光纤毫米波融合接入系统能量效率分析

随着高速移动通信需求的持续增长,"绿色通信"成为近期的研究热点。文章提出一种使用谐波生成毫米波的技术,同时结合ROF（光载无线）技术实现光纤/无线融合接入系统,该系统使用毫米波微微蜂窝接入网技术为室内移动终端提供接入服务。在此基础上,文章对上述系统进行了能量效率分析,通过与WLAN（无线局域网）接入方式的能量效率分析对比,表明该系统具有更高的数据速率和能量效率

考虑双联行星齿轮轴扭转变形的拓扑修形方法研究

针对双联行星齿轮轴在载荷作用下产生扭转变形造成行星轮系偏载、轮齿啮合冲击大等问题，提出了考虑双联行星齿轮轴扭转变形的拓扑修形方法。分析了双联行星齿轮轴扭转变形成因及其对轮系均载性能的影响，基于多体齿轮承载接触分析（PLTCA）、齿轮承载接触分析（LTCA）求解了变形下的承载传动误差与齿面载荷分配系数；利用优化智能算法求解了齿面最大修形量条件下的修形参数最优解；对所提方法进行仿真验证。结果表明，本方法能有效降低齿面单位长度载荷与传动误差幅值，一级、二级行星轮齿面单位长度载荷分别下降33.58%、21.35%，传动误差幅值下降77.74%；在减速器载荷试验台上进行实验验证，实验结果与仿真结果一致；各行星轮齿面的磨损情况均大幅改善，较好地解决了NGWN型行星轮系偏载问题，提高了设备传动精度与使用寿命

A source anonymity-based lightweight secure AODV protocol for fog-based MANET

Fog-based MANET (Mobile Ad hoc networks) is a novel paradigm of a mobile ad hoc network with the advantages of both mobility and fog computing. Meanwhile, as traditional routing protocol, ad hoc on-demand distance vector (AODV) routing protocol has been applied widely in fog-based MANET. Currently, how to improve the transmission performance and enhance security are the two major aspects in AODV’s research field. However, the researches on joint energy efficiency and security seem to be seldom considered. In this paper, we propose a source anonymity-based lightweight secure AODV (SAL-SAODV) routing protocol to meet the above requirements. In SAL-SAODV protocol, source anonymous and secure transmitting schemes are proposed and applied. The scheme involves the following three parts: the source anonymity algorithm is employed to achieve the source node, without being tracked and located; the improved secure scheme based on the polynomial of CRC-4 is applied to substitute the RSA digital signature of SAODV and guarantee the data integrity, in addition to reducing the computation and energy consumption; the random delayed transmitting scheme (RDTM) is implemented to separate the check code and transmitted data, and achieve tamper-proof results. The simulation results show that the comprehensive performance of the proposed SAL-SAODV is a trade-off of the transmission performance, energy efficiency, and security, and better than AODV and SAODV