3GPP Long Term Evolution (LTE) Application Programming Interfaces (API's) are pre-compiled and optimized C function libraries for encoding and decoding protocol messages defined within 3GPP standards documents that define ASN.1-based messages (EUTRA-RRC, S1AP, and X2AP).

API's are also available for older, 3G standard ASN.1-based API's such as NBAP, RANAP, RNSAP and RRC.

LTE API's

3GPP TS  36.331  

Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification.

	LTE-RRC Release 8 C API for Windows
	LTE-RRC Release 9 C API for Windows
	LTE-RRC Release 10 C API for Windows
	LTE-RRC Release 11 C API for Windows

3GPP TS  36.413  

Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP)

	S1AP Release 8 C API for Windows
	S1AP Release 9 C API for Windows
	S1AP Release 10 C API for Windows
	S1AP Release 11 C API for Windows

3GPP TS  36.423  

Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 Application Protocol (X2AP)

	X2AP Release 8 C API for Windows
	X2AP Release 9 C API for Windows
	X2AP Release 10 C API for Windows
	X2AP Release 11 C API for Windows

3G API's

3GPP TS 24.007 24.008 24.011

Mobile radio interface signalling layer 3; General Aspects, Core network protocols, and SMS

	NAS Release 8 thru 11 C API for Windows VS 2008
	NAS Release 8 thru 11 C API for Linux 32-bit gcc 4.x

3GPP TS  25.433

UTRAN Iub interface Node B Application Part (NBAP) signalling

	NBAP Release 8 C API for Windows
	NBAP Release 9 C API for Windows
	NBAP Release 10 C API for Windows
	NBAP Release 11 C API for Windows

3GPP TS  25.413

UTRAN Iu interface Radio Access Network Application Part (RANAP) signalling

	RANAP Release 8 C API for Windows
	RANAP Release 9 C API for Windows
	RANAP Release 10 C API for Windows
	RANAP Release 11 C API for Windows

3GPP TS  25.423

UTRAN Iur interface Radio Network Subsystem Application Part (RNSAP) signalling

	RNSAP Release 8 C API for Windows
	RNSAP Release 9 C API for Windows
	RNSAP Release 10 C API for Windows
	RNSAP Release 11 C API for Windows

3GPP TS  25.331

Radio Resource Control (RRC); Protocol specification

	RRC Release 8 C API for Windows
	RRC Release 8 C++ API for Windows
	RRC Release 9 C API for Windows
	RRC Release 10 C API for Windows
	RRC Release 11 C API for Windows