Rake reception for signature-interleaved ds CDMA in Rayleigh multipath channel

Performance of RAKE receiver in a multipath channel for direct sequence code division multiple access system (DS CDMA) can be severely impaired due to high level of multiple access interference (MAI), whose value is controlled by correlation functions of user signatures. Due to data modulation MAI becomes dependent on aperiodic user signature correlations of big shifts, which are hard to control and become even less so as multipath delay grows, leading to significant MAI increase. In this article we analyze performance of RAKE receiver for Signature-Interleaved (SI) DS CDMA in synchronous multipath Rayleigh channel in comparison with that of conventional DS CDMA. It is shown that SI DS CDMA provides better performance in terms of bit error rate (BER), especially when using specifically tailored user signatures.