Development of wireless communication technologies for future multi-gigabit data transmission

For future wireless communications, it is required to use high frequency bands for high data rate communications. However the energy consumption would be enlarged if wide band transceivers are employed, thus the techniques for improving spectrum efficiency should be also studied. This paper, firstly introduces a setup of millimeter-wave wireless transmission equipment based on OFDM scheme, it shows a realization of over gigabit transmission. Next, two spatial multiplexing techniques, “line-of-sight (LOS) multi-input-multi-output (MIMO)” and “twisted radio wave” are introduced to obtain more high date rate transmission. The maximum capacity with spatial multiplexing can be obtained in LOS channels by employing specifically designed antenna array to preserve the orthogonality of MIMO channels. From several experiments, realizations of spatial multiplexing in LOS environments are obtained. They would be steps for multiple-gigabit transmission using spatial multiplexing.