System performance of multibeam antennas HS-DSCH WCDMA system

This paper summarizes the results for system performance of the WCDMA high speed downlink shared channel (HS-DSCH), where base stations are equipped with multibeam antennas employing four fixed beams (FB) per sector. The implemented version assumes that each beam has its own HS-DSCH channel. In the FB cases the power is equally divided between the beams belonging to the same sector. Each beam employs a scrambling code, thus in total four scrambling codes per cell, compared to one scrambling code for the sector case. A secondary common pilot channel (S-CPICH) on which the UE measures the CIR is assumed to be available for the FB system. In order to investigate thoroughly the interaction between FB and HS-DSCH (analyze the effect of antenna technique), on one hand a WWW traffic model and max-CIR scheduler, and on the other hand, a continuous data stream with infinite packet size in conjunction with proportional fair scheduler, were examined. Two channel models are also investigated: the 3GPP typical urban and the pedestrian A. The results show that for four fixed beam antennas in the pedestrian A channel model and the highly dispersive channels, significant capacity gains are obtained, threefold compared to a single sector antenna.