Existing multi-input multi-output systems (MIMO) using spatial modulation (SM) have proven superior as reducing complexity while increasing the performance of the radio communication system. The essence of this method is to perform modulation on spatial and temporal domains. The objective of this paper is to give an overview of index modulation SM-MIMO and and to introduce a research orientation to develop and extend this index modulation technique to the frequency domain by applying combined index modulation in traditional OFDM systems. In this way, we hope this new index modulation method will compromise spectrum efficiency, bit error quality, as well as processing complexity. It will create a premise for research and development of 5G network equipments.