Is it mandatory to do RACH on all the cells of SENB?

Question

As per my knowledge MAC CE is used to activate CA Scell's, will they use same to activate SENB's Scells

Answer 1

Logically it would not happened that UE sends RACH to all the cells because UE will be getting different radio measurement reports and only best cells are chosen. As per my knowledge, up to 5 (including master cell) cells UE can use because carrier aggregation is supported up to 4 secondary cells and 1 primary cell.
RRC connection reconfiguration includes up to 4 secondary cells configuration.

Comments

UE will do rach on all the cells in SENB,without RACH UE will not get the UL sync.