Performance Investigation of Secondary Scrambling Codes in WCDMA Systems

This paper evaluates the system performance in macro cellular WCDMA systems with two scrambling codes per cell, without any beamforming techniques, and with different radio environments and UE receivers. Simulation results for the Web surfing service over DCH384 indicate that with two scrambling codes the cell throughput is increased with 15-18% for the PA3 channel model, depending on the receiver (RAKE/GRAKE). In case of RA3 channel, the cell throughput is increased with 8% if GRAKE receivers are used, but with RAKE, the secondary scrambling code does not give any gain. Finally, for TU3 channel, no gain can be achieved by introducing the secondary scrambling code. In general, the simulation results indicate that GRAKE performs better than RAKE in all three radio environments. Results also indicate that secondary scrambling codes can be beneficial for low activity services, and/or good radio environments