The IEEE 802. 16 standard specifies the air interface of wireless metropolitan area network （WMAN）, and aims to provide wireless broadband access for integrated voice and video services. This paper presents the efficient design and implementation of fast Frouier transform （FFT） and inverse fast Frouier transform （IFFT） for the application in IEEE 802. 16d orthogoual frequency division multiplexing （OFDM） system. In this design, a novel pipeline structure for the branch of butterfly unit （BU） is proposed, which can improve the processing symbol rate by adding the number of branch flexibly. The symmetrical ping-pang structure of random access memory （RAM） is performed to increase the system throughput. Simulation results reveal that only with 1 branch of BU, the proposed FFF/IFFT design can almost achieve the maximum bandwidth requirement of IEEE 802. 16d OFDM system. And this design has been verified by FPGA and successfully implemented in the prototype of WiMAX transceiver.
基于OFDM系统中短训练符号的相关性,对已有分组检测算法加以改进,提出了一种适用于正交频分复用(orthogonal frequency division multiplexing,OFDM)系统的分组检测算法.仿真结果表明,该算法在各种信噪比下均具有良好的检测能力.此外,对此算法进行了VLSI的优化实现,计算部分的实现方式采用流水线设计的思想,通过优化结构和分时复用内部电路单元,降低了所需电路的面积,提高了系统工作频率.在0.18μmCMOS工艺下,电路可稳定工作在155MHz频率,电路总面积为1034486μm2.
