RAN
Thesis on CRAN : https://backend.orbit.dtu.dk/ws/portalfiles/portal/123876544/ACheckoPhDThesisCRANFinalRC.pdf
https://www.researchgate.net/publication/330924336_Multi-Channel_Access_Solutions_for_5G_New_Radio :Nurul Huda Mahmood
Very good ( CRAN/Protocol Stack)