The items that need simulation include: SINR vs MCS/RB，Interference Margin，all kinds of gain(such as HARQ gain, scheduling gain, BF gain, IRC gain, TTI Bundling gain...)
The link-level simulation is generally used to get the demodulation threshold in L1, and may also be used to get the HARQ gain, IRC gain, TTI Bundling gain, BF gain(expressed in dB, such as UL IRC is xdB better than UL MRC, or DL TM7 BF is xdB better than TM2).
The system-level simulation is generally used to get the spectral efficiency under different configurations, such as DL OL/CL MIMO, DL BF and UL MRC/IRC. The HARQ/IRC/BF gains are generally expressed in percentage(for example, the cell spectral efficiency of OL MIMO is x% better than SIMO, or TM7 BF is x% better than TM2)