一种超高速移动图像传输系统的研究与仿真

针对超高速移动场景下进行图像传输的应用需求，提出了一种适用于多普勒多径信道条件的宽带无线传输系统。分析了低空航行信道模型的特点，基于时域同步正交频分复用(TDS-OFDM)技术，合理设计帧结构，采用低码率的短低密度奇偶校验(LDPC)码进行信道编码并使用正交相移键控(QPSK)调制，结合信息辅助抗多普勒频移(IAADO)方法，并对双伪随机噪声(PN)帧结构的信道估计与均衡策略进行理论推导与改进，设计出能够适应多普勒多径信道条件的基带传输系统。在计算机仿真中，本文提出的信道估计改进算法获得了0.1 dB的性能增益，该传输系统在带有1 kHz多普勒、莱斯因子为10 dB的6径信道下，利用10 MHz带宽传输3 Mbps的速率，在信噪比为-1.1 dB时达到10-4以下的误比特率，能够满足超高速移动场景下图像或者视频的传输需求。

Simulation for an ultra-high-speed mobile image transmission system

This paper presents a broadband wireless transmission system which is suitable for the multipath channel with Doppler, in order to meet the requirements of the image transmission in the ultra-high-speed mobile application. The characteristics of the low-altitude navigation channel model are studied and analyzed. Based on the Time-Domain Synchronous Orthogonal Frequency Division Multiplexing(TDS-OFDM) technology, the base band transmission system is designed for the multipath channel with Doppler, by properly designing the frame structure, using short Low Density Parity Check(LDPC) code with low code rate and Quadrature Phase Shift Keying(QPSK) modulation, combining with the Information Aided Anti Doppler Offset(IAADO) method and improving the channel estimation and equalization method for the dual PN(Pseudo Noise) frame structure. In the simulation, the proposed method of channel estimation has a gain of 0.1 dB. The transmission rate of the system can reach 3 Mbps by using 10 MHz bandwidth under the 6-path channel with 1kHz Doppler shift and 10 dB Rician factor, and the Bit Error Rate(BER) can be lower than 10-4 at -1.1 dB Signal-to-Noise Ratio(SNR). The system enables an image or video transmission in the ultra-high-speed mobile application.