Implementation Of Terminal Software Based On A-GPS/GSM Hybrid Positioning System

The A-GPS technology is a positioning technology combined mobile communication network with GPS technology into itself. And it has the excellent fixing precision in all mobile position services put forward by current mobile telecommunication service provider.At the end of 2003, FCC pointed out that the untilization of allocated spectrum varied from 15% to 85%. Cognitive Radio is a key technique to solve the spectrum underutilization problem effectively. Spectrum sensing, as the very task at which the entire operation of Cognitive Radio rests, has attracting overwhelming attention. Nevertheless, detecting the spatiotemporal spectrum holes accurately, effectively, robustly in a computationally manner is still a challenge for Spectrum Sensing.The article summarizes the author's research and development work in master period in Broad Band Communication Network Lab of BUPT. The article was divided into 2 parts:the part I includes from chapter 1 to chapter 5, and concludes the author's R&D work in A-GPS hybrid positioning system team; the partⅡincludes from chapter 6 to chapter 8, and concludes the author's R&D work in Cognitive Radio research team.In the R&D of A-GPS team, the author focuses on implementation of the terminal software. Accroading to A-GPS principal, hybrid positioning system contains three parts:positioning terminal, server and reference station. The terminal needs to fix itself by means of interaction with the server at first, then it sends location information to the server. Meantime, it should deal with all kinds of emergencies. Terminal software has been developed using a "host+target" development model:the host is PC+Debian, the target is S3C2410+Linux. The author utilizes process communication to finish application program based on Linux operating system. Upon formal testing technologies and processes, the perfect terminal software is delivered to the cooperation partner.In the R&D of Cognitive Radio team, the author focuses on the spatial spectrum holes sensing. In Cognitive Radio, analysis of the radio environment includes space-time processing of wireless signal. The author introduces the MTM-SVD algorithm and the parameter estimation method. Both of theoretical analysis and the simulation demonstrate that the parameter estimation method improves the precision in detecting spatial spectrum holes.