Dynamic Cell Location and Channel Assignment Adaptable to Fluctuation of Communication Traffic

本研究项目的目的是研究蜂窝移动通信系统中的基站定位问题和动态信道分配问题。在本研究中，每个小区具有不同的业务强度、不同的形状和不同的区域。本课题的研究内容概括如下：(1)证明了基站选址问题是一个棘手的问题；(2)提出了一种基于遗传算法的基站选址问题的近似算法；(3)基站选址问题的近似解是基站选址问题的最优解的良好逼近；(4)在业务分布不均匀的蜂窝系统中，可以用团填充来建模动态信道分配算法；(5)可以分析非均匀业务分布下基于团填充模型的动态信道分配算法的通信业务特性；(6)提出了一种基于动态信道分配的蜂窝系统通信业务特性分析方法。利用这种方法，我们可以考虑用户移动性对移动通信系统业务特性的影响。分析结果表明，该方法是有效的。这些结果有助于平衡业务强度不均匀的蜂窝系统的服务质量和频带的有效利用。研究结果也适用于蜂窝移动通信系统的优化设计。我们认为，为了使移动通信系统适应未来的各种业务，灵活性是重要的，多跳连接是增加系统灵活性的一种方式。

The objective of this research project is to investigate the base stations location problem and the dynamic channel assignment problem in cellular mobile communication systems. In this research, it is assunmed that each cell has different traffic intebsity, different shape and different area from each other. The research of this projct is summarized as follows ;(1) It is proved that the base stations location problem is intractable ;(2) An approximate algorithm, based on the genetic algorithm, for the base stations location problem is proposed ;(3) The solution obtained by the approximate algorithm for the base stations location prblem is good approximation to the opotimum solution for the base stations location problem ;(4)It is possible to model dynamic channel assignment algorthms by using Clique Packing in cellular systems where the traffic distribution is heterogeneous ;(5) It is possible to analyze the communication traffic characteristics of dynamic channel assignment algorithms on the Clique Packing model under the non uniform traffic distribution ;(6) A method for analyzing the communication traffic characteristics of cellular systems using Dynamic Channel Assignment is proposed. using this method, we can consider the effect of mobility of subscribers to mobile communication systems on the traffic characteristics. It is shown that this method is effective on the analysis.These results contribute to balancing the quality of service in cellular systems where the traffic intensity is not uniform and the efficient use of frequency bands. Also, the results are applicable to optimum design of cellular mobile communication systems.We consider that flexibility is important to adapt mobile communication systems to various kinds of service in the future and multi-hop connection is one way to add flexibility to the system.