Dynamic Decode-and-Forward Based Cooperative NOMA With Spatially Random Users

Zhou, Yong; Wong, Vincent W. S.; Schober, Robert

doi:10.1109/twc.2018.2810083

Cited by 64 publications

(40 citation statements)

References 28 publications

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“…The main idea of downlink power-domain NOMA is to apply superposition coding at the BS and to perform successive interference cancellation (SIC) at the users except the one that is allocated the highest transmit power [22], [23]. The authors in [24] evaluated the performance of NOMA in practical cellular networks and showed that NOMA with appropriate user pairing and power allocation can achieve better performance than orthogonal multiple access (OMA).…”

Section: Introductionmentioning

confidence: 99%

Intelligent Reflecting Surface for Downlink Non-Orthogonal Multiple Access Networks

Zhou

Shi

2019

2019 IEEE Globecom Workshops (GC Wkshps)

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107

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Reconfigurable intelligent surface (RIS) has recently been recognized as a promising technology that can enhance the energy-efficiency and spectrum-efficiency of wireless networks. In this paper, we consider an RIS-empowered downlink non-orthogonal multiple access (NOMA) network, where the beamforming vectors at the BS and the phase-shift matrix at the RIS are jointly optimized to minimize the total transmit power, taking into account the user ordering, the users' data rate requirements, and the reflecting elements' unit modulus constraints. However, the formulated problem is highly intractable due to non-convex bi-quadratic constraints. To this end, we present an alternating optimization framework to decouple the optimization variables and transform the quadratic programming problem in each alternating procedure into a fixed-rank matrix optimization problem via matrix lifting. By exploiting the difference between the nuclear norm and the spectral norm, we then propose a difference-ofconvex (DC) function representation for the rank function to accurately detect the feasibility of the non-convex rank-one constraints. Moreover, we develop a novel alternating DC algorithm to solve the resulting DC programming problems and prove the convergence of the proposed algorithm. To reduce the implementation complexity, we further propose a low-complexity user ordering scheme, where the ordering criterion is derived in closed-form. Simulation results demonstrate the effectiveness of deploying an RIS and the superiority of the proposed alternating DC algorithm in reducing the total transmit power. Index TermsReconfigurable intelligent surface, non-orthogonal multiple access, joint beamformer and phaseshift matrix optimization, non-convex bi-quadratic optimization, difference-of-convex programming.

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Section: Introductionmentioning

confidence: 99%

Intelligent Reflecting Surface for Downlink Non-Orthogonal Multiple Access Networks

Zhou

Shi

2019

2019 IEEE Globecom Workshops (GC Wkshps)

Self Cite

190

107

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“…which is equal to β (k+1) vi 1 eEi(v 1,i1 I 1,k+1 ) + k+1 i=1 β (k+1) αi eEi(I 1,k+1 /α i ) with the coefficients defined similar to (49) by substituting k + 1 for k. This suggests that the induction step holds and completes the proof by recurrence. At the end, by substituting k = K in (48) and (49) and noting that I 1,K = Bg, one can obtain (28) and (29).…”

Section: Appendix B Useful Integral Equations Over Ei(·)mentioning

confidence: 99%

“…(6.224.1)]. APPENDIX C PROOF OF (28) AND (29) In this appendix, we show how the expectation term involved in V 1 in (27) can be calculated in a closed form over I 1 . To begin with, let us, for the ease of notation, define α k L ′ k p ′ k /(a 1 L 1 P ), k = 1, 2, ..., K, Bg [σ 2 R + C D /g 2 ]/(a 1 L 1 P ), I 1,l K k=l+1 α k |h ′ k | 2 + Bg, l = 1, 2, ..., K − 1, and I 1,K Bg.…”

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confidence: 99%

Uplink Non-Orthogonal Multiple Access Over Mixed RF-FSO Systems

Jamali

Mahdavifar

2020

IEEE Trans. Wireless Commun.

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In this paper, we consider a relay-assisted uplink non-orthogonal multiple access (NOMA) system. In this system, two radio frequency (RF) users are grouped for simultaneous transmissions, over each resource block, to an intermediate relay.The relay then forwards the amplified version of the users' aggregated signals, in the presence of multiuser interference, to a relatively far destination. In order to cope with the users' everincreasing desire for higher data rates, a high-throughput freespace optics (FSO) link is employed as the relay-destination backhaul link. It is assumed that the FSO backhaul link is subject to Gamma-Gamma turbulence with pointing error. Also, a Rayleigh fading model is considered for the user-relay access links. Under these assumptions, we derive closed-form expressions for the outage probability and tractable forms, involving only onedimensional integrals, for the ergodic capacity. Moreover, the outage probability and ergodic capacity analysis are extended to the conventional RF-backhauled systems in the presence of multiuser interference to both relay and destination nodes, and Rician fading for the relay-destination RF link. Our results reveal the superiority of FSO backhauling for high-throughput and high-reliability NOMA systems compared to RF backhauling. This work can be considered as a general analysis of dual-hop uplink NOMA systems as well as the first attempt to incorporate power-domain NOMA in mixed RF-FSO systems.

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“…The Zhong and Zhang analyze the performance of a full‐duplex (FD) NOMA system with cooperative relaying. Recently, the performance of NOMA with cooperative relaying has been widely investigated . Kim and Lee study the capacity performance of relay based NOMA system.…”

Section: Introductionmentioning

confidence: 99%

“…Zhao et al consider a two‐user multi‐relay cooperative NOMA network with distributed space‐time coding and propose two dual RS strategies. Zhou et al propose a dynamic decode–and–forward (DDF)‐based cooperative NOMA scheme for downlink transmission with spatially random users and evaluate the performance of the network under random and distance‐based user pairing strategies.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of nonorthogonal multiple access‐based underlay cognitive relay network

Aswathi

Babu

2019

Int J Communication

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Summary This paper considers cooperative non‐orthogonal multiple access (NOMA) scheme in an underlay cognitive radio (CR) network. A single‐cell downlink cooperative NOMA system has been considered for the secondary network, consisting of a base station (BS) and two secondary users, ie, a far user and a near user. The BS employs NOMA signaling to send messages for the two secondary users where the near user is enabled to act as a half‐duplex decode‐and‐forward (DF) relay for the far user. We derive exact expressions for the outage probability experienced by both the users and the outage probability of the secondary system assuming the links to experience independent, nonidentically distributed Rayleigh fading. Further, we analyze the ergodic rates of both the users and the ergodic sum rate of the secondary network. The maximum transmit power constraint of the secondary nodes and the tolerable interference power constraint at the primary receiver are considered for the analysis. Further, the interference caused by the primary transmitter (PT) on the secondary network is also considered for the analysis. The performance of the proposed CR NOMA network has been observed to be significantly better than a CR network that uses conventional orthogonal multiple access (OMA) scheme. The analytical results are validated by extensive simulation studies.

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Dynamic Decode-and-Forward Based Cooperative NOMA With Spatially Random Users

Cited by 64 publications

References 28 publications

Intelligent Reflecting Surface for Downlink Non-Orthogonal Multiple Access Networks

Intelligent Reflecting Surface for Downlink Non-Orthogonal Multiple Access Networks

Uplink Non-Orthogonal Multiple Access Over Mixed RF-FSO Systems

Performance analysis of nonorthogonal multiple access‐based underlay cognitive relay network

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