AN EFFICIENT CODE-TIMING ESTIMATOR FOR DS-CDMA SIGNALS

In this paper, we present an efficient algorithm for estimating the co de timing of a known training sequence in an asynchronous direct-seque nce code division multiple access (DS-CDMA) system, The algorithm is a large sample maximum likelihood (LSML) estimator that is derived by m odeling the known training sequence as the desired signal and all othe r signals including the interfering signals and thermal noise as unkno wn colored Gaussian noise that is uncorrelated with the desired signal , The LSML estimator is shown to be robust against the near-far proble m and is also compared with several other code tinting estimators via numerical examples, It is found that the LSML approach can offer notic eable performance improvement, especially when the loading of the syst em is heavy.