该文档描述了关于4G和B3G的物理层传输关键技术的主要内容，包括MIMO、OFDM、OTDM、智能天线、接入技术以及SDR等知识-This document describes the 4G and B3G on the physical layer transmission main key technologies, including MIMO, OFDM, OTDM, smart antennas, access to technology and the knowledge of SD