SDR(Software Defined Radio)





Small Cell Forum


Small Cell Forum is not purely for SDR, but I wanted to introduce this since there are some documents that would help a lot for Software Architecture Design for LTE. The specific document that I wanted to introduce is nFAPI and FAPI specifications and this page will be mostly around this document. If you read this document along with analyzing the real source code from other LTE SDR project, you would have much better knowledge on overall architecture of those source code. I don't think the real source code from other LTE SDR project is written directly based on the SCF(Small Cell Forum) FAPI. So you would not see the one to one mapping between the source code and SCF document, but I am pretty sure that this document will help you understand the functionality of the source code.


Followings are a couple of Architecture diagram from nFAPI and FAPI specifications , but this document does not describe all the interface (P2~P10). The document is mostly about PHY / MAC interface. The document has a lot of functional diagram (a kind of uml diagram) that would help you understand the details of PHY/MAC process. I will reuse some of those diagrams in various places in my note.

NOTE : Following diagrams are posted with permission from SmallCellForum.



            • P2 the service discovery interface
            • P3 the positioning interface
            • P4 the network monitor mode interface
            • P5 the PHY mode control interface
            • P7 the main data path interface
            • P8 the PHY diagnostics interface
            • P9 the OAM interface
            • P10 the synchronization, frequency, phase and time