Cellular Networks, Wireless Positioning Algorithm

With the rapid development of mobile communication, we have been stepping in the third generation of mobile communication (3G) recently. That will bring about the more superior quality of voice, the more colorful multimedia services and the more added values. At the same time it becomes necessary that the function of mobile station location can he provided. The research on location service has been a hot point.This paper has introduced three typical location algorithms in detail: Chan algorithm, Taylor algorithm and Fang algorithm. The algorithms are simulated and compared in gauss noise channel environment and T1P1 channel environment.In the cellular network, if the LOS propagating way is blocked by building, waves can only propagate in NLOS way. If adopted TDOA or TOA location technique, compared with LOS situation, TOA measurement value will add a positive extra time delay, TDOA measurement value also will add an error quantity. If use the TDOA or TOA measurement value with big error to MS location, the algorithm's performance must go down, the ML estimation of MS location can not be obtain, estimate location will has big error. NLOS is the key problem of improving location precision in Cellular wireless location system. Based on T1P1 wireless channel model, this paper propose an algorithm which smoothing and restructuring TDOA measurement value to diminish influence of NLOS and improve the accuracy of the location estimation. Simulation results demonstrate the algorithm improves the accuracy of the location estimation effectively ,which is accomplished by diminishing average location error. As soon as smart antenna technique is used in 3G , utilizing Base Station to estimate angles of signal arrival is possible. Based on geometrically based single-bounced (GBSB) statistical channel model which is suited to analyzing every location algorithm, a algorithm for wireless location using the measured angles of arrival (AOA) is proposed to mitigate the NLOS propagation in this paper. In order to improve the accuracy of the location estimation, the algorithm utilized the largest angle spread and relationships drawn from the geometry of the BS and MS locations, solves the AOA-based location problem by converting it into a constrained optimization problem. Its effectiveness is verified by simulation.In the end application of data fusion technique in wireless location is introduced. Data fusion technique which combine different method and technique's advantages and uses relative priori information to fuse different type data, can acquire better output of data compared with single technique. This paper introduces a improved data fusion model based on the model of Kleine-Ostmann, and verifies the effectiveness of the data fusion model by simulation.