Simulation analysis of adaptive power control method in TD-SCDMA system

In time-division synchronous code-division multiple access (TD-SCDMA) system, power control is one of the key technologies of radio resource management. It plays a significant role in guaranteeing the high quality communication. In this paper, we propose an adaptive power control algorithm, which is easier implemented than widely used algorithms, for uplink of the power control module through a simple and reliable way. Our method is based on the step size fixed power control algorithm and we use a shift register in the receiver to deposit power control bits, on which we depend to regulate the power-adjusting step size adaptively. First, we define that the bit information be 1 or 0, if the receiving power is smaller or bigger than the target power. When there is I or 0 alternately, it means the receiving power is approximate to the target power. When there is 1 or 0 continuously, the step size needs adjusting strongly, for the receiving power is much smaller or bigger. By simulating our algorithm and the step size fixed power control algorithm in the physical layer simulation platform of TD-SCDMA system, we can see the adaptive algorithm has a better performance than the step size fixed algorithm in decreasing the Bit Error Rate (BER) of information transmission. The simulation results also show that system performance may be affected by different number of users and Doppler shift and this adaptive algorithm is applicable to small Doppler shift with the same Signal Noise Raito (SNR) to the step size fixed algorithm.