LTE Triangulation for Indoor Asset Tracking

What Is LTE?

LTE stands for long-term evolution and refers to the standardized path 3GPP has set for communications companies to upgrade their network from 3G (3rd generation) to 4G (4th generation) mobile networks. Due to the high standards set for a network to be considered 4G, many companies have marketed LTE or 4G LTE to express that their networks are moving towards or are close to 4G but haven't quite reached the rigorous minimum requirements.

How Does LTE Triangulation Work?

There are several pieces of data used in triangulation calculations that can be obtained from cell towers. The first is the signal strength, which is used to calculate a device's distance from a cell tower. The second is the angle. Cell towers have multiple antennae that send and receive signals, making it possible to know a device's direction relative to a cell tower. The third piece of information used in the triangulation calculation is the location of the tower itself. By combining these three pieces of information from several cell towers, you can determine the position of an IoT device.

LTE triangulation has been used for many years—especially prior to GPS. The main application was for operators to be able to identify the approximate location of an emergency 911 call. Other applications include refining an indoor position when GPS does not have a line of sight to a device.

Advantages

LTE provides a couple of advantages. The first advantage is a large amount of LTE infrastructure to be able to tie into and begin to use. The second advantage is the long-range over which a signal can travel. These two advantages allow for a lot of flexibility. You can attach a cellular antenna to an object, plug it into a cell network, and begin tracking the object.  

Disadvantages

The major disadvantage of LTE triangulation is its inaccuracy. The accuracy of LTE triangulation ranges from dozens of meters to a few hundred meters. This is due to large variances in signal strength resulting from interference and the large angles that cell antennae cover. In indoor environments, the accuracy of LTE won't be nearly as high as other connectivity options that rely on signal strength such as WiFi or Bluetooth.

Applications

Currently, LTE is usually used as a fallback for when other technologies are not effective. For instance, your phone will resort to using LTE triangulation when it cannot get an accurate position using GPS. Another application includes tracking a package from the sender to the receiver. A package will go through warehouses and many forms of transportation before it reaches you. LTE can track it effectively all the way. LTE is an effective solution when reliability is crucial but accuracy isn't a major requirement.