The Federal Communications Commission (FCC) has adopted regulations requiring wireless communication service providers to provide position location (PL) information for a user requesting E-911 service. The Time Difference of Arrival (TDOA) technique is one of the most promising position location techniques for cellular-type wireless communication systems. The IS-95 Code Division Multiple Access (CDMA) system is a popular choice for the companies deploying new cellular and PCS systems in North America. Hence, the feasibility of TDOA techniques in CDMA systems is an important issue for position location in the wireless systems of the future. This thesis analyzes the performance of TDOA techniques in the CDMA systems. A comparison and assessment of different algorithms for finding the time difference estimates and for solving the hyperbolic equations generated by those estimates has been made. This research also considers a measure of accuracy for TDOA position location method which is shown to be more suitable for CDMA systems and more closely matches to the FCC requirements. Among the other contributions is a proposed method to perform cross-correlations to identify only the desired user's TDOA in a multiuser environment. This thesis also evaluates the feasibility and accuracy of TDOA techniques under varying system conditions that might be encountered in real situations. This includes varying conditions of Additive White Gaussian Noise (AWGN), Multiple Access Interference (MAI), power control and loading. The effect of the mobile position and of different arrangement of base stations on TDOA accuracy is also studied. Performance comparison in AWGN and Rayleigh fading channels is made. The feasibility of using increased power levels for the 911 user in combination with interference cancellation is also studied. The effect of using a single stage of parallel interference cancellation at neighboring cell sites has also been explored. Non-ideal situations such as imperfect power control in CDMA operation has also been investigated in the context of position location. This thesis also suggests amethod to correct TDOA estimation errors in CDMA. It is shown that this improvement can give greatly improved performance even under worst-case situations. Performance comparison of results with and without that modification has also been made under various conditions. / Master of Science

La thèse a porté sur la localisation de mobile pour les systèmes UMTS-FDD. Il s'agit d'un sujet qui intéresse de plus en plus les opérateurs, notamment dans le cas de système UMTS-FDD où il existe très peu de réseaux réels. Les différentes approches permettant de localiser un émetteur ont ainsi été envisagées, et plus particulièrement, celles basées sur les mesures de puissances, les temps d'arrivée (TOA) en liaison descendante ou encore celles basées sur les angles d'arrivée (AOA) et sur toute combinaison AOA-TOA. Pour ces différentes approches, nous nous sommes intéressés aux deux principales sources d'erreur pouvant dégrader les performances de la localisation : -l'absence de trajet direct qui est une des caractéristiques des systèmes radio-mobile. -le problème d'écoute, qui est inhérent au système UMTS-FDD. A ces deux problèmes, nous avons proposé des solutions pour les differentes approches de localisation, qui soient à la fois précises et facile à mettre en oeuvre au niveau de la norme.

With the rapid development of wireless networking technology and the great growth of service demand, accurate wireless location estimation has gained considerable attention. Most wireless location system may suffer from non-line-of-sight (NLOS) propagation error, which leads to a severe degradation of position accuracy. In this thesis, we propose a hybrid TOA/AOA (time of arrival/ angle of arrival) non-line-of-sight identification and wireless location technology to cope with NLOS condition. This algorithm can simultaneously determine the number of line-of-sight (LOS) base stations (BSs) and identify them. The identification part is to collect all TOA and AOA parameters from all BSs and to use residual information to detetmine whether the NLOS error is present in measurements. The localization method only processes the LOS measurements to avoid the NLOS error and increases position accurary. The simulation results show that the location system with TOA measurements can identify three or more LOS-BSs. The system has a high identification accuracy when the number of LOS-BSs is more than three. When the number of LOS-BSs is three, the degraded identification capability leads to larger position errors. When the AOA information is available in the positioning system, the TOA is combined with AOA because the property of the AOA localization method which needs only two measurements to locate the MS makes the location system capable of identifying two LOS-BSs. When the number of LOS-BSs is two, the combination of TOA and AOA measurements maintains a higher NLOS identification accuracy and make its location performance remarkably promoted.

Because of the Agreement on Agriculture’s (AoA) Article 13, dubbed the “Peace Clause,” the challengeability of agricultural subsidies has been limited; Article 13 had the power to prevent several types of legal challenges. The Peace Clause has expired, and now many agricultural subsidies can be challenged under substantive provisions of the General Agreement on Tariffs and Trade (GATT 1994) and the Agreement on Subsidies and Countervailing Measures (SCM Agreement). However, there has been some uncertainty, because the new arrangement of agricultural subsidies’ challengeability is being defined by the interpretation and correlation of three different WTO agreements. This study verified, using a two-pronged method, that there is no conflict among the GATT 1994, the SCM Agreement and the AoA, and for this reason, they have to be applied together to regulate agricultural subsidies. This does not mean that all SCM Agreement provisions are automatically applied to agricultural subsidies, with a consequent free ride for challenges to agricultural subsidies. A successful challenge still has to overcome the SCM Agreement’s higher thresholds for challengeability compared with those of the GATT 1994 period. This condemnation became more difficult after the implementation of the WTO. Consequently, the goals established in the AoA of substantial and progressive reductions in agricultural support and protection still have to be accomplished.

Because of the Agreement on Agriculture’s (AoA) Article 13, dubbed the “Peace Clause,” the challengeability of agricultural subsidies has been limited; Article 13 had the power to prevent several types of legal challenges. The Peace Clause has expired, and now many agricultural subsidies can be challenged under substantive provisions of the General Agreement on Tariffs and Trade (GATT 1994) and the Agreement on Subsidies and Countervailing Measures (SCM Agreement). However, there has been some uncertainty, because the new arrangement of agricultural subsidies’ challengeability is being defined by the interpretation and correlation of three different WTO agreements. This study verified, using a two-pronged method, that there is no conflict among the GATT 1994, the SCM Agreement and the AoA, and for this reason, they have to be applied together to regulate agricultural subsidies. This does not mean that all SCM Agreement provisions are automatically applied to agricultural subsidies, with a consequent free ride for challenges to agricultural subsidies. A successful challenge still has to overcome the SCM Agreement’s higher thresholds for challengeability compared with those of the GATT 1994 period. This condemnation became more difficult after the implementation of the WTO. Consequently, the goals established in the AoA of substantial and progressive reductions in agricultural support and protection still have to be accomplished.

Because of the Agreement on Agriculture’s (AoA) Article 13, dubbed the “Peace Clause,” the challengeability of agricultural subsidies has been limited; Article 13 had the power to prevent several types of legal challenges. The Peace Clause has expired, and now many agricultural subsidies can be challenged under substantive provisions of the General Agreement on Tariffs and Trade (GATT 1994) and the Agreement on Subsidies and Countervailing Measures (SCM Agreement). However, there has been some uncertainty, because the new arrangement of agricultural subsidies’ challengeability is being defined by the interpretation and correlation of three different WTO agreements. This study verified, using a two-pronged method, that there is no conflict among the GATT 1994, the SCM Agreement and the AoA, and for this reason, they have to be applied together to regulate agricultural subsidies. This does not mean that all SCM Agreement provisions are automatically applied to agricultural subsidies, with a consequent free ride for challenges to agricultural subsidies. A successful challenge still has to overcome the SCM Agreement’s higher thresholds for challengeability compared with those of the GATT 1994 period. This condemnation became more difficult after the implementation of the WTO. Consequently, the goals established in the AoA of substantial and progressive reductions in agricultural support and protection still have to be accomplished.

Because of the Agreement on Agriculture’s (AoA) Article 13, dubbed the “Peace Clause,” the challengeability of agricultural subsidies has been limited; Article 13 had the power to prevent several types of legal challenges. The Peace Clause has expired, and now many agricultural subsidies can be challenged under substantive provisions of the General Agreement on Tariffs and Trade (GATT 1994) and the Agreement on Subsidies and Countervailing Measures (SCM Agreement). However, there has been some uncertainty, because the new arrangement of agricultural subsidies’ challengeability is being defined by the interpretation and correlation of three different WTO agreements. This study verified, using a two-pronged method, that there is no conflict among the GATT 1994, the SCM Agreement and the AoA, and for this reason, they have to be applied together to regulate agricultural subsidies. This does not mean that all SCM Agreement provisions are automatically applied to agricultural subsidies, with a consequent free ride for challenges to agricultural subsidies. A successful challenge still has to overcome the SCM Agreement’s higher thresholds for challengeability compared with those of the GATT 1994 period. This condemnation became more difficult after the implementation of the WTO. Consequently, the goals established in the AoA of substantial and progressive reductions in agricultural support and protection still have to be accomplished.

No description available.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Traditional angle of arrival algorithms operate with uniform receiver arrays. Non-uniform arrays typically introduce significant elevation of computation complexity. This paper utilizes the double-integration method for the accurate estimation of the angle of arrival with non-uniform receiver arrays, while maintaining high computation efficiency. Because of the simplicity, the double-integration method is not significantly affected by the increase of the number of receivers or the non-uniform configuration. This approach allows us to perform high-speed high-accuracy estimation of the two-dimensional bearing angle without the constraints of structured receiver arrays, which is important to the realization of real-time tracking of mobile acoustic sources.

There has been an increase in demand for efficient wireless systems. Smart antennas using position location are one possible way to improve the capacity of cellular systems. In order to deploy such systems successfully, the wireless network must properly exploit the processing of spatial information (ie. The uplink angle of arrival) through wireless channel models. Geometric modelling is a technique to model the wireless environment. When compared to other methods such as ray tracing simulations, geometric models allow one to classify a wide varity of environments within a single model. Secondly, there have been much research in the past to obtain empirical measurements in many different environment settings. These measurements have been recorded, however, there has been no research undertaken to systematically compare and validate the empirical findings with current geometric models. The goal of this research is to compare and constrast geometric models with empirical data in order to show which models are best suited for specific wireless environments. The uplink angle of arrival (AOA) probability distribution is the fading metric that will be used to compare and contrast these models.