System on chip

SoC (system in chip) 
The main component of a smartphone is processor because it's control all the hardware. You know that processor (Mediatek P50, P60), (snapdragon625, 636, 670), (Kirin 970) etc. Actually it's an SoC, processor it's also a part of SoC. The main component of SoC is processor (C.P.U) it's further classified as single core, dual core, quard core, octa core and architecture and clock speed. The processor is placed in SoC processor is also control all component on SoC.
The second most part is memory you know as RAM most of time the RAM  us implemented on SoC. SoC control what size and what type of the RAM be used.

The third main component is GPU (graphic processing unit). It's control like Game processing. The fourth main component is North page it's help to connect SoC with other component. There is also South page which control all Input and output function. Radio is aso on SoC which use as to select band like 2G, 3G, 4G and other Radio is use for Bluetooth and WIFI.