Analysis of the code allocation mechanism in the WCDMA

The technique of spread spectrum is already normalized to be the unique technique in future wireless systems. The system is based on the sharing of the same bandwidth simultaneously by modulating the information of every user with a specific code that distinguish him in the cell; the chip rate of which is much higher than the data bit rate. This type of access technique will generate an important interference called multiple access interference (MAI) that limits the capacity of the system. Therefore, the system capacity will depend on the types of spreading codes and how these spreading codes are allocated. We analyze the affect of spreading codes on the system capacity by studying the impact of the non-orthogonal property between these codes.