基于LDPC码的单载波频域均衡系统  

SC-FDE System Based On LDPC Codes

作　　者：敬龙江[1] 刘光辉[1] 林竞力[1] 朱维乐[1] 

机构地区：[1]电子科技大学电子工程学院,成都610054

出　　处：《电子与信息学报》2008年第4期817-821,共5页Journal of Electronics & Information Technology

摘　　要：该文设计了一种联合判决-反馈均衡的单载波频域均衡(SC-FDE)系统,该系统用固定波形的短pn序列取代常规SC-FDE系统中的循环前缀(CP),并以多个短pn序列组成的长PN序列作信道训练从而解决快变信道的初始估计和跟踪问题。针对该系统,一种在时域内对接收的多个训练序列进行平均,然后提出了在频域对信道信息进行估计的信道训练算法,该算法与传统SC-FDE系统相比,其计算复杂度较低。另外,提出了一种增加纵向校验的LDPC码用于该系统中降低信噪比门限,提高系统的整体性能。仿真结果表明在多径衰落信道中,此系统可获得较为理想的结果。This paper introduces a single-carrier system with hybrid time-frequency domain Decision Feedback Equalization （DFE）, in which the short pn （Pseudo-Noise） sequence with fixed waveform replaces the cyclic prefix （CP） in the conventional Single Carrier systems with Frequency Domain Equalization （SC-FDE）, and the long PN sequences composed of several short pn sequences are employed as the channel training sequences to complete the initial estimation and tracking for fast-varying channel. In this system, the received training sequences are averaged in time domain and then the channel is estimated in frequency domain. In comparison with traditional SC-FDE systems, its complexity is lower. Furthermore, an approach of adding sum-check blocks to original Low-Density Parity-Check （LDPC） blocks is presented, and the effective improvements of this system performance can be achieved. Finally, the simulation results show that this system works well over the fading channel.

关 键 词：单载波系统 LDPC码 频域均衡 判决-反馈均衡 循环前缀 

分 类 号：TN911.22[电子电信—通信与信息系统]