ZT-DFT-s-OFDM communication system and waveform design method for emergency rescue of mountain dense forests

Abstract

The invention discloses a ZT-DFT-s-OFDM (Zero Transform-Discrete Fourier Transform-s-Orthogonal Frequency Division Multiplexing) communication system and a waveform design method for emergency rescue of a dense mountain forest, which solve the problems of serious multipath, narrow bandwidth, low penetrability and short communication distance of the dense mountain forest and can flexibly configure subcarrier intervals and the number of subcarriers to realize broadband communication. The vegetation coverage is high in the dense forest environment, and in order to reduce the shielding of trees on signals, a proper carrier frequency is set to keep a relatively moderate wavelength, so that the penetrability of the signals in the dense forest environment is improved, and meanwhile, a receiving-transmitting end antenna with a proper size can be kept, so that the rescue burden of rescue workers is reduced, and the working efficiency is improved; a DFT extended coding technology is adopted to reduce the peak-to-average ratio of the signal, reduce the power back-off of the signal, improve the communication distance under limited transmitting power, and enhance the penetrability of the signal; the zero head and the zero tail are added, so that the inter-symbol transition is smoother, the time-frequency focusing property of the system is improved, and the out-of-band radiation of the system is reduced.

Description

technical field [0001] The invention relates to the technical field of mobile communication for emergency rescue, in particular to a ZT-DFT-s-OFDM communication system and waveform design method for emergency rescue in dense forests in mountainous areas. Background technique [0002] In recent years, major natural disasters such as forest fires, mudslides, earthquakes, and torrential rains have occurred frequently, and these natural disasters usually occur in mountainous forest areas with dense vegetation that do not have communication capabilities or disasters destroy local communication equipment, resulting in emergency communications. Interruption, which poses a serious threat to the lives and property safety of the people and rescue workers. For example, in 2019, the forest fire caused by lightning strikes in Muli County, Liangshan, Sichuan. The fire point was at an altitude of about 3,800 meters. The terrain was very complex, with steep slopes and deep valleys. , Sudde...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a ZT-DFT-s-OFDM communication system and waveform design method for emergency rescue in mountainous dense forests, which solves the problems of serious multipath, narrow bandwidth, low penetration and short communication distance in mountainous dense forests. The communication system and waveform design method of ZT-DFT-s-OFDM are adopted, and the subcarrier interval and the number of subcarriers can be flexibly configured to realize broadband communication. The vegetation coverage is high in the dense forest environment. In order to reduce the blocking of trees on the signal, the design A suitable carrier frequency is set to maintain a relatively long wavelength and an appropriate-sized transceiver antenna, thereby improving the penetration of the signal in a dense forest environment. The DFT expansion coding technology is used to reduce the peak-to-average ratio of the signal and reduce the signal loss. The power backoff improves the communication distance under limited transmission power, further strengthens the penetration of the signal, increases the zero head and zero tail, makes the transition between symbols smoother, improves the time-frequency focus of the system, and reduces the System out-of-band radiation

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