Research Of Power Control Technology In TD-SCDMA Systems

TD-SCDMA systems are interference limited, and therefore efficient interference management is necessary to enhance the capacity of the system. What is more, it is the third generation mobile communication system introduced by our Chinese. In order to suppress interference, the system introduces the combination of joint detection and smart antenna particularly. And this technology has been put into practice. Besides, power control strategy is also one of the most important approaches to reduce interference, which can effectively combat the near-far problem and corner problem.In this dissertation, the space-time discrete model of TD-SCDMA is given and the principle and approach for combination of joint detection, smart antenna and power control in uplink of TD-SCDMA were analyzed mathematically. Making use of the characters of the system, this dissertation presents an adaptive variable-step power control algorithm and the base band measurement algorithms used to estimate the input parameters of the power control based on this combination. According to the adaptive algorithm, different TPC (Transmit Power Control) command combinations correspond to different step sizes, so that the power control can track the channel change timely. Compared to the traditional way, the algorithm provides a lower probability of the wrong adjustment. Furthermore, the power control simulation model of TD-SCDMA is proposed with the S-function in MATLAB, of which the principle and approach are provided in detail in this dissertation. The algorithm is also simulated under many conditions, such as different channel environments and different control parameters. In all, with the simulation results, it is observed that the new algorithm is better than the traditional one.