Since the telephone was invented in the late nineteenth century, there has been a
steady development of telephone services, and the number of subscribers has con-
tinuously increased. One of the most revolutionary developments in telephone serv-
ice in the late twentieth century was the introduction of the cellular variety of
mobile phone services.
标签：
Engineering
Capacity
Systems
CDMA
上传时间：
2020-05-26
上传用户：shancjb
