自适应波束形成实现交织OFDMA上行链路的载波频偏补偿  

Carrier-Frequency Offset Compensation for Interleaved-OFDMA Uplink Using Adaptive Beamformer

作　　者：范达[1] 曹志刚[1] 

机构地区：[1]清华大学电子工程系,北京100084

出　　处：《电子与信息学报》2007年第8期1924-1928,共5页Journal of Electronics & Information Technology

基　　金：高等学校博士学科点专项科研基金(20030003039)资助课题

摘　　要：在OFDMA系统中,采用交织子载波分配方法可以提高频率分集和系统容量,但是发射机和接收机之间的载波频率偏移会破坏子载波间的正交性,从而导致本用户的载波间干扰以及用户间干扰。该文分析了交织OFDMA上行链路的信号结构,提出了一种采用自适应波束形成器的载波频偏补偿方法,并给出了两种自适应波束形成器:匹配滤波器和MMSE方法。仿真结果验证了MMSE自适应波束形成器的误比特率性能优于匹配滤波器以及传统的循环卷积方法。In orthogonal frequency-division multiple access （OFDMA）, closely spaced multiple subcarrier are assigned to different users for parallel signal transmission. An interleaved subcarrier-assignment scheme is preferred because it provides maximum frequency diversity and increases the capacity in frequency-selective fading channels. Carrier-frequency offsets （CFOs） between the transmitter and the receiver destroy the orthogonality and introduce Inter-Carrier Interferences （ICI） and Multi-User Interferences （MUI）. In this paper, the signal structure at the Interleaved-OFDMA uplink is first present. Then a CFO compensation method for the system, which uses adaptive beamformer, is proposed as an alternative to the circular convolution method. And two adaptive beamformers, i.e. matched filter and MMSE method are introduced. Simulation results indicate that the MMSE beamformer outperforms the matched filter and the circular convolution method.

关 键 词：正交频分多址 载波频率偏移 自适应波束形成 频率向量 循环卷积 

分 类 号：TN92[电子电信—通信与信息系统] TN911.7[电子电信—信息与通信工程]