多音CDMA调制在矿井巷道中通信性能分析

Performance Analysis of MT-CDMA Modulation in the Mine Tunnel

基于所建立的Nakagami分布矿井巷道宽带统计分段信道模型,仿真分析了多音码分多址接入(MT-CDMA)调制技术在矿井巷道中的宽带无线通信性能。研究了在矿井空直巷道和弯曲巷道条件下,多径信号的功率衰减、多普勒频移和脉冲干扰对1.8 GHz和2.4 GHz这2个典型UHF频段的矿井MT-CDMA系统误码率性能的影响.结果表明:矿井MT-CDMA系统可以有效地利用多径信号提高系统的性能,当功率衰减因子相同时,所分离出的信号路径数越多,系统误码率越低;2.4 GHz时的矿井MT-CDMA系统误码率性能一般要优于1.8 GHz时系统的误码率性能;当功率衰减、多普勒频移和脉冲干扰较大时矿井MT-CDMA系统不能可靠通信,在弯曲巷道中情况更是如此.

The bit error rate （BER） performance of multitone code-division-multiple-access （MT-CDMA） modulation in the mine tunnel was analyzed based on an established multi-section Nakagami distribution statistical channel model for wideband radio wave. In the straight or embranchment mine tunnel, the effects of attenuation of multipath signals, Doppler frequency offset and impulse interference on the BER performance of MT-CDMA at 1.8 GHz and 2.4 GHz were studied. The results show that the MT-CDMA in the mine tunnel can effectively utilize the multipath signals to improve the BER performance of the system. For the same attenuation coefficient, the more the number of multipath signals are, the better the BER performance of the system is. The BER performance of MT-CDMA in the mine tunnel at 2.4 GHz is better than that at 1.8 GHz. When the attenuation of multipath signals, Doppler frequency offset, or impulse interference is larger, the MT-CDMA in the mine tunnel may not communicate reliably, especially in the embranchment mine tunnel.