Radio Interface Layer

The Radio Interface Layer (RIL) is a key component of Microsoft's Windows Mobile OS. The technology provided by the RIL is critical for enabling wireless voice or data applications to seamlessly communicate with a GSM/GPRS or CDMA2000 1X modem on a Windows Mobile device. The RIL provides the system interface between the CellCore layer within the Windows Mobile OS and the radio protocol stack used by the wireless modem hardware. The RIL, therefore, also allows OEMs to integrate a variety of modems into their equipment by providing this interface.

The RIL comprises two separate components: a RIL driver, which processes AT commands and events; and a RIL proxy, which manages requests from the multiple clients to the single RIL driver. Except for PPP connections, all interaction between the Windows Mobile OS and the device radio stack is via the RIL. (PPP connections initially use the RIL to establish the connection, but then bypass the RIL to connect directly to the virtual serial port assigned to the modem.) In essence, the RIL accepts and converts all direct service requests from the upper layers (i.e., TAPI) into commands supported and understood by the modem.

Note that the RIL does not communicate directly with the modem, however. Instead, the final link to the modem is typically the standard serial driver provided by the OEM’s platform.

External links

----

* [http://msdn.microsoft.com/en-us/library/aa920475.aspx MSDN: Radio Interface Layer]

* [http://www.intrinsyc.com/docs/services/RIL_whitepaper_MS_Intrinsyc_June2004.pdf RIL White Paper]

* [http://www.freepatentsonline.com/6826762.html RIL Patent information]

* [http://msdn.microsoft.com/en-us/library/aa921520.aspx MSDN: CellCore]

* [http://msdn.microsoft.com/en-us/library/aa922988.aspx MSDN: CellCore Catalog Items]

* [http://msdn.microsoft.com/en-us/library/aa921992.aspx MSDN: RIL Driver]

* [http://msdn.microsoft.com/en-us/library/aa919915.aspx MSDN: RIL Proxy]