VDES系统中π/4-OQPSK调制方式仿真研究

Simulation Research on π/4-OQPSK Modulation Mode in VDES System

随着船舶自动识别系统(AIS)交换能力及链路负载与用户数量之间矛盾的日益凸显,甚高频数据交换系统(VDES)未来必将替代AIS系统。以VDES为研究背景,在对其工作机理及关键技术分析的基础上,针对该系统中的调制解调技术进行了深入研究,并以π/4-OQPSK调制方式为研究对象,对其通信过程进行仿真分析。仿真结果表明:在无信道干扰且信噪比15d B时系统误码性能在10-4以下;在莱斯信道下,当信噪比大于30d B时,系统误码性能在10-3以下。

As the contradiction between the ship＇s automatic identification system（AIS） ex- change capacity and the link load and the number of users has become increasingly promi- nent ,the VHF data exchange system（ VDES ）will certainly replace the AIS system in the fu- ture. Taking VDES as the research background, on the basis of the analysis of its working mechanism and key technologies, the modulation and demodulation technology in the system was studied in depth. The π/4-OQPSK modulation method was used as the research object, and the communication process was simulated and analyzed. The simulation results show that the system error performance is below l0^-4 when there is no channel interference and the SNR is 15dB;In the Rician channel,the BER performance is below 10^-3 when the SNR is greater than 30dB.