基于LDPC码的单载波频域均衡系统

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。

SC-FDE System Based On LDPC Codes

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.