Influence of channel estimation on the performance of a coherent DS-CDMA system

In this paper, the uplink of a coherent direct-sequence code division multiple access (DS-CDMA) system will be investigated. The channel estimation is tarried out via a control channel, which is transmitted simultaneously to the data channel, This concept is very closely related to the CODIT-CDMA concept, In the channel estimation, an averaging process is involved, which for long averaging periods, suppresses the noise influence efficiently. On the other hand, long averaging intervals Lead to systematic errors in the estimated channel coefficients due to the time-variant behavior of the channel. Taking into account these effects, a closed-form analysis of the data-channel symbol-error rate (SER) is presented. This analysis allows predicting the system's performance and helps to optimize the parameter settings for the channel estimation.