科创中国

随着半导体工艺的不断发展,片上网络中所包含的IP核数目越来越多,这时片上网络的拓扑结构对于系统的面积和性能起着决定性的作用,并且深刻的影响着系统的通信传输能力.提出了一种新的分层路由交叉片上互连网络——HRCM(Hierarchical Routing Cross-connected Mesh),将N2个2× 2全连接的子网连接成N× N的Mesh结构.采用了一种新的分层XY路由算法——HXY (Hierarchical XY).采用OPNET对该结构进行了进程层、节点层、网络层建模与仿真,结果表明在系统平均延时、系统归一化吞吐量等方面都优于传统Mesh、Xmesh结构.

在多信道无线mesh网络中,路由选择与频谱可用性之间的相互依赖性很强,这就要求设计路由协议时要充分考虑信道的选择.传统的路由协议不能很好地适用于多信道无线mesh网络,因此提出了一种基于认知无线电的无线mesh网络路由协议,其中每个节点配置两个网络接口,路由选择与信道选择同时进行,通过冲突避免的设计,充分利用了多信道的优势.仿真结果表明,相对于传统路由协议,提出的路由协议能大大提高网络的吞吐量.

To improve the performance of the positive displacement blower,it is imperative to understand the detailed internal flow characteristics or enable a visualization of flow status.However,the existing two-dimensional unsteady,three-dimensional steady or quasi-unsteady numerical simulation and theoretical analysis cannot provide the detailed flow information,which is unfavorable to improve the performance of positive displacement blower.Therefore,the unsteady flow characteristics in a three-lobe positive displacement blower are numerically investigated by solving the three-dimensional,unsteady,compressible Navier-Stokes equations coupled with RNG k-εturbulent model.In the numerical simulation,the dynamic mesh technique and overset mesh updating method are adopted.Due to the air being compressed in the process of the rotors rotating,the variation of the temperature field in the positive displacement blower is considered.By comparing the experimental measurements and the numerical results on the variation of flow rate with the outlet pressure,the maximum relative error of the flow rate is less than 2.15%even at the maximum outlet pressure condition,which means that the calculation model and numerical computational method used are effective.The numerical results show that in the intake region,the fluctuations of the inlet flow are greatly affected by the direction of the velocity vectors.In the exhaust region,the temperature changes significantly,which leads to the increase of the airflow pulsation.Through analysis on the velocity,pressure and temperature fields obtained from the numerical simulations,three-dimensional unsteady flow characteristics in the positive displacement blower are revealed.The studied results will provide useful reference for improving the performance and empirical correction in the design of the positive displacement blower.

为解决认知无线Mesh网络中专用控制信道较难获得的问题,提出一种基于POMDP的机会式频谱接入MAC协议,在不需要中心控制器和专用控制信道的协调下,实现动态频谱感知和接入.仿真结果表明,基于POMDP的接入策略能够有效提高网络频谱利用率和吞吐量,性能最优,而基于贪心算法的接入策略,在降低计算复杂度的同时,获得了较好的性能,实用性较强.

伴随着传输网络和业务的不断发展、技术的不断进步,为电信网的基础网络-传输网带来了很多的机遇,同时也提出了更高的要求,网络的安全性是运营商在网络维护和优化中考虑的重点工作之一.当前传统传输网络的发展处于相对稳定的状态,网络的优化、扩容工作逐渐代替大规模的网络新建,而针对网络中存在的隐患等问题,就需要一线维护人员重点关注,及时提出解决方案,并能及时优化解决.某省干传输网使用大量的华为SDH设备,其中包括由26台OSN设备组成的ASON网络,共122台设备.随着网络的飞速发展,传输网作为基础网络,网络安全问题越来越突出.网管监控的好坏直接影响通信服务质量的好坏,对广大用户影响也最直接,因此网管的稳定性也越来越重要.