Optimization of transmission spatial layer selection with unreliable RI in MIMO-OFDM systems

This paper investigates the optimization of transmission spatial layer selection with unreliable rank indicator (RI) in downlink MIMO-OFDM systems. Taking the relative condition number of the channel matrix into consideration, we propose a condition number based RI selection algorithm at UE side. Using the proposed condition number based RI selection algorithm, we elaborate a transmission spatial layer selection scheme based on the predicted condition number for each transmission resource block (RB) at eNB side. Simulation results show that both the condition number based RI selection algorithm and spatial layer number selection scheme yield up significant throughput improvement for MIMO-OFDM systems.