OFDM系统中子信道联合预编码技术的信号检测算法研究

Research on signal detection algorithm of sub-channel joint precoding technology in OFDM system

正交频分复用技术将多径衰落信道划分为多个相对平坦的子信道,使得接收机在信道估计等恢复技术上复杂度大大降低。OFDM系统采用子信道联合预编码技术能有效解决由于成片子载波衰落引起的数据丢失问题。由于独立信道的线性预编码技术在发送端不需要信道反馈信息,因此降低了发送设备复杂度,减少了系统延时,该编码方案适用于从用户端到基站的数据传输。通过理论分析推导了当系统采用独立信道的线性预编码技术时,接收端不能采用迫零均衡(ZF)的线性检测算法,实验仿真表明,当采用迫零均衡检测算法时,当且仅当预编码矩阵为酉矩阵时系统能达到未经预编码系统的性能。

The multipath fading channel is divided into multiple relatively flat sub-channels by OFDM,which makes the receiver＇s complexity in channel estimation reduced greatly. OFDM system with sub-channel joint precoding technology can effectively solve the problem of data loss caused by numerous carrier wave fading. Since the linear precoding technology of independent channel doesn＇t need feedback information of the channel in sending end,which can reduce the complexity of the transmitting device and system delay,this precoding scheme is suitable for data transmission from the client to the base station. In this paper,a conclusion that the linear detection algorithm of zero forcing equilibrium can＇t be adopted for receiving end when the linear precoding technology of independent channel is applied by the system is derived according to the theoretical analysis. The experimental simulation results show that the system can achieve the performance without precoding when the precoding matrix is unitary matrix and zero forcing equilibrium detection algorithm is adopted.