Transmit sector selection with link correlation for SDM/OFDM

Abstract

More spectrum-efficient techniques are required for wireless communications with a limited amount of bandwidth. Space division multiplexing (SDM) is one of the most promising techniques for achieving more efficient bandwidth utilisation, since it enables the transmission rate over multiple-input multiple-output chennels to be increased by using multiple antennas on both the transmitter and receiver sides. Recently, since the cost of RF transmitters is much higher than that of antennas, there is a growing interest in techniques that use a larger number of antennas than RF transmitters. These methods rely on selecting the optimal transmitter antennas and connecting them to the respective RF. In this case, feedback information (FBI) is required to select the optimal transmitter antenna elements. However, the transmission of FBI through a feedback channel is limited. Moreover, a multiple antenna system requires an antenna separation of five to ten wavelengths to keep the correlation coefficient below 0.7 to achieve diversity gain. In this case, the base station requires a large space to set up multiple antennas. To reduce these problems, a transmit sector antenna selection while considering the link correlation for SDM/OFDM without FBI is proposed and analysed.