Dispersed Signal Transmission and Reception Scheme for Full-Duplex Systems

Youngrok Jang,Kyeongjun Ko,Sangjoon Park,Minchae Jung,Kyungsik Min,Sooyong Choi

doi:10.1109/access.2019.2941139

Abstract

A dispersed signal transmission and reception scheme is proposed to cope with self-interference (SI) and inter-user interference (IUI) in full-duplex systems. During transmission, each identical signal of each transmitter is transmitted in multiple time slots after being multiplied by the transmission coefficients corresponding to the individual time slots. During reception, each receiver multiplies the corresponding reception coefficient by the signal received in each time slot and combines all of the signals received during all of the time slots. To cope with SI and IUI, it is shown that the orthogonality conditions between the transmission and reception coefficients should be satisfied in the transmission and reception procedures. The proposed scheme can be operated without knowledge of both the channel state information and signals of the IUI, and without conventional digital SI cancellation procedures. Simulation results show that the proposed scheme has better achievable rates and bit error rates for both downlink and uplink transmissions than conventional full-duplex systems when the signal-to-noise ratios of the desired signal are low, severe interference exists, and the number of users increases.

Highlights

Among the promising technologies used to attain higher spectral efficiencies, full-duplex systems have recently received much attention [1], [2]
Performance degradation inevitably occurs as a result of additional interference between the downlink (DL) and uplink (UL) transmissions encountered by full-duplex systems [1], [2]
The proposed scheme can be operated without knowledge of channel state information (CSI) and signals of inter-user interference (IUI), and without conventional digital SI cancellation (SIC) procedures

Summary

INTRODUCTION

Among the promising technologies used to attain higher spectral efficiencies, full-duplex systems have recently received much attention [1], [2]. DL signal, DL multiuser interference (MUI), SI, IUI, received distortion at the user k, and additive white Gaussian noise, respectively. In (2), the terms on the right-hand side denote (from left to right) the desired UL signal, UL MUI, SI, received distortion at the base station (BS), and additive white Gaussian noise, respectively. Eu,k ∼ CN (0, κu) denote the transmitter noise at the BS and user k with κd , κu 1, respectively, which models the effects of power amplifier noise, non-linearities in the digital-to-analog converter (DAC) and phase noise [5]. 1, respectively, which models the effects of gain-control noise, non-linearities in the analog-to-digital converter (ADC) and phase noise, where rcuo,knv = ycuo,knv − vu and rdco,knv = rdco,knv − vd,k denote the undistorted received signals [5]. The desired DL and UL signals are still affected by the SI and IUI at each user and by the SI at the BS, respectively, since Wd and Gu can only eliminate the DL and UL MUI, respectively

PROPOSED DISPERSED SIGNAL TRANSMISSION

SIMULATION RESULTS

CONCLUSION