The Research Of TDOA Location Algorithms For Cellular System

With the rapid development of mobile communication, wireless location technology has become the essential function in next generation mobile communication systems. The TDOA wireless location technology is highly interested recently, because of no need for strict time-synchronization between mobile station(MS) and base station(BS), wide suitability in various cellular systems, low cost and high location accuracy.By deep research, genetic algorithm (GA) and immune algorithm (IA) can be used for nonlinear optimization in TDOA-based location. In this paper, two hybrid methods based on GA and IA are proposed respectively. In order to improve the accuracy of mobile location, this paper aims at TDOA location technology and investigates the following cellular network based on location technology: performance analysis of basic TDOA location algorithm, mobile station location technology based on chaotic genetic algorithm (CGA), location technology based on immune clone selection algorithm (ICSA). The main works of the paper concentrate on the following:(1) Cellular network wireless location ways, channel models, and evaluating indicators is introduced. The mathematical model of TDOA hyperbolic equations is established, three major location algorithms based time-difference-of-arrival (TDOA) are analyzed in detail.(2) According to the defect of Chan algorithm, a hybrid location algorithm that employs Chan and CGA is proposed. The simulation result shows its effectiveness for improving location accuracy.(3) By vaccination, clone selection and adaptive immune operation, ICSA has the better performance in optimization problem than immune algorithms. A hybrid location algorithm that employs Chan and ICSA is proposed. The simulation result shows that Chan-ICSA has a higher accuracy and better searching ability.