Interstellar‐based topology control scheme for optimal clustering performance in WSN

Clustering is one of the essential operations in wireless sensor network (WSN) to ensure organized data aggregation followed by energy efficiency. However, obtaining optimal clustering performance is yet an unsolved problem in WSN. Review of existing approaches towards cluster optimization shows that effective balance between energy efficiency and topology control is still missing. Therefore, the proposed system presents a unique topology control mechanism using a novel concept of interstellar orientation toward optimizing the clustering performance in WSN. Adopting an analytical research methodology, the proposed system introduces two interstellar‐based topology control system, which targets the maximum saving of resource consumption of the cluster head. The simulated outcome of the study shows that the proposed topology control system offers significant energy conservation performance in comparison to the existing hierarchical clustering scheme in WSN.     

Antenna array techniques for nonuniform cell zooming and adaptive frequency planning

This paper proposes the antenna array system and the techniques for the nonuniform cell zooming and adaptive frequency planning which is suitable for the energy‐efficient LTE network and multitier 5G heterogeneous network. The antenna array system is designed for the beam width control and scan control in the azimuth plane. The beam tilt is controlled in the elevation plane to control the cell radius. The first feature of the antenna array system is to perform nonuniform sector size control in order to deal with the nonuniform traffic distribution. The second feature of the antenna array system is to control the beam scan in the azimuth plane for the adaptive frequency planning. The footprint control of the current work is evaluated considering the antenna array's radiation pattern and all the physical parameters. Adaptive frequency planning can mitigate cochannel interference (CCI), which may be caused due to the cell zooming techniques proposed in this work. The footprint simulations confirm that the antenna array system can control the sector size with the highest possible flexibility. The antenna array system due to these features can effectively mitigate the interference. The results also confirm that the current antenna array system outperforms the existing antenna array systems.     

A prediction-based asynchronous MAC protocol for heavy traffic load in wireless sensor networks

Radio transceiver often consumes most of energy in a sensor node. To achieve low power consumption, every node periodically schedules its radio transceiver into sleep or active state, which is usually called duty cycle mechanism in MAC protocol. In this paper, we design a novel Prediction-Based Asynchronous MAC protocol (PBA-MAC) for heavy traffic load in wireless sensor networks. PBA-MAC applies an efficient wakeup mechanism to save the energy of a sensor node as much as possible. It reduces communication cost by enabling a sender to predict the intended receiver’s wakeup time, without introducing unnecessary idle listening or overhearing cost. In addition, it introduces an exponential advance mechanism to handle the prediction error caused by clock drift and hardware platform latency. More importantly, its backcast-based retransmission characteristic can efficiently resolve severe wireless collisions caused by concurrent traffic flows. The PBA-MAC is implemented in Contiki operating system. We compare PBA-MAC to some existing energy-efficient MAC protocols. The experimental results show that PBA-MAC significantly improves network energy efficiency and reduces packet delivery latency even under heavy traffic load.     

应用高新技术改造传统产业 实现绿色环保和高效节能

文中分析高压变频器的应用前景、技术特征、关键技术和应用案例,说明了在传统产业中采用高压变频器进行技术改造,不仅降低了能耗,平均节电率超过24%,还带来了系统应用的便利性,实现了传统产业的绿色环保和高效节能。还介绍了新能源产业中的光伏逆变器产品的原理和应用情况。     

动态关断资源栅格的异构无线网络基站节能算法

针对现有的基于载频/时隙关断的基站节能算法没有考虑异构网络之间的协同或者只考虑单一的业务与实际网络情况不相适应的问题,在异构网络环境下提出了动态关断资源栅格(RG,resource grid)的基站节能新算法——DRGSM(dynamic resource grid shut mode)算法。该算法根据网络的即时负载,当有业务接入时,动态打开RG以满足业务的QoS要求;当RG闲置时,即将其关断以实现节能。仿真结果表明,所提算法较现有的基于载频/时隙关断的基站节能算法,明显地降低了能耗,提高了节能百分比。     

基于FPGA的部分并行QC-LDPC译码器高效存储方法

针对部分并行结构的准循环低密度校验(QC-LDPC)码译码器,提出了一种将译码准码字存储在信道信息和外信息存储块中的高效存储方法,该方法不需要额外的存储块来存储译码准码字,能够减少译码器实验所需的存储资源数量,并且有效降低了译码电路的布线复杂度.在Xilinx XC2V6000-5ff1152 FPGA上的实验结果表明,提出的QC-LDPC码译码器设计方法能够在降低系统的BRAM资源需求量的同时有效地提高系统的运行频率和译码吞吐量.     

送粉式激光熔覆能量有效利用率分析

通过分析熔覆过程中光束、粉末和熔池间的相互作用,提出了送粉式激光熔覆能量利用率的数学模型,并结合相关参数进行了计算。结果表明,整个熔覆过程中能量有效利用率较低。该模型客观地反映了熔覆工艺参数和工艺结果的关系,为熔覆工艺参数优化,熔覆质量的预测、评定,提供了理论依据。     

A New Design Methodology for Time-Based Capacitance-to-Digital Converters (T-CDCs)

This paper introduces a 9-bit time-based capacitance-to-digital converter (T-CDC). This T-CDC adopts a new design methodology for parasitic cancellation with a simple calibration technique. In T-CDCs, the input sensor capacitance is first converted into a delay pulse using a capacitance-to-time converter (CTC) circuit; then this delay signal is converted into a digital code through a time-to-digital converter (TDC) circuit. A prototype of the proposed T-CDC is implemented in UMC 0.13 μm CMOS technology. This T-CDC consumes 8.42 μW and achieves a maximum SNR of 45.14 dB with a conversion time of 1 μs that corresponds to a figure of merit (FoM) of 16.4 fJ/Conv.     

Optimal asymmetrical back plane biasing for energy efficient digital circuits in 28 nm UTBB FD-SOI

In this work we propose an optimal back plane biasing (OBB) scheme to be used in a UTBB FD SOI technology that minimizes the energy per operation consumption of sub threshold digital CMOS circuits. By using this OBB scheme, simulations show that more than 30% energy savings can be obtained with low threshold voltage (LVT) devices in comparison with classic symmetric back plane biasing (SBB) schemes. Additionally, this OBB scheme allows to adjust the performance of the circuit with very small energy penalties. A very simple and intuitive model, for sub threshold digital CMOS circuits, was developed to justify the benefits obtained by OBB. The results predicted by the model are confirmed with extensive simulation results. We show that the OBB approach can be applied easily to a given circuit just based on the information provided by a logic simulation of the circuit (or even an analysis of its structure) and simple electrical simulations of the pMOS and nMOS transistors. Finally, we show that the variability in the energy consumption is improved by using OBB and suggests that new sizing methodologies must be studied to fully benefit from the wide back plane voltage range available in UTBB FD SOI technology for the design of robust energy efficient digital circuits.     

一种8VSB Turbo格状编码调制方案

本文阐述这了一种适用于带限信道的８ＶＳＢ Ｔｕｒｂｏ格状编码制方案,它把纠错极强的Ｔｕｒｔｏ码和频带效率极高的格状编码调制结合,具有极强的信道传输能力。同时给出了相应的迭代译码算法及其误码率曲线。