Design and implementation of Radio Interface layer in Android video telephone system

RIL (Radio Interface layer) is a middle layer between applications and wireless module of the protocol stack, it is achieved differently in a variety of mobile platforms, but basically completes the same function which provides voice services, SMS services, data services and so on. In the Android system, as a new wireless communication business, the implementation of video telephone is more complex compared with normal voice. It needs to modify and expand towards RIL layer. This article will focus on the specific design and implementation of RIL module to illustrate.