Performance of coherent detection and RAKE for DS-CDMA uplink channels

This paper estimates the cell capacity of a cellular DS-CDMA mobile radio system that uses coherent detection, RAKE, diversity and forward error correction (FEC). Coherent detection reduces the required E_b/N₀ (bit energy to noise density power ratio). The performance of two coherent detection schemes and differential detection is compared. One of the coherent detection method uses the pilot symbols transmitted through another channel via a different spreading code, and the other uses the pilot symbols embedded periodically in the same channel as the data symbols. This paper shows that coherent detection offers a 50% higher capacity than differential detection, furthermore, by employing diversity, the cell capacity is doubled from that of 1 branch, and by RAKE combining, a 10% higher cell capacity can be achieved