Power Allocation Framework In Asynchronous Wireless Localization Networks

With the development of wireless technology, position information plays an important role in the commercial, public security, military and wideband transmission applications. In wireless location networks, with large number of nodes, wide coverage and complex structure, it is difficult to realize the clock synchronization between anchor nodes and agent nodes. It is of great significance to provide the benchmark of positioning accuracy and synchronization precision in wireless asynchronous localization network. Meanwhile, due to the limited power in wireless network, a reasonable allocation of transmission power is one of the important measures to improve the positioning accuracy. This paper takes the minimum of positioning error lower bound as the objective function and studied power optimal allocation problem in wireless asynchronous network. Specific research contents as follows.(1) To assess quantitative benchmark of localization technology and the localization algorithm in wireless asynchronous network, the Cramer-Rao lower bound of position estimation, clock offset estimation, and joint position and clock offset are provided through the analysis of framework model of wireless asynchronous network.(2) For the wireless network with a large positioning rang and low coverage of anchor node, cooperation technology can achieve good location accuracy. This paper extended the research to the performance analysis of cooperation localization network. The quantitative expressions of positioning accuracy, clock precision and joint positioning and synchronization in cooperative network is obtained, which are used to describe the lower bounds of the position and synchronous performance, which provides a theoretical basis for the further study of cooperative network. The difference of cooperative network and the non-cooperative network in positioning performance also is analyzed.(3) For the research of power allocation, with the lower bound of performance on position estimation, clock offset estimation and joint location and synchronization as the objective function and limited power as constraint condition, the systems optimization framework model is established. By proved that all optimization models are convex problems, the optimal solution can be obtained in asynchronous network with limited power. Comparison of the performance between power optimization allocation method and the uniform allocation method is made, and the influence of power allocation to the positioning and synchronization performance is analyzed under the condition of different network structure.(4) The clock synchronization precision and positioning precision influence each other. By defining the correlation coefficient of location and the synchronous and establishing the tradeoff optimization model of positioning and synchronization, the relations of positioning and synchronization on optimal allocation of power are studied.According to the analysis of performance in wireless asynchronous network, a quantitative benchmark is provided for actual localization algorithm. Meanwhile, power optimization allocation mechanism can provide reference to actual system design and deployment.