【作者】 郑杰；

【导师】 李建东； 杨小牛；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2014， 博士

【摘要】 随着业务需求的快速增长，多种无线技术飞速发展，异构无线网络已经成为未来无线网络发展的趋势。资源管理对异构无线网络的融合和协作有着重要意义。在异构无线网络中，首先面临的是选择接入控制方式的问题，选择单个网络接入(单接入)还是选择多个网络同时接入(多接入)。不同的接入控制方式将对异构无线网络的融合和资源管理产生不同的影响。同时，由于接入控制方式的不同，对应的业务分配算法也会造成很大的不同，这些问题都是异构无线网络资源管理中重要的研究内容。因此，本文将围绕异构无线网络资源管理中的接入控制与业务分配问题展开研究，首先以接入控制方式为切入点，分析对比不同接入控制方式对异构无线网络性能的影响，继而研究多接入方式下的业务分配算法，最后对异构蜂窝网络中基于干扰协调的负载分配问题进行了探讨。在国家自然科学基金重点项目“无线网络的干扰管理与容量研究”(61231008)，国家973重点基础研究发展计划课题“智能的动态网络资源管理模型与控制机制研究”(2009CB320404)，国家自然科学基金(61102057)，长江学者和创新团队发展计划(IRT0852)和高等学校创新引智计划(B08038)的共同资助下，本文对异构无线网络中的资源管理中的接入控制方式和业务分配算法以及与其息息相关的干扰管理进行了系统的研究。具体内容如下:1、针对异构无线网络中选择接入控制方式的问题，分析了三种接入控制方式，网络选择、分集多种无线接入和并行多种无线接入对异构无线网络融合性能的影响，其中网络选择指选择速率最大的单个网络接入；聚合(分集)多种无线接入指复制相同的数据流分配到不同的网络中传输；并行(复用)多种无线接入指将数据流分成多个不同的数据子流，通过不同的网络进行传输。首先，考虑了异构无线网络中多址协议和服务速率的不同，采用完全共享的机制对无线局域网络建模和采用均享的机制对蜂窝网络建模，分别得到两个网络的服务速率，然后将三种接入控制方式嵌入到马尔科夫模型中，建立马氏链，得到三种接入控制方式下系统的阻塞概率和平均时延。仿真结果表明，在不同的多址接入协议和不同的服务速率下，并行多种无线接入相比其他两种接入控制方式可以获得更小的系统平均时延。2、基于概率分流研究了异构无线网络中多接入业务分配的算法。首先，从队列的观点出发将异构无线网络看作多个队列耦合和并行的系统，得到单个网络的平均时延，进而从概率分流的角度推导了异构无线网络系统的平均时延，然后以系统的平均时延最小化为目标，以网络的稳定性为约束条件，建立优化问题。为了验证我们提出模型的有效性，采用蜂窝网络和WLAN网络组成的异构无线网络场景，并用启发式的搜索算法求解最优的分流概率，得到系统最小的平均时延。最后用马尔科夫过程建模提出的算法，并与网络选择算法进行了比较。仿真结果表明，相比网络选择算法，概率分流算法不仅降低了系统的阻塞概率，而且减小了系统的平均时延。3、在异构无线网络中，针对端到端的并行多接入传输，研究了时延最小的并行多接入业务分配问题。首先考虑了不同网络的可利用传输速率和网络时延的不同对业务分流的影响，分析了业务分流经过不同网络的传输时延，然后建立了以时延最小化为目标的优化问题，利用贝克曼变化思想证明了最优的业务分配问题存在门限值，根据业务分配门限选择传输网络的集合，并进行业务分流获得最小的传输时延，最后提出了一种联合网络选择和业务分配的并行多接入算法。仿真结果表明，在重负载情况下，与已有的算法相比，所提的算法不仅获得最大的吞吐量，并且能够有效降低业务的传输时延。4、在宏蜂窝和微微蜂窝组成的异构蜂窝网络中，研究了基于增强型小区间干扰协调(eICIC)的联合上下行的负载分配问题。为了提高几乎空白子帧(ABS)的利用率，首先提出了在eICIC的ABS子帧中配置宏蜂窝用户的上行传输，简称为UM-ABS，接着考虑了上下行的非对称信道，对于单个用户的上下行可以接入不同的基站。然后联合UM-ABS和上下行非对称信道，将宏蜂窝与微微蜂窝时域资源分配和上下行的非对称接入问题建模为优化问题，提出了松弛-取整的多项式近似算法。仿真结果表明，相比现有的算法，所提的算法显著改善了系统的吞吐量和用户的速率。更多还原

【Abstract】 With prolific growth of wireless data traffic and rapid development of the multipleradio technologies, heterogeneous wireless networks (HWNs) will be the trend infuture. Resource management plays an important role for the integrated variousnetworks. In resource management of heterogeneous wireless networks, the firstproblem is to choose access control schemes, such as the single radio access andmultiple radio access. The different access control schemes will affect the performanceof integration of heterogeneous wireless networks. Accordingly, the traffic allocationwill be disparities with the different access control schemes in heterogeneous wirelessnetworks. It is important to investigate these above problems for resource managementin heterogeneous wireless networks. This dissertation mainly focuses on the accesscontrol scheme and traffic allocation for resource management in heterogeneouswireless networks. We firstly address the effect of the access control schemes onintegrated performance of heterogeneous wireless networks. Then, the traffic allocationalgorithm for multiple radio access is to be design. Finally, we investigate the loadbalancing for interference coordination in heterogeneous networks (HetNets).The dissertation is supported by the National Nature Science Foundation of China(No.61231008), National Basic Research Program of China (No.2009CB320404),National Science Fund (No.61102057), Program for Changjiang Scholars andInnovative Research Team in University (No. IRT0852) and the111Project(No.B08038). This dissertation studies the access control scheme and traffic allocationfor resource allocation and the related interference management in the HWNs scene.The main achievements and results of this dissertation are listed as follows:1. The problem to choose access control schemes in heterogeneous wirelessnetworks is studied. We analyze the performance of three access control policies:optimal radio access technology (O-RAT) selection, the aggregated multi-radio access(A-MRA) technology and the parallel multi-radio access (P-MRA) transmission, wherethe O-RAT means that the incoming traffic always tries to access one network with themaximum service rate before admission. The A-MRA intends to allocate the same datato all networks. And the traffic will leave the system if it is accomplished first by one of these networks. The P-MRA is that the incoming traffic is split into differentnetworks. The traffic is served with the sum of the service rates provided by overallnetworks. First, we consider the different multiple access protocols and service rate ofdifferent networks. Next, the complete sharing discipline is used to model the WLANand the equal sharing discipline is used to model the celluar network, so the servicerate of the two networks can be obtainted. Then, the three access control policies areembedded into the Markov chain, the blocking probability and average delay of threeaccess control policies for HWNs can be obtainted. Simulate results show that theP-MRA policy can obtain the lower delay than the other two policies with the specificparameters of the different multiple access protocols and service rates.2. The traffic allocation for multi-radio access with probabilistic manner is studiedin heterogeneous wireless networks. First, via treating the integrated heterogeneouswireless networks as different coupled and parallel queuing systems from a queuepoint, the average delay in heterogeneous wireless networks is derived in aprobabilistic manner with the delay of single network. Then，the minimal averagedelay is formulated as an objective function with the constraint of queue stable. For thepurpose of illustrating the effectively of our proposed model, the Cellular/WLANinter-working is exploited, a heuristic search algorithm is used to get the optimalprobability of splitting traffic flow to minimize the system average delay. Further, aMarkov process is applied to evaluate the performance of the proposed schemecomparing with the network selection algorithm. Numerical results illustrate that theprobabilistic split algorithm can obtain the lower blocking probability and decrease theaverage delay compared with network selection algorithm.3. The traffic allocation to minimize delay for end to end of parallel multi-radiotransmission is studied in heterogeneous wireless networks. First, we take into accountthe effect of the available bit rate and network delay of different networks on the trafficspiltting, and analyze the transmission delay of the traffic spiltting in differentnetworks. Then, the minimal delay for traffic allocation is formulated as anoptimization problem. Based on Beckmann transformation method, we obtain thethreshold for the optimal traffic allocation. According to such threshold, a minimalsubset of admitted networks can be chosen and traffic allocation among these networkscan be done to achieve the minimum delay. Finally, a joint network selection andtraffic allocation algorithm is proposed for parallel multi-radio transmission.Simulation results show that the proposed algorithm could decrease the average delay of system and guarantee the maximum throughput under heavy load conditioncompared with the existing algorithm effectively.4. In heterogeneous network composed of spectrum-sharing macrocell andpicocell, the joint uplink and downlink of load balancing for eICIC is studied. First, wepropose configuring uplink transmission for the user in macro for almost blanksubframe (ABS) of eICIC to improve the utilization of ABS, refer to UM-ABS. Andwe assume that the user can associate with the different BSs in the downlink anduplink and consider the asymmetry channel model in the two directions. Thus, with theUM-ABS and asymmetry downlink and uplink, we adopt an optimization frameworkto investigate the problem of asymmetry association for downlink and uplink and thetime resource allocation between macrocell and picocell. The optimization problem ismixed integer programming, and then a relaxed-rounding approximate solution isprovided. Numerical results show the proposed algorithm can improve systemthroughput and obtain the rate gain for users relative to the existing approachessignificantly.更多还原