【作者】 法卢克；

【导师】 戴居丰；

【作者基本信息】 天津大学 ， 通信与信息系统， 2010， 博士

【摘要】 移动WiMAX是一项前途无量的无线宽带技术。近几年来,随着各种VoIP编解码器CODECs技术的发展,VoIP已成为最有前景的互联网应用之一。移动WiMAX和VoIP都大大节省了成本。因此,两者的完美结合具有广阔应用前景。但是,上行链路调度和资源管理仍然是一个会严重影响移动WiMAX VoIP部署的主要问题。上行链路调度和资源管理是服务基站(BS)的MAC层对可分配传输资源进行有效管理的调度操作,涉及调度业务、功率节省等操作,以达到最佳的资源利用率,提高系统性能。对于VoIP业务,IEEE 802.16e标准只定义了MAC层上行链路调度功能模块和资源管理,以及基本内容和模块的实施细则,但没有提出任何具体可行的计划或实施算法。因此,解决最常用的移动WiMAX VoIP编解码器的上行链路调度和资源管理方面的问题,具有非常重要的学术意义和实用价值。本文对IEEE 802.16e移动WiMAX标准、VoIP的编解码器技术进行了系统的分析,对移动WiMAX VoIP编解码器的上行链路调度算法和资源管理策略进行了深入的研究。论文的主要工作与贡献如下:1.针对多种移动WiMAX VoIP编解码器,设计了一种新型的综合动态上行链路调度方案CDUSP。论文通过研究802.16e标准定义的三个传统的上行链路调度业务算法以及最常用的VoIP编解码器CODECs,并根据VoIP编解码器的主要特点,将其分为单模和多模两个主要类别。对于单模和多模类别,分别根据每一类编解码器的静音压缩特性,提出了相应的新的上行链路调度算法。基于提出的这些上行链路调度算法,设计了一种新型综合动态上行链路调度方案CDUSP,该方案可以动态整合、管理在移动WiMAX的QoS调度架构内所有上行链路调度算法。它极大地优化了移动WiMAX,能有效地支持VoIP编解码器的上行传输。仿真结果和数值验证表明,与传统的算法相比,新算法不仅能有效提高资源利用率,增加总吞吐量和减少分组传输延迟,而且可以大大提升系统的容量和支持更多的语音用户。2.基于多VoIP用户共存的资源管理优化问题的研究,本文提出了一些新的资源分配算法。根据多种影响因素,如不同的语音用户静音期间、不同的CODEC的帧期间、不同的用户优先级等,预先对用户设置了不同的类型,进而采用不同的资源分配算法。影响因素值不同,用户分类和相应的资源分配算法也不同。仿真结果和数值验证证明在资源利用、总吞吐量、系统容量的增加等方面,所提出的算法更有效率。3.通过研究分析由802.16e协议定义的三个功率节省类:PSCI,PSCII,PSCIII,本文提出了两个新的功率节省改进算法,使之更适合于不同的VoIP CODECs静音压缩。第一个算法是间隔灵活型PSCII功率节省算法,它在相互静音期间利用了指数增加方法,更适合于长帧期间VolP CODECs。第二种算法是多种终止休眠方式功率节省算法,算法的基本思路是在talk-spurt期间采用PSCII,而在静音期间采用PSCI的两种不同的终止休眠方式。数值分析和仿真结果表明,所提出的算法有效地降低了在静音期间的功耗,同时满足端到端允许的最大延迟和VoIP服务质量(QoS)的低丢包率的要求。更多还原

【Abstract】 Mobile WiMAX is a promising broadband wireless technology. In recent years VoIP has emerged as one of the promising applications on the Internet with rapidly development of various VoIP CODECs technologies, both Mobile WiMAX and VoIP they share One key benefit of great cost savings due to lower deployment, implementation, maintenance and up gradation cost. Therefore, VoIP over Mobile WiMAX will play a critic role in the deployment of Mobile WiMAX networks. But, the uplink scheduling and resource management remain as a major problem that may seriously impact the deployment of VoIP over Mobile WiMAX. The uplink Scheduling and Resource Management refers to operation of serving BS (Base Station) MAC layer to effectively manage the transmission of allocable resources, which covers Scheduling Services, power saving, Handover etc., to achieve optimal resource utilization and enhanced system performance. Regarding the VoIP services the IEEE 802.16e specifications only defines the MAC layer functions modules of uplink Scheduling and Resource Management, as well as the basic content and implementation rules of these modules, but does not specifically propose any feasible schemes or implementing algorithms. Therefore, in this thesis we have concentrated our efforts on enhancing the uplink scheduling and resource management performance of the most common used VoIP CODECs over Mobile WiMAX. This thesis gives an overview of the IEEE 802.16e Mobile WiMAX standard as well as the VoIP CODECs technologies. Through this introduction we address the main challenges that affect the VoIP CODECs over Mobile WiMAX transmission. The main purposes of this thesis could be summarizes as follows:1. We designed a novel comprehensive dynamic uplink scheduling proposal (CDUSP) for all major VoIP CODECs over Mobile WiMAX. Through investigating the standard defined three conventional uplink scheduling service algorithms as well as the most common used VoIP CODECs. The CODECs have been classified into two main categories based on their characteristics and it’s silence compression performance, several novel uplink scheduling algorithms are proposed. Furthermore, our designed (CDUSP) proposal with proper modification to the uplink scheduling framework structure and procedure is planned, the CDUSP is significantly capable of dynamically integrate and manage all our proposed uplink scheduling algorithms within the Mobile WiMAX QoS scheduling framework. Besides, it greatly optimizes the Mobile WiMAX for efficiently support the VoIP CODECs uplink transmission. Through the simulation results and numerical validations, all proposed algorithms performs efficiently than the conventional algorithms over enhancement of resource utilization, total throughput, and reduction of packet transmission delay.2. Thirdly, the coexisting of multiple VoIP users resource management enhancement is investigated, through proposing different scheduling algorithms with applying multiple of our novel several grant interval schemes, to different preconfigured classified categories based on capturing several factors, based on these different factors the users classification and corresponding resource allocation schemes will be different, performance comparisons between the conventional algorithms and the proposed algorithm is given. Further, simulation result and numerical validations has proved the efficiency of the proposed algorithm over enhancement of resource utilization, total throughput, increment of system capacity, and number of voice users supported.3. Through investigating and analyzing the three power saving classes defined by 806.16e standard , we propose a new two improved power saving algorithm that greatly suitable for different VoIP CODECs with silence compression, the first algorithm is interval-flexible PSCII power saving algorithm that utilize the exponential increment scheme during the mutual silence period , this algorithm is suitable to the long frame duration , the second algorithm is called multiple termination schemes power saving algorithm , this algorithm through integrating both power saving calass (PSC) I and PSCII ,with concern to the PSCI two different mechanisms of sleep mode activation . Our proposed algorithm basically follows PSCII during talk-spurt periods, but uses the two different wake up schemes of of PSCI during silent periods. The analysis and simulation results show that our proposal reduces power consumption effectively during silent periods while satisfying the maximum allowable end-to-end delay and low packet drop probability constraints with respect to the QoS of VoIP.更多还原