On TPC decoding during soft handover in WCDMA

It has been shown in field trials as well as in system simulations that the overall system performance heavily depends on good TPC decoding in the mobile terminals during soft handover in VVCDMA. In this paper we show criteria on the TPC decoding performance in soft handover in the mobile terminal in order to have a stable up-link power control loop in WCDMA. We also show that the traditional "OR"combination of TPC commands without reliable detection gives rise to an unstable up-link power control. In the paper we examine, by simulation experiments assuming realistic terminal SIR estimation, how the TPC reliable thresholds should be chosen in the terminal such that optimized up-link performance could be achieved.