无线宽带定位网络中的资源分配优化研究

发布时间：2018-10-23 11:51

【摘要】：随着无线通信技术的迅速发展,精确位置信息是现代化信息技术提供服务的基础条件之一,而影响系统定位精度除了外界因素的影响,如网络拓扑、测量环境和测量方法等因素的影响外,还受到资源分配方案的影响。本文以无线宽带定位为背景,从无线宽带定位网络中的资源分配优化出发,通过建立功率带宽联合分配优化模型(Joint Power and Bandwidth Allocation,JPBA),为无线定位网络中的资源分配优化提供指导。通过我们的分析,功率带宽联合优化模型属于非凸问题,无法对该模型直接求解。本文首先通过最优化理论,给出了一种低复杂度、高精度的近似求解方法。由于上述最优的资源分配优化模型是基于真实目标节点的位置建立的,在实际测量定位过程中,测量得出的目标节点的位置与真实位置之间存在误差,从而导致最优JPBA存在较大误差,本文给出一种低复杂度且具备鲁棒性的资源分配优化方法,能够在目标节点的位置存在不确定性时给出鲁棒性资源分配结果。具体研究内容包括如下三个方面:第一,本文以到达时间估计的无线宽带定位网络理论为基础,基于平方定位误差界(Square Position Error Bound,SPEB)建立无线宽带定位网络中的联合功率和带宽分配优化模型,如定位精度最优模型和功率利用率最优模型。由于联合功率和带宽分配优化的模型属于非凸问题,无法直接求解。本文基于最优化理论中的几何规划知识,给出了一种低复杂度的近似求解方法。第二,在实际的定位测量中,由于先验知识不足和测量误差,测量得到的目标节点的位置与真实位置之间存在偏差,基于真实目标节点的位置的资源分配模型优化模型不具备鲁棒性。本文通过远场近似条件,提出了一种简单的鲁棒性方法,能够在目标节点位置不确定时提供具有鲁棒性的资源分配方案。第三,我们进行了大量的数值实验仿真,通过仿真结果,发现在定位性能和功率资源使用效率上,JPBA方法比单纯的功率分配优化和均匀分配好很多,验证了我们的之前的推论与设想。同时我们发现,随着目标节点位置的不确定性度的增加,最优JPBA方法的会失去定位能力,但鲁棒性的JPBA能够避免由于定位误差带来的性能大幅度下降的问题,能够为实际定位系统的设计提供了指导。
[Abstract]:With the rapid development of wireless communication technology, accurate location information is one of the basic conditions for modern information technology to provide services. Besides measuring environment and measuring method, it is also influenced by resource allocation scheme. In this paper, based on the resource allocation optimization in wireless wideband location networks, a joint power bandwidth allocation model (Joint Power and Bandwidth Allocation,JPBA) is established to provide guidance for resource allocation optimization in wireless location networks. Through our analysis, the joint power bandwidth optimization model is a non-convex problem, which can not be directly solved. In this paper, an approximate solution with low complexity and high accuracy is presented by optimization theory. Because the above optimal resource allocation optimization model is based on the location of the real target node, there is an error between the position of the target node measured and the real location in the actual measurement and positioning process. In this paper, a low complexity and robust resource allocation optimization method is presented, which can give robust resource allocation results when the location of the target node is uncertain. The specific research contents include the following three aspects: first, this paper is based on the theory of wireless broadband location network based on time of arrival estimation. Based on square location error bound (Square Position Error Bound,SPEB), an optimal model of joint power and bandwidth allocation in wireless wideband positioning networks is established, such as the optimal positioning accuracy model and the optimal power utilization model. Because the model of joint power and bandwidth allocation optimization is a non-convex problem, it can not be directly solved. Based on the knowledge of geometric programming in optimization theory, a low complexity approximate solution method is presented in this paper. Secondly, because of the lack of prior knowledge and measurement error, there is a deviation between the position of the target node and the real position in the actual positioning measurement. The optimization model of resource allocation based on the location of real target nodes is not robust. In this paper, a simple robustness method is proposed based on the far-field approximation condition, which can provide a robust resource allocation scheme when the location of the target node is uncertain. Thirdly, we have carried out a lot of numerical simulation. Through the simulation results, we find that the JPBA method is much better than the simple power allocation optimization and uniform allocation in location performance and power resource efficiency. It verifies our previous inferences and assumptions. At the same time, we find that with the increase of the uncertainty of the target node position, the optimal JPBA method will lose its localization ability, but the robust JPBA can avoid the problem of the performance degradation caused by the location error. It can provide guidance for the design of the actual positioning system.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN92

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