anyone give me a hint to implement L1 for openbsc

Hi list, I want to implement a L1 hardware and software for openbsc. But I am not familiar with openbsc framework. I saw there is a project named osmo-nitb which is a standalone application that implement L2 L3 and some other gsm network function. If I can using my L1 software connect to osmo-nitb through abis-overip? Also I notice another project osmo-bts project which implement BTS-side Layer3 and Layer2 protocol. So can I just implement BTS side L1 then combine with osmo-bts which connect to osmo-nitb? Regards!