AA.3 Association between Midambles and Channelisation Codes for special default midamble allocation
25.2213GPPPhysical channels and mapping of transport channels onto physical channels (TDD)Release 17TS
The following mapping schemes apply for the association between midambles and channelisation codes if no midamble is allocated by higher layers. Secondary channelisation codes are marked with *. These associations apply for both UL and DL.