Indoor Experiments of an E-SDM Testbed with Channel Prediction

This paper deals with experimental considerations for an eigenbeam-space division multiplexing (E-SDM) system with time division duplex downlink in multiple-input multiple-output channels. Channel information in E-SDM is necessary for a transmitter. If the time difference between the transmit weight calculation from the channel information at a transmitter and the actual transmission is large, E-SDM performance degrades because channel orthogonality is not maintained. In this study, indoor experiments of the E-SDM were performed to evaluate channel error compensation using first order extrapolation. Furthermore, simplification of transmit resource control and reduction of calculation load were proposed. Experimental results showed that channel estimation error compensation by first order extrapolation was very effective and improved bit error rate performance