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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Magnetic Field Imaging: Strengths and limitations in characterising solar cells
摘要： This paper concerns with a relay-aided massive multiple input multiple output (MIMO) cellular network. The exact closed-form expressions of both spectral ef?ciency (SE) and energy ef?ciency (EE) are obtained for downlink single-cell multi-user multi-relay massive MIMO transmission in the pilot-contaminated regime, where the number of users is larger than the pilot sequence length. Based on the theoretical results of SE and EE, we investigate the effects of some system parameters [such as number of antennas at the base station (BS), transmit power at the BS, and transmit power of each relay station (RS)] on system performance, and achieve the tradeoff between SE and EE by power control. Speci?cally, the tradeoff problem is solved by joint optimization over transmit power P of the BS and transmit power pr of each RS, so as to maximize EE while satisfying the SE requirement. With the proposition that EE function is strictly quasi-concave with either P or pr , we propose two optimization methods: 1-D searching and alternate optimization. Comparatively, the former achieves a better performance, while the latter has a lower complexity. Simulation results validate the effectiveness of the two methods.
关键词： spectral ef?ciency,Cellular networks,massive MIMO,relay,energy ef?ciency
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Tianjin, China (2019.8.4-2019.8.7)] 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Research on Optical Fiber IMU Signal Processing Based on Wavelet Algorithm
摘要： This paper concerns with a relay-aided massive multiple input multiple output (MIMO) cellular network. The exact closed-form expressions of both spectral ef?ciency (SE) and energy ef?ciency (EE) are obtained for downlink single-cell multi-user multi-relay massive MIMO transmission in the pilot-contaminated regime, where the number of users is larger than the pilot sequence length. Based on the theoretical results of SE and EE, we investigate the effects of some system parameters [such as number of antennas at the base station (BS), transmit power at the BS, and transmit power of each relay station (RS)] on system performance, and achieve the tradeoff between SE and EE by power control. Speci?cally, the tradeoff problem is solved by joint optimization over transmit power P of the BS and transmit power pr of each RS, so as to maximize EE while satisfying the SE requirement. With the proposition that EE function is strictly quasi-concave with either P or pr , we propose two optimization methods: 1-D searching and alternate optimization. Comparatively, the former achieves a better performance, while the latter has a lower complexity. Simulation results validate the effectiveness of the two methods.
关键词： spectral ef?ciency,Cellular networks,massive MIMO,relay,energy ef?ciency
更新于2025-09-19 17:13:59
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[IEEE 2019 International Vacuum Electronics Conference (IVEC) - Busan, Korea (South) (2019.4.28-2019.5.1)] 2019 International Vacuum Electronics Conference (IVEC) - Design of an Ka-Band Multiple-beam Corrugated Waveguide TWT
摘要： This paper concerns with a relay-aided massive multiple input multiple output (MIMO) cellular network. The exact closed-form expressions of both spectral ef?ciency (SE) and energy ef?ciency (EE) are obtained for downlink single-cell multi-user multi-relay massive MIMO transmission in the pilot-contaminated regime, where the number of users is larger than the pilot sequence length. Based on the theoretical results of SE and EE, we investigate the effects of some system parameters [such as number of antennas at the base station (BS), transmit power at the BS, and transmit power of each relay station (RS)] on system performance, and achieve the tradeoff between SE and EE by power control. Speci?cally, the tradeoff problem is solved by joint optimization over transmit power P of the BS and transmit power pr of each RS, so as to maximize EE while satisfying the SE requirement. With the proposition that EE function is strictly quasi-concave with either P or pr , we propose two optimization methods: 1-D searching and alternate optimization. Comparatively, the former achieves a better performance, while the latter has a lower complexity. Simulation results validate the effectiveness of the two methods.
关键词： spectral ef?ciency,Cellular networks,massive MIMO,relay,energy ef?ciency
更新于2025-09-16 10:30:52
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An Overview of OFDM-Based Visible Light Communication Systems From the Perspective of Energy Efficiency Versus Spectral Efficiency
摘要： In this paper, the energy ef?ciency and the spectral ef?ciency for orthogonal frequency division multiplexing (OFDM)-based visible light communication schemes are studied, which is crucial for practical application with limited energy resources. The conventional schemes, including asymmetrically clipped optical OFDM (ACO-OFDM), pulse-amplitude-modulated discrete multitone, and direct current biased optical OFDM, are compared in terms of energy ef?ciency and spectral ef?ciency relationship. The in?uence of power allocation for asymmetrically clipped dc biased optical OFDM and hybrid ACO-OFDM is also investigated. The energy ef?ciency and spectral ef?ciency of layered ACO-OFDM with a variable layer number are calculated and their relationship is also formulated. These conventional and hybrid modulation schemes are analyzed and compared through computer simulations, which should be considered in practice according to the requirements of illumination and transmission.
关键词： visible light communication (VLC),spectral ef?ciency,orthogonal frequency division multiplexing (OFDM),Energy ef?ciency
更新于2025-09-09 09:28:46
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Downlink resource allocation for dynamic TDMA-based VLC systems
摘要： Visible light communications (VLC) in general and resource allocation for VLC networks particularly have gained lots of attention recently. In this work, we consider the resource allocation problem of a VLC downlink transmission system employing dynamic time division multiple access where time and power variables are tuned to maximize spectral ef?ciency (SE). As for the operational conditions, we impose constraints on the average optical intensity, the energy budget and the quality-of-service. To solve the non-convex problem, we transform the objective function into a difference of concave functions by solving a second order differential inequality. Then, we propose a low-complexity algorithm to solve the resource allocation problem. Finally, we show by simulations the SE performance gains achieved by optimizing time and power allocation over the initial total power minimization solution for the considered system.
关键词： spectral ef?ciency,resource allocation,DC programming,illumination constraint,Visible light communication
更新于2025-09-09 09:28:46