Theoretical Studies on the Service Quality Evaluation and Optimal Resource Allocation in Mobile Communication Networks

(1)计算下一代移动的无线电通信系统所需频谱的方法我们提出的估计IMT-高级系统中频谱需求的方法和计算结果的建议在2007年世界无线电通信大会上获得批准和接受。我们已经在John Wiley and Sons的题为Spectrum Requirement Planning in Wireless Communications的书（248页）（2008年）中公布了技术背景和我们的研究工作。之后，我们开发了一种方法，提高了频谱的使用，并计算其效果的基础上排队模型和仿真。(2)蜂窝移动的通信网络中越区切换数的计算及其应用在蜂窝移动的通信系统中，当移动的终端从一个小区移动到另一个小区时，为了进行信道分配和位置管理，需要进行越区切换控制。我们已经开发了一个理论模型，估计在一个通信会话期间的并发数使用几何概率和更新过程的理论。该模型已被应用于确定最佳的数据更新时间在蜂窝移动的网络中的基站位置管理。(3)时变话务负荷对通信信道性能影响的评估模型。频谱资源的动态分配是未来无线电通信系统所期望的。因此，我们研究了相关随机模型中的时变过程。我们还得到了有限等候室排队系统中忙碌期持续时间的概率密度函数的显式表达式。

(1) Methodology for calculating the requires spectrum for the next generation mobile radio communication systems Our proposal of the methodology and calculation results for estimating the spectrum requirements in IMT-Advanced systems was approved and accepted in the 2007 World Radiocommunication Conference. We have published the technical background and our research work in a book entitled Spectrum Requirement Planning in Wireless Communications from John Wiley and Sons (248 pages), 2008. Afterwards, we have developed a method that improves the spectrum usage, and calculated its effects based on a queuing model and simulation.(2) Calculation of the number of handovers and its application in cellular mobile communication networks In cellular mobile communication systems, the handover control is necessary when a mobile terminal moves from one cell to another for the channel allocation and location management. We have developed a theoretical model for estimating the number of handovers during one communication session using the theories of geometric probability and renewal process. The model has been applied to determine the optimal data update time for location management at the base stations in cellular mobile networks.(3) Models for evaluating the effects of time-varying traffic load on the performance of communication channels. Dynamic allocation of spectrum resource is desirable in future radio communication systems. Therefore, we have studied the time-dependent process in relevant stochastic models. We have also obtained an explicit expression for the probability density function of a busy period duration in a queue with a finite waiting room.