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

本研究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，假设每个小区具有不同的交通强度、不同的形状和不同的面积。本课题的研究总结如下：(1)验证了基站定位问题的难处理性；(2)提出了一种基于遗传算法的基站定位问题的近似算法；(3)基站定位问题的近似解较好地逼近基站定位问题的最优解；(4)在业务量分布异构的蜂窝系统中，利用Clique Packing对动态信道分配算法进行建模是可能的；(5)在流量分布不均匀的情况下，可以分析Clique Packing模型下动态信道分配算法的通信流量特性；(6)提出了一种利用动态信道分配分析蜂窝系统通信业务特性的方法。利用该方法，我们可以考虑用户移动性对移动通信系统流量特性的影响。结果表明，该方法是有效的。这些结果有助于平衡蜂窝系统中业务强度不均匀的服务质量和有效利用频带。研究结果也可用于蜂窝移动通信系统的优化设计。我们认为灵活性是未来移动通信系统适应各种业务的重要因素，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.