Cell towers started us down the cut the cord life style, the invisible signal that started with just phone access now transmits data and internet to our mobile devices and even vehicles. There are 2 systems in place the first being GSM (Global system for Mobiles) based technology and CDMA (code division Multiple Access) technology. They provide the same function just use technology in different ways to get us to the dame end point, connectivity. These separate paths are older technology and both have merged into what is termed LTE (Long term evolution) and a 4g Standard. AS we move into 5g fully the older GSM and CDMA systems which still are being used in conjunction with 4G LTE signal, will fade away.
The new 5g global system standard is being called 5G-NR.
While this would lead you to believe full inter-compatibility between carriers it does not. They will be speaking the same language but talking on different channels and there is a problem with band frequency compatibility. Hence why you see multiple model variations of a specific brand and model phone. The internal modem is set for the channel of your carrier. Most main stream phone manufactures have overcome this with multi-band modem. That’s why for example, why all Iphone 6 and greater will work on any carrier.
Cell towers “normally” project cellular signal out 360 degrees using a triangle shape. Each of the 3 sides or antenna covers approximately 120 degrees of the full circle. Those 3 sides or sectors and designated ALpha, Beta, and Gama. There are special use antenna that we are not going to discuss here that are more focused directional in nature. Each sector has a preset range or distance that it sends it signal which is adjusted by the carrier to match with other towers to give the best coverage and in theory leave no gap of uncovered area. So by analyzing the phones signal strength the distance from the tower can be calculated. You also already now the antenna or which side of the tower the phone is connected to. By reviewing the the data from adjacent towers a location can be acquire through triangulation