基于差异化效用函数和综合权重的异构网络选择算法

发布时间：2018-10-22 17:07

【摘要】：下一代无线通信系统必然是一个融合多种不同无线网络,可以为用户提供多样化业务与无缝接入的通信系统。异构无线系统的一个基本特征就是在用户处于任何条件下,系统都可以根据当前的系统状态,选择最佳的无线接入网络为用户提供服务,并且能够根据用户的地理位置和业务类型在不同的无线接入网络之间进行无缝的切换,提供可靠的QoS保障。由于异构无线系统接入技术的异构性,各网络为满足业务QoS要求所提供的无线资源表达方式差异很大。这些差异导致无法实现在不同网络间无缝传递业务的QoS参数,因此本文在LTE/WLAN异构系统中提出了一种等效频谱带宽的概念,将不同QoS要求的业务在LTE和WLAN网络中所占用的不同网络资源统一映射到频域,业务所占用的等效频谱带宽大小可以表现业务的QOS要求。同时,很多网络选择算法的设计依赖于对各网络剩余可用资源与用户所需网络资源的比较,因此通过等效频谱带宽映射将不同无线网络中剩余资源以及用户所需资源统一到频域进行表达,使得各网络不同表征形式的网络资源具有可比性。根据LTE/WLAN等效频谱带宽的系统模型,本文设计了一种基于差异化效用函数和综合权重的网络选择算法。该算法在多属性决策算法基础上,针对每个属性的特点以及与用户满意程度的关系,设计合理的效用函数对其标准化,同时在确定属性权重的阶段,引入单目标优化决策模型综合主观权重和客观权重,使得综合权重的判决结果既能满足用户偏好又能考虑网络客观状态。仿真结果表明该网络选择算法能够使网络负载更加平衡,同时降低用户的垂直切换频率。
[Abstract]:The next generation wireless communication system must be a communication system that integrates many different wireless networks and can provide users with diversified services and seamless access. One of the basic characteristics of heterogeneous wireless systems is that under any condition, the system can choose the best wireless access network to provide service to the users according to the current state of the system. Moreover, it can seamlessly switch between different wireless access networks according to the users' geographical location and service type, and provide reliable QoS guarantee. Due to the heterogeneity of heterogeneous wireless system access technology, the wireless resource representation provided by each network to meet the requirements of QoS service is very different. These differences make it impossible to seamlessly transfer QoS parameters between different networks, so this paper presents a concept of equivalent spectrum bandwidth in LTE/WLAN heterogeneous systems. The different network resources occupied by different QoS services in LTE and WLAN networks are mapped to frequency domain uniformly, and the equivalent spectrum bandwidth occupied by the services can represent the QOS requirements of the services. At the same time, the design of many network selection algorithms depends on the comparison between the remaining available resources of each network and the network resources required by users. Therefore, the remaining resources in different wireless networks and the resources required by users are unified to express in frequency domain through the equivalent spectrum bandwidth mapping, which makes the network resources of different representations of different networks comparable. According to the system model of LTE/WLAN equivalent spectrum bandwidth, this paper designs a network selection algorithm based on differential utility function and comprehensive weight. On the basis of multi-attribute decision making algorithm, according to the characteristics of each attribute and the relationship between each attribute and the degree of user satisfaction, a reasonable utility function is designed to standardize the attribute, and at the same time, in the stage of determining attribute weight, The objective weight and subjective weight are synthesized by the single objective optimization decision model, which makes the decision result of the comprehensive weight not only satisfy the user's preference but also consider the objective state of the network. Simulation results show that the network selection algorithm can balance the network load and reduce the vertical switching frequency of users.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN92

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