Methods of enabling multiuser superposition transmission (MUST) in LTE systems are proposed. MUST operation allows simultaneous transmission for multiple co-channel users on the same time-frequency resources. A higher-layer signaling is used for configuring a UE to enable MUST. When a UE is configured by higher layer to enable MUST, the UE will monitor physical-layer control signaling carrying scheduling information and MUST-related information. Depending on whether MUST exists in each subframe, the UE derives the power allocation between the UE and its co-channel UE on allocated resource blocks. The UE also derives the power allocation based on whether it is configured for CRS-based transmission mode or DMRS-based transmission mode.