Help for a PHD Cover letter

Hi, I'm writing a cover letter for my Phd application, any advice will be greatly appreciated.

Dear Professor **** :

I am writing to apply for a PHD in ********* Lab. I’m currently employed in ******* as Research & Developor.

I’ve spend four years to get a bachelor degree in System Engineering in ****** University in 2000,then I went to the ****** State Key Laboratory of Software Development Environment, spent another two and a half years to get a master degree in Computer Science, during which I've been studying on Intelligence Transportation System and became very interested in your lab’s research.

In my first year, I took part in the ****** Project, which represents the daily operation of urban public transportation on WEB, and evaluate the operation quality through different charts and graphs. With participation of ******(nation) academy of transportation science, Bus companies, this system was built successfully, and greatly enhanced the management of urban bus transportation system.

In the second year, I’ve started to discover the potential application of cell phone communication records in transportation. Based on carefully studying on real mobile phone records (about 44G, 400 million records, 13 million residents per day), I’ve estimated the amount of passenger flow within the city per day, also I’ve found some interesting relation between the communication amount of cellular towers and its nearby environment. The latter is published in a paper “******************” in *********** Conference . I’ve also done some research on using mobile phone records to find users driving on highways in order to accurately deliver traffic information and build the demo system.

With the growing population and the progress of technology, For innovators with fantastic imaginations, there are enormous opportunities in building smart planet, smart city. Vehicles and citizens with wireless sensors are connecting the city together, however, the quality of sensor data is always far from ideal condition, how to dig and share these information while protecting individual’s privacy requires a lot of effort.

During my research, your Lab’s research, such as “**********” and other papers inspired me a lot. I would like to have the opportunity to develop PHD programme in your Lab, for which I am confident I have the skills, knowledge and competence.
Thank you very much for considering my application.

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I'm not a native English speaker, please help me, thank you.