Energy Efficiency Optimization for Wireless Power Transfer Enabled Massive MIMO Systems With Hardware Impairments

Wang, Zhengqiang; Yang, Xiaona; Wang, Xiaoyu; Yang, Xiaoxia; Fan, Zifu

doi:10.1109/access.2019.2935146

Cited by 12 publications

(14 citation statements)

References 37 publications

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“…This section presents numerical results on the performance of the proposed CSI-free RAB scheme. We assume a pathloss model with exponent 2 and a non-distance dependent loss of 40 dB (@2.4 GHz), i.e., β i = 10 −4 d −2 i , while the PB's total transmit power is set to 3 W, which matches practical PB hardware figures 9 . The performance of RAB is evaluated assuming the PB is equipped with a stepper rotary motor with M equally-spaced steps as recommended in Section III-B.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Meanwhile, the energy harvested by S i is E i = g(P i ), where g is a real function modeling the relation between the incident RF power and harvested power. Herein, we consider a simple linear EH model, i.e., g(P i ) = ηP i , where η ∈ [0, 1), for analytical tractability, thus facilitating the discussions and deriving important performance insights as in [5], [8], [9], [12], [17]. Note that using the linear model allows us to state that E[g(P i )] = g(E[P i ]), thus we can refer to power and energy indistinctly by normalizing the EH time, but more importantly, maximizing the average harvested energy translates to maximizing the average RF power, and we can focus on the latter.…”

Section: A Signal Modelmentioning

confidence: 99%

“…They showed that the number of deployed PBs play a much more relevant role for performance improvement than the number of antennas per-PB. On the other hand, the potential benefits of using massive antenna arrays for WET are discussed in [8], while an energy efficiency optimization for massive multiple-input multiple-output (MIMO) systems considering the hardware impairments at the EH sensors is carried out in [9]. The overall power transfer efficiency of a massive MIMO system is investigated in [10] as a function of the number of transmit antennas and number of EH devices.…”

Section: Introductionmentioning

confidence: 99%

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CSI-free Rotary Antenna Beamforming for Massive RF Wireless Energy Transfer

López¹,

Alves²,

Montejo‐Sánchez³

et al. 2021

Preprint

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Radio frequency (RF) wireless energy transfer (WET) is a key technology that may allow seamlessly powering future massive low-energy Internet of Things (IoT) networks. To enable efficient massive WET, channel state information (CSI)limited/free multi-antenna transmit schemes have been recently proposed in the literature. The idea is to reduce/null the energy costs to be paid by energy harvesting (EH) IoT nodes from participating in large-scale time/power-consuming CSI training, but still enable some transmit spatial gains. In this paper, we take another step forward by proposing a novel CSI-free rotary antenna beamforming (RAB) WET scheme that outperforms all state-of-the-art CSI-free schemes in a scenario where a power beacon (PB) equipped with a uniform linear array (ULA) powers a large set of surrounding EH IoT devices. RAB uses a properly designed CSI-free beamformer combined with a continuous or periodic rotation of the ULA at the PB to provide average EH gains that scale as 0.85 √ M , where M is the number of PB's antenna elements. Moreover, a rotation-specific power control mechanism was proposed to i) fairly optimize the WET process if devices' positioning information is available, and/or ii) to avoid hazards to human health in terms of specific absorption rate (SAR), which is an RF exposure metric that quantifies the absorbed power in a unit mass of human tissue. We show that RAB performance even approaches quickly (or surpasses, for scenarios with sufficiently large number of EH devices, or when using the proposed power control) the performance of a traditional full-CSI based transmit scheme, and it is also less sensitive to SAR constraints. Finally, we discuss important practicalities related to RAB such as its robustness against non line-of-sight conditions compared to other CSI-free WET schemes, and its generalizability to scenarios where the PB uses other than a ULA topology.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: A Signal Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

CSI-free Rotary Antenna Beamforming for Massive RF Wireless Energy Transfer

López¹,

Alves²,

Montejo‐Sánchez³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…In the massive MIMO system, a large number of antennas, e.g., even hundreds of antennas, are used to support the high gain beamforming and spatial multiplexing on a large scale. Currently, many efforts have been devoted to the performance analysis and optimization in the massive MIMO systems [2]- [6]. Energy efficiency optimization for wireless power transfer (WPT) enabled massive MIMO systems is investigated in [2].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, many efforts have been devoted to the performance analysis and optimization in the massive MIMO systems [2]- [6]. Energy efficiency optimization for wireless power transfer (WPT) enabled massive MIMO systems is investigated in [2]. For a massive MIMO system equipped with a uniform rectangular array (URA), an iterative rank-reduction omnidirectional…”

Section: Introductionmentioning

confidence: 99%

Analysis of Semi-Blind Channel Estimation in Multiuser Massive MIMO Systems With Perturbations

Wang

Song

2019

IEEE Access

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In the massive multiple-input multiple-output (MIMO) systems, pilot contamination and signal perturbation are two important issues in the semi-blind channel estimation methods. To evaluate the effects of pilot contamination and signal perturbation, the covariance matrix of the received signal should be obtained. In specific, the eigenvectors associated with the K largest eigenvalues of the ideal covariance matrix, contain the subspace information of the desired signals, in which the interference and partial noise are eliminated because of asymptotic orthogonality of the fading matrix. Since it is quite difficult to acquire the ideal covariance matrix, the sample covariance matrix calculated by the finite data samples is adopted to approximate the ideal covariance matrix in practice. However, the gap between the ideal covariance matrix and the sample covariance matrix leads to signal perturbation. In this paper, the perturbation analysis of a semi-blind channel estimation in the massive MIMO systems is presented. Simulation results verify the validity of our perturbation analysis. Furthermore, it is demonstrated by simulations that signal perturbation affects system performance by reshaping the eigenvectors and eigenvalue distributions of the target cell and interfering cells. INDEX TERMS Massive MIMO, pilot contamination, semi-blind channel estimation, signal perturbation.

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Hybrid Grey Wolf Optimization with Cuckoo Search‐based optimal channel estimation for energy efficient massive multiple input multiple output

Indumathi¹,

Rani²

2022

Int J Communication

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Summary The massive multiple input multiple output (mMIMO) provides reliable base station (BS) for the mobile users (MUs) with CSI (channel state information) and jointly offers spectral efficiency (SE) and energy efficiency (EE). Conversely, because of the existence of multiple transceivers at both the transmitter and receiver side, the channel estimation (CE) issue is increasingly complex and expensive in terms of hardware and energy utilization. Hence, we have proposed an effective Hybrid Grey Wolf Optimization with Cuckoo Search (GWO‐CS) based optimal channel estimation for developing energy efficient mMIMO. The proposed GWO‐CS selects the optimal channel by jointly optimizing the spectral efficiency and reduces the SINR (signal to interference plus noise ratio). Experimental analysis of the performance of the proposed approach is carried out using existing approaches. The results obtained show that, the EE of the proposed GWO‐CS based CE provides 15–37 Mbits for varying quantization bits, 22.5–25 Mbits for different user equipment (UE) ranges and 7–24 Mbits for various SE. However, the existing approaches fail to provide such EE and this proves the efficiency of proposed approach.

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Energy Efficiency Optimization for Wireless Power Transfer Enabled Massive MIMO Systems With Hardware Impairments

Cited by 12 publications

References 37 publications

CSI-free Rotary Antenna Beamforming for Massive RF Wireless Energy Transfer

CSI-free Rotary Antenna Beamforming for Massive RF Wireless Energy Transfer

Analysis of Semi-Blind Channel Estimation in Multiuser Massive MIMO Systems With Perturbations

Hybrid Grey Wolf Optimization with Cuckoo Search‐based optimal channel estimation for energy efficient massive multiple input multiple output

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