Geographical Reservation for Guaranteed Handover and Routing in Low Earth Orbit Constellations

In this paper, we address the problem of permanent guaranteed routing through a LEO satellite constellation with inter-satellite links. A reduction to a geometric problem of intersection of rectangles is given, along with algorithmic issues. We express the problem on a very simple model, and discuss the extension to more complicated schemes. We present some experimental results based on this framework that demonstrate the efficiency of the method in a call admission control process.     

Scalable Schemes for Call Admission and Handover in Cellular Networks with Multiple Services

The introduction of new service categories withdifferent bandwidth requirements, e.g., data and multimedia, to cellularmobile radio networks makes many of the traditional mechanisms for controlingtraffic unusable orless efficient. The call admission and the handover handling are of the mostsensitive issues in this extension to new services. The performance of allservices includingthe traditional voice and the new services can be dramatically affected ifappropriate schemes are not used. In this paper, we propose call admission andhandover handling schemes for a cellular mobile network that offers twoservice types: voice and data. The data connections are assumed to transmitatdifferent transmission rates that are integer multiples to that of one radiochannel. In the case of congestion, the base station asks the active dataconnections to reduce their transmission rate in order to provide freechannels for the newly arrived request of both service types. This isbasically intended for incoming handover requests. The request will berejected if the transmission rate of the active connections reaches a givenminimum rate. Similar mechanism can also be used for new call arrivals, butsome priority can be given to handovers by setting a higher transmission ratethreshold for the new call rejection. As an extension to the proposedscalability, aqueuing of new calls is also proposed and analyzed. Analytical models werebuilt for the two proposed schemes together with the traditional channelreservation scheme. The effect of different traffic and configurationparameters on the performance measures like the grade of service, blockingprobabilities, and utilization, are studied using the proposed technique.Results show that the proposed schemes provide very good performance and morefairness among the different service types.     

基于软交换的一种通用呼叫控制模型的研究

现有的呼叫控制模型不能满足多媒体与移动业务对承载的复杂控制需求.本文在不增加现有模型复杂度的前提下提出一种通用的两层、信令-承载控制相分离的呼叫控制模型SBS-CSM.SBS-CSM在核心会话控制模块完成协议无关的通用呼叫控制功能,并将信令链接与媒体链接的控制分离,将二者的控制能力独立的提供给业务.在协议接入处理模块完成具体协议的媒体链接控制功能.采用该模型的软交换系统的实测结果验证了该模型的可用性与高效性.     

一种嵌入式呼叫处理模型设计分析

介绍了呼叫处理软件开发所需要的基本技术,提出了基于Vxworks实时操作系统的软件体系结构和实时呼叫软件系统开发模型,研究了有限状态机技术、软件架构技术。引出呼叫处理分层软件架构模型,并论述了呼叫控制模块的主要功能。对呼叫控制实体进行抽象,介绍了呼叫控制实体的参数设计,给出了呼叫控制实例,对呼叫处理软件的测试及结果进行了分析。     

下一代网络开放业务接口的研究

下一代网络是基于业务驱动的网络,开放性是下一代网络的重要特征。在分析研究一些典型的开放接口技术基础上,针对Parlay X业务呼叫接口存在的缺陷,提出Parlay X增强型业务呼叫接口的改进方案,并给出其实现模型。通过使用增强型呼叫接口,应用开发商不需要掌握详细的电信知识,就能对呼叫进行持续并且有效的监控,并且以更为灵活的交互方式为用户提供丰富多彩的特殊资源。     

基于跳-分形模型的美式看涨期权定价

假设股票变化过程服从跳一分形布朗运动,根据风险中性定价原理对股票发生跳跃次数的收益求条件期望现值推导出M次离散支付红利的美式看涨期权解析定价方程,并使用外推加速法求出当M趋于无穷时方程的二重、三重正态积分多项式表达,依此计算连续支付红利美式看涨期权价值.数值模拟表明通常仅需二重正态积分多项式能产生精确价值,而在极实值状态下则需三重正态积分多项式才能满足,结合两种多项式可以编出有效数字程序评价支付红利的美式看涨期权.     

Individual blocking probabilities in the loss system G1 + ... + GN/M/1/0

Explicit formulas for the individual call loss probabilities are derived which arise when a finite collection of independent general stationary traffic streams with exponentially distributed service times are offered simultaneously to a single server. The formulas show a modified insensitivity property of the given model.     

无线移动网中呼叫接纳控制模型分析

新一代无线网应该能够同时支持传统的数据业务和实时交互式多媒体业务，并能够为用户提供QoS保证。在无线网中提供QoS保证，呼叫接纳控制扮演着重要的角色。对已有的呼叫接纳控制方面的研究成果进行了归纳、总结和分析，以期得出适合于无线移动多媒体网络的呼叫接纳控制模型。为适应当前的多媒体应用，侧重于对和适应性带宽分配相结合的接纳控制模型的分析。另外，介绍了与价格机制相结合的接纳控制模型，经济学概念的引入，为我们解决问题提供了一种新的视角。     

一种改进Parlay API增强呼叫等待保持能力的方法

通过对呼叫等待业务实例的深入分析得出Parlay API4．0规范缺乏呼叫等待保持能力，提出了一种修订终端呼叫腿状态机和增加功能接口的方法，该方法可以在保持Parlay API后向兼容性和不改变呼叫控制模型的同时增强呼叫等待保持能力，最后给出一个基于改进了的Parlay API的呼叫等待业务实例流程。     

Non-Uniform Traffic Issues in DCA Wireless Multimedia Networks

Wireless networks that utilize dynamic channel allocation (DCA) are known to perform better than those with fixed channel allocation, in terms of the call level QoS measures such as the handoff dropping probability. On account of this, the DCA networks are usually designed without the call admission control (CAC). However, given the decrease of cell sizes, together with ever increasing mobile phone and terminal population, dynamic channel allocation policies (such as channel borrowing) may not be sufficient to cope with the hot-spot area size and its traffic intensity. This paper analyses the performance of the DCA networks, both with and without the call admission control, under the hot-spot traffic regime. In such cases, the pure DCA approach fails to ensure sufficiently low level of QoS in both the hot-spot area and the surrounding cells. We propose a CAC policy that can stabilize the QoS under non-uniform traffic, whilst being easy to integrate in the distributed DCA policies.