Localization in multipath environment using hybrid method
Lim, Wee Keat.
Date of Issue2010
School of Electrical and Electronic Engineering
Positioning and Wireless Technology Centre
Conventional localization methodology leverages on the reference devices' measured parameters such as Time of Arrival (TOA) as in Global Positioning System (GPS) and Angle of Arrival (AOA) to locate the mobile device in a Line of sight (LOS) environment. It uses only LOS information to measure Euclidian distances between reference devices and mobile device and to subsequently construct independent equations needed to estimate mobile device’s position However, channel impairments such as existence of non line of sight (NLOS) and multipath seriously degrade the performance of conventional localization scheme. This makes the implementation in indoor environment difficult because indoor environment typically has many obstacles and reflectors. Current state of the art localization scheme is able to locate mobile device in 2- dimensional multipath environment by using both Line of Sight (LOS) and Non Line of Sight (NLOS) bidirectional Time of Arrival (TOA) and Angle of Arrival (AOA) information at both the mobile device and reference device side. This method has significant advantage over conventional localization because the method will be able to work even when no reference device is in LOS with the mobile device and hence this method is suitable for indoor environments. This report presents the design of a non line of sight (NLOS) localization algorithm that determines the two-dimensional position of a mobile device in a multipath environment Our proposed algorithm leverages on received signal strength (RSS) measured at the reference devices to obtain the distance of propagation. Together with the AOA measurements, the two dimensional line of possible mobile device (LPMDs) is worked out. These LPMDs will then used to determine the accurate mobile device's position. Computer simulation was performed in indoor multipath environment to compare the performance between our proposed algorithm and the existing NLOS algorithms.
DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
Final Year Project (FYP)
Nanyang Technological University