This draft of your SOP is well organized and effectively explains your background, interests, motivations, and aspirations. I have flagged areas that would benefit from additional attention and made extensive sentence-level edits to eliminate grammatical/usage issues and clarify/refine delivery.
第三周被选中的幸运儿是准备申请美国的博士学位，我们编辑者Gail L.非常细心的替得奖者修改SOP, 不仅仅是修改句型和文法上的错误，连文章的结构都做了调整!
Thank you for using wordvice! I edited your statement of purpose carefully to eliminate errors in grammar, spelling, and punctuation. To improve flow and ease of reading, I also added transitions between sentences, ideas, and paragraphs. I refined the overall struture of the essay by adjusting the paragraph order to ensure a logical structure and augmenting the final paragraph to provide a stronger and more cohesive conclusion. I also wrote several comments throughout the document, and I would recommend that you review my comments carefully before deleting or accepting them.
In general, the purpose of the statement of purpose for graduate school admissions is to state your motivation for graduate study, describe your academic/professional qualifications, and outline your career goals. Most of your essay is devoted todescribing your previous research experience, which gives the reader a very thorough overview of your accomplishments. I would encourage you to consider writing a little more specifically about your motivation for pursuing a PhD degree or about your career goals (and how earning a PhD will help you achieve those goals). For example, you might explain in greater detail what you mean by “my goal [is] to advance future wireless and multimedia technology.” Do you want to continue working on high throughput wireless network systems? After graduation, where do you plan to work (In what field? In what kind of company? What position do you want?)? How will earning a PhD enable you to be more successful in your career? You do not need to answer all these questions; rather, I would suggest using them as a way to brainstorm how to write more specifically about your goals and motivation for pursuing a doctorate.
Please let me know if you have any questions, and I wish you the best with your applications!