NMOS晶体管电荷共享导致的SRAM单元单粒子翻转恢复效应研究

基于Synopsys公司的三维器件模拟软件TCAD,本文研究了NMOS晶体管电荷共享导致SRAM单元的单粒子翻转恢复(SEUR)效应。分析了NMOS晶体管电荷共享导致SEUR效应的物理机制,系统研究了NMOS晶体管偏置(如电源电压、P阱偏置电压)和工艺参数(如P+深阱掺杂浓度、P阱接触距离)对线性能量传输翻转恢复阈值(LETrec)以及单粒子翻转脉冲宽度(PWrec)的影响。研究发现:PWrec随着电源电压的增大而增大;PWrec和LETrec随着P阱偏置电压的增大而减小;LETrec随着P+深阱掺杂浓度的增大而增大;PWrec随着P阱接触与NMOS晶体管之间距离的增大而增大,而LETrec随着P阱接触与NMOS晶体管之间距离增大而减小。本文研究结论有助于优化SRAM单元抗单粒子效应设计,尤其是基于SEUR效应的SRAM单元的抗辐照加固设计提供了理论指导。

Protocol for the application of cooperative MIMO based on clustering in sparse wireless sensor networks

Wireless sensor networks （WSN） using cooperative multiple-input multiple-output （MIMO） communication are effective tools to collect data in several environments. However, how to apply cooperative MIMO in WSN remains a critical challenge, especially in sparse WSN. In this article, a novel clustering scheme is proposed for the application of cooperative MIMO in sparse WSN by extending the traditional low-energy adaptive clustering hierarchy （LEACH） protocol. This clustering scheme solves the problem that the cluster heads （CH） cannot find enough secondary cluster heads （SCH）, which are used to cooperate and inform multiple-antenna transmitters with CHs. On the basis of this protocol, the overall energy consumption of the networks model is developed, and the optimal number of CHs is obtained. The simulation results show that this protocol is feasible for the sparse WSN. The simulation results also illustrate that this protocol provides significant energy efficiencies, even after allowing for additional overheads.

Improvement for low power high performance hybrid type CAM

Based on the analysis of typical hybrid-type content addressable memory （CAM） structures, a hybrid-type CAM architecture with lower power consumption and higher stability was proposed. This design changes the connection of a N-type metal-oxide-semiconductor （NMOS） transistor in the control circuit, which greatly reduces the power consumption during comparison by making the match line simply discharge to the NMOS threshold voltage. A comparative study was made between conventional and the proposed hybrid-type CAM architecture by semiconductor manufacturing international corporation （SMIC） 65 nm complementary metal-oxide-semiconductor （CMOS） technology. Simulation shows that the power consumption of the proposed structure is reduced by 23%. Furthermore, the proposed design also adjusts the match line （ML） discharge path. In case that, the not and type （NAND-type） block is matched and the not or type （NOR-type） block is mismatched, the jitter voltage on the match line can be decreased largely.

Tracking the events in the coverage of wireless sensor networks based on artificial neural-networks algorithms

Sensor deployment is an important problem in mobile wireless sensor networks.This paper presents a dis-tributed self-spreading deployment algorithm(SOMDA)for mobile sensors based on artificial neural-networks self-organizing maps algorithm.During the deployment,the nodes compete to track the event and cooperate to form an ordered topology.After going through the algorithm,the statistical distribution of the nodes approaches that of the events in the interest area.The performance of the algo-rithm is evaluated by the covered percentage of re-gion/events,the detecting ability and the energy equaliza-tion of the networks.The simulation results indicate that SOMDA outperforms uniform and random deployment with lossless coverage,enhancive detecting ability and signifi-cant energy equalization.

Algorithm for the placement of nodes for effective coverage

An effective method for extending wireless sensor network lifetime is presented for redundancy nodes.Because most of the existing coverage protocols are based on the circular sensing model,this paper discusses how to combine consideration of coverage and connectivity main-tenance in a single effective scheduling when the sensing model is not circular.The least redundancy coverage strat-egy(LRCS)strategy takes the smallest redundant coverage as the criterion whose goal is to maximize the lifetime of the sensor network.The sensor nodes are divided into five statuses:the judgment status,the waiting status,the activity status,the dormancy status and the exhausted status.Simu-lations show that LRCS outperforms the coverage configu-ration protocol and is suitable for various situations.It ef-fectively reduces the number of active nodes and extends the lifetime of the sensor network.