On the Frequency Allocation for Coordinated Multi-Point Joint Transmission

Hwang, June; Yu, Seung Min; Kim, Seong-Lyun; Jäntti, Riku

doi:10.1109/vetecs.2012.6240133

Cited by 6 publications

(7 citation statements)

References 3 publications

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“…Transmission techniques based on CoMP are originally proposed in long term evolution(LTE) [ 114 ] and LTE advanced [ 115 ] for improving the cell-edge throughput in multi-cell scenarios. Early studies employed directional antennas in order to improve the performance of JT-CoMP in RF [ 116 ] and VLC [ 117 ] systems, where, in the latter case, the APs are equipped with non-conventional directional LEDs pointing to the cell-edge areas. Similarly to the approach considered in FFR, CoMP techniques are also proposed to cooperatively serve users only located at cell borders [ 117 ].…”

Section: Cooperative Schemesmentioning

confidence: 99%

Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC

Morales-Céspedes

Guzmán

Jiménez

2021

Sensors

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Visible light communications (VLC) have received significant attention as a way of moving part of the saturated indoor wireless traffic to the wide and unregulated visible optical spectrum. Nowadays, VLC are considered as a suitable technology, for several applications such as high-rate data transmission, supporting internet of things communications or positioning. The signal processing originally derived from radio-frequency (RF) systems such as cooperative or precoding schemes can be applied to VLC. However, its implementation is not straightforward. Furthermore, unlike RF transmission, VLC present a predominant line-of-sight link, although a weak non-LoS component may appear due to the reflection of the light on walls, floor, ceiling and nearby objects. Blocking effects may compromise the performance of the aforementioned transmission schemes. There exist several surveys in the literature focused on VLC and its applications, but the management of the shadowing and interference in VLC requires a comprehensive study. To fill this gap, this work introduces the implementation of cooperative and precoding schemes to VLC, while remarking their benefits and drawbacks for overcoming the shadowing effects. After that, the combination of both cooperative and precoding schemes is analyzed as a way of providing resilient VLC networks. Finally, we propose several open issues that the cooperative and precoding schemes must face in order to provide satisfactory VLC performance in indoor scenarios.

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Section: Cooperative Schemesmentioning

confidence: 99%

Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC

Morales-Céspedes

Guzmán

Jiménez

2021

Sensors

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“…Thus, the transmitting SNR is an important factor in analysis of CJT in FFR-aided DAS and can not be assumed to be positive infinite. Thus the scenarios in previous literature [5][6] that assume noise is zero or small enough to be ignored are not suitable for the analysis of CJT in FFR-aided DAS. In this paper we select a classic FFR pattern.…”

Section: Decision Making On Cjt or Non-cjtmentioning

confidence: 99%

“…Consider the thermal noise power density N 0 = kT 0 [10] which has been chosen in the simulation setting of most Stateof-the-Art in this area, where k is the Boltzmann's constant k = 1.38 × 10 −23 W/K/Hz and T 0 = 290 K. Thus the thermal noise power density is N 0 = −174 dBm/Hz, which is the value in the simulation of [5] and [6]). Assuming the transmitting power is P t = 43 dBm for 5 MHz bandwidth, the transmitting SNR is γ 0 = 120 dB which is greater than the transmitting SNR threshold calculated from (16).…”

Section: B Receiving Sinrmentioning

confidence: 99%

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SNR Threshold for Distributed Antenna Systems in Cloud Radio Access Networks

Dutkiewicz

Fang

et al. 2015

2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall)

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Abstract-A distributed antenna system (DAS) architecture is a key enabler for Cloud Radio Access Networks (CRAN) where geographically separated base stations are connected to a centralized processing and decision making unit. Many schemes have been proposed to leverage Fractional Frequency Reuse (FFR) and co-ordinated joint transmission between base stations to improve cell-edge performance for static network deployments. In this paper, we investigate dynamic decision making that whether co-ordinated joint transmission should be selected in the downlink of a FFR-aided DAS. We derive the transmitting Signal-to-Noise-Ratio (SNR) threshold that co-ordinated joint transmission can provide better performance if the transmitting SNR is below this threshold. We simulated a three-cell cluster layout with FFR and the numerical results agree with our analytical results. We show that the transmitting SNR threshold is critical in the FFR-aided DAS analysis and can be used as a guide in the CRAN network planning and the evaluation of DAS performance.

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“…6,7 Additionally, the convex optimization method was applied to derive the optimal control solution under OEI conditions. [8][9][10] However, to incorporate these solutions into OPPAV's existing control law, changes would have to be made to the architecture of the mixer controller that generates motor commands. Such alterations would escalate the complexity of the control software.…”

Section: Introductionmentioning

confidence: 99%

Evaluating one engine inoperative conditions in subscale electric vertical take-off and landing aircraft: An in-depth tethered hover test analysis

Kang,

Cho,

Choi

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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The direction of propeller rotation in a distributed electric-powered vertical take-off and landing (eVTOL) aircraft significantly influences control forces and induced drag during both helicopter and fixed-wing modes. This study proposes a strategy to determine the most effective rotational direction for each propeller. This approach effectively mitigates one-engine-inoperative (OEI) conditions during helicopter mode for a subscale eVTOL referred to as the optionally piloted personal air vehicle (OPPAV). Moreover, the study developed an optimal control law using the linear programming method, which minimizes the maximum power required for individual motors under OEI conditions. The lowest maximum power was achieved under OEI conditions when both the front and rear propellers in each pod rotated in the same direction. Furthermore, to validate this proposed control law, a tethered hover test was performed using the subscale OPPAV under OEI conditions. Our findings demonstrate that determining the rotational direction of propellers using the newly proposed reconfiguration control method significantly enhances the safety of eVTOL aircraft operating under OEI conditions.

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On the Frequency Allocation for Coordinated Multi-Point Joint Transmission

Cited by 6 publications

References 3 publications

Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC

Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC

SNR Threshold for Distributed Antenna Systems in Cloud Radio Access Networks

Evaluating one engine inoperative conditions in subscale electric vertical take-off and landing aircraft: An in-depth tethered hover test analysis

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