- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Adaptive resource allocation in FSO/RF multiuser system with proportional fairness for UAV application
摘要： The combination of free space optic(FSO) and unmanned aerial vehicle (UAV) can be a promising solution to last-mile problem because of FSO high bandwidth and flexibility of UAV. However, FSO is vulnerable to the atmospheric turbulence and transmitter configuration is limited on UAV. Therefore, in this paper, we investigate an adaptive resource allocation strategy to provide relative fair and high transmission capacity for users. In the proposed network model, the downlink scenario is considered and ground station communicates with UAV and its local users by FSO and RF links, respectively. According to the channel conditions and rate requirements from users, channel and power assignments should satisfy the capacity demand in reasonable. To this end, we decompose the original channel and power allocation problem with high computational complexity into low-complexity subproblems, corresponding to channel allocation in RF transmission phase and channel matching and power allocation in FSO transmission phase. Then, a heuristic efficient resource assignment algorithm is proposed to achieve the optimal capacity distribution for users. Numerical results show that the proposed method can asymptotically achieve optimal throughput. Furthermore, system throughput is higher at low transmitting power requirement than those of other existing methods.
关键词： UAV,proportional fairness,mixed FSO/RF,efficient resource allocation,channel capacity
更新于2025-09-23 15:23:52
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Improvement of optical fiber channel capacity using compressed non-orthogonal frequency quadrature amplitude modulation
摘要： A new modulation scheme, that can increase the channel capacity of optical ?ber link, is proposed in this paper. It is implemented by using a non-orthogonal frequency shift keying (FSK), quadrature amplitude modulation (QAM), and sparse sinusoidal sampling based on a compressed sensing. The proposed technique can allow us to have the improved transmission capacity because frequency spacing among digitally sample RF subcarriers becomes much narrower than the channel bandwidth by the non-orthogonality and the total signal length can be reduced by using the sparse sinusoidal sampling. For experimental veri?cation, a 64-non-orthogonal frequency quadrature amplitude modulation (NoFQAM) signal is generated using non-orthogonal 4-FSK and 16-QAM. The total length of 64-NoFQAM signal is reduced up to 60% at the bit error rate (BER) of 4 × 10?5 by the sparse sinusoidal sampling. The BER of 2 × 10?5 was measured at a frequency spacing between digitally sampled RF subcarriers corresponding to 10% of channel bandwidth (500 MHz). The 7.5-Gb/s transmission of 64-NoFQAM signal with the channel bandwidth of 500 MHz was demonstrated successfully by using 50-km and 300-km optical ?ber link.
关键词： Non-orthogonal frequency quadrature amplitude modulation,Sparse sinusoidal sampling,Channel capacity,L1-minimization,Compressed sensing
更新于2025-09-23 15:19:57
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Annals of Computer Science and Information Systems [IEEE 2019 Federated Conference on Computer Science and Information Systems - (2019.9.1-2019.9.4)] Proceedings of the 2019 Federated Conference on Computer Science and Information Systems - Improving Real-Time Performance of U-Nets for Machine Vision in Laser Process Control
摘要： This paper considers a multi-cell network with base stations (BSs) equipped with large dual-polarized antenna arrays. We derive closed-form expressions of network performance in terms of user signal-to-interference-and-noise ratio both with perfect channel state information and in the presence of pilot contamination. In general, a dual-polarized system enjoys the reduction in pilot contamination and multiuser interference due to orthogonal polarizations, while the available BS array dimension is reduced in each polarized direction compared with a monopole antenna setup. The derived results, however, reveal that the performance of a dual polarization system can be optimized by properly setting receive antenna polarizations, and fortunately, the optimal performance behaves identically to that of a monopole-antenna one in massive MIMO. We ?nally verify the observations by numerical simulations.
关键词： dual-polarized antenna,multi-cell,pilot contamination,channel capacity,Massive MIMO
更新于2025-09-23 15:19:57
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Capacity analysis of free space optical communication system under atmospheric turbulence
摘要： In this paper, the analytical channel capacity of the free space optical (FSO) system under weak, moderate and strong turbulence is derived. The FSO channel statistics follows the log-normal distribution under weak turbulence and follows the Gamma–Gamma distribution under moderate and strong turbulence. The three generally used adaptive transmission schemes in FSO communication system are as follows (1) optimal simultaneous power and rate adaptation, (2) optimal rate adaptation with constant transmit power, and (3) truncated channel inversion with a fixed rate. The closed-form approximations for the average ergodic channel capacity for these adaptive transmission schemes under different atmospheric turbulence without any pointing error are derived. Simulation results depict the excellent agreement of the proposed analytical models with the Monte Carlo simulation.
关键词： Channel capacity,Free space optical communication,Signal to noise ratio,Adaptive transmission,Atmospheric turbulence
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - 2x2 Polarized MIMO Antenna Selection Based on Correlation Coefficients
摘要： Multiple-input–multiple-output (MIMO) systems with orthogonal electric and magnetic states of polarization is suggested to make full use of antenna dimensions. Generally speaking, lower correlation coefficients between sub-channels result in higher system capacity, yet for polarized MIMO with orthogonal electric and magnetic antenna dipoles, system under ideal condition of zero correlation may perform less than some actual condition with specific correlation coefficients. Specific pairs of antennas of electric or magnetic antenna dipoles are found to be able to achieve such correlation coefficients, which make them perform better than common polarized MIMO antennas.
关键词： MIMO,channel capacity,magnetic antenna dipoles,polarization,antenna selection,correlation coefficient
更新于2025-09-19 17:13:59
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[IEEE 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Bengaluru, India (2018.12.17-2018.12.19)] 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Polydispersed Metal Nanoparticles at the Interface for Improved Optoelectronic Properties in Perovskite Photovoltaics
摘要： This paper considers a multi-cell network with base stations (BSs) equipped with large dual-polarized antenna arrays. We derive closed-form expressions of network performance in terms of user signal-to-interference-and-noise ratio both with perfect channel state information and in the presence of pilot contamination. In general, a dual-polarized system enjoys the reduction in pilot contamination and multiuser interference due to orthogonal polarizations, while the available BS array dimension is reduced in each polarized direction compared with a monopole antenna setup. The derived results, however, reveal that the performance of a dual polarization system can be optimized by properly setting receive antenna polarizations, and fortunately, the optimal performance behaves identically to that of a monopole-antenna one in massive MIMO. We ?nally verify the observations by numerical simulations.
关键词： channel capacity,dual-polarized antenna,multi-cell,Massive MIMO,pilot contamination
更新于2025-09-16 10:30:52
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Exact distributions for bit error rate and channel capacity in free-space optical communication
摘要： Bit error rate (BER) and channel capacity are two important metrics to assess the performance of free-space optical communication (FSOC) systems. Due to the fading of the optical signal owing to the atmospheric effects, these two quantities behave as random variables. Most of the studies in this direction have focused on the calculation of only the average of these quantities. However, since the complete information about a random variable is encoded in its distribution, it is more informative to examine the latter itself. In this work, the authors derive exact probability density function (PDF) expressions for the BER and the channel capacity for an arbitrary irradiance model. In particular, they investigate these exact results for log-normal, gamma-gamma, and K distributions. For the BER analysis, they focus on the binary phase shift keying and quadrature phase shift keying modulation schemes. The authors' analytical reults are found to be in conformity with Monte Carlo simulations. The exact PDFs of the BER and the channel capacity reveal that there are several instances when the average is unable to capture the actual behaviour of these quantities, and therefore one must be careful in drawing conclusions based on the first moment only.
关键词： binary phase shift keying,bit error rate,quadrature phase shift keying,gamma-gamma distribution,channel capacity,log-normal distribution,K distribution,probability density function,free-space optical communication
更新于2025-09-12 10:27:22
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[IEEE 2018 International Conference on Information and Communications Technology (ICOIACT) - Yogyakarta (2018.3.6-2018.3.7)] 2018 International Conference on Information and Communications Technology (ICOIACT) - Dynamical characteristics of the FSO transmission capacity in the presence of Rician turbulence
摘要： In this paper temporal behavior of the free-space optics (FSO) channel capacity under the influence of Rician turbulence is considered. Expressions for the Cumulative Distribution Function (CDF), Probability Density Function (PDF), and the Level Crossing Rate (LCR) of the transmitted FSO signal exposed to Rician turbulence are derived, and numerical results graphically presented.
关键词： FSO,channel capacity,Rician turbulence,PDF,LCR
更新于2025-09-10 09:29:36
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Compact Quadruple Band MIMO Antenna for 5G Mobile Applications
摘要： A design of compact quadruple band MIMO antenna for 5G mobile applications is proposed. The MIMO antenna consists of 8 antenna elements, each two of them are symmetrically placed on the orthogonal frame corners of the substrate, closely located to each other and connected by a short neutral line. Each antenna element consists of two feeding ports which operate at different frequencies. One feeding port operates at 3.5-3.9 GHz and the other feeding port operates at three bands, which are 2.3-2.5 GHz, 3.3-3.5 GHz and 4.25-4.45 GHz. The radiation efficiencies of all four bands are above 50% and ECC of the antenna elements are below 0.2, the calculated ergodic channel capacities with a 20 dB SNR at four bands reach to 87% of the ideal case at 3.6 GHz, 87.5% at 2.4 GHz, 82.7% at 3.4 GHz and 83.2% at 4.3 GHz, respectively, which are close to the ideal case of 8×8 MIMO system.
关键词： quadruple band antenna,5G mobile communication,channel capacity,mobile antennas,MIMO antenna
更新于2025-09-04 15:30:14
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Dual‐mode and triple‐band 10‐antenna handset array and its multiple‐input multiple‐output performance evaluation in 5G
摘要： A 10-element multiple-input multiple-output (MIMO) handset antenna array with triple-band operation in the long-term evolution band 42 (3400-3600 MHz), band 43 (3600-3800 MHz), and band 46 (5150-5925 MHz) is studied in this article. Acceptable antenna performances are obtained by using polarization and pattern diversity techniques. To assess the multiplexing performances of the handset array in 5G, an 8-element base station array covering 3.4-7.1 GHz is presented and studied. An 8 × 10 MIMO system incorporating 8 transmit antennas, propagation scenario and 10 receive antennas is successfully reported, and its multiplexing performances are evaluated. The computed channel capacities in the low and high bands can be as high as 43.3 bps/Hz and 41.6 bps/Hz, which are promising for multi-gigabit-per-second (multi-Gbps) data transmission in 5G. The effects of user's hand and low MIMO order on the channel capacities are also investigated. Results show the robust performances of the proposed antenna system.
关键词： MIMO antenna,5G,channel capacity,mobile handset
更新于2025-09-04 15:30:14