Dynamic transmission mode selection in LTE/LTE-Advanced system

Recently, the LTE (Long Term Evolution) and LTE-Advanced systems, developed by the 3GPP (Third Generation Partnership Project), has been proposed as the candidate for the 4G systems (forth mobile communication systems). The combination of OFDM (orthogonal frequency division multiplexing) and MIMO (multiple-input multiple-output) transmission technologies has been introduced into LTE systems for achieving high system performance required by 4G systems. Furthermore, the closed-loop concept with codebook based precoding MIMO and dynamic transmission mode selection, termed as RI (rank indicator) selection, have also been deployed in LTE systems to provide robust link connection and large cell coverage. In this manuscript, the authors focused on the study of dynamic transmission mode selection and its implementation in LTE systems. Different RI selection schemes were proposed in this manuscript with the corresponding downlink performance evaluation. According to the analytical and numerical results, the authors conclude that the mutual information based scheme is the best candidate for RI selection in LTE/LTE-Advanced compliant systems.