中文摘要：

该文提出一种应用于VHF-FM频段的数字调频广播（DFM）的模式自适应的OFDM参数设计方法,根据信道的多普勒频移范围设计了两种传输模式。为了有效抵抗频率选择性衰落,需要合理设置OFDM码元循环前缀和有用数据部分长度之比;合理地选择有用数据部分长度,使得不仅能在有限带宽内得到尽可能多的子载波还能降低对多普勒频移的敏感性;考虑到可用子载波个数对工程实现复杂度和数据传输效率的影响,通过合理设置以实现两者间的良好折中。通过与有着相同信道模型的DRM-Plus系统参数建议相比,该方法不仅能抵抗频率选择性衰落,而且具有多普勒频移敏感性更低、工程实现复杂度更低和数据传输效率更高的优点。利用现有时域同步捕获算法仿真,表明所设计的参数在DFM系统中具有可用性。

英文摘要：

The paper proposes a mode-adaptive OFDM parameters design method for Digital Frequency Modulation （DFM） radio used in the VHF-FM, and designes two transmission modes according to the Doppler shift range under different channel profiles. In order to effectively counteract frequency-selective fading, it is necessary to set the length-ratio between cyclic prefix and useful part of the OFDM symbol; reasonably choosing the length of the useful part, makes more sub-carriers acquired within the limited bandwidth and the sensitivity to Doppler shift decreased; considering the influence to engineering complexity and data transmission efficiency brought by the number of available sub-carriers, the suitable choice of the number can realize a good trade off. Contrast to the existing parameter suggestions in the DRM-Plus system which has the same channel circumstances the proposed method can not only counteract frequency-selective fading, but also have advantages of lower sensitivity to Doppler shift, lower engineering complexity and higher data transmission efficiency. Simulated with the existing synchronization acquisition algorithms in time domain, the results show that the proposed parameters can be used in the DFM system.