LCS efficiency methods of a mobile terminal in monitoring system applications

Two efficiency methods for a location service (LCS) by use the wideband code division multiple access (WCDMA) interface, in the frequency division duplex (FDD) mode, are outlined. The LCS in the WCDMA/FDD technique is based on the actual relative time differences (RTDs) between base stations of the monitoring cellular network. The proposed methods enable calculation of the geographical position of a mobile station (MS) without knowledge of the RTDs. The first method is supported by round trip time (RTT), and in the second case, an elimination process of RTDs is based on idle period downlink (IPDL) mode. The elimination of the RTD parameters significantly simplifies the localization process in the 3G (3rd Generation) real-life monitoring cellular networks. The comparison and usefulness of the methods for the location service implementation are analyzed. The simulation model and results of the proposed methods are presented. These results show that in the studied radio environment, the proposed algorithms fulfill the requirements for emergency calls from cellular phones in relation to accuracy of MS position calculation.