MIMO mode switching algorithm based on CQI correction of TD-LTE

In practical wireless environment, channel status always changes due to the movements of mobile terminals, and hence it is difficult to ensure the system efficiency by using single multiple input multiple output (MIMO) mode. Actually, various transmission and multiple input multiple output (MIMO) modes are defined in long term evolution (LTE) system. For different channel conditions, the base station can switch the MIMO modes adaptively based on the feedback information of user equipment (UE). This paper proposes a MIMO switching algorithm of TD-LTE based on channel quality indicator (CQI) correction. In our proposal, a base station selects a corresponding MIMO mode according to current channel status estimated by using the spectral efficiency of modified CQI and block error rate (BLER). Our proposal can compatibly support the terminal which does not allow antenna alternative transmission in dual-stream beamforming, and reduces the deviation of reported CQI. The simulation results of intra-mode switching and inter-mode switching of TM3 and TM8 justifies the effectiveness of the proposed MIMO switching algorithm.