MBSFN Transmission/Transmission in MBSFN mode : This refers to a simulcast transmission technique realized by transmission of identical waveforms at the same time from multiple cells. An MBSFN Transmission from multiple cells within the MBSFN Area is seen as a single transmission by a UE.
MBSFN Area : This is an area which consists of a group of cells within an MBSFN Synchronization Area, which are co-ordinated to achieve an MBSFN Transmission.
Except for the MBSFN Area Reserved Cells, all cells within an MBSFN Area contribute to the MBSFN Transmission and advertise its availability.
The UE many only need to consider a subset of the MBSFN areas that are configured, i.e when it knows which MBSFN area applies for the services it wants to recieve.