| 1 | OFDMA-PON with MQAM downlink for flexible allocation显示文摘In this paper, the 40-Gbps orthogonal frequency division multiple access(OFDMA) technology enabled by subcarrier allocation in the form of integrated architecture for the intra-cell is proposed in the downlink transmission passive broadband optical access system. The data-carrying subcarriers in the inverse fast Fourier transform/fast Fourier transform(IFFT/FFT) size of1 024 points are successfully divided into three sub-channels,in which each sub-channel has 256 useful subcarriers, by using adaptive dynamic bandwidth allocation(DBA). Taking the inherent advantages of M-ary quadrature amplitude modulation(MQAM)modulation mechanism into account, the performance of the absolutely identical MQAM format over the different sub-channels for the downstream OFDMA-passive optical network(PON) is investigated based on the intensity modulation direct detection(IMDD) system by simulations. The results show that three parallel4 QAM or 16 QAM or 64 QAM OFDMA data, which are transmitted over three sub-channels, is more suitable for different sub-channel allocations, respectively. In addition, comparing with single port4/16/64 QAM OFDM over the same access system, the receiver sensitivity economizes – 0.6 d Bm, 0.6 d Bm, 4.6 d Bm at the bit error rate(BER) value of 10-3 respectively. | HE Chao WANG Ruyan TAN Zefu TAN Xiang’an | 2019 | Journal of Systems Engineering and Electronics2019，30，6： | 1 |
| 2 | Particle Swarm Optimization Bat Algorithm Path Automatically Planning Research for Police Drones in Hilly Cities显示文摘Mountain cities are complex asymmetric dynamic network architectures,and the flight of UAVs in this environment is subject to various constraints,while efficiency is a crucial factor in the trajectory planning of police UAVs,which need to maintain high efficiency and safe flight paths between their starting and ending points,but the traditional trajectory planning method cannot meet the requirements of rapid maneuvering of police UAVs.To achieve this,a 3D terrain map is built,an objective function is established for the flight cost in the UAV trajectory planning process,and a planning algorithm called particle swarm optimization bat algorithm(PSOBA)is proposed.PSOBA combines the characteristics of the bat algorithm(BA)and the particle swarm optimization algorithm(PSO)to improve population diversity and resolve the delayed convergence issue in the last phases of BA.Simulation results show that PSOBA is more effective than BA,with a search time for the best solution that is approximately 20.43%shorter and a convergence value of the objective function that is approximately 38%smaller.PSOBA is also able to plan a quicker,shorter,and safer flight path compared to other trail planning algorithms that enhance the bat algorithm.These findings suggest that PSOBA is a powerful algorithm with potential application value in UAV trajectory planning control in the mobile intelligence era.Contribute to the service of public social security. | Jing XUE Zefu TAN Nina DAI Guoping LEI Chao HE | 2024 | Journal of Systems Science and Information2024，12，1： | 0 |
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