自从1899年人类第一次利用无线电波进行无线电报通信以来,无线电通信发生了巨大的变化,其中最近的,也是最具有革命性的变化就是无线电移动通信和在此基础上发展起来的个人通信。 最早的陆地无线电移动通信,是1921年在美国警察部门使用的车载无线电。由于无线移动通信方 Radiocommunications have seen tremendous changes since the first human use of radio waves for radio communications in 1899, and one of the most recent and most revolutionary changes has been radio-based mobile communications and personal communications developed there. The earliest terrestrial radio mobile communications was the in-car radio used by the U.S. police department in 1921. Due to wireless mobile communication side