Fundamental Limits And Optimal Resource Allocation In Asynchronous Cooperative Localization Networks

With the development of advanced wireless techniques,wireless network localization is now a promising solution for position estimation in a multitude of scenarios.Position information is the basis of many modern wireless services and applications,such as global navigation,search and rescue,cellular localization and environmental monitoring,etc.However,in the non-cooperative strategy,high accuracy results can only be achieved by high cost or high density anchor deployment.One proper solution to this problem is cooperative localization,it ensures high localization accuracy.It’s very difficult to do the same between nodes’ crystal oscillator and realize the clock synchronization between anchors and agents,the asynchronous localization is better close to the reality.In limited wireless resources localization network,it’s an important topic to discuss reasonable allocation of resources and make the optimal localization precision.This subject takes Square Position Error Bound(SPEB)as the objective function and discuss the resources allocation problem in wireless asynchronous cooperative network.Specific research contents include the following aspects:In order to give a measure of localization,this paper established the asynchronous cooperative localization system model.On this basis,the fundamental limits of asynchronous cooperative wideband localization have been derived in terms of the SPEB,which is essentially the Cramer Rao Lower Bound(CRLB)of position estimation,through the Schur Complement the original EFIM of JPOE.,we can respectively get the CRLB of synchronization(clock offset estimation)and position.According to the CRLB about the fundamental limits of joint position and clock offset estimation(JPOE)in the cooperative manner,we extract some mathematical characteristics of the lower bound,give the geometric model of three dimensional space and explains the physical meaning of it.Taking the method of dimension reduction,we give other localization algorithm of geometric model and the interpretation of physical meaning.We establish a general resource(including power and bandwidth)allocation framework where the lower bound of joint position and clock offset estimation(JPOE)is selected as the objective function.We established a framework in the network and make the optimal and uniform resources allocation under the power and bandwidth.This resource allocation problem can be approximately solved by an accurate iterative searching(IS)method with strong convergence properties.Cooperative localization and synchronization are both better than the non-cooperative ones when the system is subject to the global resource constraints.The paper give a new concept--synchronous cooperation,comparing with cooperative localization,both are mutually promote.We analyze the geometrical characteristics of it,the synchronization(clock offset estimation)can be treated equivalently as one dimensional localization.We first show the expression between synchronization and position,it’s a strong guarantee to further explore the relationship about synchronization and position.