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

Abstract

In this paper, we analyze the performance of cooperative power domain non-orthogonal multiple access (NOMA) in power line communication (PLC) networks. Due to the high signal attenuation of the source to user links, a relay aids communication from the source to two users. With half-duplex transmission, the source transmits a superimposed symbol in the first phase. The relay utilizes amplify-and-forward (AF) and decode-and-forward (DF) protocol on the received superimposed signal and forwards it to the users in the second phase. We derive analytic expressions for the outage probability and the system throughput of the proposed system under a PLC log-normal channel with impulsive noise. Based on the results for AF NOMA relaying case, we analyze the system performance at high signal-to-noise ratio (SNR) and derive closed-form lower and upper bounds for the outage probability. Simulation results show an improvement in the outage probability and the system throughput performance of the AF and DF NOMA schemes compared to the NOMA without relaying transmission and conventional orthogonal multiple access scheme. Furthermore, the impact of the channel variance is highlighted in the results. It is shown that the DF NOMA has a better outage probability than the AF NOMA scheme for low channel variance scenarios (i.e., less branches and connected loads in the PLC network). However, as the channel variance increases, AF NOMA scheme has similar outage probability performance as the DF NOMA scheme. In addition, it is shown that the system throughput is enhanced when the relay employs DF relaying compared to AF relaying.

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

“…Hence, the adaptive scheme proposed in [18] showed enhanced throughput performance when compared to both the TDMA and conventional cooperative NOMA schemes. A comparative study of AF and DF protocols for one-way relayaided NOMA scheme in PLC networks was considered in [19]. Based on the results, it was shown that while DF relaying performs better than AF relaying in good fading scenarios, the two relaying protocols achieve similar performance in bad fading scenarios.…”

“…The aforementioned works [16]- [19] focused on one-way relaying under the assumption of perfect SIC. However, perfect SIC is difficult to achieve in practice due to imperfect signal decoding, synchronization, imperfect channel state information (CSI), and high signal attenuation issues [21], [22].…”

“…The users recover their intended signals with the near user utilizing SIC. In contrast to the existing works in [16]- [19], we examine the impact of imperfect SIC in the NOMA PLC TWR network. The previous works in [16] and [17] analyzed only the ergodic capacity performance while [18] and [19] studied only the outage probability performance.…”

“…In contrast to the existing works in [16]- [19], we examine the impact of imperfect SIC in the NOMA PLC TWR network. The previous works in [16] and [17] analyzed only the ergodic capacity performance while [18] and [19] studied only the outage probability performance. This paper presents a more comprehensive analysis of the outage probability and ergodic rates of the proposed system in delay-limited (DL) and delay-tolerant (DT) transmission modes by considering both perfect and imperfect SIC scenarios.…”

“…This paper presents a more comprehensive analysis of the outage probability and ergodic rates of the proposed system in delay-limited (DL) and delay-tolerant (DT) transmission modes by considering both perfect and imperfect SIC scenarios. Furthermore, in contrast to [16]- [19], where the analytic results are expressed in integral form, we derive closed-form expressions for the outage probability and ergodic rate by leveraging the Gauss-Chebyshev quadrature. This technique offers an efficient way to compute the integrals.…”