Title: Integration of Satellite Navigation RF Receiver Paths into Mobile Radio Platforms
Abstract: This work presents solutions for the system design of a robust RF front-end for satellite navigation standards, the procedures related to the platform integration as well as the influence of a mobile transmitter on the satellite navigation receiver performance. Different receiver architectures are considered from inter-system interference and CMOS process characteristics point of view. The system concept covers the implementation of GPS, Galileo, UMTS, GSM, and cdma2000 standards using the Zero-IF and Low-IF architectures. A feasibility study of the systems covers the analysis of wireless regulations as well as performance criteria, such as the overall gain, noise figure, IIP3 of the RF chain, phase noise requirements, and VCO tuning range. The major part of this work is dedicated to the coexistence of different standards in one platform. For this purpose, analysis of inter-system interference is presented for the critical receiver path dedicated to the reception of GPS and Galileo signals. The functionality of the navigation receiver is investigated in a mobile environment with active mobile transmitters of different types. System analysis of the navigation receiver requirements is done based on the proposed system design tool and combined Advanced Design System and Matlab simulations. Finally, the design rules for the integration of a satellite navigation receiver in a mobile platform are presented. Following general system considerations, two alternative architectures are presented, which cover different market requirements. A single chip receiver for the GPS, Galileo, UMTS, cdma2000, and GSM standards is presented for the first time. A feasibility study for the implementation of a multi-standard, multimode RF front-end enabling utilization of Location Based Services in a mobile handset using the assisted-GPS system together with GSM, cdma2000, and UMTS support is presented. The assisted-GPS system and the future assisted-Galileo require augmentation information from either GSM or UMTS network. Having the requirement of a multimode operation on one hand and the cost and interoperability in diverse platforms on the other, a reconfigurable setup with a short analog part - where the implemented standard depends only on the off-chip components - is proposed. Two RF paths are foreseen in the implementation. Hence, a baseband processor is able first to acquire the assistance data via the mobile path and use it for the further conditioning of the navigation signals received via the complementary path. The chip has been fabricated in a 130 nm CMOS process. System considerations are confirmed with on-chip measurements of the gain, noise figure, linearity, and the VCO phase noise and tuning range. Prospects for future work are presented including a technology shrink, new RF front-end architectures and improvements in operation of the existing chip. The alternative solution is designed for high-end devices and satellite navigation receivers working with very low GPS signal levels. In this case, the chip supports the assisted-GPS standard and is able to work with signals 55~dB below the thermal noise floor of the receiver. Cost and current consumption optimization is done to create a product tailored for the competitive feature phone market. For the first time, a new configuration of a navigation RF front-end is proposed, with a fully integrated interstage filtering in the form of a combined System-on-Chip solution. An advanced digital control for the RF front-end is proposed, enabling the adaptation of the system performance to the current environment based on measurements and analysis done on the chip. In this case, no information about the blocker coming from the mobile platform is required, which is an advantage over the solutions existing on the market. The architecture is based on a Low-IF architecture in a 65 nm CMOS process. The filterless front-end performance is confirmed with system simulations and measurements of the implemented chip. The presented work can be treated as a guideline for RF system and concept engineers implementing satellite navigation RF front-end receivers in mobile platforms, where the focus is on interference mitigation and new filterless architectures.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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Cited By Count: 1
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