Research Of Mobile Positioning Strategies In Fixed Relaying Cellular Network

Mobile location services become more and more popular with the huge market potential, while the multi-hop network architecture is also attractive and going to be the trend of mobile communications. This paper investigates the mobile positioning technologies and strategies in the new network architecture ---- the fixed relaying cellular network, and manages to raise the positioning performance and increase the accuracy.The positioning schemes based on the signal strength are not paid enough attention due to the instability against the surrounding environments. But it still has incomparable advantages of low cost, universality and easy realization. A positioning scheme based on the differences of signal fading in fixed relaying cellular network is proposed. The method, that can reduce the impact of shadow effects, is adaptive to different path loss models and does not require any hardware modification on network or mobile devices. Moreover, with the cooperative measurements provided by fixed relays, better accuracy can be achieved with less signaling cost. Simulation results show that the positioning accuracy of the proposed scheme is better than traditional schemes.In the non-line-of-sight transmission environments, the accuracy can not be guaranteed only by real-time measurement. To avoid the influence of non-line-of-sight transmission and further improve the overall performance, a GPS-assisted strategy for collecting a priori information is also proposed. In this strategy, the mobile terminals that enhanced with GPS modules are able to offer a priori information to the mobile network efficiently own to the cooperative measurements from the fixed relays in the cell. Finally, under the strategy, some mathematical methods such as statistical theory and pattern recognition are introduced for mobile location estimation based on the a priori information database. Simulations evaluate the validation of the proposed strategy and give comparisons between the performances of different statistical methods.