Joint User Grouping and Decoding Order in Uplink/Downlink MISO/SIMO-NOMA

Do, Dinh‐Thuan; Nguyen, Thanh-Luan; Ekin, Sabit; Kaleem, Zeeshan; Vozňák, Miroslav

doi:10.1109/access.2020.3013835

Cited by 11 publications

(4 citation statements)

References 50 publications

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“…We adopt maximal ratio combining (MRC) beamforming at the receiver as described in [51], where beamforming vector v n is defined as…”

Section: B Uplink Transmissionmentioning

confidence: 99%

Throughput Maximization of Wireless Powered IoT Network With Hybrid NOMA-TDMA Scheme: A Genetic Algorithm Approach

Afridi,

Hameed,

García

et al. 2024

IEEE Access

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In this study, we explore a hybrid non-orthogonal multiple access and time division multiple access (NOMA-TDMA) approach designed to maximize sum throughput in a wireless powered Internet of Things (IoT) network (WPIN). Hybrid access points send energy signals to users on downlink, and users in various groups utilize that harvested energy to transmit information on uplink. This process is facilitated by the NOMA-TDMA scheme wherein users of the same group use NOMA for simultaneous transmissions, and separate time slots are assigned to each group through TDMA. Under this hybrid NOMA-TDMA scheme, the main objective is to enhance the network's sum throughput by jointly optimizing both the allocation of time for downlink and uplink and the downlink beamforming vectors. Given the complex interdependence of variables, the problem is inherently non-convex, making it difficult to solve numerically. Therefore, we reformulate the problem as a bi-level programming problem-the outer-level sub-problem addresses beamforming vectors using a genetic algorithm while the inner-level sub-problem deals with the allocation of downlink and uplink time through the Lagrange multiplier method. Numerical results show that the proposed hybrid NOMA-TDMA scheme outperforms baseline schemes like orthogonal multiple access and equal time allocation, in terms of the sum throughput of the WPIN.INDEX TERMS Internet of Things (IoT), wireless powered IoT network (WPIN), multiple input single output (MISO), wireless energy transfer (WET), wireless information transfer (WIT), energy harvesting, non-orthogonal multiple access (NOMA), orthogonal multiple access (OMA), genetic algorithm (GA), Lagrange multiplier (LM).

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“…We adopt maximal ratio combining (MRC) beamforming at the receiver as described in [51], where beamforming vector v n is defined as…”

Section: B Uplink Transmissionmentioning

confidence: 99%

Throughput Maximization of Wireless Powered IoT Network With Hybrid NOMA-TDMA Scheme: A Genetic Algorithm Approach

Afridi,

Hameed,

García

et al. 2024

IEEE Access

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“…Such a validation method provides a fair comparison for each GS and shows how beneficial or not to join the diversity-based reception scheme. Since the 4 th GS experienced an outage and its record revealed no packets, the assessment process was performed versus the 1 st , 2 nd , 3 rd , 5 th , and 6 th records and the results are shown in Figures 10,11,12,13, and 14, respectively. For more detailed validation results depicted in numbers, Tables VI, VII, VIII, IX, and X, are also provided accompanied with comments.…”

Section: Ml(pktmentioning

confidence: 99%

“…Receiver-based diversity combining is a well-known technique which has been deeply studied, maturely developed, and widely applied in different mobile communication systems. For example, a site-based diversity was overviewed in [11] as an effective scheme to mitigate rain attenuation effects on satellites signals at tropical climates, a cluster diversity combining was suggested to accelerate the delivery of indoor autonomous vehicles' emergency alerts with less required rebroadcasts according to [12], a single-input multiple-output (SIMO) structure was presented to combine two downlinks from two receiving nodes by a Maximal Ratio Combiner (MRC) as a part of the study presented in [13] to improve the performance of a nonorthogonal multiple access (NOMA) network, the deep fading consequences inside tunnels were suppressed by utilizing multiple properly spaced antennas in a diversity scheme as confirmed in [14], MRC was deployed to enhance the performance by combining faded signals received by spatially distributed cellular base stations as depicted in [15], and the study conducted in [16] concluded that increasing transmit and receive antennas improved the performance in high-mobility communication systems even when rapidly switching channels.…”

Section: Introductionmentioning

confidence: 99%

Embracing Small Satellites Into Future 6G Inclusive IoT Coverage: A Deployment of Diversity-Based Theoretical Framework

Al-Anbagi,

Vertat

2023

IEEE Access

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The popular small satellites already attracted attention towards the integration into the future ubiquitous Internet of Things (IoT) networks. Small satellites can act as IoT base stations to efficiently collect data from sensors in remote areas and offload it to ground stations (GSs). The size constraints of small satellites, however, impose limited power resources and tiny antennas onboard. Consequently, weak signals and outages are more probable at GSs. Therefore, GSs must utilize high gain antennas with complex and expensive steering resources to collect such weak signals through a single radio link. This traditional scheme can track only one satellite at a time with more vulnerability to outages resulting from possible severe signal degradations or from steering engine failures. To contribute to a successful integration of the popular small satellites into the future sixth generation (6G) inclusive IoT networks, this work validates the concept of diversity combining in improving the reception of small satellites signals. Six versions of the small satellite VZLUSAT-2's beacon were recorded by six simple software defined radio GSs registered at SatNOGS network and then combined. To assess the quality of the combined version, its errors are compared to the errors of the individual versions. According to the findings, if the GSs worked cooperatively in a diversity mode, they could generate a combined version that was always better than any other individually received stream. Furthermore, such a diversity-based scheme reduces the probability of outages and enables the simultaneous tracking of multiple satellites at each GS.

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“…More sophisticated strategies for creating polarization subsets can be easily employed with the above precoding choice. The topic of user grouping in NOMA has been widely studied in the literature [27], [28]. However, our objective is not to develop an optimal user grouping strategy, but to shed light on the fundamental performance gains that our proposed scheme can render.…”

Section: B Polarization Assignment and Formation Of Subsetsmentioning

confidence: 99%

IRS-Assisted Massive MIMO-NOMA Networks: Exploiting Wave Polarization

Sena¹,

Nardelli²,

Costa³

et al. 2020

Preprint

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A dual-polarized intelligent reflecting surface (IRS) can contribute to a better multiplexing of interfering wireless users. In this paper, we use this feature to improve the performance of dual-polarized massive multiple-input multiple-output (MIMO) with non-orthogonal multiple access (NOMA) under imperfect successive interference cancellation (SIC). By considering the downlink of a multi-cluster scenario, the IRSs assist the base station (BS) to multiplex subsets of users in the polarization domain.Our novel strategy alleviates the impact of imperfect SIC and enables users to exploit polarization diversity with near-zero inter-subset interference. To this end, the IRSs are optimized to mitigate transmissions originated at the BS from the interfering polarization. The formulated optimization is transformed into quadratic constrained quadratic sub-problems, which makes it possible to obtain the optimal solution via interior-points methods. We also derive analytically a closed-form expression for the users' ergodic rates by considering large numbers of reflecting elements. This is followed by representative simulation examples and comprehensive discussions. The results show that when the IRSs are large enough, the proposed scheme always outperforms conventional massive MIMO-NOMA and MIMO-OMA systems even if SIC error propagation is present. It is also confirmed that dualpolarized IRSs can make cross-polar transmissions beneficial to the users, allowing them to improve their performance through diversity.

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Joint User Grouping and Decoding Order in Uplink/Downlink MISO/SIMO-NOMA

Cited by 11 publications

References 50 publications

Throughput Maximization of Wireless Powered IoT Network With Hybrid NOMA-TDMA Scheme: A Genetic Algorithm Approach

Throughput Maximization of Wireless Powered IoT Network With Hybrid NOMA-TDMA Scheme: A Genetic Algorithm Approach

Embracing Small Satellites Into Future 6G Inclusive IoT Coverage: A Deployment of Diversity-Based Theoretical Framework

IRS-Assisted Massive MIMO-NOMA Networks: Exploiting Wave Polarization

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