Enhancements to MIMO Enabled Cells in WCDMA Cellular Systems

Multiple input multiple output (MIMO) technologies are being introduced in wideband code division multiple access (WCDMA) systems to improve their spectral efficiency. Application of MIMO requires pilot and data signals to be transmitted in the downlink (DL) from each of the two antennas of the base station (BS). At certain time instants, however, single antenna (SA) transmissions may yield instantaneously improved performance compared to MIMO, even though MIMO improves performance at other times. Performance gains of discontinuous secondary pilot transmissions and single antenna transmissions to MIMO MS schemes are investigated by simulation. Practical implementation issues are analyzed to validate deployment feasibility and estimate practical throughput gains compared to the simulation results.