摘要
分时长期演进(TD-LTE)系统为了满足各种环境的需要,支持6种不同的带宽和基带速率。为了满足TD-LTE系统多带宽和多速率的要求,设计了一种兼容TD-LTE多带宽和多速率的多带宽数字下变频方案。方案中采用了时分复用技术、抽取滤波的合理搭配和高性能滤波器实现了资源优化和输出信号的高信噪比。此外,对数字混频器和抗混叠滤波器进行改进,设计出了基于坐标旋转数字计算法(CORDIC)的流水线型混频器和高速并行可配置滤波器。软件仿真和硬件测试证明了TD-LTE多带宽数字下变频的正确性,且具有灵活性、高性能和低资源消耗的特点以及较高的工程实用价值。
Time division-long term evolution( TD-LTE) system needs to support six different bandwidths and baseband rates,in order to satisfy the requirements of various environments. To meet the demand of multi-bandwidth and multi-rate in TD-LTE system,a multi-bandwidth digital down converter( DDC)scheme is designed which can support the flexible switch of multi-bandwidth and multi-rate. The proposed scheme takes advantage of the time division multiplexing,the reasonable collocation and the high performance filter techniques to achieve resource optimization and high signal-to-noise ratio( SNR) of output signal. In addition,a parallel Coordinate Rotation Digital Compute( CORDIC) frequency mixer and a high speed parallel configurable filter are proposed by improving the digital mixer and anti-aliasing filter.Software simulations and hardware tests verify the correctness of the multi-bandwidth DDC scheme. And the proposed scheme is featured by flexibility,high performance,low resource consumption and high value for practical engineering.
引文
[1]ANDREWS J G,BUZZI S,CHOI W,et al.What will 5Gbe?[J].IEEE Journalon Selected Areasin Communications,2014,32(6):1065-1082.
[2]OMRI A,BOUALLEGUE R.New transmission scheme for MIMO-OFDM system[J].International Journal of Next-Generation Networks,2011,3(1):11-19.
[3]LIN Z H,XIAO P,VUCETIC B,et al.Analysis of receiver algorithms for LTE SC-FDMA based uplink MIM systems[J].IEEE Transactions on Wireless Communications,2010,9(1):60-65.
[4]ZHANG Q X,SU X X.The design of digital down converter based on FPGA[C]//Proceedings of 2012 Wireless Communications,Networking and Mobile Computing(Wi COM).Shanghai:IEEE,2012:1-4.
[5]张庭伟,袁正午,周牧,等.一种改进的多模数字下变频结构及其FPGA实现[J].电讯技术,2013,53(12):1592-1597.ZHANG Tingwei,YUAN Zhengwu,ZHOU Mu,et al.An improved multimode digital down converter structure and its FPGA implementation[J].Telecommunication Engineering,2013,53(12):1592-1597.(in Chinese)
[6]The 3rd Generation Partnership Project.Physical channels and modulation:3GPP TS 36.101 v11.5.0[S].Valbonne,France:3GPP Support Office,2013:204-211.
[7]牛光辉,苏鹏.带通采样在多载波数字中频接收机中的应用[J].电讯技术,2008,48(1):47-51.NIU Guanghui,SU Peng.Bandpass sampling and its application in digital IF receiver[J].Telecommunication Engineering,2008,48(1):47-51.(in Chinese)
[8]LEI Z H,WANG W L.The design of NCO based on CORDIC algorithm and implementation in FPGA[C]//Proceedings of 2011 International Conference on Electronics,Communications and Control(ICECC).Ningbo:IEEE,2011:2902-2905.