An MID-Based Load Balancing Approach for Topic-Based Pub-Sub Overlay Construction

A large proportion of Internet of Things (IoT) applications are internally publish/subscribe in nature,and traditional architecture cannot support them efficiently and flexibly.In essence,supporting efficient publish/subscribe systems requires data-oriented naming and efficient multicast.Since deployment of native IP-based multicast has failed,overlay-based multicast has become the practical choice.Since load balancing between heterogeneous nodes is an important issue,designing an optimal load balancing ove...     

一种基于流标记合并和流分类改进的IP交换机

以VC合并原理为基础,将其改进为流标记合并的路由记录方法,这种方法允许多条路由映射到同一个标记上,这样就实现了一种可以扩展的映射方法,使得IP交换机不仅可以对长流交换,对部分短流也可实现交换.     

采用RADIUS协议的AAA系统的研究

AAA是认证、授权、计费系统的简称,用来完成对用户身份合法性的鉴别、权限的分配、话单的采集、费用的结算等功能。其核心模块Radius服务器与网络接入服务器之间的通信协议采用RADIUS协议。通过对RADIUS协议层次结构、软件结构特点、工作原理及认证计费流程的详细分析,验证了AAA系统采用RADIUS协议的可行性。     

动态信道分配在TD-SCDMA系统中的应用研究

针对TD-SCDMA系统,充分结合TD-SCDMA系统的关键技术、资源特点、业务特点和干扰特点,寻求适用于该系统(包括频域载频、时域时隙、码域码道和空域位置)的最优组合动态信道分配策略,为了比较该策略下不同动态信道分配(DCA)算法性能,提出了4种DCA算法,并结合实际情况建立仿真模型,通过正确设置仿真参数,进行系统级仿真,以确定各种动态信道分配算法,各种仿真参数设置对系统呼阻率的影响。仿真结果表明,TD-SC- DMA系统是下行受限的系统,其上、下行干扰门限理想值分别为1.5和3.1左右。     

Surface Coverage Algorithm in Directional Sensor Networks for Three-Dimensional Complex Terrains

Coverage is an important issue in the area of wireless sensor networks, which reflects the monitoring quality of the sensor networks in scenes. Most sensor coverage research focuses on the ideal two-dimensional(2-D) plane and full three-dimensional(3-D) space. However, in many real-world applications, the target field is a3-D complex surface, which makes conventional methods unsuitable. In this paper, we study the coverage problem in directional sensor networks for complex 3-D terrains, and design a new surface coverage algorithm. Based on a 3-D directional sensing model of nodes, this algorithm employs grid division, simulated annealing, and local optimum ideas to improve the area coverage ratio by optimizing the position coordinates and the deviation angles of the nodes, which results in coverage enhancement for complex 3-D terrains. We also conduct extensive simulations to evaluate the performance of our algorithms.     

GSM Co-Channel and Adjacent Channel Interference Analysis and Optimization

Most current Global System for Mobile Communications (GSM) frequency planning methods evaluate the interference and assign frequencies based on measurement reports.Assigning the same or adjacent frequencies to cells close to each other will introduce co-channel and adjacent channel interference which will reduce network performance.Traditionally,man power is used to check and allocate new frequencies which is time consuming and the accuracy is not satisfactory.This paper presents an intelligent analysis met...     

MC-CDMA信道均衡技术性能分析

分析了频率选择性衰落信道中 ,MC CDMA(多载波 码分多址 )系统下行链路采用相位均衡、最大比合并以及受控均衡等 3种均衡技术时系统的误码率性能。给出了相应的数值计算结果和计算机模拟结果。从此可知 ,采用最佳门限受控均衡时 ,系统误码率性能最好 ,频谱效率最高     

Parlay CC API与SIP的逻辑关系

首先描述了ParlayCCAPI(Parlay规范中的呼叫控制应用程序接口)和SIP(会话初始化协议)的逻辑组成与结构,然后通过SIP与ParlayCCAPI逻辑关系比较,给出了从SIP到ParlayCCAPI的方法、响应码和地址的映射关系,最后给出了基于SIP的ParlayCCAPI构建基本会话的时序图,并通过模拟实验说明基于SIP的ParlayCCAPI主要功能是可以实现的。     

IP网络接纳控制的研究

在深入研究了各种接纳控制技术的基础上,论述了基于探测接纳方法的优势,同时分析了探测方法可能出现的问题。提出了一种改进的基于探测的接纳控制技术即在传统的基于探测的方法上加载了"改进的链路探测标签"机制。最后,通过仿真实验证明了改进方法有效。