An eNodeB sends sps-configuration to an UE by using the "RRC Connection Reconfiguration" message.
As per my knowledge, SPS- scheduling is used where data packets are very small and comes to the UE with a regular interval for example: voice data packet.
So when an eNodeB modifies or adds a bearer for an UE, it may sends sps-configuration within the "Radio Resource config dedicated" IE which in turn goes within the "RRC Connection Reconfiguration" message to an UE.
Please correct if I am wrong. Thanks in advance.