Can an android phone be converted to SDR using its radio hardware interfaces? I have recently been reading about SDRs and based on what I have understood so far SDR consists of a radio hardware capable of transmitting and/or receiving radio signals within a given radio spectrum range and a software backbone to control its radio operations, so I thought it should be possible to achieve similar operations using an android smartphone therefore I tried to search for projects in the internet and the closest I have found is SDR Touch which requires an external dedicated hardware. Now since a smartphone has so many radio interfaces (Cellular, Wi-Fi, Bluetooth, GPS etc.) is it somehow possible that I can make a project (using root or whatever) that utilizes smartphone's radio components and why isn't there any project that exists performing such functionalities?.
It is very hard because usually radio drivers are proprietary

But there is Nexmon project that turn nexus 5 into SDR