针对无线电导航系统多径信道下的多址干扰和天波干扰,结合串行干扰抵消器和并行干扰抵消器的优点,提出了一种改进的混合干扰抵消方法,与串行干扰抵消器和并行干扰抵消器相比,它在复杂度和误码率性能之间进行了折衷,仿真结果与理论分析相符。分析了估计误差对干扰抵消性能的影响,估计误差较小时第二级干扰抵消比传统接收机误码率改善近2个数量级。采用FPGA技术对其进行了硬件电路设计,并进行了实验验证,结果表明本文提出的改进的混合干扰抵消算法具有复杂度低、硬件实现容易等特点,能够有效的改善弱信号的信噪比,很好的消除多址干扰和天波干扰,具有较高的实际应用价值。
To eliminate the multiple access interference (MAI) and sky-wave interference under multi-path channel in the radio navigation system, an improved hybrid interference cancellation (HIC) technique that combines the advantages of both the successive interference canceller (SIC) and the parallel interference canceller (PIC) is proposed in this paper. The method makes a trade-off between complexity and performance compared with the SIC and PIC. The simulation results are matched with the theory analysis. The influence of the estimation error on the interference cancellation performance is analyzed and when the estimation error is small, the BER in the second stage of the improved HIC has a better performance almost 2 orders than the traditional receivers. The hardware circuit was designed by the FPGA technique and the experiment results show that the improved HIC can improve the Signal-to-Noise (SNR) of the weak signal effectively and have a good performance to eliminate the MAI and the sky-wave in- terference with the advantages of low complexity and easy hardware realization. Thus, the improved HIC technique has high practical application value.