OFDM系统信道估计和自适应分配算法的研究

在多径衰落的信道中,用固定调制方式的分配技术可能会造成OFDM系统资源浪费,考虑如何将自适应分配技术与OFDM相结合成为提高移动通信性能的关键技术。本文中提出一种基于动态信噪比SNR切换门限的自适应算法,该算法在保证通信质量所需BER的前提下,结合OFDM和PSK/QAM调制方式的优势,按照各个子信道的状态分配比特信息量和功率大小,使所需要的发射功率达到最优化。本算法能提高OFDM的频谱利用率,也能使系统获得更优的性能。

Research on channel estimation and adaptive allocation algorithm for OFDM systems

In multi-path fading channel,the use of a fixed modulation technique in OFDM systems will cause waste of resources.How to take the adaptive modulation techniques in OFDM systems is the key technology for improving the mobile communication.An adaptive algorithm based on dynamic SNR switching levels is given in this paper.To ensure the BER of communication quality,this algorithm can distribute bits and power in accordance with the state of various channels and achieve the optimum,under the advantages of PSK and QAM these two types of modulation.The simulation results show that this algorithm could improve the spectrum efficiency of OFDM systems and also yield significantly better performance.