Shu (Marloon) Wang

How to Improve Forward Link Positioning ... ? III. Hearability and Accuracy 1x HDP Enhancements Enhanced Location Based Services Support in cdma2000 Enhance Downlink Positioning in WiMAX/16m How Wide A Widband Channel Should Be? IEEE ICC 2008 Tutorial, Location Based Services for Mobiles Location Based Services for Mobiles: I. Introduction There are many ways locating a mobile in a cellular network. The basic methods include dead reckon, proximity sensing, signal signature tracking, trilateration, multilateration, triangulation, etc. Some major approaches for cellular networks can be illustrated in Figure 1. Figure 1. Mobile Positioning Techniques, IEEE ICC 2008 "Location Based Services for Mobiles" Positioning performance is understood through quantifying the two parameters, hearability and accuracy. Hearability indicates how many hearable good references a terminal can track in a single snapshot. A typical number should be not less than 4. Accuracy is a well-...

[IEEE C802.16m-08/1105 Network Assisted GPS (N-GPS) Positioning in WiMAX/16m] [Location Based Service for Mobiles I: Technologies and Standards] GPS - Global Positioning System Figure 1. GPS System Archiecture: Space Segment, Control Segment and User Segment GPS is a Global Navigation Satellite System for determining the positions of receivers using signals broadcast by satellites.  It was developed and operated by US government to enhance the effectiveness of allied and US military forces.  The first experimental Block-I GPS satellite was launched in 1978. Since 1983, GPS has become an aid to civilian navigation worldwide, and a useful tool for survey, commerce, and scientific uses.  As of September 2007, there are 31 actively broadcasting satellites in the GPS constellation.  Satellites orbit 20,163 kilometers above the earth at 3.87 km/s.  6 orbital planes, each with 4+ satellites. Typically 6 to 12 satellites are visible from any plac...