基于OFDMA毫微微蜂窝频谱分配算法的研究

发布时间：2018-10-19 13:29

【摘要】：随着信息技术的飞速发展,用户对高速数据流量的要求日益增高,频谱资源成为影响通信发展的一个关键性因素。因此,频谱资源的合理分配至关重要。各种频谱分配技术受到广泛研究,其中动态频谱资源管理作为研究热点。毫微微蜂窝(Femtocell)支持更高的数据速率,在宏蜂窝网络和毫微微蜂窝网络中,如何利用空闲信道的频谱资源是研究的方向之一。本文分析了频谱分配算法与图论的关系,将图论的着色理论有效运用到OFDMA下行链路的频谱资源分配中,为了降低毫微微蜂窝之间的同层干扰,对Femtocell基站形成的无向干扰拓扑图,进行着色分簇。在正交频分多址接入技术的Femtocell网络中,给出了宏蜂窝和Femtocell双层网络架构,研究了基于约束性遗传算法的频谱资源分配方案。如何对频谱资源分配过程进行建模进行了深入的分析以及根据网络的业务服务质量等级合理分配频谱资源,提出了两种适用于Femtocell网络的频谱分配策略。基于OFDMA的Femtocell网络中,根据基站中用户数目的差异,提出了基于用户数目的频谱资源分配方案,根据基站中用户数目的不同,建立目标函数,运用约束性遗传算法实现自适应频谱资源分配。利用遗传算法不断更新迭代种群,逐步接近最优解,实现频谱资源的合理分配。MATALB仿真结果表明:每个基站分配的频带资源基本随用户数的变化而变化。在满足公平性的前提下,提高用户体验的同时,避免了频谱资源的浪费。在基站中用户数目差异性的基础上,提出了基于用户需求的自适应频谱资源分配方案。对基站中每个用户的业务类型进行量化并建立目标函数。MATALB仿真结果表明:每个基站所分配的带宽基本随基站中用户需求的变化而变化,基于用户需求的频谱资源分配方案与基于用户数目的频谱资源分配方案相比,公平性得到进一步提升,更进一步地提高了用户体验,实现了频谱资源的高效利用。基于OFDMA的Femtocell网络中,深入学习了混合式频谱接入方案。由于Femtocell基站密集部署,在OFDMA下行链路的传输过程中,存在着同层干扰和跨层干扰。本文在充分考虑同层干扰和跨层干扰的情况下,运用图论着色理论减少邻近毫微微蜂窝基站之间的干扰。仿真结果表明网络效用和网络吞吐量均有所提升。本文提出的资源分配算法,可以有效提高用户服务质量,改善频谱利用率并使得公平性得到改善,在毫微微蜂窝网络中实现频谱资源的合理分配具有现实意义。
[Abstract]:With the rapid development of information technology, the demand of users for high-speed data flow is increasing day by day. Spectrum resources become a key factor affecting the development of communications. Therefore, the rational allocation of spectrum resources is very important. A variety of spectrum allocation techniques have been widely studied, among which dynamic spectrum resource management is a research hotspot. Femto cellular (Femtocell) supports higher data rate. In macrocellular networks and femto cellular networks, how to utilize spectrum resources of free channels is one of the research directions. In this paper, the relationship between spectrum allocation algorithm and graph theory is analyzed. The coloring theory of graph theory is effectively applied to the spectrum resource allocation of OFDMA downlink. In order to reduce the same layer interference between femto cells, the undirected interference topology graph formed by Femtocell base station is obtained. Coloring clustering. In the Femtocell network based on orthogonal frequency division multiple access (OFDMA), the macrocellular and Femtocell double layer network architecture is presented, and the spectrum resource allocation scheme based on constrained genetic algorithm is studied. Based on the analysis of the modeling of spectrum resource allocation and the rational allocation of spectrum resources according to the quality of service (QoS) of the network, two kinds of spectrum allocation strategies for Femtocell networks are proposed. In the Femtocell network based on OFDMA, according to the difference of the number of users in the base station, a spectrum resource allocation scheme based on the number of users is proposed, and the objective function is established according to the difference of the number of users in the base station. Adaptive spectrum resource allocation is realized by constrained genetic algorithm. The genetic algorithm is used to update the iterative population and approach the optimal solution step by step to realize the rational allocation of spectrum resources. The MATALB simulation results show that the frequency band resources allocated by each base station basically vary with the number of users. On the premise of fairness, the user experience is improved and the waste of spectrum resources is avoided. Based on the difference of the number of users in a base station, an adaptive spectrum resource allocation scheme based on user requirements is proposed. The MATALB simulation results show that the bandwidth allocated by each base station basically changes with the change of the user's requirements in the base station. Compared with the spectrum resource allocation scheme based on the number of users the fairness of the spectrum resource allocation scheme based on user needs is further improved the user experience is further improved and the efficient utilization of spectrum resources is realized. In the Femtocell network based on OFDMA, the hybrid spectrum access scheme is studied in depth. Due to the intensive deployment of Femtocell base stations, there are interlayer interference and interlayer interference in the transmission of OFDMA downlink. In this paper, we use graph coloring theory to reduce interference between adjacent femto cellular base stations by fully considering the same layer interference and cross layer interference. Simulation results show that both network utility and network throughput are improved. The resource allocation algorithm proposed in this paper can effectively improve the quality of service of users, improve spectrum efficiency and improve fairness. It is of practical significance to achieve a reasonable allocation of spectrum resources in femto cellular networks.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

【相似文献】