Relay node is introduced in LTE-advanced. Relay node has less transmission power as compare to macro eNodeBs . But the relay node can be deployed with the macro eNodeBs to provide enhanced coverage and capacity at the cell level.
In case of MBMS services, there is a term MBSFN area. All the cells/eNodeBs belong to a MBSFN Area are timely synchronized. When all the eNodeBs or a subset of eNodeBs transmit same data at the location (frequency) and time. Even at the cell edge , there is no impact on data quality receives by an UE. From this understanding, I don't think so relay node need to be deployed.
