A de-correlated modified code tracking loop for synchronous direct-sequence code-division multiple-access systems

A de-correlated modified code tracking loop (D-MCTL) is presented for synchronous direct-sequence code-division multiple-access (DS/CDMA) systems. It is found that the S curve of a traditional modified code tracking loop (MCTL) may be severely distorted; even the multiple access interference (MAI) is low at the ideal sampling instant. The proposed D-MCTL alleviates the effect of MAI at ±1 chip interval caused by interfering users and achieves a better S curve with a zero timing offset. Computer simulations based on Gold code sequences are used to verify the results