1G，2G，3G，4G，5G的发展和通讯原理https://blog.csdn.net/wuyuzun/article/details/81328437?ops_request_misc=&request_id=&biz_id=102&utm_term=4g%E9%80%9A%E8%AF%9D%E5%8A%9F%E8%83%BD%E5%8E%9F%E7%90%86&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-3-.first_rank_v2_pc_rank_v29&spm=1018.2226.3001.4187
