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991.
With the objective of taking full use of channel resource, we proposed two utility based dynamic subcarrier allocation (DSA) algorithms for the single carrier frequency division multiple access (SC-FDMA) system, which are the proportional fair frugality constrained (PF-FC) algorithm and the weighted proportional fair frugality constrained (WPF-FC) algorithm. The two proposed algorithms are designed under the frugality constraint (FC) control consideration so as to avoid service rate waste and improve the spectrum efficiency. Moreover, the queuing buffer model in this paper is established on a finite size structure rather than the traditional infinite queuing manner, which is more consistent with the practical transmission condition. Simulation results indicate that the two proposed algorithms can both achieve significantly better system rate-sum capacity and quality of service (QoS) performance than their primary algorithms, and are more applicable for the heterogeneous traffic. 相似文献
992.
Throughput oriented forwarders selection analysis for opportunistic routing in wireless mesh network
Opportunistic routing explicitly takes advantage of the broadcast nature of wireless communications by using a set of forwarders to opportunistically perform packet forwarding. A key issue in the design of opportunistic routing protocols is the forwarder list selection problem. This paper proposes a novel routing metric which shows the end-to-end throughput and a corresponding throughput oriented opportunistic routing forwarder-selecting algorithm throughput oriented forwarders selection (TOFS) through analyzing forwarding characteristics of forwarders. The algorithm puts forward a constraint mechanism that controls the number of forwarders by constraint of throughput for forwarders selection, achieving a better balance between number of forwarders and effective link stability by introducing the factor of transmission time. Simulation results show that the algorithm can improve the network end-to-end throughput effectively over existing methods. 相似文献
993.
WU Jin 《中国邮电高校学报(英文版)》2013,20(2):113-119
There are two main problems in the threshold denoising method based on wavelet transform. One is the difficulty of threshold selection, and the other is the inconsistence of the dip and curved events in the low signal-to-noise ratio (SNR) seismic data after denoising. In image denoising, multistage median filtering can preserve the details of the signal. So we proposed a denoising algorithm in wavelet transform domain based on multistage median filtering. Using this method the flat region and the edge region are differentiated by the difference between the maximum mid-value and the minimum mid-value, which preserves the details, thus improves the denoising effect. The simulation data and the real data processing results reveal that this method has stronger ability in separating signal from noise than that of the threshold denoising method. 相似文献
994.
A design of 13 Gbit/s vertical cavity surface emitting laser (VCSEL) driver using 0.18 μm complementary metal oxide semiconductor (CMOS) technology is presented in this paper. The core unit of the driver consists of pre-amplify stage and output stage circuit. Techniques of three stages differential amplifier with low impedance load and active feedback are employed in pre-amplify stage, and technique of C3A is adopted in output stage to acquire low power consumption and high speed. The experimental results show that the circuit can work at the data rate of 10 Gbit/s and maximum of 13.2 Gbit/s. The output modulation current is up to 12.5 mA and the power dissipation is only 68 mW with a 1.8 V power supply. 相似文献
995.
窄线宽激光器线宽测量方法 总被引:1,自引:0,他引:1
回顾了窄线宽激光器线宽测量的各种方法和发展过程,介绍了利用光外差法测量窄线宽激光器线宽的基本原理,描述了双光束外差法和延时自外差法的不同测试机理。针对延时零拍自外差法容易引起的系统误差,说明了光源调制和光路调制移频非零拍自外差法不同改进方案的优缺点。综述了窄线宽激光器测量线宽的新方法。对窄线宽激光器线宽测量方法进行了较全面的梳理,从发展过程看双光束外差法和延时自外差法有着各自的测量优势。 相似文献
996.
997.
本文详细分析了现阶段学生在“信号与系统”和“数字信号处理”等课程学习过程中存在的问题,整合优化了课程体系,更新了教学内容,建立了系统科学的信号处理课程架构.课程组坚持创新教学改革思路,坚持应用设计能力培养与理论教学并重的理念,全方位开展教学内容与实验体系改革,全面培养学生综合应用与设计能力. 相似文献
998.
随着人们生活水平的提高和人口老龄化的发展,对医疗器械的创新发展也提出了更高要求,而半导体技术在医疗设备创新方面发挥着重要作用。安森美半导体身为推动高能效创新的半导体厂商,其多款医疗半导体产品居于领先地位,例如用于助听器的数字信号处理(DSP)SoC的市场份额高居全球第一。通过提供完整的医疗半导体解决方案,安森美半导体帮助创新型医疗电子产品实现更高的集成度、小型化、高能效、易用性、便携性和耐久性,配合医疗设备智能化、移动化等趋势的发展。 相似文献
999.