基于误码率的软件无线电射频干扰效应分析

针对通信系统工作过程中受到外界电磁干扰而无法通信的问题，研究了基于软件无线电的电磁干扰效应及误码特征。通过分析典型软件无线电电磁信号传输特性及其信息链路电磁干扰耦合路径，设计了软件无线电通信干扰实验系统。该系统利用Simulink软件观测、记录通信信号眼图、星座图信息等受扰特征，并通过分析接收信号的误码率，给出了不同干扰信号对通信系统的影响规律：当同频干扰功率达到-40 dBm时通信开始出现误码，干扰功率每增加5 dB,误码率增加一个量级，干扰功率增加到-18 dBm时，误码率达到阈值0.25;邻频干扰误码率随干扰功率变化趋势与同频干扰一致，但出现误码的最小干扰功率更大；带外强干扰信号也会影响通信系统可靠性，在相同误码率情况下，需要更大的干扰信号功率且大小与信号频偏成正比。

Analysis of radio frequency interference effect of software defined radio based on bit error rate

For the problem that the communication system is unable to communicate due to external electromagnetic interference,the electromagnetic interference effects and error characteristics based on software defined radio(SDR) are studied.By analyzing the transmission characteristics of typical SDR electromagnetic signals and the electromagnetic interference coupling path of information link,an SDR communication interference experimental system is designed.The system uses Simulink software to observe and record the disturbed characteristics of communication signal eye diagram and constellation information,and gives the influence law of different interference signals on the communication system by analyzing the bit error rate(BER) of the received signal.When the co-channel interference power reaches -40 dBm,the communication begins to appear bit error.When the interference power increases by 5 dB,the BER increases by one order of magnitude.When the interference power increases to -18 dBm,the BER reaches the threshold value of 0.25.The variation trend of BER of adjacent frequency interference with interference power is consistent with that of same frequency interference,but the minimum interference power with bit error is greater.Strong out-of-band interference signal will also affect the reliability of communication system.Under the same BER,greater interference signal power is required,and the value is directly proportional to the signal frequency offset.