SIR estimation for closed loop power control with space time transmit diversity in WCDMA FDD downlink

Abstract

In this paper, the SIR estimation for fast closed loop power control (CLPC) of WCDMA FDD downlink with space time transmit diversity (STTD) is analysed. It is shown that without STTD encoding / decoding of the DPCCH pilot symbols of the two antennas, the SIR estimation suffers from inter-antenna interference. Without modifying the DPCCH pilot patterns in the current 3GPP standard [3], near-hest performance is achieved by using all the pilot symbols for signal power estimation but only the STTD decoded shaded symbols for interference estimation, to avoid the inter-antenna interference.