Performance Analysis of Two-Way Relaying in Cooperative Power Line Communications

Abstract

This paper studies the performance of a half-duplex (HD) two-way relay (TWR) in power line communication (PLC) over a log-normal fading channel with impulsive noise. We consider the two common relaying protocols: amplify-and-forward (AF) and decode-and-forward (DF). For the DF relaying, we apply physical-layer network coding (PNC) and analog-network coding (ANC) to the PLC TWR. We derive analytic expressions for the average sum capacity and the outage probability of the system. The Monte Carlo simulations are provided throughout to validate our analysis. The analytical results show a tight approximation to the simulation results. We compare the one-way relay (OWR) to the TWR and show that the HD spectral efficiency loss incurred by the OWR can be sufficiently mitigated in PLC. However, the outage probability of the TWR is inferior to that of the OWR. To enhance the outage performance of the PLC TWR, we implement a hybrid PLC/wireless (HPW) system, where all nodes are equipped with the PLC and wireless capabilities. Data transmission occurs over the two parallel links. The diversity in the transmission allows the TWR to improve its outage performance in the AF and DF protocols. The impact of the impulsive noise, inherent to the PLC channels, is also highlighted in the simulation results. It is shown that the impulsive noise severely impairs system performance. INDEX TERMS Two-way relaying, average capacity, outage probability, power line communication (PLC), PLC/wireless diversity.

Cooperative Non-Orthogonal Multiple Access over Log-Normal Power Line Communication Channels

“…Our results are validated through Monte Carlo simulations averaged over 10 5 channel realizations. To characterize the power line attenuation, we adopt the following parameters: b 0 = 9.4 × 10 −3 , b 1 = 4.2 × 10 −7 , k = 0.7 and f = 30 MHz [9]. The power allocation coefficients of the NOMA transmission are fixed such that a 1 = 0.75 and a 2 = 0.25 [19][20][21].…”

“…The advent of NOMA has enabled research on many conventional techniques, one of which is cooperative relaying [5][6][7][8][9]. In cooperative communications, the relay usually operates with amplify-and-forward (AF) or decode-and-forward (DF) protocols where the advantage of the AF protocol lies in its low processing cost compared to the DF protocol [9]. However, it is shown that the two protocols generally achieve very similar performance when the relay to user link is unreliable [10].…”

Two-Way Relaying Non-Orthogonal Multiple Access With Imperfect Successive Interference Cancellation in Power Line Communications

“…Denote the S 1 to R and S 2 to R channels as h 1 and h 2 , respectively. To simplify the analysis, we assume that the two hops are independent which is a common assumption in the literature [11], [12], [16] and [17]. We assume that the MAC and BC channels are reciprocal in the time division duplex (TDD) operation with negligible pilot overhead [26], [27].…”

“…In [11], AF two-way relays (TWRs) exploit network coding to facilitate bidirectional communication between two nodes. For AF and DF relaying, the authors of [12] derived closed-form expressions for the ergodic capacity and showed that TWRs can greatly improve the spectral efficiency (SE) compared to one-way relays (OWRs) in PLC networks. Furthermore, multiple-input multiple-out (MIMO) and orthogonal frequency division multiplexing (OFDM) combined with optimal power allocation are shown to achieve the dual goals of robustness against frequency selectivity and high capacity performance [13], [14].…”

“…Therefore, the TWR is an effective relaying scheme to ensure high link reliability and SE. We consider an in-door PLC network where the channel and noise are modeled by the log-normal distribution and Bernoulli-Gaussian model, respectively [12]. With the relay as the reference, the users are denoted as near and far users based on their attenuation.…”