Inter-Terminal Interference Evaluation of Full Duplex MIMO Using Measured Channel

Abstract

The usage of this PDF file must comply with the IEICE Provisions on Copyright. The author(s) can distribute this PDF file for research and educational (nonprofit) purposes only. Distribution by anyone other than the author(s) is prohibited.SUMMARY In-band full-duplex (FD) Multiple-Input and Multiple-Output (MIMO) communication performs uplink and downlink transmission at the same time using the same frequency. In this system, the spectral efficiency is theoretically double that of conventional duplex schemes, such as Time Division Duplex (TDD) and Frequency Division Duplex (FDD). However, this system suffers interference because the uplink and downlink streams coexist within the same channel. Especially at the terminal side, it is quite difficult for the terminal to eliminate the interference signals from other terminals since it has no knowledge about the contents of the interference signals. This paper presents an inter-terminal interference suppression method between the uplink and downlink signals assuming the multi-user environment. This method uses eigen-beamforming at the transmitting terminal to direct the null to the other terminal. Since this beamforming technique reduces the degrees of freedom available, the interference suppression performance and transmitting data-rate have a trade-off relation. This study investigates the system capacity characteristics in multi-user fullduplex MIMO communication using the propagation channel information measured in an actual outdoor experiment and shows that the proposed communication scheme offers higher system capacity than the conventional scheme. key words: MIMO, full duplex, interference reduction, inter-terminal interference

Partial Nulling Regularized Block Diagonalization Using Unfair Channel Selection for Post-Coding with Low-Complexity

“…In (8), the complexity of ΣH k Σk + αI −1/2 is K (18N T + Ni ) in [19]. Since the dimensions of Vk and ΣH k Σk + αI −1/2 are N T × N T , the complexity of multiplication between Vk and ΣH k Σk + αI −1/2 is 8KN 3 T .…”

“…According to the IEEE 802.11 ac and 802.11 ax, MU-MIMO systems are available. In [7,8], the performances of MU-MIMO are shown in actual indoor and outdoor environment. MU-MIMO systems are expected to provide significant multiplexing and diversity gains while MU-MIMO systems resolve some of the issues associated with conventional single user (SU) MIMO.…”