多径衰落信道下多音干扰OFDM系统性能分析

针对无线通信面临的干扰问题，对多径衰落信道下的正交频分复用（OFDM）系统的抗多音干扰性能进行了研究. 在给出系统模型的基础上，对经历多径衰落信道后的受干扰接收信号进行分析，计算了有用信号和各干扰信号分量的数学统计特性，并在此基础上推导了系统的误比特率公式. 对系统进行了误比特率仿真，仿真结果表明，理论值与仿真结果能很好吻合，增大子载波间隔可减弱多音干扰对系统的干扰效果. 另外，当干扰信号功率较大时，全音干扰效果较好；反之则宜集中干扰功率对部分子载波实施干扰. 

Performance Evaluation of OFDM System Under Multipath Fading and Multi-Tone Jamming

Orthogonal frequency division multiplexing(OFDM)is an attractive technology for wireless communication. Considering the vulnerability of being jammed for wireless system, the OFDM performance under multi-tone jamming and multipath fading was investigated. Firstly, the system model was described. Then, the received signals, affected by multi-path fading and jamming, were investigated theoretically. The statistical of the useful part and the interference of received signal was analyzed and finally, the bit error rate (BER) was achieved. Simulation results show that theoretical results agree well with the simulated ones. The jamming effect can be alleviated by increasing the subcarrier spacing. Expected results also show that the all-tone jamming is effective for big jamming power signal while the partial-tone jamming is better for small jamming power signal.