统一扩频测控系统中相位噪声影响分析及其抑制方法研究

Research on Phase Noise Effects and Mitigation in Unified Spread Spectrum TT&C System

统一扩频测控系统是在MC-CDMA为主的多载波通信体制的基础上建立起来的,MC-CDMA等多载波通信体制的基础是正交频分复用(orthogonal frequency division multiplexing,OFDM)技术;相对于传统的单载波系统,采用OFDM技术的统一扩频测控系统对于载波频率偏移和相位噪声的影响尤为敏感,所以在系统设计时必须考虑相噪的跟踪与抑制;文章在分析相位噪声对统一扩频测控系统性能影响的基础上,用有限个正弦波近似的方法建立相噪的频域线性参数模型,并基于该模型提出了加入相噪估计导频来跟踪相噪的方法;由于导频与数据子载波之间有空子载波作为保护间隔,该方法可以估计出相噪的高阶频谱分量,从而达到了很好的相噪抑制效果。

Unified Spread Spectrum TT＆C System is based on Multi--carrier communication system, which is occupied by MC--CD- MA. And the base of Multi--carrier communication system such as MC CDMA is technology of OFDM. Compared with the traditional sin gle carrier system, we must consider the tracking and Mitigation in the design of the Unified Spread Spectrum TT＆C System. Because the Unified Spread Spectrum TT＆C System which use the technology of OFDM is particularly sensitive to the offset of carrier frequency and the effect of Phase Noise. This paper analysised the effect of Phase Noise to Unified Spread Spectrum TT＆C System, on this basis, the method which approximate by finite sine waves was used to establish the model of the frequency domain parameters in phase noise, and brought up the method of tracking Phase Noise by adding the estimated pilot of Phase Noise. Because of null subcarriers between pilot and data subcarriers, this method can estimate the component of high order frequency spectrum in Phase Noise, finally to mitigate Phase Noise very well.