bi-direction

• Orthogonal frequency division multiplexing ( ofdm ) is a multi - carrier digital modulation technique . its conception has come out for a long time , however , it is recently that it ' s recognized as an proposed method in broadband bi - direction wireless data communications with the development of multimedia services
  正交频分复用( ofdm )技术是一种多载波数字调制技术，虽然ofdm的概念已经存在了很长时间，但是直到最近，随著多媒体业务的发展，它才被人们认识到是一种实现高速双向无线数据通信的良好方法。