The environment of the wireless communication system in the coal mine has unique characteristics： great noise, strong multiple path interference, and the wireless communication of orthogonal frequency division multip...The environment of the wireless communication system in the coal mine has unique characteristics： great noise, strong multiple path interference, and the wireless communication of orthogonal frequency division multiplexing （OFDM） in underground coal mine is sensitive to the frequency selection of multiple path fading channel, whose decoding is separated from the traditional channel estimation algorithm. In order to increase its accuracy and reliability, a new iterating channel estimation algorithm combining the logarithm likelihood ratio （LLR） decode iterate based on the maximum likelihood estimation （ML） is proposed in this paper, which estimates iteration channel in combination with LLR decode. Without estimating the channel noise power, it exchanges the information between the ML channel estimation and the LLR decode using the feedback information of LLR decode. The decoding speed is very quick, and the satisfied result will be obtained by iterating in some time. The simulation results of the shortwave broadband channel in the coal mine show that the error rate of the system is basically convergent after the iteration in two times.展开更多
In order to establish an effective wireless communication system in an underground coal-mine environment, the propagation of radio waves through a rectangular-like mine tunnel was investigated by jointly, considering ...In order to establish an effective wireless communication system in an underground coal-mine environment, the propagation of radio waves through a rectangular-like mine tunnel was investigated by jointly, considering both the dielectric constant and the reflectance of a mine tunnel. By combining free space and modified waveguide propagation models, we propose a new hybrid propagation model based on ray tracing. Simulation results have shown the effectiveness of establishing a wireless Local Area Network (LAN) in this coal-mine environment. The results of this research will be very useful as a guide in the design and development of tunnel wireless LAN systems.展开更多
文摘The environment of the wireless communication system in the coal mine has unique characteristics： great noise, strong multiple path interference, and the wireless communication of orthogonal frequency division multiplexing （OFDM） in underground coal mine is sensitive to the frequency selection of multiple path fading channel, whose decoding is separated from the traditional channel estimation algorithm. In order to increase its accuracy and reliability, a new iterating channel estimation algorithm combining the logarithm likelihood ratio （LLR） decode iterate based on the maximum likelihood estimation （ML） is proposed in this paper, which estimates iteration channel in combination with LLR decode. Without estimating the channel noise power, it exchanges the information between the ML channel estimation and the LLR decode using the feedback information of LLR decode. The decoding speed is very quick, and the satisfied result will be obtained by iterating in some time. The simulation results of the shortwave broadband channel in the coal mine show that the error rate of the system is basically convergent after the iteration in two times.
基金supported by the National Natural Science Foundation of China (No.10974044)the Open Project of the Key Lab of the Technique of Electricity Transmission, Distribution and Conservation in Changzhou, China
文摘In order to establish an effective wireless communication system in an underground coal-mine environment, the propagation of radio waves through a rectangular-like mine tunnel was investigated by jointly, considering both the dielectric constant and the reflectance of a mine tunnel. By combining free space and modified waveguide propagation models, we propose a new hybrid propagation model based on ray tracing. Simulation results have shown the effectiveness of establishing a wireless Local Area Network (LAN) in this coal-mine environment. The results of this research will be very useful as a guide in the design and development of tunnel wireless LAN systems.
