On the design of low-frequency broadcasting system and its applications to disaster management

摘要

In this paper, we present a new and dependable disaster broadcasting network. The urgent information is broadcasted in the low-frequency band of 40–80kHz and modulated with reliable pulse width modulation(PWM). The coverage of one low-frequency broadcasting station is more than 500km. With excellent propagation characteristics, the low-frequency signal could penetrate into remote areas which are usually lack of telecommunication infrastructure. To promulgate the hazard information to general people of one specific area, the hierarchical data structure is proposed. A series of field measurement, test and theoretical comparisons are conducted to evaluate the performance of low-frequency system. It is shown from our experimental results that the low-frequency broadcasting network is a dependable and cost-effective solution in disaster management. Finally, a sustainable heterogeneous and layered ICT network designed for disaster management is drawn.