Successive Decode-and-Forward Relaying With Privacy-Aware Interference Suppression

Abstract

Successive relaying holds the promise of achieving spatial diversity gain for single-antenna users while recovering the multiplexing loss due to the half-duplex relaying in B5G/6G. However, how to mitigate inter-relay interference (IRI) with privacy protection in low complexity remains open. In this paper, we present a successive decode-and-forward (DF) relaying protocol based on an analog network interference cancellation (NICE) method, which may suppress IRI, using linear processing without decoding the signals from the source. More specifically, a relay actively keeps receiving signals from the source, which are then used as prior knowledge to enable an amplify-and-cancel (AC) IRI mitigation strategy. The AC based IRI suppression is capable of improving high information privacy, because a relay does not need to know codebooks used by other relays and will not decode any signals intended for other relays. We obtain the closed-form expression of the minimum residual interference power, based on which the average throughput and the optimal diversity-multiplexing tradeoff (DMT) are presented. The DMT analysis along with simulations shows that the proposed method outperforms conventional two-timeslot half-duplex relaying in terms of the spectral efficiency. It also achieves lower complexity than CAO-SIR based on decodeand-cancel (DC) in [1] and lower IRI than the successive amplify-and-forward (AF) relaying in [2].

A Three-Phase CDRT Strategy Based on Successive Relay for Smart Grid

“…Research shows that SR technology can recover the multiplexing loss of HD relay network while ensuring the diversity gain [14]. However, in the SR system, the relay in the transmitting state will cause interference to the relay in the receiving state, which is called inter-relay interference (IRI) [13,15]. The work in [13] propose a SR based cooperative NOMA (SR−NOMA) system which employs amplify-and-forward (AF) relays instead of DF relays for more flexible in handling the IRI.…”

SNR Threshold-Based Relay Association and Random Phase Rotation for Cooperative Communication

“…To resolve this issue, many self-interference-mitigation methods have been studied [21], [25], [26], [31], [32]. By contrast, because there is no self-interference between retransmitted and received signals at the half-duplex RN, it can be readily implemented and has been actively studied [1], [13], [16], [18]- [20], [22], [24], [27], [28].…”

“…However, second-hop channel state information (CSI) is required at the RN, which would burden the cooperative networks. By contrast, the D&F RN requires more computational capability and consumes relatively more power compared to the A&F RN, and the incorrectly decoded message signals interfere with the message recovery at the DN [13], [15], [16], [19], [22]. To reduce the decoding complexity at the D&F RN, a preprocessingand-forward (PF)-type RN that detects the message symbols and processes them at the symbol level before the retransmission with less computational complexity has been proposed [20], [28].…”

Performance Modeling and Analysis of BASUR-CARQ Protocol Based on Interrelay Interference Cancellation

“…Therefore, the interference cancellation (IC) is required at relay to avoid performance degradation. Wei et al [9] caused relays to actively store the source signals as priori knowledges to cancel IRI. Marey and Moustafa [10] separated the transmission from source and forwarding relay using carriers with the same frequency but in phase quadrature to achieve IRI-free.…”