Adequate spreading codes to reduce MAI in quasi‐synchronous MC‐DS‐CDMA system

In this study, the authors consider the effect of multiple access interference (MAI) on the performance of a quasi‐synchronous multicarrier direct‐sequence code‐division multiple access (QS‐MC‐DS‐CDMA) system. An analytical expression of the bit error rate (BER) is derived for a QS‐MC‐DS‐CDMA system over additive white Gaussian noise channel. The BER performance degradation is proportional to the squares of the even correlation function (ECF) and odd correlation function (OCF) of the spreading codes. The obtained results show that the adequate spreading code is a set of binary zero correlation zone sequences with both zero ECF and OCF. The construction of the latter codes remains a challenge for researchers in the field of code design.