.
If for one of the above reasons a carrier cannot put a tower up where they would like. They now are forced to co-locate on another tower in the area. This is being done more and more but this also causes other issues. The higher on the tower you place the antenna’s the better coverage you can get. Thus, the first one or owner will usually get better coverage. If one carrier has to share a tower with another, this means that the first carrier will have an advantage over the other. Thus making it hard to get customers the service they want and expect. Also, if they are competing against each other, the one carrier that owns the tower can make the lease so high that it takes the second carrier beyond their justification for being in the area to begin with. In other words carrier “A” can make it too expensive to compete against carrier “B” in an area.
Now you see why one person can have phone service in an area and another doesn’t. This is why it’s important for the consumer to look at where they want their phone to work before they sign a contract with a carrier. Most places, if Carrier “A” isn’t there and Carrier “B” is, you may have a chance to roam but then Carrier “C” must be using the same digital technology that you have for it to work.
Posted in Misc Topics and tagged att, cdma, Cell Phone, Cell Site, cellular phone, Code division multiple access, gsm, mobile phone, service, tower, Verizon, wirelesswith no comments yet.