Statistical CSIT Aided User Scheduling for Broadcast MU-MISO System

Abstract: Recent studies show that the statistical channel state information (SCSI) helps to largely increase the capacity of communication systems when the instantaneous perfect CSI (IPCSI) is unavailable. In this paper, we consider multi-user multipleinput- single-output (MU-MISO) broadcast channels where the transmitter has the knowledge of SCSI. The major issue concerned in our work is to improve the average group-rate of the whole system by scheduling users over different time slots. With SCSI at the transmitter side, we are able to precode signals and hence compute the theoretical achievable group-rate of arbitrary user groups. Based on the group-rates, we propose tier-2 Munkres user scheduling algorithm (T2-MUSA) which leads to higher average group-rate than existing algorithms with generally better fairness. The optimality of the proposed algorithm in energy-fair user scheduling space is proved and we derive a lower bound of a special case to verify the validity of our simulations. In addition, many conventional user scheduling algorithms maintain queue stability by solving a weighted sum-rate (WSR) problem, using queue lengths to represent weight coefficients. Inspired by T2-MUSA we propose a QoS-based Munkres user scheduling algorithm (QB-MUSA) aimed at stabilizing queue lengths and maximizing throughput. In results, we show that QB-MUSA exhibits higher throughput than the conventional weighted sumrate (WSR) based algorithm

Research on mathematical model and calculation simulation of wireless sensor solar cells in Internet of Things

Abstract Wireless sensor is an important part of the Internet of Things, which uses solar cells as power supply. Therefore, it is of great significance to study the characteristics of solar cells. In this paper, a new mathematical model of photovoltaic power generation is established, and the tuning methods of light intensity, temperature, photocurrent, reverse current, and open-circuit voltage are introduced in detail. The simulation experiment of software calculation shows that this method can accurately test the performance characteristics of the PV module. Under different conditions, the mathematical model can calculate the output voltage, the output current, the output power, and the power characteristic curve. The conclusions of this paper have practical application and guiding significance for solar cells as wireless sensor energy sources

Bi-Directional Cuk Equalizer-Based Li-Ion Battery Pack Equalization Control Strategy Research

For the secure usage of battery charging and discharging within electric vehicles, the study of cell pack equalization technology is essential. Therefore, in this paper, an improved Bidirectional Cuk equalizer (BCEQ) structure based on a variable-domain fuzzy PID (VFPID) control equalization strategy is recommended in stages. With the new equalization topology, only half of the capacitive and inductive components are needed to transfer energy between any two individual cells in the power supply. In addition, the proposed VFPID control strategy further improves the efficiency of the equalization model by dynamically adjusting the magnitude of the equalization current parameters. Through simulation experiments, the improved topology was capable of substantially lessening the equalization time and increasing energy utilization by more than 4%. In comparison with the fuzzy PID (FPID) algorithm, around 27.3% faster equalization times can be achieved with the VFPID algorithm; the VFPID algorithm also performed well under the Dynamic Stress Test (DST) condition, demonstrating that the topology and equalization strategy suggested in this paper can successfully address the inconsistency of the FPID algorithm. It has been revealed that the topology and equalization methodology offered in this paper is effective in solving the battery pack inconsistency

Inducing factors and deformation mechanism of the Zhangjiacitang landslide in the Three Gorges Reservoir Area

Abstract Landslides are the most widely distributed geological hazards in the Three Gorges Reservoir Area (TGRA). Understanding the deformation mechanism and evolution of landslides is of great significance for their prevention and control. In this study, we focused on the Zhangjiacitang landslide, a typical bank landslide in the TGRA. We analyzed the relationship between landslide deformation and water level fluctuations and rainfall, based on accumulated displacement monitoring data, to clarify their triggering factors and deformation mechanism. The results show that the Zhangjiacitang landslide is a large-scale accumulation landslide. Under the influence of cyclic water level fluctuations and periodic rainfall, the accumulated displacement–time curve shows a “stepped” characteristic. Heavy rainfall emerged as the primary factor influencing the deformation of the Zhangjiacitang landslide, leading to substantial deformation throughout different periods. The deformation of the landslide exhibited a positive correlation with the intensity of rainfall. In contrast, the impact of water level changes on the landslide deformation was more intricate. A rapid water level drop (> 0.3 m/d) tended to intensify the landslide deformation, while the slow water level drop period (< 0.3 m/d) did not exhibit such an effect. This study emphasizes the need for closely monitoring the landslide status during heavy rainfall periods and rapid water level decline periods. The findings of this study provide a certain reference for landslide monitoring, early warning, prevention and control in the TGRA

Research on optical 32QAM-OFDM-PON access scheme with different numbers of sub-carriers using DMT modulation

An optical 32QAM-OFDM-PON system with different numbers of sub-carriers using discrete multitone (DMT) modulation and demodulation is designed and demonstrated by experiment. Electron-optic generation, directly photoelectric detection, and electrical self-mixing reception of 32QAM-OFDM downstream signals are achieved. 5Gb/s 32QAM-OFDM downlink signals with different numbers of sub-carriers are successfully transmitted over 42 km SMF-28. Peak-to average power ratio (PAPR) characteristic, computational complexity and bit error rate (BER) performance are analyzed. The results show that the sub-carriers numbers of 32QAM-OFDM downlink signals should be carefully selected according to the actual requirements, if spectral efficiency, PAPR characteristic, computational complexity and receiver sensitivity are considered