CAJ | 학술논문

针对可变扩频长度(VSL)的多速率 DS / CDMA 信号伪码周期的盲估计问题进行了研究，将一般单速率直扩信号二次功率谱伪码周期估计的方法扩展到多速率 DS / CDMA 模型。该方法首先将接收的多速率 DS / CDMA 信号进行采样，并对其求一次功率谱，再将一次谱作为输入信号作傅里叶变换并取模、平方，从而得到信号的二次功率谱。通过推导证明，多速率 DS / CDMA 信号的二次功率谱在扩频码周期的整数倍处出现尖锐的谱线，且不同速率用户的二次谱线幅度是不同的，利用这些幅度差异区分不同速率并通过估计谱线之间的距离即可获得不同速率信号的伪码周期。仿真表明该算法在低信噪比下适用，在-15 dB能够利用较少数据同时估计多组速率的伪码周期。
침대가변확빈장도(VSL)적다속솔 DS / CDMA 신호위마주기적맹고계문제진행료연구，장일반단속솔직확신호이차공솔보위마주기고계적방법확전도다속솔 DS / CDMA 모형。해방법수선장접수적다속솔 DS / CDMA 신호진행채양，병대기구일차공솔보，재장일차보작위수입신호작부리협변환병취모、평방，종이득도신호적이차공솔보。통과추도증명，다속솔 DS / CDMA 신호적이차공솔보재확빈마주기적정수배처출현첨예적보선，차불동속솔용호적이차보선폭도시불동적，이용저사폭도차이구분불동속솔병통과고계보선지간적거리즉가획득불동속솔신호적위마주기。방진표명해산법재저신조비하괄용，재-15 dB능구이용교소수거동시고계다조속솔적위마주기。
The blind periodic estimation of the PN sequence in variable-spreading-length(VSL) multirate direct-sequence code division multiple access(DS / CDMA) systems is considered. The method of the re-processing of the power spectrum which is used to estimate the period of general DS-SS signal is extended to multirate DS / CDMA model. Firstly,the received signal is sampled and its power spectrum is estimated, then Fourier transform is directly used to the power spectrum to modulo and square the value,and so repro-cessing of the power spectrum is obtained. The derivation proves that the power spectrum reprocessing of the multirate DS / CDMA signal will arise varied amplitude sharp pulse with interval equal to the period of these different rates users’ PN sequence,accordingly,the periods of the different rates users’ PN sequence can be acquired. The computer simulation results show that the method can work well under the lower sig-nal-to-noise ratio(SNR) input signals and it is able to estimate many rates by taking advantage of less da-ta at the same time at -15 dB SNR.