Interference Exploitation in Full-Duplex Communications: Trading Interference Power for Both Uplink and Downlink Power Savings

Abstract

This paper considers a multiuser full-duplex (FD) wireless communication system, where a FD radio base station (BS) serves multiple single-antenna half-duplex (HD) uplink and downlink users simultaneously. Unlike conventional interference mitigation approaches, we propose to use the knowledge of the data symbols and the channel state information (CSI) at the FD radio BS to exploit the multi-user interference constructively rather than to suppress it. We propose a multi-objective optimisation problem (MOOP) via the weighted Tchebycheff method to study the trade-off between the two desirable system design objectives namely the total downlink transmit power minimisation and the total uplink transmit power minimisation problems at the same time ensuring the required quality-ofservice (QoS) for all users. In the proposed MOOP, we adapt the QoS constraints for the downlink users to accommodate constructive interference (CI) for both generic phase shift keying (PSK) modulated signals as well as for quadrature amplitude modulated (QAM) signals. We also extended our work to a robust design to study the system with imperfect uplink, downlink and self-interference CSI. Simulation results and analysis show that, significant power savings can be obtained. More importantly, however, the MOOP approach here allows for the power saved to be traded off for both uplink and downlink power savings, leading to an overall energy efficiency improvement in the wireless link.Index Terms-full-duplex, multi-objective optimization, constructive interference, power minimization, robust design.

Multiple Antenna Systems With Hardware Impairments: New Performance Limits

“…In addition, they treat the SI signal as an undesired additive distortion. Whereas, it is justified from the information theoretic definition of mutual information that treating the SI term as mere interference will result in a loss of useful information [24], [25]. Moreover, both research studies did not investigate whether the HWIs exhibit symmetric or asymmetric distortion characteristics.…”

A Scalable Performance-Complexity Trade-off for Full Duplex Beamforming

“…Note that, w.r.t. [23] here we include the receive beamforming in the MOOP instead of assuming a ZF receiver. It can be observed that, due to the substitution of the conventional downlink SINR constraint with the CI SINR constraint, the constraint B1 is now convex.…”

“…Most relevant to the focus of this paper are [21]- [23]. The authors in [21] investigated the power efficient resource allocation for a MU-MIMO FD system.…”

“…They extended their work to a robust and secure FD system model in the presence of roaming users (eavesdroppers) in [22]. In [23], the concept of interference exploitation in multiuser FD systems was presented, where the knowledge of the downlink data symbols at the FD BS was utilized to constructively exploit interference rather than suppress it. In addition to the significant power savings achieved compared to the existing solutions, it was shown that although the concept of constructive interference was applied for downlink transmission, the benefits extend to uplink transmission.…”

Large Scale Antenna Selection and Precoding for Interference Exploitation

“…While the proposed schemes have been specifically tailored for Phase-Shift Keying (PSK) modulation scenarios, recent works have shown that such concepts can be readily adapted to accommodate CI exploitation in Quadrature Amplitude Modulation (QAM) [40], [41]. In fact, the authors in [42] have proven that the benefits of CI can extend to 16-QAM modulations by allowing the predictable interference at the BS to constructively superimpose with the desired signal at the receiver side.…”