目前移动自组织网(Ad hoc Network)被越来越多的方面应用,对它的研究也越来越多的关注。由于网络结构的特殊性,其物理层的安全性,信道及调制方式等均有其特殊要求。本文中在Ad hoc物理层采用跳频正交频分复用的调制方式,并讨论了其同步...目前移动自组织网(Ad hoc Network)被越来越多的方面应用,对它的研究也越来越多的关注。由于网络结构的特殊性,其物理层的安全性,信道及调制方式等均有其特殊要求。本文中在Ad hoc物理层采用跳频正交频分复用的调制方式,并讨论了其同步问题。展开更多
Considering the Gaussian asymptotic features of OFDM signals,the identification method of it is proposed in this paper by using the cumulants of the wavelet transform coefficients in different layer in a low SNR circu...Considering the Gaussian asymptotic features of OFDM signals,the identification method of it is proposed in this paper by using the cumulants of the wavelet transform coefficients in different layer in a low SNR circumstance.Furthermore,taking the coexistence of the OFDM and Frequency Hopping(FH) signals into account,a new way to separate FH and OFDM signals is proposed based on SPWVD spectrum cancellation,and it can be used to estimate the FH parameters.The simulation results show that the OFDM and single-carrier signals can be identified with a high correct rate of 95% even at-6 dB SNR;meanwhile,the separation of mixed OFDM and FH signals can be achieved with a low SNR of-6 dB,and FH parameters can be estimated accurately.It shows that the recognition performance is improved by about 5 dB compared with the traditional method.展开更多
基金This paper was supported by the Fundamental Research Funds for the Central Universities （BUPT Project under Grant No.2009RC0316） the National Science Foundation of China under Ccant No. 60871081 Beijing Natural Science Foundation Design and fabrication of miniature smart antenna based on rnetarmterials under Crant No. 4112039, Nokia-BUPT Union Fund （2000009）.
文摘Considering the Gaussian asymptotic features of OFDM signals,the identification method of it is proposed in this paper by using the cumulants of the wavelet transform coefficients in different layer in a low SNR circumstance.Furthermore,taking the coexistence of the OFDM and Frequency Hopping(FH) signals into account,a new way to separate FH and OFDM signals is proposed based on SPWVD spectrum cancellation,and it can be used to estimate the FH parameters.The simulation results show that the OFDM and single-carrier signals can be identified with a high correct rate of 95% even at-6 dB SNR;meanwhile,the separation of mixed OFDM and FH signals can be achieved with a low SNR of-6 dB,and FH parameters can be estimated accurately.It shows that the recognition performance is improved by about 5 dB compared with the traditional method.
