【作者】 李希金；

【导师】 纪红；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2011， 博士

【摘要】 随着无线通信技术的迅速发展,各种无线接入技术的应用给移动用户带来越来越丰富的无线业务体验和更高的带宽、更快的数据传输速率。但与此同时,无线接入网络类型的多样化与彼此间的不兼容也给用户和电信运营商带来了很多的问题。由于各种无线接入网络在覆盖范围、资源管理和服务支持等方面具有良好的互补特性,网络融合已经成为异构无线网络发展的必然趋势,“融合和发展”必将成为未来移动通信发展的方向。通过不同类型和不同特性的无线接入网络的融合,用户可以获得无处不在的、综合以及有质量保证的业务,真正实现“任何人在任何时间、任何地点,可以享受任何种类的信息服务”的目标。对异构无线网络系统的融合是一项非常复杂的工程,其核心在于实现对异构无线网络资源的联合管理,资源管理机制的成功与否直接决定了融合系统的性能。要实现异构无线网络资源联合管理,必须要解决许多关键性的技术问题,如频谱资源共享、联合呼叫接纳控制,以及联合带宽分配机制等问题。一些研究机构、项目组织已经开展了相关研究,但是仍存在一定不足之处,如未能提供完整的解决方案、不具备通用性等。针对上述问题,本文以提高异构无线网络资源管理的性能和效率为目标,对异构无线网络资源管理中的呼叫接纳控制、频谱资源共享与借用、联合信道资源分配等关键技术展开重点研究,提出了相应的改进机制和算法,并通过建立数学模型和计算机仿真进行了性能分析。本文的主要工作和创新点如下：1)提出了一种异构无线网络中的频谱资源借用算法。该算法将空闲频谱纳入频谱池进行统一管理,用户以非透明方式共享频谱资源,所有频谱资源的分配和回收都由重配置管理模块统一管理。所提算法以整体性能最优准则设计了适用于异构无线环境下频谱借用的最佳借用选择标准,可以设置不同的借用细则从而最大化整体频谱资源利用率。仿真结果表明,该算法在业务量较大时可以显著提高频谱资源利用效率,降低呼叫阻塞率,有效地解决热点覆盖问题。2)设计了一种异构无线网络中联合呼叫接纳控制管理机制。该机制引入了基于半马尔科夫决策过程的决策理论,根据业务的优先级别,在尽量保证用户QoS需求的前提下,以提高整体网络吞吐量为优化目标,具有良好的可扩展性和独立性。仿真结果表明,该算法有效地处理了异构无线网络间负载不均衡与业务QoS需求之间的矛盾,降低了业务的平均阻塞率,提高了网络吞吐量。3)提出了一种异构无线网络中联合信道资源分配算法。该算法基于非合作博弈理论,构建具有多约束的最优化问题模型,以最大化异构无线网络信道资源总效用为首要目标,兼顾信道资源分配的公平性与合理性,使得融合网络中的系统总效用达到最大。仿真结果表明,该算法取得了较高的带宽资源总效用,同时保证了信道资源分配的公平性与合理性。更多还原

【Abstract】 With the fast developing of advanced wireless communication technologies, the deployment of various wireless access networks give mobile users abundant wireless services, together with wider band-width and faster data transmitting rate. At the same time, the diversity of wireless networks and the following non-compatible problem bring mobile users and communication operation enterprises more troubles. Because of the respective features of these wireless access networks such as cover-range, resource management mechanism and service support, the integration of heterogeneous wireless networks has become the inevitable trend. Through the integration of heterogeneous networks with different types and characteristics, mobile users could enjoy ubiquitous, synthetical and QoS-guaranteed services, so as to realize the communication goal of "whoever, whenever, wherever, however, whatever".The integration of heterogeneous wireless network is very complex, in which the key issue is to realize JRRM (joint radio resource management). The performance of integrated system is decided by JRRM, to realize JRRM in heterogeneous wireless networks, several key technologies have to be improved first, such as spectrum sharing, joint call admission control, and joint bandwidth allocation strategy. Some research institutions and project organizations have done relative investigations with plenty of results. However, several problems are still under discussion.To solve above problems, this thesis aims to improve the performance and efficiency of JRRM in heterogeneous networks, emphasizing on joint call admission control, spectrum borrowing, and joint channel allocation schemes. Some improved mechanisms and schemes are proposed, and the performance of these schemes is analyzed through constructing mathematical models and simulations. The major contribution of this thesis is listed as follows:1) Proposing a spectrum borrowing scheme in heterogeneous wireless networks. This scheme takes idle channels into a spectrum pool, with unified management of these channels. All users share them in non-transparent way, and the PRM (Proxy re-configuration management) takes charge in resource allocation and recovery. The proposed scheme designs a spectrum borrowing selection method by the best overall performance criterion, in which spectrum utility is maximized by setting different borrowing levels. Simulation results show that, proposed scheme gets higher spectrum utilization ratio and decreased session blocking probability especially in case of high-loaded environment.2) Designing a joint call admission control mechanism for heterogeneous networks. Based on semi-Markov decision process, this scheme takes overall network throughput as optimal purpose, and gains good expansibility and independency with QoS guaranteed. Simulation results show that, proposed scheme efficiently solves the conflict between unbalanced network load and QoS demand of users. As a result, session blocking probability is decreased and the throughput of networks is promoted.3) Proposing a joint channel allocation scheme in heterogeneous wireless networks. The scheme establishes an optimized model with multiple constraints based on the theory of non-cooperative game, aiming to maximize the overall channel utilization. The fairy and rationality issues are taken into consideration. Simulation results show that, the proposed scheme gets higher bandwidth utility, with better fairness in channel allocation.更多还原