Abstract: A new adaptive variable-step joint Closed-Loop Power Control（CLPC） algorithm based on the errors of Signal-to-Interference Ratio（SIR） and the history memories of Transmit Power Control（TPC） command bits is proposed which respectively brings wide and minute factor to track the channel degradation.Simulations results show convergence speed and precision of the algorithm is improved compared with conventional method.It can be applied to realistic systems.

Key words: Closed-Loop Power Control（CLPC）, Signal-to-Interference Ratio（SIR）, Transmit Power Control（TPC）

摘要： 提出了一种新的自适应变步长的联合闭环功率控制方法，分别根据信噪比（SIR）的差值产生粗调因子和功率控制命令（TPC）的历史记录产生微调因子来跟踪信道的快慢衰落。仿真结果表明，该算法提高了收敛速度和收敛精度，具有较好的适用价值。

关键词: 闭环功率控制, 信噪比, 功率控制命令