电子科技大学学报
電子科技大學學報
전자과기대학학보
JOURNAL OF UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA
2013年
1期
44-47
,共4页
克拉美劳界%直扩信号%扩频序列%子空间分解%未知频偏
剋拉美勞界%直擴信號%擴頻序列%子空間分解%未知頻偏
극랍미로계%직확신호%확빈서렬%자공간분해%미지빈편
Cramer-Rao lower bound CRB%direct sequence spread spectrum signal%spreading sequence%subspace decomposition%unknown carrier offset
针对未知频偏下的直扩信号,通过将载频吸收至扩频波形中,提出了一种有效的基于协方差矩阵子空间分解的扩频序列估计算法.通过信号子空间分解,提高了含有未知频偏信息的扩频波形估计的信噪比,从而降低了载频估计难度.在随机信号模型条件下,还推导了扩频波形估计器的克拉美劳界.在低信噪比条件下,仿真验证了该算法的有效性.
針對未知頻偏下的直擴信號,通過將載頻吸收至擴頻波形中,提齣瞭一種有效的基于協方差矩陣子空間分解的擴頻序列估計算法.通過信號子空間分解,提高瞭含有未知頻偏信息的擴頻波形估計的信譟比,從而降低瞭載頻估計難度.在隨機信號模型條件下,還推導瞭擴頻波形估計器的剋拉美勞界.在低信譟比條件下,倣真驗證瞭該算法的有效性.
침대미지빈편하적직확신호,통과장재빈흡수지확빈파형중,제출료일충유효적기우협방차구진자공간분해적확빈서렬고계산법.통과신호자공간분해,제고료함유미지빈편신식적확빈파형고계적신조비,종이강저료재빈고계난도.재수궤신호모형조건하,환추도료확빈파형고계기적극랍미로계.재저신조비조건하,방진험증료해산법적유효성.
In this paper, by absorbing the carrier frequency into the spreading waveform, an efficient algorithm to estimate the spreading sequence of direct sequence spread spectrum (DSSS) signals with unknown carrier offset is proposed. The proposed algorithm is based on the subspace decomposition of covariance matrix. The signal to noise ratio (SNR) of the spreading waveform estimation with unknown carrier offset is improved by signal subspace decomposition, which reduces the difficulty in carrier frequency estimation. Under the stochastic signal model assumption, we also derive the Cramer-Rao lower bound (CRB) of spreading waveform estimators. Simulation results demonstrate the effectiveness of proposed algorithm in lower SNR situations.
