CAJ | 학술논문

针对散射远距离通信时传输损耗大的问题，采用多进制正交扩频技术。给出了系统发射、接收模型，仿真了AWGN信道下几种不同进制的误码率曲线并与理论误码率曲线进行了对比。推导了瑞利衰落信道下的误码率公式，在低速散射衰落信道下对16进制正交扩频系统进行了仿真，验证了公式的正确性，并分析了最大多普勒频移对系统的影响。给出了两重、四重分集下的系统性能。通过与传统直扩系统的性能对比，进一步说明将多进制正交扩频与时间分集技术相结合，应用到低速散射通信系统中可以提高系统性能。
침대산사원거리통신시전수손모대적문제，채용다진제정교확빈기술。급출료계통발사、접수모형，방진료AWGN신도하궤충불동진제적오마솔곡선병여이론오마솔곡선진행료대비。추도료서리쇠락신도하적오마솔공식，재저속산사쇠락신도하대16진제정교확빈계통진행료방진，험증료공식적정학성，병분석료최대다보륵빈이대계통적영향。급출료량중、사중분집하적계통성능。통과여전통직확계통적성능대비，진일보설명장다진제정교확빈여시간분집기술상결합，응용도저속산사통신계통중가이제고계통성능。
To solve the problem of big transmission loss in remote communication,the M?ary orthogonal spread spectrum is put to use?The transmitter and receiver models are given?Several bit error rate curves for different?ary in the AWGN channel are simulated and compared with theory bit error rate curves?The formula of bit error rate in rayleigh fading channel are derived?Furthermore,the hexadec?imal orthogonal spread spectrum system in the low?speed rayleigh fading channel is simulated,which is verified correctly by comparison with the formula?And the effect of max Doppler frequency shift on the system performance is analyzed?Finally,the system performance with double diversity and that with quadruple diversity are discussed?Compared with the traditional DSSS system,the results show that the application of M?ary orthogonal spread spectrum with time diversity technology to the low?speed troposcatter communication can im?prove the performance of system.